* [PATCH v6 01/25] KVM: arm64: Generalize trace clock
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 02/25] KVM: arm64: Donate MMIO to the hypervisor Mostafa Saleh
` (23 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
IOMMU drivers need to track time, mainly for timeouts.
Generalize the tracing clock functions in the hypervsior, so they can
be used from IOMMU drivers.
1) Make the compilation independent from tracing.
2) As drivers might need to use that quite early, provide default
values for the clock data based on cntfrq_el0, the driver can
keep using these values without calling hyp_clock_update() as
they don't need to sync with the host timers.
This is mainly used for timeouts, so a malicious host can DoS the
system or cause premature timeouts which likely end up in hyp panic,
that should be acceptable as neither of those would undermine the
security guarantees.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/clock.h | 11 ++-----
arch/arm64/kvm/hyp/nvhe/Makefile | 4 +--
arch/arm64/kvm/hyp/nvhe/clock.c | 44 ++++++++++++++++++++++---
arch/arm64/kvm/hyp/nvhe/setup.c | 5 +++
arch/arm64/kvm/hyp/nvhe/trace.c | 4 +--
5 files changed, 51 insertions(+), 17 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/clock.h b/arch/arm64/kvm/hyp/include/nvhe/clock.h
index 9f429f5c0664..e6a0e43af88d 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/clock.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/clock.h
@@ -5,12 +5,7 @@
#include <asm/kvm_hyp.h>
-#ifdef CONFIG_NVHE_EL2_TRACING
-void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc);
-u64 trace_clock(void);
-#else
-static inline void
-trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) { }
-static inline u64 trace_clock(void) { return 0; }
-#endif
+void hyp_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc);
+u64 hyp_clock_ns(void);
+int hyp_clock_init(void);
#endif
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 62cdfbff7562..89d0533921f9 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -26,10 +26,10 @@ hyp-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o
hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \
cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o
hyp-obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
- ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o ../vgic-v5-sr.o
+ ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o ../vgic-v5-sr.o clock.o
hyp-obj-y += ../../../kernel/smccc-call.o
hyp-obj-$(CONFIG_LIST_HARDENED) += list_debug.o
-hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += clock.o trace.o events.o
+hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += trace.o events.o
hyp-obj-y += $(lib-objs)
# Path to simple_ring_buffer.c
diff --git a/arch/arm64/kvm/hyp/nvhe/clock.c b/arch/arm64/kvm/hyp/nvhe/clock.c
index 32fc4313fe43..53d0bd55e866 100644
--- a/arch/arm64/kvm/hyp/nvhe/clock.c
+++ b/arch/arm64/kvm/hyp/nvhe/clock.c
@@ -18,7 +18,41 @@ static struct clock_data {
u64 cyc_overflow64;
} data[2];
u64 cur;
-} trace_clock_data;
+} clock_data;
+
+#define HYP_CLK_SEC_TO_NS 1000000000UL
+
+int hyp_clock_init(void)
+{
+ u32 timer_freq = read_sysreg(cntfrq_el0);
+ u32 shift = 32;
+ u64 mult;
+
+ /*
+ * KVM will not initialize if FW didn't set cntfrq_el0, that is already
+ * part of the boot protocol.
+ */
+ if (!timer_freq)
+ return -ENODEV;
+
+ /* Timer freq can't be larger than 1Ghz by spec. */
+ if (timer_freq > HYP_CLK_SEC_TO_NS)
+ return -EINVAL;
+
+ /* Simplified logic from clocks_calc_mult_shift() */
+ do {
+ mult = (HYP_CLK_SEC_TO_NS << shift);
+ mult = div_u64(mult, timer_freq);
+ if (mult <= (~0U))
+ break;
+ shift--;
+ } while (shift > 0);
+
+ clock_data.data[0].shift = shift;
+ clock_data.data[0].mult = mult;
+ clock_data.data[0].cyc_overflow64 = ULONG_MAX / mult;
+ return 0;
+}
static u64 __clock_mult_uint128(u64 cyc, u32 mult, u32 shift)
{
@@ -30,9 +64,9 @@ static u64 __clock_mult_uint128(u64 cyc, u32 mult, u32 shift)
}
/* Does not guarantee no reader on the modified bank. */
-void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
+void hyp_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
{
- struct clock_data *clock = &trace_clock_data;
+ struct clock_data *clock = &clock_data;
u64 bank = clock->cur ^ 1;
clock->data[bank].mult = mult;
@@ -45,9 +79,9 @@ void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
}
/* Use untrusted host data */
-u64 trace_clock(void)
+u64 hyp_clock_ns(void)
{
- struct clock_data *clock = &trace_clock_data;
+ struct clock_data *clock = &clock_data;
u64 bank = smp_load_acquire(&clock->cur);
u64 cyc, ns;
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index d8e5b563fd3d..8041f6e80cd1 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -10,6 +10,7 @@
#include <asm/kvm_pgtable.h>
#include <asm/kvm_pkvm.h>
+#include <nvhe/clock.h>
#include <nvhe/early_alloc.h>
#include <nvhe/ffa.h>
#include <nvhe/gfp.h>
@@ -312,6 +313,10 @@ void __noreturn __pkvm_init_finalise(void)
};
pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
+ ret = hyp_clock_init();
+ if (ret)
+ goto out;
+
ret = fix_host_ownership();
if (ret)
goto out;
diff --git a/arch/arm64/kvm/hyp/nvhe/trace.c b/arch/arm64/kvm/hyp/nvhe/trace.c
index a6ca27b18e15..e30de840e6c2 100644
--- a/arch/arm64/kvm/hyp/nvhe/trace.c
+++ b/arch/arm64/kvm/hyp/nvhe/trace.c
@@ -35,7 +35,7 @@ static bool hyp_trace_buffer_loaded(struct hyp_trace_buffer *trace_buffer)
void *tracing_reserve_entry(unsigned long length)
{
return simple_ring_buffer_reserve(this_cpu_ptr(trace_buffer.simple_rbs), length,
- trace_clock());
+ hyp_clock_ns());
}
void tracing_commit_entry(void)
@@ -285,7 +285,7 @@ void __tracing_update_clock(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc)
}
/* ...we can now override the old one and swap. */
- trace_clock_update(mult, shift, epoch_ns, epoch_cyc);
+ hyp_clock_update(mult, shift, epoch_ns, epoch_cyc);
}
int __tracing_reset(unsigned int cpu)
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 02/25] KVM: arm64: Donate MMIO to the hypervisor
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 01/25] KVM: arm64: Generalize trace clock Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 03/25] iommu/arm-smmu-v3: Split code with hyp Mostafa Saleh
` (22 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add a function to donate MMIO to the hypervisor so IOMMU hypervisor
drivers can protect and access the MMIO of IOMMUs.
As donating MMIO is very rare, and we don’t need to encode the full
state, it’s reasonable to have a separate function to do this.
It will init the host s2 page table with an invalid leaf with the owner ID
to prevent the host from mapping the page on faults.
Also, prevent kvm_pgtable_stage2_unmap() from removing owner ID from
stage-2 PTEs, as this can be triggered from recycle logic under memory
pressure. There is no code relying on this, as all ownership changes is
done via kvm_pgtable_stage2_set_owner()
For the error path in IOMMU drivers, add a function to donate MMIO
back from hyp to host. However, that leaks the hypervisor virtual
address range which should be acceptable as this is quite rare and
it matches the behaviour of fix_map/block.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 +
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 119 +++++++++++++++++-
arch/arm64/kvm/hyp/pgtable.c | 9 +-
3 files changed, 121 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 3cbfae0e3dda..ff440204d2c7 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -36,6 +36,8 @@ int __pkvm_guest_share_host(struct pkvm_hyp_vcpu *vcpu, u64 gfn);
int __pkvm_guest_unshare_host(struct pkvm_hyp_vcpu *vcpu, u64 gfn);
int __pkvm_host_unshare_hyp(u64 pfn);
int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages);
+int __pkvm_host_donate_hyp_mmio(phys_addr_t addr, size_t size, unsigned long *haddr);
+int __pkvm_hyp_donate_host_mmio(phys_addr_t addr, size_t size);
int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);
int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages);
int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 28a471d1927c..2fb20a63a417 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -353,6 +353,38 @@ int __pkvm_prot_finalize(void)
return 0;
}
+/* Unmap MMIO region while skipping donated PTEs. */
+static int host_stage2_unmap_mmio_region(u64 start, u64 size)
+{
+ struct kvm_pgtable *pgt = &host_mmu.pgt;
+ u64 unmap_start = start;
+ u64 addr = start;
+ kvm_pte_t pte;
+ int ret = 0;
+ u8 level;
+
+ while (addr < start + size) {
+ ret = kvm_pgtable_get_leaf(pgt, addr, &pte, &level);
+ if (ret)
+ return ret;
+ if (!kvm_pte_valid(pte) && pte != 0) {
+ if (addr > unmap_start) {
+ ret = kvm_pgtable_stage2_unmap(pgt, unmap_start,
+ addr - unmap_start);
+ if (ret)
+ return ret;
+ }
+ addr += kvm_granule_size(level);
+ unmap_start = addr;
+ } else {
+ addr += kvm_granule_size(level);
+ }
+ }
+ if (addr > unmap_start)
+ ret = kvm_pgtable_stage2_unmap(pgt, unmap_start, addr - unmap_start);
+ return ret;
+}
+
static int host_stage2_unmap_dev_all(void)
{
struct kvm_pgtable *pgt = &host_mmu.pgt;
@@ -363,11 +395,11 @@ static int host_stage2_unmap_dev_all(void)
/* Unmap all non-memory regions to recycle the pages */
for (i = 0; i < hyp_memblock_nr; i++, addr = reg->base + reg->size) {
reg = &hyp_memory[i];
- ret = kvm_pgtable_stage2_unmap(pgt, addr, reg->base - addr);
+ ret = host_stage2_unmap_mmio_region(addr, reg->base - addr);
if (ret)
return ret;
}
- return kvm_pgtable_stage2_unmap(pgt, addr, BIT(pgt->ia_bits) - addr);
+ return host_stage2_unmap_mmio_region(addr, BIT(pgt->ia_bits) - addr);
}
/*
@@ -1087,6 +1119,89 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages)
return ret;
}
+int __pkvm_host_donate_hyp_mmio(phys_addr_t addr, size_t size, unsigned long *haddr)
+{
+ kvm_pte_t pte;
+ u64 offset;
+ int ret;
+
+ /* Only before de-privilege. */
+ if (static_branch_unlikely(&kvm_protected_mode_initialized))
+ return -EPERM;
+
+ if (!PAGE_ALIGNED(addr | size))
+ return -EINVAL;
+
+ ret = __pkvm_create_private_mapping(addr, size, PAGE_HYP_DEVICE, haddr);
+ if (ret)
+ return ret;
+
+ host_lock_component();
+ for (offset = 0; offset < size; offset += PAGE_SIZE) {
+ if (addr_is_memory(addr + offset)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ ret = kvm_pgtable_get_leaf(&host_mmu.pgt, addr + offset, &pte, NULL);
+ if (ret)
+ goto unlock;
+ if (pte && !kvm_pte_valid(pte)) {
+ ret = -EPERM;
+ goto unlock;
+ }
+ }
+ /*
+ * We set HYP as the owner of the MMIO pages in the host stage-2, for:
+ * - host aborts: host_stage2_adjust_range() would fail for invalid non zero PTEs.
+ * - recycle under memory pressure: host_stage2_unmap_dev_all() would call
+ * kvm_pgtable_stage2_unmap() which will not clear non zero invalid ptes (counted).
+ * - other MMIO donation: Would fail as we check that the PTE is valid or empty.
+ */
+ ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt,
+ addr, size, &host_s2_pool,
+ KVM_HOST_INVALID_PTE_TYPE_DONATION,
+ FIELD_PREP(KVM_HOST_DONATION_PTE_OWNER_MASK, PKVM_ID_HYP));
+unlock:
+ host_unlock_component();
+ return ret;
+}
+
+int __pkvm_hyp_donate_host_mmio(phys_addr_t addr, size_t size)
+{
+ kvm_pte_t pte;
+ u64 offset;
+ int ret = 0;
+
+ if (static_branch_unlikely(&kvm_protected_mode_initialized))
+ return -EPERM;
+
+ if (!PAGE_ALIGNED(addr | size))
+ return -EINVAL;
+
+ host_lock_component();
+ for (offset = 0; offset < size; offset += PAGE_SIZE) {
+ if (addr_is_memory(addr + offset)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ ret = kvm_pgtable_get_leaf(&host_mmu.pgt, addr + offset, &pte, NULL);
+ if (ret)
+ goto unlock;
+ if (!pte || kvm_pte_valid(pte)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ if (FIELD_GET(KVM_HOST_DONATION_PTE_OWNER_MASK, pte) != PKVM_ID_HYP) {
+ ret = -EPERM;
+ goto unlock;
+ }
+ }
+ WARN_ON(host_stage2_idmap_locked(addr, size, PKVM_HOST_MMIO_PROT));
+unlock:
+ host_unlock_component();
+ return ret;
+}
+
int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages)
{
u64 phys = hyp_pfn_to_phys(pfn);
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 0c1defa5fb0f..b64a50f9bfa8 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1159,13 +1159,8 @@ static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
kvm_pte_t *childp = NULL;
bool need_flush = false;
- if (!kvm_pte_valid(ctx->old)) {
- if (stage2_pte_is_counted(ctx->old)) {
- kvm_clear_pte(ctx->ptep);
- mm_ops->put_page(ctx->ptep);
- }
- return 0;
- }
+ if (!kvm_pte_valid(ctx->old))
+ return stage2_pte_is_counted(ctx->old) ? -EPERM : 0;
if (kvm_pte_table(ctx->old, ctx->level)) {
childp = kvm_pte_follow(ctx->old, mm_ops);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 03/25] iommu/arm-smmu-v3: Split code with hyp
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 01/25] KVM: arm64: Generalize trace clock Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 02/25] KVM: arm64: Donate MMIO to the hypervisor Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 12:44 ` Jason Gunthorpe
2026-05-01 11:19 ` [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code Mostafa Saleh
` (21 subsequent siblings)
24 siblings, 1 reply; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The KVM SMMUv3 driver would re-use some of the cmdq and ste code
inside the hypervisor, move these functions to a new common C file that
is shared between the host kernel and the hypervisor.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/Makefile | 2 +-
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.c | 114 +++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 161 ------------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 61 +++++++
4 files changed, 176 insertions(+), 162 deletions(-)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
diff --git a/drivers/iommu/arm/arm-smmu-v3/Makefile b/drivers/iommu/arm/arm-smmu-v3/Makefile
index 493a659cc66b..c9ce392e6d31 100644
--- a/drivers/iommu/arm/arm-smmu-v3/Makefile
+++ b/drivers/iommu/arm/arm-smmu-v3/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_ARM_SMMU_V3) += arm_smmu_v3.o
-arm_smmu_v3-y := arm-smmu-v3.o
+arm_smmu_v3-y := arm-smmu-v3.o arm-smmu-v3-common-lib.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_IOMMUFD) += arm-smmu-v3-iommufd.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_SVA) += arm-smmu-v3-sva.o
arm_smmu_v3-$(CONFIG_TEGRA241_CMDQV) += tegra241-cmdqv.o
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
new file mode 100644
index 000000000000..62744c8548a8
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ * Arm SMMUv3 driver functions shared with hypervisor.
+ */
+
+#include "arm-smmu-v3.h"
+#include <asm-generic/errno-base.h>
+
+#include <linux/string.h>
+
+int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
+{
+ memset(cmd, 0, 1 << CMDQ_ENT_SZ_SHIFT);
+ cmd[0] |= FIELD_PREP(CMDQ_0_OP, ent->opcode);
+
+ switch (ent->opcode) {
+ case CMDQ_OP_TLBI_EL2_ALL:
+ case CMDQ_OP_TLBI_NSNH_ALL:
+ break;
+ case CMDQ_OP_PREFETCH_CFG:
+ cmd[0] |= FIELD_PREP(CMDQ_PREFETCH_0_SID, ent->prefetch.sid);
+ break;
+ case CMDQ_OP_CFGI_CD:
+ cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SSID, ent->cfgi.ssid);
+ fallthrough;
+ case CMDQ_OP_CFGI_STE:
+ cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
+ cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_LEAF, ent->cfgi.leaf);
+ break;
+ case CMDQ_OP_CFGI_CD_ALL:
+ cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
+ break;
+ case CMDQ_OP_CFGI_ALL:
+ /* Cover the entire SID range */
+ cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_RANGE, 31);
+ break;
+ case CMDQ_OP_TLBI_NH_VA:
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
+ fallthrough;
+ case CMDQ_OP_TLBI_EL2_VA:
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
+ cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
+ cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
+ cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
+ cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_VA_MASK;
+ break;
+ case CMDQ_OP_TLBI_S2_IPA:
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
+ cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
+ cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
+ cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
+ cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_IPA_MASK;
+ break;
+ case CMDQ_OP_TLBI_NH_ASID:
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
+ fallthrough;
+ case CMDQ_OP_TLBI_NH_ALL:
+ case CMDQ_OP_TLBI_S12_VMALL:
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
+ break;
+ case CMDQ_OP_TLBI_EL2_ASID:
+ cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
+ break;
+ case CMDQ_OP_ATC_INV:
+ cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
+ cmd[0] |= FIELD_PREP(CMDQ_ATC_0_GLOBAL, ent->atc.global);
+ cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SSID, ent->atc.ssid);
+ cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SID, ent->atc.sid);
+ cmd[1] |= FIELD_PREP(CMDQ_ATC_1_SIZE, ent->atc.size);
+ cmd[1] |= ent->atc.addr & CMDQ_ATC_1_ADDR_MASK;
+ break;
+ case CMDQ_OP_PRI_RESP:
+ cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
+ cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SSID, ent->pri.ssid);
+ cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SID, ent->pri.sid);
+ cmd[1] |= FIELD_PREP(CMDQ_PRI_1_GRPID, ent->pri.grpid);
+ switch (ent->pri.resp) {
+ case PRI_RESP_DENY:
+ case PRI_RESP_FAIL:
+ case PRI_RESP_SUCC:
+ break;
+ default:
+ return -EINVAL;
+ }
+ cmd[1] |= FIELD_PREP(CMDQ_PRI_1_RESP, ent->pri.resp);
+ break;
+ case CMDQ_OP_RESUME:
+ cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_SID, ent->resume.sid);
+ cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_RESP, ent->resume.resp);
+ cmd[1] |= FIELD_PREP(CMDQ_RESUME_1_STAG, ent->resume.stag);
+ break;
+ case CMDQ_OP_CMD_SYNC:
+ if (ent->sync.msiaddr) {
+ cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_IRQ);
+ cmd[1] |= ent->sync.msiaddr & CMDQ_SYNC_1_MSIADDR_MASK;
+ } else {
+ cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_SEV);
+ }
+ cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSH, ARM_SMMU_SH_ISH);
+ cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSIATTR, ARM_SMMU_MEMATTR_OIWB);
+ break;
+ default:
+ return -ENOENT;
+ }
+
+ return 0;
+}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index e8d7dbe495f0..cb64f88989f0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -125,33 +125,6 @@ static void parse_driver_options(struct arm_smmu_device *smmu)
}
/* Low-level queue manipulation functions */
-static bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
-{
- u32 space, prod, cons;
-
- prod = Q_IDX(q, q->prod);
- cons = Q_IDX(q, q->cons);
-
- if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
- space = (1 << q->max_n_shift) - (prod - cons);
- else
- space = cons - prod;
-
- return space >= n;
-}
-
-static bool queue_full(struct arm_smmu_ll_queue *q)
-{
- return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
- Q_WRP(q, q->prod) != Q_WRP(q, q->cons);
-}
-
-static bool queue_empty(struct arm_smmu_ll_queue *q)
-{
- return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
- Q_WRP(q, q->prod) == Q_WRP(q, q->cons);
-}
-
static bool queue_consumed(struct arm_smmu_ll_queue *q, u32 prod)
{
return ((Q_WRP(q, q->cons) == Q_WRP(q, prod)) &&
@@ -170,12 +143,6 @@ static void queue_sync_cons_out(struct arm_smmu_queue *q)
writel_relaxed(q->llq.cons, q->cons_reg);
}
-static void queue_inc_cons(struct arm_smmu_ll_queue *q)
-{
- u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;
- q->cons = Q_OVF(q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
-}
-
static void queue_sync_cons_ovf(struct arm_smmu_queue *q)
{
struct arm_smmu_ll_queue *llq = &q->llq;
@@ -207,12 +174,6 @@ static int queue_sync_prod_in(struct arm_smmu_queue *q)
return ret;
}
-static u32 queue_inc_prod_n(struct arm_smmu_ll_queue *q, int n)
-{
- u32 prod = (Q_WRP(q, q->prod) | Q_IDX(q, q->prod)) + n;
- return Q_OVF(q->prod) | Q_WRP(q, prod) | Q_IDX(q, prod);
-}
-
static void queue_poll_init(struct arm_smmu_device *smmu,
struct arm_smmu_queue_poll *qp)
{
@@ -240,14 +201,6 @@ static int queue_poll(struct arm_smmu_queue_poll *qp)
return 0;
}
-static void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
-{
- int i;
-
- for (i = 0; i < n_dwords; ++i)
- *dst++ = cpu_to_le64(*src++);
-}
-
static void queue_read(u64 *dst, __le64 *src, size_t n_dwords)
{
int i;
@@ -268,108 +221,6 @@ static int queue_remove_raw(struct arm_smmu_queue *q, u64 *ent)
}
/* High-level queue accessors */
-static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
-{
- memset(cmd, 0, 1 << CMDQ_ENT_SZ_SHIFT);
- cmd[0] |= FIELD_PREP(CMDQ_0_OP, ent->opcode);
-
- switch (ent->opcode) {
- case CMDQ_OP_TLBI_EL2_ALL:
- case CMDQ_OP_TLBI_NSNH_ALL:
- break;
- case CMDQ_OP_PREFETCH_CFG:
- cmd[0] |= FIELD_PREP(CMDQ_PREFETCH_0_SID, ent->prefetch.sid);
- break;
- case CMDQ_OP_CFGI_CD:
- cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SSID, ent->cfgi.ssid);
- fallthrough;
- case CMDQ_OP_CFGI_STE:
- cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
- cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_LEAF, ent->cfgi.leaf);
- break;
- case CMDQ_OP_CFGI_CD_ALL:
- cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
- break;
- case CMDQ_OP_CFGI_ALL:
- /* Cover the entire SID range */
- cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_RANGE, 31);
- break;
- case CMDQ_OP_TLBI_NH_VA:
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
- fallthrough;
- case CMDQ_OP_TLBI_EL2_VA:
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
- cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
- cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
- cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
- cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_VA_MASK;
- break;
- case CMDQ_OP_TLBI_S2_IPA:
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
- cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
- cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
- cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
- cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_IPA_MASK;
- break;
- case CMDQ_OP_TLBI_NH_ASID:
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
- fallthrough;
- case CMDQ_OP_TLBI_NH_ALL:
- case CMDQ_OP_TLBI_S12_VMALL:
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
- break;
- case CMDQ_OP_TLBI_EL2_ASID:
- cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
- break;
- case CMDQ_OP_ATC_INV:
- cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
- cmd[0] |= FIELD_PREP(CMDQ_ATC_0_GLOBAL, ent->atc.global);
- cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SSID, ent->atc.ssid);
- cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SID, ent->atc.sid);
- cmd[1] |= FIELD_PREP(CMDQ_ATC_1_SIZE, ent->atc.size);
- cmd[1] |= ent->atc.addr & CMDQ_ATC_1_ADDR_MASK;
- break;
- case CMDQ_OP_PRI_RESP:
- cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
- cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SSID, ent->pri.ssid);
- cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SID, ent->pri.sid);
- cmd[1] |= FIELD_PREP(CMDQ_PRI_1_GRPID, ent->pri.grpid);
- switch (ent->pri.resp) {
- case PRI_RESP_DENY:
- case PRI_RESP_FAIL:
- case PRI_RESP_SUCC:
- break;
- default:
- return -EINVAL;
- }
- cmd[1] |= FIELD_PREP(CMDQ_PRI_1_RESP, ent->pri.resp);
- break;
- case CMDQ_OP_RESUME:
- cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_SID, ent->resume.sid);
- cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_RESP, ent->resume.resp);
- cmd[1] |= FIELD_PREP(CMDQ_RESUME_1_STAG, ent->resume.stag);
- break;
- case CMDQ_OP_CMD_SYNC:
- if (ent->sync.msiaddr) {
- cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_IRQ);
- cmd[1] |= ent->sync.msiaddr & CMDQ_SYNC_1_MSIADDR_MASK;
- } else {
- cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_SEV);
- }
- cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSH, ARM_SMMU_SH_ISH);
- cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSIATTR, ARM_SMMU_MEMATTR_OIWB);
- break;
- default:
- return -ENOENT;
- }
-
- return 0;
-}
-
static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu,
struct arm_smmu_cmdq_ent *ent)
{
@@ -1827,18 +1678,6 @@ static void arm_smmu_free_cd_tables(struct arm_smmu_master *master)
}
/* Stream table manipulation functions */
-static void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
- dma_addr_t l2ptr_dma)
-{
- u64 val = 0;
-
- val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, STRTAB_SPLIT + 1);
- val |= l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK;
-
- /* The HW has 64 bit atomicity with stores to the L2 STE table */
- WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
-}
-
struct arm_smmu_ste_writer {
struct arm_smmu_entry_writer writer;
u32 sid;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index ef42df4753ec..9b8c5fb7282b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1142,6 +1142,67 @@ void arm_smmu_install_ste_for_dev(struct arm_smmu_master *master,
int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
struct arm_smmu_cmdq *cmdq, u64 *cmds, int n,
bool sync);
+int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent);
+
+/* Queue functions shared between kernel and hyp. */
+static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
+{
+ u32 space, prod, cons;
+
+ prod = Q_IDX(q, q->prod);
+ cons = Q_IDX(q, q->cons);
+
+ if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
+ space = (1 << q->max_n_shift) - (prod - cons);
+ else
+ space = cons - prod;
+
+ return space >= n;
+}
+
+static inline bool queue_full(struct arm_smmu_ll_queue *q)
+{
+ return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
+ Q_WRP(q, q->prod) != Q_WRP(q, q->cons);
+}
+
+static inline bool queue_empty(struct arm_smmu_ll_queue *q)
+{
+ return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
+ Q_WRP(q, q->prod) == Q_WRP(q, q->cons);
+}
+
+static inline u32 queue_inc_prod_n(struct arm_smmu_ll_queue *q, int n)
+{
+ u32 prod = (Q_WRP(q, q->prod) | Q_IDX(q, q->prod)) + n;
+ return Q_OVF(q->prod) | Q_WRP(q, prod) | Q_IDX(q, prod);
+}
+
+static inline void queue_inc_cons(struct arm_smmu_ll_queue *q)
+{
+ u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;
+ q->cons = Q_OVF(q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
+}
+
+static inline void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
+{
+ int i;
+
+ for (i = 0; i < n_dwords; ++i)
+ *dst++ = cpu_to_le64(*src++);
+}
+
+static inline void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
+ dma_addr_t l2ptr_dma)
+{
+ u64 val = 0;
+
+ val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, STRTAB_SPLIT + 1);
+ val |= l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK;
+
+ /* The HW has 64 bit atomicity with stores to the L2 STE table */
+ WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
+}
#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v6 03/25] iommu/arm-smmu-v3: Split code with hyp
2026-05-01 11:19 ` [PATCH v6 03/25] iommu/arm-smmu-v3: Split code with hyp Mostafa Saleh
@ 2026-05-01 12:44 ` Jason Gunthorpe
2026-05-04 12:13 ` Mostafa Saleh
0 siblings, 1 reply; 38+ messages in thread
From: Jason Gunthorpe @ 2026-05-01 12:44 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 11:19:05AM +0000, Mostafa Saleh wrote:
> +int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
> +{
> + memset(cmd, 0, 1 << CMDQ_ENT_SZ_SHIFT);
> + cmd[0] |= FIELD_PREP(CMDQ_0_OP, ent->opcode);
Hopefully I get to it today, but I am going to post a series that will
move this logic into the headers while deleting arm_smmu_cmdq_ent. It
should be directly usable for pkvm as well to achieve this same split
without having to shove a giant inline into a header file.
https://github.com/jgunthorpe/linux/commits/iommu_pt_arm64/
cover-letter: Remove SMMUv3 struct arm_smmu_cmdq_ent
Jason
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v6 03/25] iommu/arm-smmu-v3: Split code with hyp
2026-05-01 12:44 ` Jason Gunthorpe
@ 2026-05-04 12:13 ` Mostafa Saleh
0 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-04 12:13 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 09:44:45AM -0300, Jason Gunthorpe wrote:
> On Fri, May 01, 2026 at 11:19:05AM +0000, Mostafa Saleh wrote:
> > +int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
> > +{
> > + memset(cmd, 0, 1 << CMDQ_ENT_SZ_SHIFT);
> > + cmd[0] |= FIELD_PREP(CMDQ_0_OP, ent->opcode);
>
> Hopefully I get to it today, but I am going to post a series that will
> move this logic into the headers while deleting arm_smmu_cmdq_ent. It
> should be directly usable for pkvm as well to achieve this same split
> without having to shove a giant inline into a header file.
>
> https://github.com/jgunthorpe/linux/commits/iommu_pt_arm64/
>
> cover-letter: Remove SMMUv3 struct arm_smmu_cmdq_ent
I see it’s already posted, I will go through it and provide feedback there.
Thanks,
Mostafa
>
> Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (2 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 03/25] iommu/arm-smmu-v3: Split code with hyp Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 12:41 ` Jason Gunthorpe
2026-05-01 11:19 ` [PATCH v6 05/25] iommu/arm-smmu-v3: Move IDR parsing to common functions Mostafa Saleh
` (20 subsequent siblings)
24 siblings, 1 reply; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Range TLB invalidation has a very specific algorithm. Instead of
re-writing it for the hypervisor, move it to a function that can
be re-used.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 65 ++++--------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 76 +++++++++++++++++++++
2 files changed, 88 insertions(+), 53 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index cb64f88989f0..c22832d26495 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2362,68 +2362,27 @@ static void arm_smmu_tlb_inv_context(void *cookie)
arm_smmu_domain_inv(smmu_domain);
}
+static void __arm_smmu_cmdq_batch_add(void *__opaque,
+ struct arm_smmu_cmdq_batch *cmds,
+ struct arm_smmu_cmdq_ent *cmd)
+{
+ struct arm_smmu_device *smmu = (struct arm_smmu_device *)__opaque;
+
+ arm_smmu_cmdq_batch_add(smmu, cmds, cmd);
+}
+
static void arm_smmu_cmdq_batch_add_range(struct arm_smmu_device *smmu,
struct arm_smmu_cmdq_batch *cmds,
struct arm_smmu_cmdq_ent *cmd,
unsigned long iova, size_t size,
size_t granule, size_t pgsize)
{
- unsigned long end = iova + size, num_pages = 0, tg = pgsize;
- size_t inv_range = granule;
-
if (WARN_ON_ONCE(!size))
return;
- if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
- num_pages = size >> tg;
-
- /* Convert page size of 12,14,16 (log2) to 1,2,3 */
- cmd->tlbi.tg = (tg - 10) / 2;
-
- /*
- * Determine what level the granule is at. For non-leaf, both
- * io-pgtable and SVA pass a nominal last-level granule because
- * they don't know what level(s) actually apply, so ignore that
- * and leave TTL=0. However for various errata reasons we still
- * want to use a range command, so avoid the SVA corner case
- * where both scale and num could be 0 as well.
- */
- if (cmd->tlbi.leaf)
- cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
- else if ((num_pages & CMDQ_TLBI_RANGE_NUM_MAX) == 1)
- num_pages++;
- }
-
- while (iova < end) {
- if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
- /*
- * On each iteration of the loop, the range is 5 bits
- * worth of the aligned size remaining.
- * The range in pages is:
- *
- * range = (num_pages & (0x1f << __ffs(num_pages)))
- */
- unsigned long scale, num;
-
- /* Determine the power of 2 multiple number of pages */
- scale = __ffs(num_pages);
- cmd->tlbi.scale = scale;
-
- /* Determine how many chunks of 2^scale size we have */
- num = (num_pages >> scale) & CMDQ_TLBI_RANGE_NUM_MAX;
- cmd->tlbi.num = num - 1;
-
- /* range is num * 2^scale * pgsize */
- inv_range = num << (scale + tg);
-
- /* Clear out the lower order bits for the next iteration */
- num_pages -= num << scale;
- }
-
- cmd->tlbi.addr = iova;
- arm_smmu_cmdq_batch_add(smmu, cmds, cmd);
- iova += inv_range;
- }
+ arm_smmu_tlb_inv_build(cmd, iova, size, granule,
+ pgsize, smmu->features & ARM_SMMU_FEAT_RANGE_INV,
+ smmu, __arm_smmu_cmdq_batch_add, cmds);
}
static bool arm_smmu_inv_size_too_big(struct arm_smmu_device *smmu, size_t size,
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 9b8c5fb7282b..7be41dbe5aaa 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1204,6 +1204,82 @@ static inline void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
}
+/**
+ * arm_smmu_tlb_inv_build - Create a range invalidation command
+ * @cmd: Base command initialized with OPCODE (S1, S2..), vmid and asid
+ * @iova: Start IOVA to invalidate
+ * @size: Size of range
+ * @granule: Granule of invalidation
+ * @pgsize: Page size of the invalidation
+ * @is_range: Use range invalidation commands
+ * @opaque: Pointer to pass to add_cmd
+ * @add_cmd: Function to send/batch the invalidation command
+ * @cmds: Incase of batching, it includes the pointer to the batch
+ */
+static inline void arm_smmu_tlb_inv_build(struct arm_smmu_cmdq_ent *cmd,
+ unsigned long iova, size_t size,
+ size_t granule, unsigned long pgsize,
+ bool is_range, void *opaque,
+ void (*add_cmd)(void *_opaque,
+ struct arm_smmu_cmdq_batch *cmds,
+ struct arm_smmu_cmdq_ent *cmd),
+ struct arm_smmu_cmdq_batch *cmds)
+{
+ unsigned long end = iova + size, num_pages = 0, tg = pgsize;
+ size_t inv_range = granule;
+
+ if (is_range) {
+ num_pages = size >> tg;
+
+ /* Convert page size of 12,14,16 (log2) to 1,2,3 */
+ cmd->tlbi.tg = (tg - 10) / 2;
+
+ /*
+ * Determine what level the granule is at. For non-leaf, both
+ * io-pgtable and SVA pass a nominal last-level granule because
+ * they don't know what level(s) actually apply, so ignore that
+ * and leave TTL=0. However for various errata reasons we still
+ * want to use a range command, so avoid the SVA corner case
+ * where both scale and num could be 0 as well.
+ */
+ if (cmd->tlbi.leaf)
+ cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
+ else if ((num_pages & CMDQ_TLBI_RANGE_NUM_MAX) == 1)
+ num_pages++;
+ }
+
+ while (iova < end) {
+ if (is_range) {
+ /*
+ * On each iteration of the loop, the range is 5 bits
+ * worth of the aligned size remaining.
+ * The range in pages is:
+ *
+ * range = (num_pages & (0x1f << __ffs(num_pages)))
+ */
+ unsigned long scale, num;
+
+ /* Determine the power of 2 multiple number of pages */
+ scale = __ffs(num_pages);
+ cmd->tlbi.scale = scale;
+
+ /* Determine how many chunks of 2^scale size we have */
+ num = (num_pages >> scale) & CMDQ_TLBI_RANGE_NUM_MAX;
+ cmd->tlbi.num = num - 1;
+
+ /* range is num * 2^scale * pgsize */
+ inv_range = num << (scale + tg);
+
+ /* Clear out the lower order bits for the next iteration */
+ num_pages -= num << scale;
+ }
+
+ cmd->tlbi.addr = iova;
+ add_cmd(opaque, cmds, cmd);
+ iova += inv_range;
+ }
+}
+
#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
void arm_smmu_sva_notifier_synchronize(void);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code
2026-05-01 11:19 ` [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code Mostafa Saleh
@ 2026-05-01 12:41 ` Jason Gunthorpe
2026-05-04 12:15 ` Mostafa Saleh
0 siblings, 1 reply; 38+ messages in thread
From: Jason Gunthorpe @ 2026-05-01 12:41 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 11:19:06AM +0000, Mostafa Saleh wrote:
> Range TLB invalidation has a very specific algorithm. Instead of
> re-writing it for the hypervisor, move it to a function that can
> be re-used.
I think this is too narrow.
You should start at __arm_smmu_domain_inv_range() and shove all of
that callchain into a new file "arm-smmuv3-tlbi.c" which you can then
double compile for pkvm.
pkvm would have to present the tlbi description and the invs array
which shouldn't be hard for it. Then it will enjoy all the same
hypervisor optimizations we are working on for the normal driver.
I am about to send a patch series here for iommupt that significantly
alters this. I think it will help your pkvm effort as the invalidation
entry point becomes significantly decoupled from the
iommu subsystem:
static void arm_smmu_domain_tlbi_inv(struct arm_smmu_tlbi *tlbi,
struct arm_smmu_invs *invs)
struct arm_smmu_tlbi {
struct arm_smmu_domain *smmu_domain; // Can be removed
unsigned long start;
unsigned long last;
u8 leaf_levels_bitmap;
u8 table_levels_bitmap;
};
Which pkvm should have no trouble invoking. It has to build an invs,
but I guess that is pretty simple and done once at boot for pkvm?
Once done all the fiddly bits about building the commands would be
shared. There is really no reason this should differ anyhow.
https://github.com/jgunthorpe/linux/commits/iommu_pt_arm64/
cover-letter: Organize SMMUv3 the invalidation flow so iommupt can use it
Jason
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code
2026-05-01 12:41 ` Jason Gunthorpe
@ 2026-05-04 12:15 ` Mostafa Saleh
0 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-04 12:15 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 09:41:43AM -0300, Jason Gunthorpe wrote:
> On Fri, May 01, 2026 at 11:19:06AM +0000, Mostafa Saleh wrote:
> > Range TLB invalidation has a very specific algorithm. Instead of
> > re-writing it for the hypervisor, move it to a function that can
> > be re-used.
>
> I think this is too narrow.
>
> You should start at __arm_smmu_domain_inv_range() and shove all of
> that callchain into a new file "arm-smmuv3-tlbi.c" which you can then
> double compile for pkvm.
>
> pkvm would have to present the tlbi description and the invs array
> which shouldn't be hard for it. Then it will enjoy all the same
> hypervisor optimizations we are working on for the normal driver.
>
> I am about to send a patch series here for iommupt that significantly
> alters this. I think it will help your pkvm effort as the invalidation
> entry point becomes significantly decoupled from the
> iommu subsystem:
>
> static void arm_smmu_domain_tlbi_inv(struct arm_smmu_tlbi *tlbi,
> struct arm_smmu_invs *invs)
>
> struct arm_smmu_tlbi {
> struct arm_smmu_domain *smmu_domain; // Can be removed
> unsigned long start;
> unsigned long last;
> u8 leaf_levels_bitmap;
> u8 table_levels_bitmap;
> };
>
I am not sure if it’s worth it, the hypervisor is much simpler, there
is a single page table, it’s locked (also identity mapped), it’s
updated on VM boot/teardown only, we don’t even use iotlb_gather at
the moment, although possible but I wanted to keep this series as
simple as I can then we can add more features later.
So this patch is the least intrusive change, as whatever the main SMMUv3
driver does, the range tlb invalidation logic is the same.
But I am happy to experiment with that when posted.
Thanks,
Mostafa
> Which pkvm should have no trouble invoking. It has to build an invs,
> but I guess that is pretty simple and done once at boot for pkvm?
>
> Once done all the fiddly bits about building the commands would be
> shared. There is really no reason this should differ anyhow.
>
> https://github.com/jgunthorpe/linux/commits/iommu_pt_arm64/
>
> cover-letter: Organize SMMUv3 the invalidation flow so iommupt can use it
>
> Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v6 05/25] iommu/arm-smmu-v3: Move IDR parsing to common functions
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (3 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 12:47 ` Jason Gunthorpe
2026-05-01 11:19 ` [PATCH v6 06/25] iommu/io-pgtable-arm: Rework to use the iommu-pages API Mostafa Saleh
` (19 subsequent siblings)
24 siblings, 1 reply; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Move parsing of IDRs to functions so that it can be re-used
from the hypervisor.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.c | 110 +++++++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 112 +++---------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 5 +
3 files changed, 130 insertions(+), 97 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
index 62744c8548a8..e6dd087e2999 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
@@ -112,3 +112,113 @@ int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
return 0;
}
+
+u32 smmu_idr0_features(u32 reg)
+{
+ u32 features = 0;
+
+ /* 2-level structures */
+ if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
+ features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
+
+ if (reg & IDR0_CD2L)
+ features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
+
+ /*
+ * Translation table endianness.
+ * We currently require the same endianness as the CPU, but this
+ * could be changed later by adding a new IO_PGTABLE_QUIRK.
+ */
+ switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
+ case IDR0_TTENDIAN_MIXED:
+ features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
+ break;
+#ifdef __BIG_ENDIAN
+ case IDR0_TTENDIAN_BE:
+ features |= ARM_SMMU_FEAT_TT_BE;
+ break;
+#else
+ case IDR0_TTENDIAN_LE:
+ features |= ARM_SMMU_FEAT_TT_LE;
+ break;
+#endif
+ }
+
+ /* Boolean feature flags */
+ if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
+ features |= ARM_SMMU_FEAT_PRI;
+
+ if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
+ features |= ARM_SMMU_FEAT_ATS;
+
+ if (reg & IDR0_SEV)
+ features |= ARM_SMMU_FEAT_SEV;
+
+ if (reg & IDR0_MSI)
+ features |= ARM_SMMU_FEAT_MSI;
+
+ if (reg & IDR0_HYP)
+ features |= ARM_SMMU_FEAT_HYP;
+
+ switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
+ case IDR0_STALL_MODEL_FORCE:
+ features |= ARM_SMMU_FEAT_STALL_FORCE;
+ fallthrough;
+ case IDR0_STALL_MODEL_STALL:
+ features |= ARM_SMMU_FEAT_STALLS;
+ }
+
+ if (reg & IDR0_S1P)
+ features |= ARM_SMMU_FEAT_TRANS_S1;
+
+ if (reg & IDR0_S2P)
+ features |= ARM_SMMU_FEAT_TRANS_S2;
+
+ return features;
+}
+
+u32 smmu_idr3_features(u32 reg)
+{
+ u32 features = 0;
+
+ if (FIELD_GET(IDR3_RIL, reg))
+ features |= ARM_SMMU_FEAT_RANGE_INV;
+ if (FIELD_GET(IDR3_FWB, reg))
+ features |= ARM_SMMU_FEAT_S2FWB;
+
+ return features;
+}
+
+u32 smmu_idr5_to_oas(u32 reg)
+{
+ switch (FIELD_GET(IDR5_OAS, reg)) {
+ case IDR5_OAS_32_BIT:
+ return 32;
+ case IDR5_OAS_36_BIT:
+ return 36;
+ case IDR5_OAS_40_BIT:
+ return 40;
+ case IDR5_OAS_42_BIT:
+ return 42;
+ case IDR5_OAS_44_BIT:
+ return 44;
+ case IDR5_OAS_48_BIT:
+ return 48;
+ case IDR5_OAS_52_BIT:
+ return 52;
+ }
+ return 0;
+}
+
+unsigned long smmu_idr5_to_pgsize(u32 reg)
+{
+ unsigned long pgsize_bitmap = 0;
+
+ if (reg & IDR5_GRAN64K)
+ pgsize_bitmap |= SZ_64K | SZ_512M;
+ if (reg & IDR5_GRAN16K)
+ pgsize_bitmap |= SZ_16K | SZ_32M;
+ if (reg & IDR5_GRAN4K)
+ pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
+ return pgsize_bitmap;
+}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index c22832d26495..96d5e7f80ce7 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -4815,57 +4815,17 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
/* IDR0 */
reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
- /* 2-level structures */
- if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
- smmu->features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
-
- if (reg & IDR0_CD2L)
- smmu->features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
-
- /*
- * Translation table endianness.
- * We currently require the same endianness as the CPU, but this
- * could be changed later by adding a new IO_PGTABLE_QUIRK.
- */
- switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
- case IDR0_TTENDIAN_MIXED:
- smmu->features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
- break;
-#ifdef __BIG_ENDIAN
- case IDR0_TTENDIAN_BE:
- smmu->features |= ARM_SMMU_FEAT_TT_BE;
- break;
-#else
- case IDR0_TTENDIAN_LE:
- smmu->features |= ARM_SMMU_FEAT_TT_LE;
- break;
-#endif
- default:
+ smmu->features |= smmu_idr0_features(reg);
+ if (!(smmu->features & (ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE))) {
dev_err(smmu->dev, "unknown/unsupported TT endianness!\n");
return -ENXIO;
}
-
- /* Boolean feature flags */
- if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
- smmu->features |= ARM_SMMU_FEAT_PRI;
-
- if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
- smmu->features |= ARM_SMMU_FEAT_ATS;
-
- if (reg & IDR0_SEV)
- smmu->features |= ARM_SMMU_FEAT_SEV;
-
- if (reg & IDR0_MSI) {
- smmu->features |= ARM_SMMU_FEAT_MSI;
- if (coherent && !disable_msipolling)
- smmu->options |= ARM_SMMU_OPT_MSIPOLL;
- }
-
- if (reg & IDR0_HYP) {
- smmu->features |= ARM_SMMU_FEAT_HYP;
- if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
- smmu->features |= ARM_SMMU_FEAT_E2H;
- }
+ if (coherent && !disable_msipolling &&
+ smmu->features & ARM_SMMU_FEAT_MSI)
+ smmu->options |= ARM_SMMU_OPT_MSIPOLL;
+ if (smmu->features & ARM_SMMU_FEAT_HYP &&
+ cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
+ smmu->features |= ARM_SMMU_FEAT_E2H;
arm_smmu_get_httu(smmu, reg);
@@ -4877,21 +4837,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
dev_warn(smmu->dev, "IDR0.COHACC overridden by FW configuration (%s)\n",
str_true_false(coherent));
- switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
- case IDR0_STALL_MODEL_FORCE:
- smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
- fallthrough;
- case IDR0_STALL_MODEL_STALL:
- smmu->features |= ARM_SMMU_FEAT_STALLS;
- }
-
- if (reg & IDR0_S1P)
- smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
-
- if (reg & IDR0_S2P)
- smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
-
- if (!(reg & (IDR0_S1P | IDR0_S2P))) {
+ if (!(smmu->features & (ARM_SMMU_FEAT_TRANS_S1 | ARM_SMMU_FEAT_TRANS_S2))) {
dev_err(smmu->dev, "no translation support!\n");
return -ENXIO;
}
@@ -4950,10 +4896,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
/* IDR3 */
reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
- if (FIELD_GET(IDR3_RIL, reg))
- smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
- if (FIELD_GET(IDR3_FWB, reg))
- smmu->features |= ARM_SMMU_FEAT_S2FWB;
+ smmu->features |= smmu_idr3_features(reg);
if (FIELD_GET(IDR3_BBM, reg) == 2)
smmu->features |= ARM_SMMU_FEAT_BBML2;
@@ -4965,43 +4908,18 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
smmu->evtq.max_stalls = FIELD_GET(IDR5_STALL_MAX, reg);
/* Page sizes */
- if (reg & IDR5_GRAN64K)
- smmu->pgsize_bitmap |= SZ_64K | SZ_512M;
- if (reg & IDR5_GRAN16K)
- smmu->pgsize_bitmap |= SZ_16K | SZ_32M;
- if (reg & IDR5_GRAN4K)
- smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
+ smmu->pgsize_bitmap = smmu_idr5_to_pgsize(reg);
/* Input address size */
if (FIELD_GET(IDR5_VAX, reg) == IDR5_VAX_52_BIT)
smmu->features |= ARM_SMMU_FEAT_VAX;
- /* Output address size */
- switch (FIELD_GET(IDR5_OAS, reg)) {
- case IDR5_OAS_32_BIT:
- smmu->oas = 32;
- break;
- case IDR5_OAS_36_BIT:
- smmu->oas = 36;
- break;
- case IDR5_OAS_40_BIT:
- smmu->oas = 40;
- break;
- case IDR5_OAS_42_BIT:
- smmu->oas = 42;
- break;
- case IDR5_OAS_44_BIT:
- smmu->oas = 44;
- break;
- case IDR5_OAS_52_BIT:
- smmu->oas = 52;
+ smmu->oas = smmu_idr5_to_oas(reg);
+ if (smmu->oas == 52)
smmu->pgsize_bitmap |= 1ULL << 42; /* 4TB */
- break;
- default:
+ else if (!smmu->oas) {
dev_info(smmu->dev,
- "unknown output address size. Truncating to 48-bit\n");
- fallthrough;
- case IDR5_OAS_48_BIT:
+ "unknown output address size. Truncating to 48-bit\n");
smmu->oas = 48;
}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 7be41dbe5aaa..64618299d03a 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1144,6 +1144,11 @@ int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
bool sync);
int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent);
+u32 smmu_idr0_features(u32 reg);
+u32 smmu_idr3_features(u32 reg);
+u32 smmu_idr5_to_oas(u32 reg);
+unsigned long smmu_idr5_to_pgsize(u32 reg);
+
/* Queue functions shared between kernel and hyp. */
static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
{
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v6 05/25] iommu/arm-smmu-v3: Move IDR parsing to common functions
2026-05-01 11:19 ` [PATCH v6 05/25] iommu/arm-smmu-v3: Move IDR parsing to common functions Mostafa Saleh
@ 2026-05-01 12:47 ` Jason Gunthorpe
2026-05-04 12:16 ` Mostafa Saleh
0 siblings, 1 reply; 38+ messages in thread
From: Jason Gunthorpe @ 2026-05-01 12:47 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 11:19:07AM +0000, Mostafa Saleh wrote:
> Move parsing of IDRs to functions so that it can be re-used
> +unsigned long smmu_idr5_to_pgsize(u32 reg)
> +{
> + unsigned long pgsize_bitmap = 0;
> +
> + if (reg & IDR5_GRAN64K)
> + pgsize_bitmap |= SZ_64K | SZ_512M;
> + if (reg & IDR5_GRAN16K)
> + pgsize_bitmap |= SZ_16K | SZ_32M;
> + if (reg & IDR5_GRAN4K)
> + pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
> + return pgsize_bitmap;
> +}
I think this should include:
> + smmu->oas = smmu_idr5_to_oas(reg);
> + if (smmu->oas == 52)
> smmu->pgsize_bitmap |= 1ULL << 42; /* 4TB */
> - break;
ie it should return the supported page sizes by inspecting all the
idrs and don't leave this tricky bit to be open coded..
Jason
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v6 05/25] iommu/arm-smmu-v3: Move IDR parsing to common functions
2026-05-01 12:47 ` Jason Gunthorpe
@ 2026-05-04 12:16 ` Mostafa Saleh
0 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-04 12:16 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 09:47:16AM -0300, Jason Gunthorpe wrote:
> On Fri, May 01, 2026 at 11:19:07AM +0000, Mostafa Saleh wrote:
> > Move parsing of IDRs to functions so that it can be re-used
> > +unsigned long smmu_idr5_to_pgsize(u32 reg)
> > +{
> > + unsigned long pgsize_bitmap = 0;
> > +
> > + if (reg & IDR5_GRAN64K)
> > + pgsize_bitmap |= SZ_64K | SZ_512M;
> > + if (reg & IDR5_GRAN16K)
> > + pgsize_bitmap |= SZ_16K | SZ_32M;
> > + if (reg & IDR5_GRAN4K)
> > + pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
> > + return pgsize_bitmap;
> > +}
>
> I think this should include:
>
> > + smmu->oas = smmu_idr5_to_oas(reg);
> > + if (smmu->oas == 52)
> > smmu->pgsize_bitmap |= 1ULL << 42; /* 4TB */
> > - break;
>
> ie it should return the supported page sizes by inspecting all the
> idrs and don't leave this tricky bit to be open coded..
This way was easier as each function only returns one thing, otherwise
we have to pass stuff by address as we can’t pass the smmu struct as it
is not shared between the drivers.
But no strong opinion, I can change that.
Thanks,
Mostafa
>
> Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v6 06/25] iommu/io-pgtable-arm: Rework to use the iommu-pages API
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (4 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 05/25] iommu/arm-smmu-v3: Move IDR parsing to common functions Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 12:24 ` Jason Gunthorpe
2026-05-01 11:19 ` [PATCH v6 07/25] KVM: arm64: iommu: Introduce IOMMU driver infrastructure Mostafa Saleh
` (18 subsequent siblings)
24 siblings, 1 reply; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
To prepare for supporting io-pgtable-arm in the pKVM hypervisor,
we need to abstract away standard kernel allocations, frees, virt/phys
conversions, and DMA API mapping.
This patch introduces a set of generic wrappers in iommu-pages.h:
- iommu_alloc_data
- iommu_free_data
- iommu_virt_to_phys
- iommu_phys_to_virt
- iommu_pages_dma_map
- iommu_pages_dma_mapping_error
- iommu_pages_dma_unmap
The io-pgtable-arm.c code is updated to universally use these new
wrappers instead of standard kernel kmalloc_obj, kfree, virt_to_phys,
dma_map_single, etc. This abstraction makes it easy to replace them with
hypervisor-specific implementations in a later patch.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/io-pgtable-arm.c | 37 ++++++++++++++++------------------
drivers/iommu/iommu-pages.h | 36 +++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+), 20 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 0208e5897c29..e765021308f9 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -15,7 +15,6 @@
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/types.h>
-#include <linux/dma-mapping.h>
#include <asm/barrier.h>
@@ -143,7 +142,7 @@
#define ARM_MALI_LPAE_MEMATTR_WRITE_ALLOC 0x8DULL
/* IOPTE accessors */
-#define iopte_deref(pte,d) __va(iopte_to_paddr(pte, d))
+#define iopte_deref(pte, d) iommu_phys_to_virt(iopte_to_paddr(pte, d))
#define iopte_type(pte) \
(((pte) >> ARM_LPAE_PTE_TYPE_SHIFT) & ARM_LPAE_PTE_TYPE_MASK)
@@ -245,7 +244,7 @@ static inline bool arm_lpae_concat_mandatory(struct io_pgtable_cfg *cfg,
static dma_addr_t __arm_lpae_dma_addr(void *pages)
{
- return (dma_addr_t)virt_to_phys(pages);
+ return (dma_addr_t)iommu_virt_to_phys(pages);
}
static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
@@ -272,15 +271,15 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
return NULL;
if (!cfg->coherent_walk) {
- dma = dma_map_single(dev, pages, size, DMA_TO_DEVICE);
- if (dma_mapping_error(dev, dma))
+ dma = iommu_pages_dma_map(dev, pages, size);
+ if (iommu_pages_dma_mapping_error(dev, dma))
goto out_free;
/*
* We depend on the IOMMU being able to work with any physical
* address directly, so if the DMA layer suggests otherwise by
* translating or truncating them, that bodes very badly...
*/
- if (dma != virt_to_phys(pages))
+ if (dma != iommu_virt_to_phys(pages))
goto out_unmap;
}
@@ -288,7 +287,7 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
out_unmap:
dev_err(dev, "Cannot accommodate DMA translation for IOMMU page tables\n");
- dma_unmap_single(dev, dma, size, DMA_TO_DEVICE);
+ iommu_pages_dma_unmap(dev, dma, size);
out_free:
if (cfg->free)
@@ -304,8 +303,7 @@ static void __arm_lpae_free_pages(void *pages, size_t size,
void *cookie)
{
if (!cfg->coherent_walk)
- dma_unmap_single(cfg->iommu_dev, __arm_lpae_dma_addr(pages),
- size, DMA_TO_DEVICE);
+ iommu_pages_dma_unmap(cfg->iommu_dev, __arm_lpae_dma_addr(pages), size);
if (cfg->free)
cfg->free(cookie, pages, size);
@@ -316,8 +314,7 @@ static void __arm_lpae_free_pages(void *pages, size_t size,
static void __arm_lpae_sync_pte(arm_lpae_iopte *ptep, int num_entries,
struct io_pgtable_cfg *cfg)
{
- dma_sync_single_for_device(cfg->iommu_dev, __arm_lpae_dma_addr(ptep),
- sizeof(*ptep) * num_entries, DMA_TO_DEVICE);
+ iommu_pages_flush_incoherent(cfg->iommu_dev, ptep, 0, sizeof(*ptep) * num_entries);
}
static void __arm_lpae_clear_pte(arm_lpae_iopte *ptep, struct io_pgtable_cfg *cfg, int num_entries)
@@ -395,7 +392,7 @@ static arm_lpae_iopte arm_lpae_install_table(arm_lpae_iopte *table,
arm_lpae_iopte old, new;
struct io_pgtable_cfg *cfg = &data->iop.cfg;
- new = paddr_to_iopte(__pa(table), data) | ARM_LPAE_PTE_TYPE_TABLE;
+ new = paddr_to_iopte(iommu_virt_to_phys(table), data) | ARM_LPAE_PTE_TYPE_TABLE;
if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS)
new |= ARM_LPAE_PTE_NSTABLE;
@@ -616,7 +613,7 @@ static void arm_lpae_free_pgtable(struct io_pgtable *iop)
struct arm_lpae_io_pgtable *data = io_pgtable_to_data(iop);
__arm_lpae_free_pgtable(data, data->start_level, data->pgd);
- kfree(data);
+ iommu_free_data(data);
}
static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
@@ -930,7 +927,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
return NULL;
- data = kmalloc_obj(*data);
+ data = iommu_alloc_data(sizeof(*data), GFP_KERNEL);
if (!data)
return NULL;
@@ -1053,11 +1050,11 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
wmb();
/* TTBR */
- cfg->arm_lpae_s1_cfg.ttbr = virt_to_phys(data->pgd);
+ cfg->arm_lpae_s1_cfg.ttbr = iommu_virt_to_phys(data->pgd);
return &data->iop;
out_free_data:
- kfree(data);
+ iommu_free_data(data);
return NULL;
}
@@ -1149,11 +1146,11 @@ arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
wmb();
/* VTTBR */
- cfg->arm_lpae_s2_cfg.vttbr = virt_to_phys(data->pgd);
+ cfg->arm_lpae_s2_cfg.vttbr = iommu_virt_to_phys(data->pgd);
return &data->iop;
out_free_data:
- kfree(data);
+ iommu_free_data(data);
return NULL;
}
@@ -1223,7 +1220,7 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
/* Ensure the empty pgd is visible before TRANSTAB can be written */
wmb();
- cfg->arm_mali_lpae_cfg.transtab = virt_to_phys(data->pgd) |
+ cfg->arm_mali_lpae_cfg.transtab = iommu_virt_to_phys(data->pgd) |
ARM_MALI_LPAE_TTBR_READ_INNER |
ARM_MALI_LPAE_TTBR_ADRMODE_TABLE;
if (cfg->coherent_walk)
@@ -1232,7 +1229,7 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
return &data->iop;
out_free_data:
- kfree(data);
+ iommu_free_data(data);
return NULL;
}
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
index ae9da4f571f6..e1945193ad7f 100644
--- a/drivers/iommu/iommu-pages.h
+++ b/drivers/iommu/iommu-pages.h
@@ -7,6 +7,7 @@
#ifndef __IOMMU_PAGES_H
#define __IOMMU_PAGES_H
+#include <linux/dma-mapping.h>
#include <linux/iommu.h>
/**
@@ -145,4 +146,39 @@ void iommu_pages_stop_incoherent_list(struct iommu_pages_list *list,
void iommu_pages_free_incoherent(void *virt, struct device *dma_dev);
#endif
+static inline void *iommu_alloc_data(size_t size, gfp_t gfp)
+{
+ return kmalloc(size, gfp);
+}
+
+static inline void iommu_free_data(void *p)
+{
+ kfree(p);
+}
+
+static inline phys_addr_t iommu_virt_to_phys(void *virt)
+{
+ return virt_to_phys(virt);
+}
+
+static inline void *iommu_phys_to_virt(phys_addr_t phys)
+{
+ return phys_to_virt(phys);
+}
+
+static inline dma_addr_t iommu_pages_dma_map(struct device *dev, void *virt, size_t size)
+{
+ return dma_map_single(dev, virt, size, DMA_TO_DEVICE);
+}
+
+static inline int iommu_pages_dma_mapping_error(struct device *dev, dma_addr_t dma)
+{
+ return dma_mapping_error(dev, dma);
+}
+
+static inline void iommu_pages_dma_unmap(struct device *dev, dma_addr_t dma, size_t size)
+{
+ dma_unmap_single(dev, dma, size, DMA_TO_DEVICE);
+}
+
#endif /* __IOMMU_PAGES_H */
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v6 06/25] iommu/io-pgtable-arm: Rework to use the iommu-pages API
2026-05-01 11:19 ` [PATCH v6 06/25] iommu/io-pgtable-arm: Rework to use the iommu-pages API Mostafa Saleh
@ 2026-05-01 12:24 ` Jason Gunthorpe
2026-05-04 12:19 ` Mostafa Saleh
0 siblings, 1 reply; 38+ messages in thread
From: Jason Gunthorpe @ 2026-05-01 12:24 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 11:19:08AM +0000, Mostafa Saleh wrote:
> To prepare for supporting io-pgtable-arm in the pKVM hypervisor,
> we need to abstract away standard kernel allocations, frees, virt/phys
> conversions, and DMA API mapping.
>
> This patch introduces a set of generic wrappers in iommu-pages.h:
> - iommu_alloc_data
> - iommu_free_data
> - iommu_virt_to_phys
> - iommu_phys_to_virt
> - iommu_pages_dma_map
> - iommu_pages_dma_mapping_error
> - iommu_pages_dma_unmap
Wah? This has nothing to do with iommu pages? This just leaking
everything iommu pages abstracted out :(
When I said to use iommu-pages, I meant to use the existing API, not a
completely different one.
From an iommu-pages perspective the issue is this code open codes
dma_map_single()/etc instead of using the API surface
iommu_pages_start_incoherent()
This is annoying to fix beacuse the external allocator messes it up,
but I think with some #ifdef you can probably fix it up.
So.. I suggest you update it to use the iommu_pages API, #ifdef out
the allocator so the pkvm pkvm doesn't need to deal with it. Then
compile a special iommu-pages for the pkvm side presenting the same
API.
You should have a pkvm shim header that provides
kmalloc/kfree/virt_to_phys in the normal way and just #include that in
io-pgtable when doing a pkvm build instead of hacking up all the code.
Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v6 06/25] iommu/io-pgtable-arm: Rework to use the iommu-pages API
2026-05-01 12:24 ` Jason Gunthorpe
@ 2026-05-04 12:19 ` Mostafa Saleh
0 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-04 12:19 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 09:24:24AM -0300, Jason Gunthorpe wrote:
> On Fri, May 01, 2026 at 11:19:08AM +0000, Mostafa Saleh wrote:
> > To prepare for supporting io-pgtable-arm in the pKVM hypervisor,
> > we need to abstract away standard kernel allocations, frees, virt/phys
> > conversions, and DMA API mapping.
> >
> > This patch introduces a set of generic wrappers in iommu-pages.h:
> > - iommu_alloc_data
> > - iommu_free_data
> > - iommu_virt_to_phys
> > - iommu_phys_to_virt
> > - iommu_pages_dma_map
> > - iommu_pages_dma_mapping_error
> > - iommu_pages_dma_unmap
>
> Wah? This has nothing to do with iommu pages? This just leaking
> everything iommu pages abstracted out :(
>
> When I said to use iommu-pages, I meant to use the existing API, not a
> completely different one.
>
> From an iommu-pages perspective the issue is this code open codes
> dma_map_single()/etc instead of using the API surface
> iommu_pages_start_incoherent()
>
> This is annoying to fix beacuse the external allocator messes it up,
> but I think with some #ifdef you can probably fix it up.
>
> So.. I suggest you update it to use the iommu_pages API, #ifdef out
> the allocator so the pkvm pkvm doesn't need to deal with it. Then
> compile a special iommu-pages for the pkvm side presenting the same
> API.
I see, we still need to leave the DMA-API calls for the custom config,
as I am not sure if it can use pages not backed by the vmemmap, I
pushed that into a separate function so it’s easily compiled out.
Without this patch, now it looks like:
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 0208e5897c29..1583b9916b09 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -248,26 +248,15 @@ static dma_addr_t __arm_lpae_dma_addr(void *pages)
return (dma_addr_t)virt_to_phys(pages);
}
-static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
- struct io_pgtable_cfg *cfg,
- void *cookie)
+static void *__arm_lpae_cfg_alloc(size_t size, gfp_t gfp,
+ struct io_pgtable_cfg *cfg,
+ void *cookie)
{
struct device *dev = cfg->iommu_dev;
- size_t alloc_size;
dma_addr_t dma;
void *pages;
- /*
- * For very small starting-level translation tables the HW requires a
- * minimum alignment of at least 64 to cover all cases.
- */
- alloc_size = max(size, 64);
- if (cfg->alloc)
- pages = cfg->alloc(cookie, alloc_size, gfp);
- else
- pages = iommu_alloc_pages_node_sz(dev_to_node(dev), gfp,
- alloc_size);
-
+ pages = cfg->alloc(cookie, size, gfp);
if (!pages)
return NULL;
@@ -289,26 +278,67 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
out_unmap:
dev_err(dev, "Cannot accommodate DMA translation for IOMMU page tables\n");
dma_unmap_single(dev, dma, size, DMA_TO_DEVICE);
-
out_free:
- if (cfg->free)
- cfg->free(cookie, pages, size);
- else
- iommu_free_pages(pages);
-
+ cfg->free(cookie, pages, size);
return NULL;
}
-static void __arm_lpae_free_pages(void *pages, size_t size,
- struct io_pgtable_cfg *cfg,
- void *cookie)
+static void __arm_lpae_cfg_free(void *pages, size_t size,
+ struct io_pgtable_cfg *cfg,
+ void *cookie)
{
if (!cfg->coherent_walk)
dma_unmap_single(cfg->iommu_dev, __arm_lpae_dma_addr(pages),
size, DMA_TO_DEVICE);
- if (cfg->free)
- cfg->free(cookie, pages, size);
+ cfg->free(cookie, pages, size);
+}
+
+static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
+ struct io_pgtable_cfg *cfg,
+ void *cookie)
+{
+ struct device *dev = cfg->iommu_dev;
+ size_t alloc_size;
+ void *pages;
+
+ /*
+ * For very small starting-level translation tables the HW requires a
+ * minimum alignment of at least 64 to cover all cases.
+ */
+ alloc_size = max(size, 64);
+ if (cfg->alloc)
+ return __arm_lpae_cfg_alloc(alloc_size, gfp, cfg, cookie);
+
+ pages = iommu_alloc_pages_node_sz(dev_to_node(dev), gfp, alloc_size);
+ if (!pages)
+ return NULL;
+
+ if (!cfg->coherent_walk) {
+ int ret = iommu_pages_start_incoherent(pages, dev);
+
+ if (ret) {
+ if (ret == -EOPNOTSUPP)
+ dev_err(dev, "Cannot accommodate DMA translation for IOMMU page tables\n");
+ iommu_free_pages(pages);
+ return NULL;
+ }
+ }
+
+ return pages;
+}
+
+static void __arm_lpae_free_pages(void *pages, size_t size,
+ struct io_pgtable_cfg *cfg,
+ void *cookie)
+{
+ if (cfg->free) {
+ __arm_lpae_cfg_free(pages, size, cfg, cookie);
+ return;
+ }
+
+ if (!cfg->coherent_walk)
+ iommu_pages_free_incoherent(pages, cfg->iommu_dev);
else
iommu_free_pages(pages);
}
Thanks,
Mostafa
>
> You should have a pkvm shim header that provides
> kmalloc/kfree/virt_to_phys in the normal way and just #include that in
> io-pgtable when doing a pkvm build instead of hacking up all the code.
Ok, I can do that in another change, but I believe it's better to
change the usage in this file to arm_lpae_*(virt_to_phys...) so it's
clear which parts are intended for that.
Thanks,
Mostafa
>
> Jason
^ permalink raw reply related [flat|nested] 38+ messages in thread
* [PATCH v6 07/25] KVM: arm64: iommu: Introduce IOMMU driver infrastructure
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (5 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 06/25] iommu/io-pgtable-arm: Rework to use the iommu-pages API Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 08/25] KVM: arm64: iommu: Shadow host stage-2 page table Mostafa Saleh
` (17 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
To establish DMA isolation, KVM needs an IOMMU driver which provides
ops implemented at EL2.
Only one driver can be used and is registered with
kvm_iommu_register_driver() by passing pointer to the ops.
This must be called before module_init() which is the point KVM
initializes.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/include/asm/kvm_host.h | 5 +++++
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 13 +++++++++++++
arch/arm64/kvm/hyp/nvhe/Makefile | 3 ++-
arch/arm64/kvm/hyp/nvhe/iommu/iommu.c | 20 +++++++++++++++++++
arch/arm64/kvm/hyp/nvhe/setup.c | 5 +++++
arch/arm64/kvm/iommu.c | 26 +++++++++++++++++++++++++
7 files changed, 72 insertions(+), 2 deletions(-)
create mode 100644 arch/arm64/kvm/hyp/include/nvhe/iommu.h
create mode 100644 arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
create mode 100644 arch/arm64/kvm/iommu.c
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 851f6171751c..52898d2a3ec6 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1733,4 +1733,9 @@ static __always_inline enum fgt_group_id __fgt_reg_to_group_id(enum vcpu_sysreg
long kvm_get_cap_for_kvm_ioctl(unsigned int ioctl, long *ext);
+#ifndef __KVM_NVHE_HYPERVISOR__
+struct kvm_iommu_ops;
+int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops);
+#endif
+
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 59612d2f277c..0ddef54f7434 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -24,7 +24,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
vgic/vgic-its.o vgic/vgic-debug.o vgic/vgic-v3-nested.o \
- vgic/vgic-v5.o
+ vgic/vgic-v5.o iommu.o
kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o
kvm-$(CONFIG_ARM64_PTR_AUTH) += pauth.o
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
new file mode 100644
index 000000000000..1ac70cc28a9e
--- /dev/null
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ARM64_KVM_NVHE_IOMMU_H__
+#define __ARM64_KVM_NVHE_IOMMU_H__
+
+#include <asm/kvm_host.h>
+
+struct kvm_iommu_ops {
+ int (*init)(void);
+};
+
+int kvm_iommu_init(void);
+
+#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 89d0533921f9..606c0e1b7bd0 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -24,7 +24,8 @@ CFLAGS_switch.nvhe.o += -Wno-override-init
hyp-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \
- cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o
+ cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o \
+ iommu/iommu.o
hyp-obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o ../vgic-v5-sr.o clock.o
hyp-obj-y += ../../../kernel/smccc-call.o
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
new file mode 100644
index 000000000000..406c8fb9b3b9
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IOMMU operations for pKVM
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <nvhe/iommu.h>
+
+/* Only one set of ops supported */
+struct kvm_iommu_ops *kvm_iommu_ops;
+
+
+int kvm_iommu_init(void)
+{
+ /* Keep DMA isolation optional. */
+ if (!kvm_iommu_ops || !kvm_iommu_ops->init)
+ return 0;
+
+ return kvm_iommu_ops->init();
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 8041f6e80cd1..1f6b221db9a0 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -14,6 +14,7 @@
#include <nvhe/early_alloc.h>
#include <nvhe/ffa.h>
#include <nvhe/gfp.h>
+#include <nvhe/iommu.h>
#include <nvhe/memory.h>
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>
@@ -329,6 +330,10 @@ void __noreturn __pkvm_init_finalise(void)
if (ret)
goto out;
+ ret = kvm_iommu_init();
+ if (ret)
+ goto out;
+
ret = hyp_ffa_init(ffa_proxy_pages);
if (ret)
goto out;
diff --git a/arch/arm64/kvm/iommu.c b/arch/arm64/kvm/iommu.c
new file mode 100644
index 000000000000..f247384fa193
--- /dev/null
+++ b/arch/arm64/kvm/iommu.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Google LLC
+ * Author: Mostafa Saleh <smostafa@google.com>
+ */
+
+#include <linux/kvm_host.h>
+
+extern struct kvm_iommu_ops *kvm_nvhe_sym(kvm_iommu_ops);
+
+static DEFINE_MUTEX(kvm_iommu_reg_lock);
+
+int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops)
+{
+ guard(mutex)(&kvm_iommu_reg_lock);
+
+ /* Only protected KVM before de-privilege. */
+ if (!is_protected_kvm_enabled() || is_kvm_arm_initialised())
+ return -EINVAL;
+
+ if (kvm_nvhe_sym(kvm_iommu_ops))
+ return -EBUSY;
+
+ kvm_nvhe_sym(kvm_iommu_ops) = hyp_ops;
+ return 0;
+}
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 08/25] KVM: arm64: iommu: Shadow host stage-2 page table
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (6 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 07/25] KVM: arm64: iommu: Introduce IOMMU driver infrastructure Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 13:00 ` Jason Gunthorpe
2026-05-01 11:19 ` [PATCH v6 09/25] KVM: arm64: iommu: Add memory pool Mostafa Saleh
` (16 subsequent siblings)
24 siblings, 1 reply; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Create a page-table for the IOMMU that shadows the host CPU stage-2
to establish DMA isolation.
An initial snapshot is created after the driver init, then
on every permission change a callback would be called for
the IOMMU driver to update the page table.
There are 3 different ways to add the callback:
1) In the high level memory transitions: (__pkvm_host_donate_hyp(),
__pkvm_host_donate_guest()...
2) In Lower level functions covering all transitions
- host_stage2_set_owner_metadata_locked() which covers:
- __pkvm_host_donate_hyp()
- __pkvm_host_donate_guest()
- __pkvm_host_donate_hyp()
- __pkvm_guest_unshare_host()
- host_stage2_set_owner_locked() only for ID_HOST which covers:
- __pkvm_hyp_donate_host()
- __pkvm_host_force_reclaim_page_guest()
- __pkvm_host_reclaim_page_guest()
- __pkvm_guest_share_host()
3) In the lowest level function __host_update_page_state(), which
requires only one callback. However, in that case the page state
is not enough as we might need to know the old state also.
Option #3 was implemented here.
For some cases, an SMMUv3 may be able to share the same page-table
used with the host CPU stage-2 directly.
However, this is too strict and requires changes to the core hypervisor
page-table code, plus it would require the hypervisor to handle IOMMU
page-faults. This can be added later as an optimization for SMMUV3.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 4 +
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 2 +
arch/arm64/kvm/hyp/nvhe/iommu/iommu.c | 108 +++++++++++++++++-
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 35 ++++++
4 files changed, 146 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index 1ac70cc28a9e..6277d845cdcf 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -3,11 +3,15 @@
#define __ARM64_KVM_NVHE_IOMMU_H__
#include <asm/kvm_host.h>
+#include <asm/kvm_pgtable.h>
struct kvm_iommu_ops {
int (*init)(void);
+ int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot);
};
int kvm_iommu_init(void);
+int kvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
+ enum kvm_pgtable_prot prot);
#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index ff440204d2c7..f7faecc3b70a 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -54,6 +54,8 @@ int __pkvm_host_test_clear_young_guest(u64 gfn, u64 nr_pages, bool mkold, struct
int __pkvm_host_mkyoung_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu);
bool addr_is_memory(phys_addr_t phys);
+u64 find_mem_range_from(u64 start, bool *is_memory);
+
int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id);
int kvm_host_prepare_stage2(void *pgt_pool_base);
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
index 406c8fb9b3b9..1db52bd87c38 100644
--- a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
+++ b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
@@ -4,17 +4,119 @@
*
* Copyright (C) 2022 Linaro Ltd.
*/
+#include <linux/iommu.h>
+
#include <nvhe/iommu.h>
+#include <nvhe/mem_protect.h>
+#include <nvhe/spinlock.h>
/* Only one set of ops supported */
struct kvm_iommu_ops *kvm_iommu_ops;
+/* Protected by host_mmu.lock */
+static bool kvm_idmap_initialized;
+
+static inline int pkvm_to_iommu_prot(enum kvm_pgtable_prot prot)
+{
+ int iommu_prot = 0;
+
+ if (prot & KVM_PGTABLE_PROT_R)
+ iommu_prot |= IOMMU_READ;
+ if (prot & KVM_PGTABLE_PROT_W)
+ iommu_prot |= IOMMU_WRITE;
+
+ /* We don't understand that, might be dangerous. */
+ WARN_ON(prot & ~PKVM_HOST_MEM_PROT);
+ return iommu_prot;
+}
+
+static int __snapshot_host_stage2(const struct kvm_pgtable_visit_ctx *ctx,
+ enum kvm_pgtable_walk_flags visit)
+{
+ u64 start = ctx->addr;
+ u64 end = start + kvm_granule_size(ctx->level);
+ kvm_pte_t pte = *ctx->ptep;
+ bool is_memory;
+ u64 region_end;
+ int prot;
+ int ret;
+
+ /*
+ * Keep annotated PTEs unmapped, and map everything else even lazily
+ * mapped MMIO with pte == 0, as the IOMMU can't handle page faults.
+ * That maps the whole address space which can be large, but that doesn't
+ * use a lot of memory as it will be mostly large block (1 GB with 4kb pages)
+ */
+ if (pte && !kvm_pte_valid(pte))
+ return 0;
+
+ if (kvm_pte_valid(pte)) {
+ prot = pkvm_to_iommu_prot(kvm_pgtable_stage2_pte_prot(pte));
+ /* If the range is mapped in a single PTE, it must be the same type.*/
+ if (!addr_is_memory(start))
+ prot |= IOMMU_MMIO;
+
+ return kvm_iommu_ops->host_stage2_idmap(start, end, prot);
+ }
+
+ /* In case of invalid PTE, we need to figure out which part of it is MMIO */
+ do {
+ prot = IOMMU_READ | IOMMU_WRITE;
+ region_end = find_mem_range_from(start, &is_memory);
+ region_end = min(end, region_end);
+ if (!is_memory)
+ prot |= IOMMU_MMIO;
+
+ ret = kvm_iommu_ops->host_stage2_idmap(start, region_end, prot);
+ if (ret)
+ return ret;
+
+ start = region_end;
+ } while (start < end);
+
+ return 0;
+}
+
+static int kvm_iommu_snapshot_host_stage2(void)
+{
+ int ret;
+ struct kvm_pgtable_walker walker = {
+ .cb = __snapshot_host_stage2,
+ .flags = KVM_PGTABLE_WALK_LEAF,
+ };
+ struct kvm_pgtable *pgt = &host_mmu.pgt;
+
+ hyp_spin_lock(&host_mmu.lock);
+ ret = kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker);
+ /* Start receiving calls to host_stage2_idmap. */
+ kvm_idmap_initialized = !ret;
+ hyp_spin_unlock(&host_mmu.lock);
+
+ return ret;
+}
int kvm_iommu_init(void)
{
- /* Keep DMA isolation optional. */
- if (!kvm_iommu_ops || !kvm_iommu_ops->init)
+ int ret;
+
+ if (!kvm_iommu_ops || !kvm_iommu_ops->init ||
+ !kvm_iommu_ops->host_stage2_idmap)
+ return 0;
+
+ ret = kvm_iommu_ops->init();
+ if (ret)
+ return ret;
+
+ return kvm_iommu_snapshot_host_stage2();
+}
+
+int kvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
+ enum kvm_pgtable_prot prot)
+{
+ hyp_assert_lock_held(&host_mmu.lock);
+
+ if (!kvm_idmap_initialized)
return 0;
- return kvm_iommu_ops->init();
+ return kvm_iommu_ops->host_stage2_idmap(start, end, pkvm_to_iommu_prot(prot));
}
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 2fb20a63a417..b54cb72ed88c 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -15,6 +15,7 @@
#include <hyp/fault.h>
#include <nvhe/gfp.h>
+#include <nvhe/iommu.h>
#include <nvhe/memory.h>
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>
@@ -481,6 +482,14 @@ static int check_range_allowed_memory(u64 start, u64 end)
return 0;
}
+u64 find_mem_range_from(u64 start, bool *is_memory)
+{
+ struct kvm_mem_range r;
+
+ *is_memory = !!find_mem_range(start, &r);
+ return r.end;
+}
+
static bool range_is_memory(u64 start, u64 end)
{
struct kvm_mem_range r;
@@ -577,8 +586,34 @@ int host_stage2_idmap_locked(phys_addr_t addr, u64 size,
static void __host_update_page_state(phys_addr_t addr, u64 size, enum pkvm_page_state state)
{
+ enum pkvm_page_state old = get_host_state(hyp_phys_to_page(addr));
+ enum kvm_pgtable_prot prot = 0;
+
for_each_hyp_page(page, addr, size)
set_host_state(page, state);
+
+ /*
+ * Any transition to PKVM_NOPAGE, unmaps the page from the host
+ * Any transition to PKVM_PAGE_SHARED_BORROWED, maps the page in the host
+ * Any transition to PKVM_PAGE_SHARED_OWNED is ignored as page is already mapped.
+ * Transitions to PKVM_PAGE_OWNED from anything but PKVM_NOPAGE are ignored.
+ * Transitions to PKVM_PAGE_OWNED from PKVM_NOPAGE will map the page.
+ */
+ if ((state == PKVM_PAGE_SHARED_OWNED) ||
+ ((state == PKVM_PAGE_OWNED) && (old != PKVM_NOPAGE)))
+ return;
+
+ if ((state == PKVM_PAGE_SHARED_BORROWED) ||
+ (state == PKVM_PAGE_OWNED))
+ prot = PKVM_HOST_MEM_PROT;
+
+ /*
+ * Only update the IOMMU from here, as MMIO can't transition after
+ * de-privilege, that will need to change when device assignment
+ * is supported.
+ * And WARN on failure as we can't unroll at this point.
+ */
+ WARN_ON(kvm_iommu_host_stage2_idmap(addr, addr + size, prot));
}
#define KVM_HOST_DONATION_PTE_OWNER_MASK GENMASK(3, 1)
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v6 08/25] KVM: arm64: iommu: Shadow host stage-2 page table
2026-05-01 11:19 ` [PATCH v6 08/25] KVM: arm64: iommu: Shadow host stage-2 page table Mostafa Saleh
@ 2026-05-01 13:00 ` Jason Gunthorpe
2026-05-04 12:28 ` Mostafa Saleh
0 siblings, 1 reply; 38+ messages in thread
From: Jason Gunthorpe @ 2026-05-01 13:00 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 11:19:10AM +0000, Mostafa Saleh wrote:
> Create a page-table for the IOMMU that shadows the host CPU stage-2
> to establish DMA isolation.
Is there a reason you can't just use the CPU S2 for the iommu?
ie the CCA RMM is doing that, it is how ARM imagined this stuff would
work.
Once you start supporting DMA like this you have no choice but to keep
a fully populated at all times S2 around, why not use that for the CPU
too to avoid faults?
I guess there is a reason, but maybe explain in the commit message?
It sure would be simpler, you wouldn't have to mess with iopgtable at
all...
Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* Re: [PATCH v6 08/25] KVM: arm64: iommu: Shadow host stage-2 page table
2026-05-01 13:00 ` Jason Gunthorpe
@ 2026-05-04 12:28 ` Mostafa Saleh
0 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-04 12:28 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 10:00:06AM -0300, Jason Gunthorpe wrote:
> On Fri, May 01, 2026 at 11:19:10AM +0000, Mostafa Saleh wrote:
> > Create a page-table for the IOMMU that shadows the host CPU stage-2
> > to establish DMA isolation.
>
> Is there a reason you can't just use the CPU S2 for the iommu?
>
> ie the CCA RMM is doing that, it is how ARM imagined this stuff would
> work.
>
> Once you start supporting DMA like this you have no choice but to keep
> a fully populated at all times S2 around, why not use that for the CPU
> too to avoid faults?
>
> I guess there is a reason, but maybe explain in the commit message?
>
> It sure would be simpler, you wouldn't have to mess with iopgtable at
> all...
Sharing the page table is tricky, this is something I have been thinking
about and my plan was to work on it after this series as it has some
constraints and would require core KVM changes.
So far this is the list of requirements/changes needed share the
stage-2 page table (besides the obvious: same page table format,
granularity, endianness...)
1) HW BBM is not supported in the hypervisor page table, that’s
because it can generate TLB conflict aborts, which the hypervisor
can not handle because of the limited syndrome information.
We can rely on FEAT_BBML3 which was newly introduced to work
around that, it’s quite niche and not supported in KVM yet or
have an allow list similar to the kernel
(as in cpu_supports_bbml2_noabort()) which also limits the number
of CPUs that can run this.
2) Handling page faults, devices must be able to stall and let the
hypervisor handle the page fault (which has to proxy through the
kernel as the hypervisor doesn’t handle interrupts), this includes
also IO page faults which are hard to get right from the HW which
and may lead to system stability issues or lockups.
Alternatively, we can pin the stage-2 pages, that would require some
hypercalls, hacks to the driver/IOMMU API and possibly new semantics
in the DMA-API for IDENTITY devices as they will still need to pin
the pages as they are actually in stage-2 translation and not bypass.
3) SMMUv3 must be coherent.
4) Support BTM/DVM for TLB invalidation, otherwise some hooks are
still required (although not io-pgtable-arm)
This is not the complete list, I am sure I will run into more issues
when prototyping this.
IMO, 1, 2 are the most tricky parts. It's more work and runs on very
limited systems, However, it can be implemented as an optimization)
which is my plan.
I am not sure how CCA deals with that, I’d expect they have a lot of
constraints on CPUs/SMMUs and DMA capable devices on those systems.
Thanks,
Mostafa
>
> Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v6 09/25] KVM: arm64: iommu: Add memory pool
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (7 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 08/25] KVM: arm64: iommu: Shadow host stage-2 page table Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 10/25] KVM: arm64: iommu: Support DABT for IOMMU Mostafa Saleh
` (15 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
IOMMU drivers would require to allocate memory for the shadow page
table. Similar to the host stage-2 CPU page table, the IOMMU pool
is allocated early from the carveout and it's memory is added in
a pool which the IOMMU driver can allocate from and reclaim at
run time.
As this is too early for drivers to use init calls, set the number of
page allocated from the kernel command line "kvm-arm.hyp_iommu_pages".
Later when the driver registers, it will pass how many pages it
needs, and if it was less than what was allocated, it will fail
to register.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../admin-guide/kernel-parameters.txt | 4 +++
arch/arm64/include/asm/kvm_host.h | 3 +-
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 7 +++-
arch/arm64/kvm/hyp/nvhe/iommu/iommu.c | 21 +++++++++++-
arch/arm64/kvm/hyp/nvhe/setup.c | 12 ++++++-
arch/arm64/kvm/iommu.c | 33 ++++++++++++++++++-
arch/arm64/kvm/pkvm.c | 1 +
7 files changed, 76 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cf3807641d89..5e49946ff7ed 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3283,6 +3283,10 @@ Kernel parameters
trap: set WFI instruction trap
notrap: clear WFI instruction trap
+ kvm-arm.hyp_iommu_pages=
+ [KVM, ARM, EARLY]
+ Number of pages allocated for the IOMMU pool from the
+ KVM carveout when running in protected mode.
kvm_cma_resv_ratio=n [PPC,EARLY]
Reserves given percentage from system memory area for
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 52898d2a3ec6..17f4cce86ec3 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1735,7 +1735,8 @@ long kvm_get_cap_for_kvm_ioctl(unsigned int ioctl, long *ext);
#ifndef __KVM_NVHE_HYPERVISOR__
struct kvm_iommu_ops;
-int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops);
+int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops, unsigned int pool_pages);
+unsigned int kvm_iommu_pages(void);
#endif
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index 6277d845cdcf..eba94b4f6050 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -10,8 +10,13 @@ struct kvm_iommu_ops {
int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot);
};
-int kvm_iommu_init(void);
+int kvm_iommu_init(void *pool_base, unsigned int nr_pages);
int kvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
enum kvm_pgtable_prot prot);
+
+/* Returns zeroed memory. */
+void *kvm_iommu_donate_pages(u8 order);
+void kvm_iommu_reclaim_pages(void *ptr);
+
#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
index 1db52bd87c38..53cb5e4b0aac 100644
--- a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
+++ b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
@@ -15,6 +15,7 @@ struct kvm_iommu_ops *kvm_iommu_ops;
/* Protected by host_mmu.lock */
static bool kvm_idmap_initialized;
+static struct hyp_pool iommu_pages_pool;
static inline int pkvm_to_iommu_prot(enum kvm_pgtable_prot prot)
{
@@ -95,7 +96,7 @@ static int kvm_iommu_snapshot_host_stage2(void)
return ret;
}
-int kvm_iommu_init(void)
+int kvm_iommu_init(void *pool_base, unsigned int nr_pages)
{
int ret;
@@ -103,6 +104,14 @@ int kvm_iommu_init(void)
!kvm_iommu_ops->host_stage2_idmap)
return 0;
+ if (!nr_pages)
+ return -ENOMEM;
+
+ ret = hyp_pool_init(&iommu_pages_pool, hyp_virt_to_pfn(pool_base),
+ nr_pages, 0);
+ if (ret)
+ return ret;
+
ret = kvm_iommu_ops->init();
if (ret)
return ret;
@@ -120,3 +129,13 @@ int kvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
return kvm_iommu_ops->host_stage2_idmap(start, end, pkvm_to_iommu_prot(prot));
}
+
+void *kvm_iommu_donate_pages(u8 order)
+{
+ return hyp_alloc_pages(&iommu_pages_pool, order);
+}
+
+void kvm_iommu_reclaim_pages(void *ptr)
+{
+ hyp_put_page(&iommu_pages_pool, ptr);
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 1f6b221db9a0..215014e42c27 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -23,6 +23,9 @@
unsigned long hyp_nr_cpus;
+/* See kvm_iommu_pages() */
+unsigned int hyp_kvm_iommu_pages;
+
#define hyp_percpu_size ((unsigned long)__per_cpu_end - \
(unsigned long)__per_cpu_start)
@@ -34,6 +37,7 @@ static void *selftest_base;
static void *ffa_proxy_pages;
static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
static struct hyp_pool hpool;
+static void *iommu_base;
static int divide_memory_pool(void *virt, unsigned long size)
{
@@ -71,6 +75,12 @@ static int divide_memory_pool(void *virt, unsigned long size)
if (!ffa_proxy_pages)
return -ENOMEM;
+ if (hyp_kvm_iommu_pages) {
+ iommu_base = hyp_early_alloc_contig(hyp_kvm_iommu_pages);
+ if (!iommu_base)
+ return -ENOMEM;
+ }
+
return 0;
}
@@ -330,7 +340,7 @@ void __noreturn __pkvm_init_finalise(void)
if (ret)
goto out;
- ret = kvm_iommu_init();
+ ret = kvm_iommu_init(iommu_base, hyp_kvm_iommu_pages);
if (ret)
goto out;
diff --git a/arch/arm64/kvm/iommu.c b/arch/arm64/kvm/iommu.c
index f247384fa193..213429ceb549 100644
--- a/arch/arm64/kvm/iommu.c
+++ b/arch/arm64/kvm/iommu.c
@@ -7,10 +7,11 @@
#include <linux/kvm_host.h>
extern struct kvm_iommu_ops *kvm_nvhe_sym(kvm_iommu_ops);
+extern unsigned int kvm_nvhe_sym(hyp_kvm_iommu_pages);
static DEFINE_MUTEX(kvm_iommu_reg_lock);
-int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops)
+int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops, unsigned int pool_pages)
{
guard(mutex)(&kvm_iommu_reg_lock);
@@ -21,6 +22,36 @@ int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops)
if (kvm_nvhe_sym(kvm_iommu_ops))
return -EBUSY;
+ /* See kvm_iommu_pages() */
+ if (pool_pages > kvm_nvhe_sym(hyp_kvm_iommu_pages)) {
+ kvm_err("Not enough memory for the IOMMU pool, need 0x%x pages, check kvm-arm.hyp_iommu_pages",
+ pool_pages);
+ return -ENOMEM;
+ }
+
kvm_nvhe_sym(kvm_iommu_ops) = hyp_ops;
return 0;
}
+
+unsigned int kvm_iommu_pages(void)
+{
+ /*
+ * This is used very early during setup_arch() before any initcalls
+ * or any drivers are registered.
+ * This value is set by a command line option.
+ * Later, when the driver is registered, it will pass the number
+ * pages needed for it's page tables, if it was less that what
+ * the system has already allocated, the registration will fail.
+ */
+ return kvm_nvhe_sym(hyp_kvm_iommu_pages);
+}
+
+/* Number of pages to reserve for iommu pool*/
+static int __init early_hyp_iommu_pages(char *arg)
+{
+ if (!arg)
+ return -EINVAL;
+
+ return kstrtouint(arg, 0, &kvm_nvhe_sym(hyp_kvm_iommu_pages));
+}
+early_param("kvm-arm.hyp_iommu_pages", early_hyp_iommu_pages);
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 053e4f733e4b..79dd14db4919 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -63,6 +63,7 @@ void __init kvm_hyp_reserve(void)
hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
hyp_mem_pages += pkvm_selftest_pages();
hyp_mem_pages += hyp_ffa_proxy_pages();
+ hyp_mem_pages += kvm_iommu_pages();
/*
* Try to allocate a PMD-aligned region to reduce TLB pressure once
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 10/25] KVM: arm64: iommu: Support DABT for IOMMU
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (8 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 09/25] KVM: arm64: iommu: Add memory pool Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 11/25] iommu/arm-smmu-v3-kvm: Add SMMUv3 driver Mostafa Saleh
` (14 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The pKVM SMMUv3 driver needs to trap and emulate access to the MMIO
space of the SMMUv3 to provide emulation for the kernel driver.
Add a handler for DABTs for IOMMU drivers to be able to do so.
In case the host causes a data abort, check if it's part of IOMMU
emulation first.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 3 ++-
arch/arm64/kvm/hyp/nvhe/iommu/iommu.c | 15 +++++++++++++++
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 15 +++++++++++++++
3 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index eba94b4f6050..e1b6f16391cc 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -8,6 +8,7 @@
struct kvm_iommu_ops {
int (*init)(void);
int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot);
+ bool (*dabt_handler)(struct user_pt_regs *regs, u64 esr, u64 addr);
};
int kvm_iommu_init(void *pool_base, unsigned int nr_pages);
@@ -18,5 +19,5 @@ int kvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
/* Returns zeroed memory. */
void *kvm_iommu_donate_pages(u8 order);
void kvm_iommu_reclaim_pages(void *ptr);
-
+bool kvm_iommu_host_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr);
#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
index 53cb5e4b0aac..b1474db016e5 100644
--- a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
+++ b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c
@@ -4,6 +4,10 @@
*
* Copyright (C) 2022 Linaro Ltd.
*/
+#include <asm/kvm_hyp.h>
+
+#include <hyp/adjust_pc.h>
+
#include <linux/iommu.h>
#include <nvhe/iommu.h>
@@ -139,3 +143,14 @@ void kvm_iommu_reclaim_pages(void *ptr)
{
hyp_put_page(&iommu_pages_pool, ptr);
}
+
+bool kvm_iommu_host_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr)
+{
+ if (kvm_iommu_ops && kvm_iommu_ops->dabt_handler &&
+ kvm_iommu_ops->dabt_handler(regs, esr, addr)) {
+ /* DABT handled by the driver, skip to next instruction. */
+ kvm_skip_host_instr();
+ return true;
+ }
+ return false;
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index b54cb72ed88c..5c64007dba4d 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -788,6 +788,12 @@ static void host_inject_mem_abort(struct kvm_cpu_context *host_ctxt)
inject_host_exception(esr);
}
+static bool is_mmio_dabt(u64 esr)
+{
+ return (ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_LOW) &&
+ (esr & ESR_ELx_ISV);
+}
+
void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
{
struct kvm_vcpu_fault_info fault;
@@ -810,6 +816,15 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
BUG_ON(!(fault.hpfar_el2 & HPFAR_EL2_NS));
addr = FIELD_GET(HPFAR_EL2_FIPA, fault.hpfar_el2) << 12;
+ /*
+ * Emulate data aborts for IOMMU drivers, other access will be denied
+ * by host_stage2_adjust_range()
+ */
+ if (is_mmio_dabt(esr) && !addr_is_memory(addr) &&
+ kvm_iommu_host_dabt_handler(&host_ctxt->regs,
+ esr, addr | FAR_TO_FIPA_OFFSET(fault.far_el2)))
+ return;
+
switch (host_stage2_idmap(addr)) {
case -EPERM:
host_inject_mem_abort(host_ctxt);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 11/25] iommu/arm-smmu-v3-kvm: Add SMMUv3 driver
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (9 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 10/25] KVM: arm64: iommu: Support DABT for IOMMU Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 12/25] iommu/arm-smmu-v3-kvm: Add the kernel driver Mostafa Saleh
` (13 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
From: Jean-Philippe Brucker <jean-philippe@linaro.org>
Add the skeleton for an Arm SMMUv3 driver at EL2.
The driver rely on an array of SMMUv3s on the system, where at
init it will donate the array and the resources of the SMMUv3s
so they can't be changed by the host after de-privilege.
This array will be populated in the next patch.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 5 ++
drivers/iommu/arm/Kconfig | 9 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 87 +++++++++++++++++++
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 27 ++++++
4 files changed, 128 insertions(+)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 606c0e1b7bd0..8a75739db947 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -33,6 +33,11 @@ hyp-obj-$(CONFIG_LIST_HARDENED) += list_debug.o
hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += trace.o events.o
hyp-obj-y += $(lib-objs)
+HYP_SMMU_V3_DRV_PATH = ../../../../../drivers/iommu/arm/arm-smmu-v3
+
+hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += $(HYP_SMMU_V3_DRV_PATH)/pkvm/arm-smmu-v3.o \
+ $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o
+
# Path to simple_ring_buffer.c
CFLAGS_trace.nvhe.o += -I$(srctree)/kernel/trace/
diff --git a/drivers/iommu/arm/Kconfig b/drivers/iommu/arm/Kconfig
index 5fac08b89dee..916f4723238d 100644
--- a/drivers/iommu/arm/Kconfig
+++ b/drivers/iommu/arm/Kconfig
@@ -141,3 +141,12 @@ config QCOM_IOMMU
select ARM_DMA_USE_IOMMU
help
Support for IOMMU on certain Qualcomm SoCs.
+
+config ARM_SMMU_V3_PKVM
+ bool "ARM SMMUv3 support for protected Virtual Machines"
+ depends on KVM && ARM64 && ARM_SMMU_V3=y
+ help
+ Enable a SMMUv3 driver in the KVM hypervisor, to protect VMs against
+ memory accesses from devices owned by the host.
+
+ Say Y here if you intend to enable KVM in protected mode.
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
new file mode 100644
index 000000000000..9afc314d0acc
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pKVM hyp driver for the Arm SMMUv3
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <asm/kvm_hyp.h>
+
+#include <nvhe/iommu.h>
+#include <nvhe/mem_protect.h>
+
+#include "arm_smmu_v3.h"
+
+size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
+struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
+
+#define for_each_smmu(smmu) \
+ for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
+ (smmu) != &kvm_hyp_arm_smmu_v3_smmus[kvm_hyp_arm_smmu_v3_count]; \
+ (smmu)++)
+
+/* Put the device in a state that can be probed by the host driver. */
+static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
+{
+ WARN_ON(__pkvm_hyp_donate_host_mmio(smmu->mmio_addr, smmu->mmio_size));
+ smmu->base = NULL;
+}
+
+static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
+{
+ unsigned long haddr;
+ int ret;
+
+ if (!PAGE_ALIGNED(smmu->mmio_addr | smmu->mmio_size))
+ return -EINVAL;
+
+ ret = __pkvm_host_donate_hyp_mmio(smmu->mmio_addr, smmu->mmio_size, &haddr);
+ if (ret)
+ return ret;
+
+ smmu->base = (void __iomem *)haddr;
+
+ return 0;
+}
+
+/* Called while is the host is still trusted. */
+static int smmu_init(void)
+{
+ size_t smmu_arr_size = PAGE_ALIGN(sizeof(*kvm_hyp_arm_smmu_v3_smmus) *
+ kvm_hyp_arm_smmu_v3_count);
+ struct hyp_arm_smmu_v3_device *smmu;
+ u64 pfn, nr_pages;
+ int ret;
+
+ kvm_hyp_arm_smmu_v3_smmus = kern_hyp_va(kvm_hyp_arm_smmu_v3_smmus);
+ pfn = hyp_virt_to_pfn(kvm_hyp_arm_smmu_v3_smmus);
+ nr_pages = smmu_arr_size >> PAGE_SHIFT;
+
+ ret = __pkvm_host_donate_hyp(pfn, nr_pages);
+ if (ret)
+ return ret;
+
+ for_each_smmu(smmu) {
+ ret = smmu_init_device(smmu);
+ if (ret)
+ goto out_reclaim_smmu;
+ }
+
+ return 0;
+
+out_reclaim_smmu:
+ while (smmu != kvm_hyp_arm_smmu_v3_smmus)
+ smmu_deinit_device(--smmu);
+ WARN_ON(__pkvm_hyp_donate_host(pfn, nr_pages));
+ return ret;
+}
+
+static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
+{
+ return 0;
+}
+
+/* Shared with the kernel driver in EL1 */
+struct kvm_iommu_ops smmu_ops = {
+ .init = smmu_init,
+ .host_stage2_idmap = smmu_host_stage2_idmap,
+};
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
new file mode 100644
index 000000000000..0d9e48b201f5
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_ARM_SMMU_V3_H
+#define __KVM_ARM_SMMU_V3_H
+
+#include <asm/kvm_asm.h>
+
+/*
+ * Parameters from the trusted host:
+ * @mmio_addr base address of the SMMU registers
+ * @mmio_size size of the registers resource
+ *
+ * Other members are filled and used at runtime by the SMMU driver.
+ * @base Virtual address of SMMU registers
+ */
+struct hyp_arm_smmu_v3_device {
+ phys_addr_t mmio_addr;
+ size_t mmio_size;
+ void __iomem *base;
+};
+
+extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
+#define kvm_hyp_arm_smmu_v3_count kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count)
+
+extern struct hyp_arm_smmu_v3_device *kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_smmus);
+#define kvm_hyp_arm_smmu_v3_smmus kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_smmus)
+
+#endif /* __KVM_ARM_SMMU_V3_H */
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 12/25] iommu/arm-smmu-v3-kvm: Add the kernel driver
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (10 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 11/25] iommu/arm-smmu-v3-kvm: Add SMMUv3 driver Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 13/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW Mostafa Saleh
` (12 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
When KVM runs in protected mode, and CONFIG_ARM_SMMU_V3_PKVM
is enabled, it will manage the SMMUv3 HW using trap and emulate
and present emulated SMMUs to the host kernel.
In that case, those SMMUs will be on the aux bus, so make it
possible to the driver to probe those devices.
Otherwise, everything else is the same as the KVM emulation
complies with the architecture,so the driver doesn't need
to be modified.
Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/Makefile | 1 +
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c | 188 ++++++++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 43 ++++
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 2 +
4 files changed, 234 insertions(+)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
diff --git a/drivers/iommu/arm/arm-smmu-v3/Makefile b/drivers/iommu/arm/arm-smmu-v3/Makefile
index c9ce392e6d31..c3fc5c4a4a1e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/Makefile
+++ b/drivers/iommu/arm/arm-smmu-v3/Makefile
@@ -4,5 +4,6 @@ arm_smmu_v3-y := arm-smmu-v3.o arm-smmu-v3-common-lib.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_IOMMUFD) += arm-smmu-v3-iommufd.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_SVA) += arm-smmu-v3-sva.o
arm_smmu_v3-$(CONFIG_TEGRA241_CMDQV) += tegra241-cmdqv.o
+arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_PKVM) += arm-smmu-v3-kvm.o
obj-$(CONFIG_ARM_SMMU_V3_KUNIT_TEST) += arm-smmu-v3-test.o
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
new file mode 100644
index 000000000000..9765d3d636d7
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pKVM host driver for the Arm SMMUv3
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_pkvm.h>
+
+#include <linux/auxiliary_bus.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include "arm-smmu-v3.h"
+#include "pkvm/arm_smmu_v3.h"
+
+extern struct kvm_iommu_ops kvm_nvhe_sym(smmu_ops);
+
+static size_t kvm_arm_smmu_count;
+static struct hyp_arm_smmu_v3_device *kvm_arm_smmu_array;
+static size_t kvm_arm_smmu_cur;
+
+static void kvm_arm_smmu_array_free(void)
+{
+ int order;
+
+ order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
+ free_pages((unsigned long)kvm_arm_smmu_array, order);
+}
+
+static int kvm_arm_smmu_array_alloc(void)
+{
+ int smmu_order;
+ struct device_node *np;
+
+ for_each_compatible_node(np, NULL, "arm,smmu-v3")
+ kvm_arm_smmu_count++;
+
+ if (!kvm_arm_smmu_count)
+ return -ENODEV;
+ smmu_order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
+ kvm_arm_smmu_array = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, smmu_order);
+ if (!kvm_arm_smmu_array)
+ return -ENOMEM;
+ return 0;
+}
+
+static unsigned int smmu_hyp_pgt_pages(void)
+{
+ struct device_node *np = of_find_compatible_node(NULL, NULL, "arm,smmu-v3");
+
+ /*
+ * SMMUv3 uses the same format as the CPU stage-2 and hence have the same memory
+ * requirements, we add extra 500 pages for L2 STEs.
+ * Only one set of memory is allocated as the page table is shared between all
+ * the SMMUs.
+ */
+ if (np) {
+ of_node_put(np);
+ return host_s2_pgtable_pages() + 500;
+ }
+
+ return 0;
+}
+
+static struct platform_driver smmuv3_nesting_driver;
+static int smmuv3_nesting_probe(struct platform_device *pdev)
+{
+ struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+
+ /* Only device tree, ACPI not supported. */
+ if (!dev->of_node)
+ return -EINVAL;
+
+ if (kvm_arm_smmu_cur >= kvm_arm_smmu_count)
+ return -ENOSPC;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ if (of_property_read_bool(dev->of_node, "cavium,cn9900-broken-page1-regspace"))
+ return -EINVAL;
+
+ smmu->mmio_addr = res->start;
+ smmu->mmio_size = resource_size(res);
+ if (smmu->mmio_size < SZ_128K) {
+ dev_err(dev, "MMIO region too small(%pr)\n", res);
+ return -EINVAL;
+ }
+
+ if (of_dma_is_coherent(dev->of_node))
+ smmu->features |= ARM_SMMU_FEAT_COHERENCY;
+
+ kvm_arm_smmu_cur++;
+ return 0;
+}
+
+static int kvm_arm_smmu_v3_register(void)
+{
+ size_t nr_pages = smmu_hyp_pgt_pages();
+ int ret;
+
+ if (!is_protected_kvm_enabled() || !nr_pages)
+ return 0;
+
+ ret = kvm_arm_smmu_array_alloc();
+ if (ret)
+ goto out_err;
+
+ ret = platform_driver_probe(&smmuv3_nesting_driver, smmuv3_nesting_probe);
+ if (ret)
+ goto out_free;
+
+ ret = kvm_iommu_register_driver(kern_hyp_va(lm_alias(&kvm_nvhe_sym(smmu_ops))),
+ nr_pages);
+ if (ret)
+ goto out_unregister;
+
+ /*
+ * These variables are stored in the nVHE image, and won't be accessible
+ * after KVM initialization. Ownership of kvm_arm_smmu_array will be
+ * transferred to the hypervisor as well.
+ */
+ kvm_hyp_arm_smmu_v3_smmus = kvm_arm_smmu_array;
+ kvm_hyp_arm_smmu_v3_count = kvm_arm_smmu_cur;
+ return ret;
+
+out_unregister:
+ platform_driver_unregister(&smmuv3_nesting_driver);
+out_free:
+ kvm_arm_smmu_array_free();
+out_err:
+ kvm_arm_smmu_count = 0;
+ kvm_arm_smmu_array = NULL;
+ return ret;
+};
+
+static int smmu_create_aux_device(struct device *dev, void *data)
+{
+ static int dev_id;
+ struct auxiliary_device *auxdev;
+
+ auxdev = __devm_auxiliary_device_create(dev, "protected_kvm",
+ "smmu_v3_emu", NULL, dev_id++);
+ if (!auxdev)
+ return -ENODEV;
+
+ auxdev->dev.parent = dev;
+ return 0;
+}
+
+static int kvm_arm_smmu_v3_post_init(void)
+{
+ if (!kvm_arm_smmu_count)
+ return 0;
+
+ /*
+ * If the hypervisor part of the driver fails, KVM will not initialise.
+ */
+ if (!is_kvm_arm_initialised()) {
+ kvm_arm_smmu_array_free();
+ return 0;
+ }
+
+ WARN_ON(driver_for_each_device(&smmuv3_nesting_driver.driver, NULL,
+ NULL, smmu_create_aux_device));
+
+ return 0;
+}
+
+static const struct of_device_id smmuv3_nested_of_match[] = {
+ { .compatible = "arm,smmu-v3", },
+ { },
+};
+
+static struct platform_driver smmuv3_nesting_driver = {
+ .driver = {
+ .name = "smmuv3-nesting",
+ .of_match_table = smmuv3_nested_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+late_initcall(kvm_arm_smmu_v3_post_init);
+subsys_initcall(kvm_arm_smmu_v3_register);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 96d5e7f80ce7..61e6ab364086 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -11,6 +11,7 @@
#include <linux/acpi.h>
#include <linux/acpi_iort.h>
+#include <linux/auxiliary_bus.h>
#include <linux/bitops.h>
#include <linux/crash_dump.h>
#include <linux/delay.h>
@@ -5335,6 +5336,48 @@ static struct platform_driver arm_smmu_driver = {
module_driver(arm_smmu_driver, platform_driver_register,
arm_smmu_driver_unregister);
+#ifdef CONFIG_ARM_SMMU_V3_PKVM
+/*
+ * Now we have 2 devices, the aux device bound to this driver, and pdev
+ * which is the physical platform device bound to the KVM driver but not used.
+ * However, this driver keeps using the platform device for 2 reasons:
+ * 1) Simplicity: Avoiding changing big parts of the code assuming
+ * the underlying device is a platform device.
+ * 2) Dealing with DMA-API, irqs(MSIs), RPM... requires the physical device.
+ */
+
+static int arm_smmu_device_probe_emu(struct auxiliary_device *auxdev,
+ const struct auxiliary_device_id *id)
+{
+ struct device *parent = auxdev->dev.parent;
+
+ dev_info(&auxdev->dev, "Probing from %s\n", dev_name(parent));
+ return arm_smmu_device_probe(to_platform_device(parent));
+}
+
+static void arm_smmu_device_remove_emu(struct auxiliary_device *auxdev)
+{
+ arm_smmu_device_remove(to_platform_device(auxdev->dev.parent));
+}
+
+const struct auxiliary_device_id arm_smmu_aux_table[] = {
+ { .name = "protected_kvm.smmu_v3_emu" },
+ { },
+};
+
+struct auxiliary_driver arm_smmu_driver_emu = {
+ .driver = {
+ .suppress_bind_attrs = true,
+ },
+ .name = "arm-smmu-v3-emu",
+ .id_table = arm_smmu_aux_table,
+ .probe = arm_smmu_device_probe_emu,
+ .remove = arm_smmu_device_remove_emu,
+};
+
+module_auxiliary_driver(arm_smmu_driver_emu);
+#endif
+
MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
MODULE_AUTHOR("Will Deacon <will@kernel.org>");
MODULE_ALIAS("platform:arm-smmu-v3");
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
index 0d9e48b201f5..744ee2b7f0b4 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -8,6 +8,7 @@
* Parameters from the trusted host:
* @mmio_addr base address of the SMMU registers
* @mmio_size size of the registers resource
+ * @features Features of SMMUv3, subset of the main driver
*
* Other members are filled and used at runtime by the SMMU driver.
* @base Virtual address of SMMU registers
@@ -16,6 +17,7 @@ struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
size_t mmio_size;
void __iomem *base;
+ u32 features;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 13/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (11 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 12/25] iommu/arm-smmu-v3-kvm: Add the kernel driver Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 12:51 ` Jason Gunthorpe
2026-05-01 11:19 ` [PATCH v6 14/25] iommu/arm-smmu-v3-kvm: Add MMIO emulation Mostafa Saleh
` (11 subsequent siblings)
24 siblings, 1 reply; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Probe SMMU features from the IDR register space, most of
the logic is common with the kernel.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 6 --
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 6 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 78 +++++++++++++++++++
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 6 ++
4 files changed, 90 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 61e6ab364086..157acde0436d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -4738,12 +4738,6 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
return 0;
}
-#define IIDR_IMPLEMENTER_ARM 0x43b
-#define IIDR_PRODUCTID_ARM_MMU_600 0x483
-#define IIDR_PRODUCTID_ARM_MMU_700 0x487
-#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
-#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
-
static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
{
u32 reg;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 64618299d03a..f904f4d19609 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -84,6 +84,12 @@ struct arm_vsmmu;
#define IIDR_REVISION GENMASK(15, 12)
#define IIDR_IMPLEMENTER GENMASK(11, 0)
+#define IIDR_IMPLEMENTER_ARM 0x43b
+#define IIDR_PRODUCTID_ARM_MMU_600 0x483
+#define IIDR_PRODUCTID_ARM_MMU_700 0x487
+#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
+#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
+
#define ARM_SMMU_AIDR 0x1C
#define ARM_SMMU_CR0 0x20
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 9afc314d0acc..d9945db9e102 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -10,6 +10,7 @@
#include <nvhe/mem_protect.h>
#include "arm_smmu_v3.h"
+#include "../arm-smmu-v3.h"
size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
@@ -26,6 +27,77 @@ static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
smmu->base = NULL;
}
+static bool smmu_nesting_supported(struct hyp_arm_smmu_v3_device *smmu)
+{
+ unsigned int implementer, productid, variant, revision;
+ u32 reg;
+
+ if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1) ||
+ !(smmu->features & ARM_SMMU_FEAT_TRANS_S2))
+ return false;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
+ implementer = FIELD_GET(IIDR_IMPLEMENTER, reg);
+ productid = FIELD_GET(IIDR_PRODUCTID, reg);
+ variant = FIELD_GET(IIDR_VARIANT, reg);
+ revision = FIELD_GET(IIDR_REVISION, reg);
+
+ if (implementer != IIDR_IMPLEMENTER_ARM)
+ return true;
+
+ if (productid == IIDR_PRODUCTID_ARM_MMU_600)
+ return variant >= 2;
+ else if (productid == IIDR_PRODUCTID_ARM_MMU_700)
+ return !(variant < 1 || revision < 1);
+
+ return true;
+}
+
+/*
+ * Mini-probe and validation for the hypervisor.
+ */
+static int smmu_probe(struct hyp_arm_smmu_v3_device *smmu)
+{
+ u32 reg;
+
+ /* Similar to the kernel, rely on firmware override. */
+ if (!(smmu->features & ARM_SMMU_FEAT_COHERENCY))
+ return -EINVAL;
+
+ /* IDR0 */
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
+
+ smmu->features |= smmu_idr0_features(reg);
+ if (!smmu_nesting_supported(smmu))
+ return -ENXIO;
+
+ if (!(smmu->features & (ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE)))
+ return -ENXIO;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
+ if (reg & (IDR1_TABLES_PRESET | IDR1_QUEUES_PRESET | IDR1_REL))
+ return -EINVAL;
+
+ smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, reg);
+ /* Follows the kernel logic */
+ if (smmu->sid_bits <= STRTAB_SPLIT)
+ smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
+ smmu->features |= smmu_idr3_features(reg);
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);
+ smmu->pgsize_bitmap = smmu_idr5_to_pgsize(reg);
+
+ smmu->oas = smmu_idr5_to_oas(reg);
+ if (smmu->oas == 52)
+ smmu->pgsize_bitmap |= 1ULL << 42;
+ else if (!smmu->oas)
+ smmu->oas = 48;
+
+ return 0;
+}
+
static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
{
unsigned long haddr;
@@ -39,8 +111,14 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
return ret;
smmu->base = (void __iomem *)haddr;
+ ret = smmu_probe(smmu);
+ if (ret)
+ goto out_ret;
return 0;
+out_ret:
+ smmu_deinit_device(smmu);
+ return ret;
}
/* Called while is the host is still trusted. */
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
index 744ee2b7f0b4..82b84673e85b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -12,12 +12,18 @@
*
* Other members are filled and used at runtime by the SMMU driver.
* @base Virtual address of SMMU registers
+ * @oas PA size
+ * @pgsize_bitmap Supported page sizes
+ * @sid_bits Max number of SID bits supported
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
size_t mmio_size;
void __iomem *base;
u32 features;
+ unsigned long oas;
+ unsigned long pgsize_bitmap;
+ unsigned int sid_bits;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* Re: [PATCH v6 13/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW
2026-05-01 11:19 ` [PATCH v6 13/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW Mostafa Saleh
@ 2026-05-01 12:51 ` Jason Gunthorpe
2026-05-04 12:30 ` Mostafa Saleh
0 siblings, 1 reply; 38+ messages in thread
From: Jason Gunthorpe @ 2026-05-01 12:51 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 11:19:15AM +0000, Mostafa Saleh wrote:
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 61e6ab364086..157acde0436d 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -4738,12 +4738,6 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
> return 0;
> }
>
> -#define IIDR_IMPLEMENTER_ARM 0x43b
> -#define IIDR_PRODUCTID_ARM_MMU_600 0x483
> -#define IIDR_PRODUCTID_ARM_MMU_700 0x487
> -#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
> -#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
> -
> static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
> {
> u32 reg;
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index 64618299d03a..f904f4d19609 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -84,6 +84,12 @@ struct arm_vsmmu;
> #define IIDR_REVISION GENMASK(15, 12)
> #define IIDR_IMPLEMENTER GENMASK(11, 0)
>
> +#define IIDR_IMPLEMENTER_ARM 0x43b
> +#define IIDR_PRODUCTID_ARM_MMU_600 0x483
> +#define IIDR_PRODUCTID_ARM_MMU_700 0x487
> +#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
> +#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
> +
> #define ARM_SMMU_AIDR 0x1C
Lets put these hunks in some earlier patch to migrate out the
functions/etc
I think all these pkvm/arm-smmu-v3.c should just be building up the
driver.
> +static bool smmu_nesting_supported(struct hyp_arm_smmu_v3_device *smmu)
> +{
> + unsigned int implementer, productid, variant, revision;
> + u32 reg;
> +
> + if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1) ||
> + !(smmu->features & ARM_SMMU_FEAT_TRANS_S2))
> + return false;
> +
> + reg = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
> + implementer = FIELD_GET(IIDR_IMPLEMENTER, reg);
> + productid = FIELD_GET(IIDR_PRODUCTID, reg);
> + variant = FIELD_GET(IIDR_VARIANT, reg);
> + revision = FIELD_GET(IIDR_REVISION, reg);
> +
> + if (implementer != IIDR_IMPLEMENTER_ARM)
> + return true;
> +
> + if (productid == IIDR_PRODUCTID_ARM_MMU_600)
> + return variant >= 2;
> + else if (productid == IIDR_PRODUCTID_ARM_MMU_700)
> + return !(variant < 1 || revision < 1);
> +
> + return true;
> +}
Why not share all this errata stuff with the idr parsing code too?
We already have ARM_SMMU_FEAT_NESTING that has the above calculation.
The two drivers use the same ARM_SMMU_FEAT system, I would expect one
chunk of shared code to compute the FEATs, who cares if pkvm doesn't
use all of them?
Use the same errata logic and so on to get to the feat bitmap.
Jason
^ permalink raw reply [flat|nested] 38+ messages in thread* Re: [PATCH v6 13/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW
2026-05-01 12:51 ` Jason Gunthorpe
@ 2026-05-04 12:30 ` Mostafa Saleh
0 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-04 12:30 UTC (permalink / raw)
To: Jason Gunthorpe
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jean-philippe, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Fri, May 01, 2026 at 09:51:48AM -0300, Jason Gunthorpe wrote:
> On Fri, May 01, 2026 at 11:19:15AM +0000, Mostafa Saleh wrote:
> > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > index 61e6ab364086..157acde0436d 100644
> > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > @@ -4738,12 +4738,6 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
> > return 0;
> > }
> >
> > -#define IIDR_IMPLEMENTER_ARM 0x43b
> > -#define IIDR_PRODUCTID_ARM_MMU_600 0x483
> > -#define IIDR_PRODUCTID_ARM_MMU_700 0x487
> > -#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
> > -#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
> > -
> > static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
> > {
> > u32 reg;
> > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> > index 64618299d03a..f904f4d19609 100644
> > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> > @@ -84,6 +84,12 @@ struct arm_vsmmu;
> > #define IIDR_REVISION GENMASK(15, 12)
> > #define IIDR_IMPLEMENTER GENMASK(11, 0)
> >
> > +#define IIDR_IMPLEMENTER_ARM 0x43b
> > +#define IIDR_PRODUCTID_ARM_MMU_600 0x483
> > +#define IIDR_PRODUCTID_ARM_MMU_700 0x487
> > +#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
> > +#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
> > +
> > #define ARM_SMMU_AIDR 0x1C
>
> Lets put these hunks in some earlier patch to migrate out the
> functions/etc
>
> I think all these pkvm/arm-smmu-v3.c should just be building up the
> driver.
Will do.
>
> > +static bool smmu_nesting_supported(struct hyp_arm_smmu_v3_device *smmu)
> > +{
> > + unsigned int implementer, productid, variant, revision;
> > + u32 reg;
> > +
> > + if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1) ||
> > + !(smmu->features & ARM_SMMU_FEAT_TRANS_S2))
> > + return false;
> > +
> > + reg = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
> > + implementer = FIELD_GET(IIDR_IMPLEMENTER, reg);
> > + productid = FIELD_GET(IIDR_PRODUCTID, reg);
> > + variant = FIELD_GET(IIDR_VARIANT, reg);
> > + revision = FIELD_GET(IIDR_REVISION, reg);
> > +
> > + if (implementer != IIDR_IMPLEMENTER_ARM)
> > + return true;
> > +
> > + if (productid == IIDR_PRODUCTID_ARM_MMU_600)
> > + return variant >= 2;
> > + else if (productid == IIDR_PRODUCTID_ARM_MMU_700)
> > + return !(variant < 1 || revision < 1);
> > +
> > + return true;
> > +}
>
> Why not share all this errata stuff with the idr parsing code too?
>
> We already have ARM_SMMU_FEAT_NESTING that has the above calculation.
>
> The two drivers use the same ARM_SMMU_FEAT system, I would expect one
> chunk of shared code to compute the FEATs, who cares if pkvm doesn't
> use all of them?
>
> Use the same errata logic and so on to get to the feat bitmap.
Makes sense.
Thanks,
Mostafa
>
> Jason
^ permalink raw reply [flat|nested] 38+ messages in thread
* [PATCH v6 14/25] iommu/arm-smmu-v3-kvm: Add MMIO emulation
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (12 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 13/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 15/25] iommu/arm-smmu-v3-kvm: Shadow the command queue Mostafa Saleh
` (10 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add data abort handler for the SMMUs, at the moment most registers
are just passthrough.
In the next patches CMDQ/STE emulation will be added which inserts
logic to some register access.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 143 ++++++++++++++++++
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 10 ++
2 files changed, 153 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index d9945db9e102..cce5a51b4656 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -8,6 +8,7 @@
#include <nvhe/iommu.h>
#include <nvhe/mem_protect.h>
+#include <nvhe/trap_handler.h>
#include "arm_smmu_v3.h"
#include "../arm-smmu-v3.h"
@@ -106,6 +107,7 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (!PAGE_ALIGNED(smmu->mmio_addr | smmu->mmio_size))
return -EINVAL;
+ hyp_spin_lock_init(&smmu->lock);
ret = __pkvm_host_donate_hyp_mmio(smmu->mmio_addr, smmu->mmio_size, &haddr);
if (ret)
return ret;
@@ -144,6 +146,8 @@ static int smmu_init(void)
goto out_reclaim_smmu;
}
+ BUILD_BUG_ON(sizeof(hyp_spinlock_t) != sizeof(u32));
+
return 0;
out_reclaim_smmu:
@@ -153,6 +157,144 @@ static int smmu_init(void)
return ret;
}
+static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
+ struct user_pt_regs *regs,
+ u64 esr, u32 off)
+{
+ bool is_write = esr & ESR_ELx_WNR;
+ unsigned int len = BIT((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT);
+ int rd = (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT;
+ const u64 read_write = -1ULL;
+ const u64 no_access = 0;
+ u64 mask = no_access;
+ const u64 read_only = is_write ? no_access : read_write;
+ bool is_xzr = (rd == 31);
+ u64 val = is_xzr ? 0 : regs->regs[rd];
+
+ switch (off) {
+ case ARM_SMMU_IDR0:
+ if (len != sizeof(u32))
+ break;
+ /* Clear stage-2 support, hide MSI to avoid write back to cmdq */
+ mask = read_only & ~(IDR0_S2P | IDR0_VMID16 | IDR0_MSI | IDR0_HYP);
+ break;
+ /* Passthrough the register access for bisectiblity, handled later */
+ case ARM_SMMU_CMDQ_BASE:
+ case ARM_SMMU_CMDQ_PROD:
+ case ARM_SMMU_CMDQ_CONS:
+ case ARM_SMMU_STRTAB_BASE:
+ case ARM_SMMU_STRTAB_BASE_CFG:
+ case ARM_SMMU_GBPA:
+ mask = read_write;
+ break;
+ case ARM_SMMU_CR0:
+ if (len != sizeof(u32))
+ break;
+ mask = read_write;
+ break;
+ case ARM_SMMU_CR1: {
+ /* Based on Linux implementation */
+ u64 cr1_template = FIELD_PREP(CR1_TABLE_SH, ARM_SMMU_SH_ISH) |
+ FIELD_PREP(CR1_TABLE_OC, CR1_CACHE_WB) |
+ FIELD_PREP(CR1_TABLE_IC, CR1_CACHE_WB) |
+ FIELD_PREP(CR1_QUEUE_SH, ARM_SMMU_SH_ISH) |
+ FIELD_PREP(CR1_QUEUE_OC, CR1_CACHE_WB) |
+ FIELD_PREP(CR1_QUEUE_IC, CR1_CACHE_WB);
+ if (len != sizeof(u32))
+ break;
+ /* Don't mess with shareability/cacheability. */
+ if (is_write) {
+ WARN_ON(val != cr1_template);
+ val = cr1_template;
+ }
+ mask = read_write;
+ break;
+ }
+
+ /* Allowed 32 bit registers. */
+ case ARM_SMMU_EVTQ_PROD + SZ_64K:
+ case ARM_SMMU_EVTQ_CONS + SZ_64K:
+ case ARM_SMMU_EVTQ_IRQ_CFG1:
+ case ARM_SMMU_EVTQ_IRQ_CFG2:
+ case ARM_SMMU_PRIQ_PROD + SZ_64K:
+ case ARM_SMMU_PRIQ_CONS + SZ_64K:
+ case ARM_SMMU_PRIQ_IRQ_CFG1:
+ case ARM_SMMU_PRIQ_IRQ_CFG2:
+ case ARM_SMMU_GERRORN:
+ case ARM_SMMU_GERROR_IRQ_CFG1:
+ case ARM_SMMU_GERROR_IRQ_CFG2:
+ case ARM_SMMU_IRQ_CTRLACK:
+ case ARM_SMMU_IRQ_CTRL:
+ case ARM_SMMU_CR0ACK:
+ case ARM_SMMU_CR2:
+ if (len != sizeof(u32))
+ break;
+ mask = read_write;
+ break;
+ /* Allowed 64 bit registers. */
+ case ARM_SMMU_EVTQ_BASE:
+ case ARM_SMMU_EVTQ_IRQ_CFG0:
+ case ARM_SMMU_PRIQ_BASE:
+ case ARM_SMMU_PRIQ_IRQ_CFG0:
+ case ARM_SMMU_GERROR_IRQ_CFG0:
+ if (len != sizeof(u64))
+ break;
+ mask = read_write;
+ break;
+ /* Allowed RO 32 bit registers. */
+ case ARM_SMMU_IIDR:
+ case ARM_SMMU_IDR5:
+ case ARM_SMMU_IDR3:
+ case ARM_SMMU_IDR1:
+ case ARM_SMMU_GERROR:
+ if (len != sizeof(u32))
+ break;
+ mask = read_only;
+ };
+
+ if (WARN_ON(!mask))
+ goto out_ret;
+
+ if (is_write) {
+ if (len == sizeof(u64))
+ writeq_relaxed(val & mask, smmu->base + off);
+ else
+ writel_relaxed(val & mask, smmu->base + off);
+
+ return true;
+ }
+
+ if (len == sizeof(u64))
+ val = readq_relaxed(smmu->base + off) & mask;
+ else
+ val = readl_relaxed(smmu->base + off) & mask;
+ /*
+ * Device might be read senstive, so do it but ignore writing
+ * back for xzr.
+ */
+ if (!is_xzr)
+ regs->regs[rd] = val;
+
+out_ret:
+ return true;
+}
+
+static bool smmu_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr)
+{
+ struct hyp_arm_smmu_v3_device *smmu;
+ bool ret;
+
+ for_each_smmu(smmu) {
+ if (addr < smmu->mmio_addr || addr >= smmu->mmio_addr + smmu->mmio_size)
+ continue;
+ hyp_spin_lock(&smmu->lock);
+ ret = smmu_dabt_device(smmu, regs, esr, addr - smmu->mmio_addr);
+ hyp_spin_unlock(&smmu->lock);
+ return ret;
+ }
+ return false;
+}
+
static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
{
return 0;
@@ -162,4 +304,5 @@ static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
struct kvm_iommu_ops smmu_ops = {
.init = smmu_init,
.host_stage2_idmap = smmu_host_stage2_idmap,
+ .dabt_handler = smmu_dabt_handler,
};
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
index 82b84673e85b..263b0fef262d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -4,6 +4,10 @@
#include <asm/kvm_asm.h>
+#ifdef __KVM_NVHE_HYPERVISOR__
+#include <nvhe/spinlock.h>
+#endif
+
/*
* Parameters from the trusted host:
* @mmio_addr base address of the SMMU registers
@@ -15,6 +19,7 @@
* @oas PA size
* @pgsize_bitmap Supported page sizes
* @sid_bits Max number of SID bits supported
+ * @lock Lock to protect SMMU
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -24,6 +29,11 @@ struct hyp_arm_smmu_v3_device {
unsigned long oas;
unsigned long pgsize_bitmap;
unsigned int sid_bits;
+#ifdef __KVM_NVHE_HYPERVISOR__
+ hyp_spinlock_t lock;
+#else
+ u32 lock;
+#endif
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 15/25] iommu/arm-smmu-v3-kvm: Shadow the command queue
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (13 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 14/25] iommu/arm-smmu-v3-kvm: Add MMIO emulation Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 16/25] iommu/arm-smmu-v3-kvm: Add CMDQ functions Mostafa Saleh
` (9 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
At boot allocate a command queue per SMMU which is used as a shadow
by the hypervisor.
The command queue size is 64K which is more than enough, as the
hypervisor would consume all the entries per a command queue prod
write, which means it can handle up to 4096 at a time.
Then, the host command queue needs to be pinned in a shared state, so
it can't be donated to VMs, and avoid tricking the hypervisor into
accessing them. This is done each time the command queue is enabled,
and undone each time the command queue is disabled.
The hypervisor won’t access the host command queue when it is disabled
from the host.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c | 25 ++++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 122 +++++++++++++++++-
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 8 ++
3 files changed, 154 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
index 9765d3d636d7..fccbc34de087 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -15,6 +15,8 @@
#include "arm-smmu-v3.h"
#include "pkvm/arm_smmu_v3.h"
+#define SMMU_KVM_CMDQ_ORDER 4
+
extern struct kvm_iommu_ops kvm_nvhe_sym(smmu_ops);
static size_t kvm_arm_smmu_count;
@@ -24,6 +26,15 @@ static size_t kvm_arm_smmu_cur;
static void kvm_arm_smmu_array_free(void)
{
int order;
+ int i;
+
+ for (i = 0 ; i < kvm_arm_smmu_cur ; ++i) {
+ struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[i];
+
+ if (smmu->cmdq.base_dma)
+ free_pages((unsigned long)phys_to_virt(smmu->cmdq.base_dma),
+ SMMU_KVM_CMDQ_ORDER);
+ }
order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
free_pages((unsigned long)kvm_arm_smmu_array, order);
@@ -70,6 +81,7 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
struct device *dev = &pdev->dev;
struct resource *res;
+ void *cmdq_base;
/* Only device tree, ACPI not supported. */
if (!dev->of_node)
@@ -95,6 +107,19 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
if (of_dma_is_coherent(dev->of_node))
smmu->features |= ARM_SMMU_FEAT_COHERENCY;
+ /*
+ * Allocate the shadow command queue, it doesn't have to be the same
+ * size as the host.
+ * Only populate base_dma and llq.max_n_shift, the hypervisor will init
+ * the rest.
+ */
+ cmdq_base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, SMMU_KVM_CMDQ_ORDER);
+ if (!cmdq_base)
+ return -ENOMEM;
+
+ smmu->cmdq.base_dma = virt_to_phys(cmdq_base);
+ smmu->cmdq.llq.max_n_shift = SMMU_KVM_CMDQ_ORDER + PAGE_SHIFT - CMDQ_ENT_SZ_SHIFT;
+
kvm_arm_smmu_cur++;
return 0;
}
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index cce5a51b4656..3b77796dafc7 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -11,7 +11,6 @@
#include <nvhe/trap_handler.h>
#include "arm_smmu_v3.h"
-#include "../arm-smmu-v3.h"
size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
@@ -21,10 +20,68 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
(smmu) != &kvm_hyp_arm_smmu_v3_smmus[kvm_hyp_arm_smmu_v3_count]; \
(smmu)++)
+#define cmdq_size(cmdq) ((1 << ((cmdq)->llq.max_n_shift)) * CMDQ_ENT_DWORDS * 8)
+
+static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_CMDQEN, smmu->cr0);
+}
+
+/*
+ * CMDQ, STE host copies are accessed by the hypervisor, we share them to
+ * - Prevent the host from passing protected VM memory.
+ * - Having them mapped in the hyp page table.
+ */
+static int smmu_share_pages(phys_addr_t addr, size_t size)
+{
+ size_t nr_pages = PAGE_ALIGN(size + (addr & ~PAGE_MASK)) >> PAGE_SHIFT;
+ phys_addr_t base = addr & PAGE_MASK;
+ int i, ret;
+
+ for (i = 0 ; i < nr_pages ; ++i) {
+ if (__pkvm_host_share_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT)) {
+ while (i--)
+ __pkvm_host_unshare_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT);
+ return -EPERM;
+ }
+ }
+
+ ret = hyp_pin_shared_mem(hyp_phys_to_virt(base),
+ hyp_phys_to_virt(base + nr_pages * PAGE_SIZE));
+ if (ret) {
+ for (i = 0 ; i < nr_pages ; ++i)
+ __pkvm_host_unshare_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT);
+ }
+
+ return ret;
+}
+
+static int smmu_unshare_pages(phys_addr_t addr, size_t size)
+{
+ size_t nr_pages = PAGE_ALIGN(size + (addr & ~PAGE_MASK)) >> PAGE_SHIFT;
+ phys_addr_t base = addr & PAGE_MASK;
+ int i, ret;
+
+ hyp_unpin_shared_mem(hyp_phys_to_virt(base),
+ hyp_phys_to_virt(base + nr_pages * PAGE_SIZE));
+
+ for (i = 0 ; i < nr_pages ; ++i) {
+ ret = __pkvm_host_unshare_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
/* Put the device in a state that can be probed by the host driver. */
static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
{
WARN_ON(__pkvm_hyp_donate_host_mmio(smmu->mmio_addr, smmu->mmio_size));
+
+ if (smmu->cmdq.base)
+ WARN_ON(__pkvm_hyp_donate_host(smmu->cmdq.base_dma >> PAGE_SHIFT,
+ cmdq_size(&smmu->cmdq) >> PAGE_SHIFT));
smmu->base = NULL;
}
@@ -99,6 +156,31 @@ static int smmu_probe(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+/*
+ * The kernel part of the driver will allocate the shadow cmdq,
+ * and zero it. This function only donates it.
+ */
+static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
+{
+ size_t cmdq_nr_pages = cmdq_size(&smmu->cmdq) >> PAGE_SHIFT;
+ int ret;
+
+ ret = __pkvm_host_donate_hyp(smmu->cmdq.base_dma >> PAGE_SHIFT, cmdq_nr_pages);
+ if (ret)
+ return ret;
+
+ smmu->cmdq.base = hyp_phys_to_virt(smmu->cmdq.base_dma);
+ smmu->cmdq.prod_reg = smmu->base + ARM_SMMU_CMDQ_PROD;
+ smmu->cmdq.cons_reg = smmu->base + ARM_SMMU_CMDQ_CONS;
+ smmu->cmdq.q_base = smmu->cmdq.base_dma |
+ FIELD_PREP(Q_BASE_LOG2SIZE, smmu->cmdq.llq.max_n_shift);
+ smmu->cmdq.ent_dwords = CMDQ_ENT_DWORDS;
+ writel_relaxed(0, smmu->cmdq.prod_reg);
+ writel_relaxed(0, smmu->cmdq.cons_reg);
+ writeq_relaxed(smmu->cmdq.q_base, smmu->base + ARM_SMMU_CMDQ_BASE);
+ return 0;
+}
+
static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
{
unsigned long haddr;
@@ -117,7 +199,12 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (ret)
goto out_ret;
+ ret = smmu_init_cmdq(smmu);
+ if (ret)
+ goto out_ret;
+
return 0;
+
out_ret:
smmu_deinit_device(smmu);
return ret;
@@ -157,6 +244,22 @@ static int smmu_init(void)
return ret;
}
+static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ u32 shift = smmu->cmdq_host.q_base & Q_BASE_LOG2SIZE;
+
+ smmu->cmdq_host.llq.max_n_shift = min(shift, 19);
+ smmu->cmdq_host.base_dma = smmu->cmdq_host.q_base & Q_BASE_ADDR_MASK;
+ WARN_ON(smmu_share_pages(smmu->cmdq_host.base_dma,
+ cmdq_size(&smmu->cmdq_host)));
+}
+
+static void smmu_emulate_cmdq_disable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ WARN_ON(smmu_unshare_pages(smmu->cmdq_host.base_dma,
+ cmdq_size(&smmu->cmdq_host)));
+}
+
static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
struct user_pt_regs *regs,
u64 esr, u32 off)
@@ -180,6 +283,14 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
break;
/* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_CMDQ_BASE:
+ if (is_write) {
+ /* Not allowed by the architecture */
+ if (WARN_ON(is_cmdq_enabled(smmu)))
+ break;
+ smmu->cmdq_host.q_base = val;
+ }
+ mask = read_write;
+ break;
case ARM_SMMU_CMDQ_PROD:
case ARM_SMMU_CMDQ_CONS:
case ARM_SMMU_STRTAB_BASE:
@@ -190,6 +301,15 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
case ARM_SMMU_CR0:
if (len != sizeof(u32))
break;
+ if (is_write) {
+ bool last_cmdq_en = is_cmdq_enabled(smmu);
+
+ smmu->cr0 = val;
+ if (!last_cmdq_en && is_cmdq_enabled(smmu))
+ smmu_emulate_cmdq_enable(smmu);
+ else if (last_cmdq_en && !is_cmdq_enabled(smmu))
+ smmu_emulate_cmdq_disable(smmu);
+ }
mask = read_write;
break;
case ARM_SMMU_CR1: {
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
index 263b0fef262d..cc1ad4c19845 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -8,6 +8,8 @@
#include <nvhe/spinlock.h>
#endif
+#include "../arm-smmu-v3.h"
+
/*
* Parameters from the trusted host:
* @mmio_addr base address of the SMMU registers
@@ -20,6 +22,9 @@
* @pgsize_bitmap Supported page sizes
* @sid_bits Max number of SID bits supported
* @lock Lock to protect SMMU
+ * @cmdq CMDQ as observed by HW
+ * @cmdq_host Host view of the CMDQ, only q_base and llq used.
+ * @cr0 Last value of CR0
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -34,6 +39,9 @@ struct hyp_arm_smmu_v3_device {
#else
u32 lock;
#endif
+ struct arm_smmu_queue cmdq;
+ struct arm_smmu_queue cmdq_host;
+ u32 cr0;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 16/25] iommu/arm-smmu-v3-kvm: Add CMDQ functions
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (14 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 15/25] iommu/arm-smmu-v3-kvm: Shadow the command queue Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 17/25] iommu/arm-smmu-v3-kvm: Emulate CMDQ for host Mostafa Saleh
` (8 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add functions to access the command queue, there are 2 main usage:
- Hypervisor's own commands, as TLB invalidation, would use functions
as smmu_send_cmd(), which creates and sends a command.
- Add host commands to the shadow command queue, after being filtered,
these will be added with smmu_add_cmd_raw.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 14 ++-
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 107 ++++++++++++++++++
2 files changed, 115 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index f904f4d19609..3fc499608d76 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1156,19 +1156,21 @@ u32 smmu_idr5_to_oas(u32 reg);
unsigned long smmu_idr5_to_pgsize(u32 reg);
/* Queue functions shared between kernel and hyp. */
-static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
+static inline u32 queue_space(struct arm_smmu_ll_queue *q)
{
- u32 space, prod, cons;
+ u32 prod, cons;
prod = Q_IDX(q, q->prod);
cons = Q_IDX(q, q->cons);
if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
- space = (1 << q->max_n_shift) - (prod - cons);
- else
- space = cons - prod;
+ return (1 << q->max_n_shift) - (prod - cons);
+ return cons - prod;
+}
- return space >= n;
+static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
+{
+ return queue_space(q) >= n;
}
static inline bool queue_full(struct arm_smmu_ll_queue *q)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 3b77796dafc7..aac455599728 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -6,6 +6,7 @@
*/
#include <asm/kvm_hyp.h>
+#include <nvhe/clock.h>
#include <nvhe/iommu.h>
#include <nvhe/mem_protect.h>
#include <nvhe/trap_handler.h>
@@ -22,6 +23,31 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
#define cmdq_size(cmdq) ((1 << ((cmdq)->llq.max_n_shift)) * CMDQ_ENT_DWORDS * 8)
+/*
+ * Wait until @cond is true.
+ * Return 0 on success, or -ETIMEDOUT
+ */
+#define smmu_wait(use_wfe, _cond) \
+({ \
+ int __ret = 0; \
+ u64 delay = hyp_clock_ns() + ARM_SMMU_POLL_TIMEOUT_US * 1000; \
+ \
+ while (!(_cond)) { \
+ if (use_wfe) { \
+ wfe(); \
+ if ((_cond)) \
+ break; \
+ } else { \
+ cpu_relax(); \
+ } \
+ if (hyp_clock_ns() >= delay) { \
+ __ret = -ETIMEDOUT; \
+ break; \
+ } \
+ } \
+ __ret; \
+})
+
static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
{
return FIELD_GET(CR0_CMDQEN, smmu->cr0);
@@ -74,6 +100,87 @@ static int smmu_unshare_pages(phys_addr_t addr, size_t size)
return 0;
}
+__maybe_unused
+static bool smmu_cmdq_has_space(struct arm_smmu_queue *cmdq, u32 n)
+{
+ struct arm_smmu_ll_queue *llq = &cmdq->llq;
+
+ WRITE_ONCE(llq->cons, readl_relaxed(cmdq->cons_reg));
+ return queue_has_space(llq, n);
+}
+
+static bool smmu_cmdq_full(struct arm_smmu_queue *cmdq)
+{
+ struct arm_smmu_ll_queue *llq = &cmdq->llq;
+
+ WRITE_ONCE(llq->cons, readl_relaxed(cmdq->cons_reg));
+ return queue_full(llq);
+}
+
+static bool smmu_cmdq_empty(struct arm_smmu_queue *cmdq)
+{
+ struct arm_smmu_ll_queue *llq = &cmdq->llq;
+
+ WRITE_ONCE(llq->cons, readl_relaxed(cmdq->cons_reg));
+ return queue_empty(llq);
+}
+
+static void smmu_add_cmd_raw(struct hyp_arm_smmu_v3_device *smmu,
+ u64 *cmd)
+{
+ struct arm_smmu_queue *q = &smmu->cmdq;
+ struct arm_smmu_ll_queue *llq = &q->llq;
+
+ queue_write(Q_ENT(q, llq->prod), cmd, CMDQ_ENT_DWORDS);
+ llq->prod = queue_inc_prod_n(llq, 1);
+}
+
+static int smmu_add_cmd(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmdq_ent *ent)
+{
+ int ret;
+ u64 cmd[CMDQ_ENT_DWORDS];
+
+ ret = smmu_wait(false, !smmu_cmdq_full(&smmu->cmdq));
+ if (ret)
+ return ret;
+
+ ret = arm_smmu_cmdq_build_cmd(cmd, ent);
+ if (ret)
+ return ret;
+
+ smmu_add_cmd_raw(smmu, cmd);
+ writel(smmu->cmdq.llq.prod, smmu->cmdq.prod_reg);
+ return 0;
+}
+
+static int smmu_sync_cmd(struct hyp_arm_smmu_v3_device *smmu)
+{
+ int ret;
+ struct arm_smmu_cmdq_ent cmd = {
+ .opcode = CMDQ_OP_CMD_SYNC,
+ };
+
+ ret = smmu_add_cmd(smmu, &cmd);
+ if (ret)
+ return ret;
+
+ return smmu_wait(smmu->features & ARM_SMMU_FEAT_SEV,
+ smmu_cmdq_empty(&smmu->cmdq));
+}
+
+__maybe_unused
+static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmdq_ent *cmd)
+{
+ int ret = smmu_add_cmd(smmu, cmd);
+
+ if (ret)
+ return ret;
+
+ return smmu_sync_cmd(smmu);
+}
+
/* Put the device in a state that can be probed by the host driver. */
static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
{
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 17/25] iommu/arm-smmu-v3-kvm: Emulate CMDQ for host
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (15 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 16/25] iommu/arm-smmu-v3-kvm: Add CMDQ functions Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 18/25] iommu/arm-smmu-v3-kvm: Shadow stream table Mostafa Saleh
` (7 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Don’t allow access to the command queue from the host:
- ARM_SMMU_CMDQ_BASE: Only allowed to be written when CMDQ is disabled, we
use it to keep track of the host command queue base.
Reads return the saved value.
- ARM_SMMU_CMDQ_PROD: Writes trigger command queue emulation which sanitise
and filters the whole range. Reads returns the host copy.
- ARM_SMMU_CMDQ_CONS: Writes move the sw copy of the cons, but the host
can’t skip commands once submitted. Reads return the emulated value and
the error bits in the actual cons.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 128 +++++++++++++++++-
1 file changed, 124 insertions(+), 4 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index aac455599728..1633a3cf8a3b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -100,7 +100,6 @@ static int smmu_unshare_pages(phys_addr_t addr, size_t size)
return 0;
}
-__maybe_unused
static bool smmu_cmdq_has_space(struct arm_smmu_queue *cmdq, u32 n)
{
struct arm_smmu_ll_queue *llq = &cmdq->llq;
@@ -351,6 +350,92 @@ static int smmu_init(void)
return ret;
}
+static bool smmu_filter_command(struct hyp_arm_smmu_v3_device *smmu, u64 *command)
+{
+ u64 command0 = le64_to_cpu(command[0]);
+ u64 command1 = le64_to_cpu(command[1]);
+ u64 type = FIELD_GET(CMDQ_0_OP, command0);
+
+ switch (type) {
+ case CMDQ_OP_CFGI_STE:
+ /* TBD: SHADOW_STE*/
+ break;
+ case CMDQ_OP_CFGI_ALL:
+ {
+ /*
+ * Linux doesn't use range STE invalidation, and only use this
+ * for CFGI_ALL, which is done on reset and not on an new STE
+ * being used.
+ * Although, this is not architectural we rely on the current Linux
+ * implementation.
+ */
+ if ((FIELD_GET(CMDQ_CFGI_1_RANGE, command1) != 31))
+ return true;
+ break;
+ }
+ case CMDQ_OP_TLBI_NH_ASID:
+ case CMDQ_OP_TLBI_NH_VA:
+ case 0x13: /* CMD_TLBI_NH_VAA: Not used by Linux */
+ {
+ /* Only allow VMID = 0 */
+ if (FIELD_GET(CMDQ_TLBI_0_VMID, command0) != 0)
+ return true;
+ break;
+ }
+ case 0x10: /* CMD_TLBI_NH_ALL: Not used by Linux */
+ case CMDQ_OP_TLBI_EL2_ALL:
+ case CMDQ_OP_TLBI_EL2_VA:
+ case CMDQ_OP_TLBI_EL2_ASID:
+ case CMDQ_OP_TLBI_S12_VMALL:
+ case CMDQ_OP_TLBI_S2_IPA:
+ case 0x23: /* CMD_TLBI_EL2_VAA: Not used by Linux */
+ return true;
+ case CMDQ_OP_CMD_SYNC:
+ if (FIELD_GET(CMDQ_SYNC_0_CS, command0) == CMDQ_SYNC_0_CS_IRQ) {
+ /* Allow it, but let the host timeout, as this should never happen. */
+ command0 &= ~CMDQ_SYNC_0_CS;
+ command0 |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_SEV);
+ command1 &= ~CMDQ_SYNC_1_MSIADDR_MASK;
+ }
+ break;
+ }
+
+ return false;
+}
+
+static int smmu_emulate_cmdq_insert(struct hyp_arm_smmu_v3_device *smmu)
+{
+ u64 *host_cmdq = hyp_phys_to_virt(smmu->cmdq_host.q_base & Q_BASE_ADDR_MASK);
+ bool use_wfe = smmu->features & ARM_SMMU_FEAT_SEV, skip;
+ u64 cmd[CMDQ_ENT_DWORDS];
+ int idx, ret;
+ u32 space;
+
+ if (!is_cmdq_enabled(smmu))
+ return 0;
+
+ space = (1 << (smmu->cmdq_host.llq.max_n_shift)) - queue_space(&smmu->cmdq_host.llq);
+ /* Wait for the command queue to have some space. */
+ ret = smmu_wait(use_wfe, smmu_cmdq_has_space(&smmu->cmdq, space));
+ if (ret)
+ return ret;
+
+ while (space--) {
+ idx = Q_IDX(&smmu->cmdq_host.llq, smmu->cmdq_host.llq.cons);
+ queue_inc_cons(&smmu->cmdq_host.llq);
+
+ memcpy(cmd, &host_cmdq[idx * CMDQ_ENT_DWORDS], CMDQ_ENT_DWORDS << 3);
+ skip = smmu_filter_command(smmu, cmd);
+ if (WARN_ON(skip))
+ continue;
+ smmu_add_cmd_raw(smmu, cmd);
+ }
+
+ writel(smmu->cmdq.llq.prod, smmu->cmdq.prod_reg);
+
+ return smmu_wait(use_wfe, smmu_cmdq_empty(&smmu->cmdq));
+}
+
static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
{
u32 shift = smmu->cmdq_host.q_base & Q_BASE_LOG2SIZE;
@@ -388,18 +473,51 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
/* Clear stage-2 support, hide MSI to avoid write back to cmdq */
mask = read_only & ~(IDR0_S2P | IDR0_VMID16 | IDR0_MSI | IDR0_HYP);
break;
- /* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_CMDQ_BASE:
+ /*
+ * Although allowed to use smaller size, we rely on the SMMUv3 driver
+ * using 64-bit store instruction for simplicity.
+ */
+ if (len != sizeof(u64))
+ break;
if (is_write) {
/* Not allowed by the architecture */
if (WARN_ON(is_cmdq_enabled(smmu)))
break;
smmu->cmdq_host.q_base = val;
+ goto out_ret;
+ } else {
+ val = smmu->cmdq_host.q_base;
+ goto out_update_regs;
}
- mask = read_write;
- break;
case ARM_SMMU_CMDQ_PROD:
+ if (len != sizeof(u32))
+ break;
+ if (is_write) {
+ smmu->cmdq_host.llq.prod = val;
+ WARN_ON(smmu_emulate_cmdq_insert(smmu));
+ goto out_ret;
+ } else {
+ val = smmu->cmdq_host.llq.prod;
+ goto out_update_regs;
+ }
case ARM_SMMU_CMDQ_CONS:
+ if (len != sizeof(u32))
+ break;
+ if (is_write) {
+ if (WARN_ON(is_cmdq_enabled(smmu)))
+ break;
+
+ smmu->cmdq_host.llq.cons = val;
+ goto out_ret;
+ } else {
+ /* Propagate errors back to the host.*/
+ u32 cons = readl_relaxed(smmu->base + ARM_SMMU_CMDQ_CONS);
+
+ val = smmu->cmdq_host.llq.cons | (CMDQ_CONS_ERR & cons);
+ goto out_update_regs;
+ }
+ /* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_STRTAB_BASE:
case ARM_SMMU_STRTAB_BASE_CFG:
case ARM_SMMU_GBPA:
@@ -495,6 +613,8 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
val = readq_relaxed(smmu->base + off) & mask;
else
val = readl_relaxed(smmu->base + off) & mask;
+
+out_update_regs:
/*
* Device might be read senstive, so do it but ignore writing
* back for xzr.
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 18/25] iommu/arm-smmu-v3-kvm: Shadow stream table
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (16 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 17/25] iommu/arm-smmu-v3-kvm: Emulate CMDQ for host Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 19/25] iommu/arm-smmu-v3-kvm: Shadow STEs Mostafa Saleh
` (6 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Allocate the shadow stream table per SMMU.
We choose the size of that table to be 1MB which is the
max size used by host in the case of 2 levels.
All the host writes are still paththrough for bisectibility, that
is changed next where CFGI commands will be trapped and used to
update the shadow copy hypervisor that will be used by HW.
Similar to the command queue, the host stream table is
shared/unshared each time the SMMU is enabled/disabled.
Handling of L2 tables is also done in the next patch when
the shadowing is added.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c | 21 ++-
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 122 ++++++++++++++++++
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 10 ++
3 files changed, 152 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
index fccbc34de087..7aec558eea29 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -16,6 +16,13 @@
#include "pkvm/arm_smmu_v3.h"
#define SMMU_KVM_CMDQ_ORDER 4
+/*
+ * Use the max value of L1 the kernel uses, that also covers the worst case
+ * for linear tables as it is mandatory according to the spec to support 2
+ * lvl tables if SIDSIZE >= 7
+ */
+#define SMMU_KVM_STRTAB_ORDER (get_order(STRTAB_MAX_L1_ENTRIES * \
+ sizeof(struct arm_smmu_strtab_l1)))
extern struct kvm_iommu_ops kvm_nvhe_sym(smmu_ops);
@@ -34,6 +41,9 @@ static void kvm_arm_smmu_array_free(void)
if (smmu->cmdq.base_dma)
free_pages((unsigned long)phys_to_virt(smmu->cmdq.base_dma),
SMMU_KVM_CMDQ_ORDER);
+ if (smmu->strtab_dma)
+ free_pages((unsigned long)phys_to_virt(smmu->strtab_dma),
+ SMMU_KVM_STRTAB_ORDER);
}
order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
@@ -80,8 +90,8 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
{
struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
struct device *dev = &pdev->dev;
+ void *cmdq_base, *strtab;
struct resource *res;
- void *cmdq_base;
/* Only device tree, ACPI not supported. */
if (!dev->of_node)
@@ -120,6 +130,15 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
smmu->cmdq.base_dma = virt_to_phys(cmdq_base);
smmu->cmdq.llq.max_n_shift = SMMU_KVM_CMDQ_ORDER + PAGE_SHIFT - CMDQ_ENT_SZ_SHIFT;
+ strtab = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, SMMU_KVM_STRTAB_ORDER);
+ if (!strtab) {
+ free_pages((unsigned long)cmdq_base, SMMU_KVM_CMDQ_ORDER);
+ return -ENOMEM;
+ }
+
+ smmu->strtab_dma = virt_to_phys(strtab);
+ smmu->strtab_size = PAGE_SIZE << SMMU_KVM_STRTAB_ORDER;
+
kvm_arm_smmu_cur++;
return 0;
}
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 1633a3cf8a3b..d15c9e5aa998 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -16,6 +16,14 @@
size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
+/* strtab accessors */
+#define strtab_log2size(smmu) (FIELD_GET(STRTAB_BASE_CFG_LOG2SIZE, (smmu)->host_ste_cfg))
+#define strtab_size(smmu) ((1UL << strtab_log2size(smmu)) * STRTAB_STE_DWORDS * 8)
+#define strtab_host_base(smmu) ((smmu)->host_ste_base & STRTAB_BASE_ADDR_MASK)
+#define strtab_split(smmu) (FIELD_GET(STRTAB_BASE_CFG_SPLIT, (smmu)->host_ste_cfg))
+#define strtab_l1_size(smmu) ((1UL << (strtab_log2size(smmu) - strtab_split(smmu))) * \
+ (sizeof(struct arm_smmu_strtab_l1)))
+
#define for_each_smmu(smmu) \
for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
(smmu) != &kvm_hyp_arm_smmu_v3_smmus[kvm_hyp_arm_smmu_v3_count]; \
@@ -53,6 +61,11 @@ static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
return FIELD_GET(CR0_CMDQEN, smmu->cr0);
}
+static bool is_smmu_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_SMMUEN, smmu->cr0);
+}
+
/*
* CMDQ, STE host copies are accessed by the hypervisor, we share them to
* - Prevent the host from passing protected VM memory.
@@ -188,6 +201,11 @@ static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
if (smmu->cmdq.base)
WARN_ON(__pkvm_hyp_donate_host(smmu->cmdq.base_dma >> PAGE_SHIFT,
cmdq_size(&smmu->cmdq) >> PAGE_SHIFT));
+
+ if (smmu->strtab_cfg.linear.table ||
+ smmu->strtab_cfg.l2.l1tab)
+ WARN_ON(__pkvm_hyp_donate_host(hyp_phys_to_pfn(smmu->strtab_dma),
+ smmu->strtab_size >> PAGE_SHIFT));
smmu->base = NULL;
}
@@ -287,6 +305,45 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+static int smmu_init_strtab(struct hyp_arm_smmu_v3_device *smmu)
+{
+ struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
+ int ret;
+ u32 reg;
+
+ ret = __pkvm_host_donate_hyp(hyp_phys_to_pfn(smmu->strtab_dma),
+ smmu->strtab_size >> PAGE_SHIFT);
+ if (ret)
+ return ret;
+
+ if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
+ unsigned int last_sid_idx =
+ arm_smmu_strtab_l1_idx((1ULL << smmu->sid_bits) - 1);
+
+ cfg->l2.l1tab = hyp_phys_to_virt(smmu->strtab_dma);
+ cfg->l2.l1_dma = smmu->strtab_dma;
+ cfg->l2.num_l1_ents = min(last_sid_idx + 1, STRTAB_MAX_L1_ENTRIES);
+
+ reg = FIELD_PREP(STRTAB_BASE_CFG_FMT,
+ STRTAB_BASE_CFG_FMT_2LVL) |
+ FIELD_PREP(STRTAB_BASE_CFG_LOG2SIZE,
+ ilog2(cfg->l2.num_l1_ents) + STRTAB_SPLIT) |
+ FIELD_PREP(STRTAB_BASE_CFG_SPLIT, STRTAB_SPLIT);
+ } else {
+ cfg->linear.table = hyp_phys_to_virt(smmu->strtab_dma);
+ cfg->linear.ste_dma = smmu->strtab_dma;
+ cfg->linear.num_ents = 1UL << smmu->sid_bits;
+ reg = FIELD_PREP(STRTAB_BASE_CFG_FMT,
+ STRTAB_BASE_CFG_FMT_LINEAR) |
+ FIELD_PREP(STRTAB_BASE_CFG_LOG2SIZE, smmu->sid_bits);
+ }
+
+ writeq_relaxed((smmu->strtab_dma & STRTAB_BASE_ADDR_MASK) | STRTAB_BASE_RA,
+ smmu->base + ARM_SMMU_STRTAB_BASE);
+ writel_relaxed(reg, smmu->base + ARM_SMMU_STRTAB_BASE_CFG);
+ return 0;
+}
+
static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
{
unsigned long haddr;
@@ -309,6 +366,10 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (ret)
goto out_ret;
+ ret = smmu_init_strtab(smmu);
+ if (ret)
+ goto out_ret;
+
return 0;
out_ret:
@@ -436,6 +497,46 @@ static int smmu_emulate_cmdq_insert(struct hyp_arm_smmu_v3_device *smmu)
return smmu_wait(use_wfe, smmu_cmdq_empty(&smmu->cmdq));
}
+static int smmu_update_ste_shadow(struct hyp_arm_smmu_v3_device *smmu, bool enabled)
+{
+ size_t strtab_size;
+ u32 fmt = FIELD_GET(STRTAB_BASE_CFG_FMT, smmu->host_ste_cfg);
+
+ /* Linux doesn't change the fmt nor size of the strtab in the run time. */
+ if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
+ if ((fmt != STRTAB_BASE_CFG_FMT_2LVL) ||
+ (strtab_split(smmu) != STRTAB_SPLIT) ||
+ (strtab_log2size(smmu) > (ilog2(STRTAB_MAX_L1_ENTRIES) + STRTAB_SPLIT)) ||
+ (strtab_split(smmu) >= strtab_log2size(smmu)))
+ return -EINVAL;
+ strtab_size = strtab_l1_size(smmu);
+ } else {
+ if ((fmt != STRTAB_BASE_CFG_FMT_LINEAR) ||
+ (strtab_log2size(smmu) > smmu->sid_bits))
+ return -EINVAL;
+ strtab_size = strtab_size(smmu);
+ }
+
+ if (enabled)
+ return smmu_share_pages(strtab_host_base(smmu), strtab_size);
+
+ return smmu_unshare_pages(strtab_host_base(smmu), strtab_size);
+}
+
+static void smmu_emulate_enable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ /* Enabling SMMU without CMDQ, means TLB invalidation won't work. */
+ if (WARN_ON(!is_cmdq_enabled(smmu)))
+ return;
+
+ WARN_ON(smmu_update_ste_shadow(smmu, true));
+}
+
+static void smmu_emulate_disable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ WARN_ON(smmu_update_ste_shadow(smmu, false));
+}
+
static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
{
u32 shift = smmu->cmdq_host.q_base & Q_BASE_LOG2SIZE;
@@ -519,7 +620,23 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
}
/* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_STRTAB_BASE:
+ if (is_write) {
+ /* Must only be written when SMMU_CR0.SMMUEN == 0.*/
+ if (is_smmu_enabled(smmu))
+ break;
+ smmu->host_ste_base = val;
+ }
+ mask = read_write;
+ break;
case ARM_SMMU_STRTAB_BASE_CFG:
+ if (is_write) {
+ /* Must only be written when SMMU_CR0.SMMUEN == 0.*/
+ if (is_smmu_enabled(smmu))
+ break;
+ smmu->host_ste_cfg = val;
+ }
+ mask = read_write;
+ break;
case ARM_SMMU_GBPA:
mask = read_write;
break;
@@ -528,12 +645,17 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
break;
if (is_write) {
bool last_cmdq_en = is_cmdq_enabled(smmu);
+ bool last_smmu_en = is_smmu_enabled(smmu);
smmu->cr0 = val;
if (!last_cmdq_en && is_cmdq_enabled(smmu))
smmu_emulate_cmdq_enable(smmu);
else if (last_cmdq_en && !is_cmdq_enabled(smmu))
smmu_emulate_cmdq_disable(smmu);
+ if (!last_smmu_en && is_smmu_enabled(smmu))
+ smmu_emulate_enable(smmu);
+ else if (last_smmu_en && !is_smmu_enabled(smmu))
+ smmu_emulate_disable(smmu);
}
mask = read_write;
break;
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
index cc1ad4c19845..6a73cf6b8873 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -15,6 +15,8 @@
* @mmio_addr base address of the SMMU registers
* @mmio_size size of the registers resource
* @features Features of SMMUv3, subset of the main driver
+ * @strtab_dma Phys address of stream table
+ * @strtab_size Stream table size
*
* Other members are filled and used at runtime by the SMMU driver.
* @base Virtual address of SMMU registers
@@ -25,6 +27,9 @@
* @cmdq CMDQ as observed by HW
* @cmdq_host Host view of the CMDQ, only q_base and llq used.
* @cr0 Last value of CR0
+ * @host_ste_cfg Host stream table config
+ * @host_ste_base Host stream table base
+ * @strtab_cfg Stream table as seen by HW
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -42,6 +47,11 @@ struct hyp_arm_smmu_v3_device {
struct arm_smmu_queue cmdq;
struct arm_smmu_queue cmdq_host;
u32 cr0;
+ dma_addr_t strtab_dma;
+ size_t strtab_size;
+ u64 host_ste_cfg;
+ u64 host_ste_base;
+ struct arm_smmu_strtab_cfg strtab_cfg;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 19/25] iommu/arm-smmu-v3-kvm: Shadow STEs
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (17 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 18/25] iommu/arm-smmu-v3-kvm: Shadow stream table Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 20/25] iommu/arm-smmu-v3-kvm: Share other queues Mostafa Saleh
` (5 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add STE emulation, when the host sends the CFGI_STE command.
Copy the STE as is to the shadow owned by the hypervisor, in the
next patch, stage-2 page table will be attached.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 114 +++++++++++++++++-
1 file changed, 108 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index d15c9e5aa998..d92811ef2af5 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -23,6 +23,9 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
#define strtab_split(smmu) (FIELD_GET(STRTAB_BASE_CFG_SPLIT, (smmu)->host_ste_cfg))
#define strtab_l1_size(smmu) ((1UL << (strtab_log2size(smmu) - strtab_split(smmu))) * \
(sizeof(struct arm_smmu_strtab_l1)))
+#define strtab_hyp_base(smmu) ((smmu)->features & ARM_SMMU_FEAT_2_LVL_STRTAB ? \
+ (u64 *)(smmu)->strtab_cfg.l2.l1tab :\
+ (u64 *)(smmu)->strtab_cfg.linear.table)
#define for_each_smmu(smmu) \
for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
@@ -305,6 +308,91 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
+ struct arm_smmu_ste *host_ste_out)
+{
+ u64 *host_ste_base = hyp_phys_to_virt(strtab_host_base(smmu));
+ struct arm_smmu_strtab_l1 host_l1_desc;
+ struct arm_smmu_strtab_l2 *l2ptr;
+ phys_addr_t host_l2_tab;
+ int ret;
+
+ host_l1_desc.l2ptr = le64_to_cpu(READ_ONCE(host_ste_base[arm_smmu_strtab_l1_idx(sid)]));
+ if (!(host_l1_desc.l2ptr & STRTAB_L1_DESC_SPAN))
+ return -EINVAL;
+
+ host_l2_tab = host_l1_desc.l2ptr & STRTAB_L1_DESC_L2PTR_MASK;
+ /* Share and pin the table before accessing it. */
+ ret = smmu_share_pages(host_l2_tab, sizeof(struct arm_smmu_strtab_l2));
+ if (ret)
+ return ret;
+
+ l2ptr = hyp_phys_to_virt(host_l2_tab);
+ memcpy(host_ste_out, &l2ptr->stes[arm_smmu_strtab_l2_idx(sid)],
+ STRTAB_STE_DWORDS << 3);
+ WARN_ON(smmu_unshare_pages(host_l2_tab, sizeof(struct arm_smmu_strtab_l2)));
+ return 0;
+}
+
+static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool leaf)
+{
+ struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
+ struct arm_smmu_ste *hyp_ste_ptr, *host_ste_ptr, host_ste_copy;
+ u64 *hyp_ste_base = strtab_hyp_base(smmu);
+ int ret;
+
+ /*
+ * Linux only uses leaf = 1, when leaf is 0, we need to verify that this
+ * is a 2 level table and reshadow of l2.
+ * Also, we rely on Linux only issuing CFGI_STE to attach a device when
+ * the SMMU is enabled.
+ */
+ if (!leaf || !is_smmu_enabled(smmu) ||
+ (sid >= (1UL << strtab_log2size(smmu))))
+ return -EINVAL;
+
+ if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB)) {
+ struct arm_smmu_ste *hyp_table = (struct arm_smmu_ste *)hyp_ste_base;
+ u64 *host_ste_base = hyp_phys_to_virt(strtab_host_base(smmu));
+ struct arm_smmu_ste *host_table = (struct arm_smmu_ste *)host_ste_base;
+
+ if (sid >= cfg->linear.num_ents)
+ return -E2BIG;
+
+ hyp_ste_ptr = &hyp_table[sid];
+ host_ste_ptr = &host_table[sid];
+ } else {
+ struct arm_smmu_strtab_l1 *l1tab = (struct arm_smmu_strtab_l1 *)hyp_ste_base;
+ u32 l1_idx = arm_smmu_strtab_l1_idx(sid);
+ struct arm_smmu_strtab_l2 *l2ptr;
+
+ if (l1_idx >= cfg->l2.num_l1_ents)
+ return -E2BIG;
+
+ host_ste_ptr = &host_ste_copy;
+ ret = smmu_get_host_l2_ste(smmu, sid, host_ste_ptr);
+ if (ret)
+ return ret;
+
+ if (!l1tab[l1_idx].l2ptr) {
+ struct arm_smmu_strtab_l2 *l2table;
+
+ /* No hypervisor entry, first time the L2 is populated. */
+ l2table = kvm_iommu_donate_pages(get_order(sizeof(*l2table)));
+ if (!l2table)
+ return -ENOMEM;
+ arm_smmu_write_strtab_l1_desc(&l1tab[l1_idx], hyp_virt_to_phys(l2table));
+ }
+ l2ptr = hyp_phys_to_virt(le64_to_cpu(l1tab[l1_idx].l2ptr) &
+ STRTAB_L1_DESC_L2PTR_MASK);
+ hyp_ste_ptr = &l2ptr->stes[arm_smmu_strtab_l2_idx(sid)];
+ }
+
+ memcpy(hyp_ste_ptr->data, host_ste_ptr->data, STRTAB_STE_DWORDS << 3);
+
+ return 0;
+}
+
static int smmu_init_strtab(struct hyp_arm_smmu_v3_device *smmu)
{
struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
@@ -419,8 +507,14 @@ static bool smmu_filter_command(struct hyp_arm_smmu_v3_device *smmu, u64 *comman
switch (type) {
case CMDQ_OP_CFGI_STE:
- /* TBD: SHADOW_STE*/
+ {
+ u32 sid = FIELD_GET(CMDQ_CFGI_0_SID, command[0]);
+ u32 leaf = FIELD_GET(CMDQ_CFGI_1_LEAF, command[1]);
+
+ if (smmu_reshadow_ste(smmu, sid, leaf))
+ return true;
break;
+ }
case CMDQ_OP_CFGI_ALL:
{
/*
@@ -618,25 +712,33 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
val = smmu->cmdq_host.llq.cons | (CMDQ_CONS_ERR & cons);
goto out_update_regs;
}
- /* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_STRTAB_BASE:
+ if (len != sizeof(u64))
+ break;
if (is_write) {
/* Must only be written when SMMU_CR0.SMMUEN == 0.*/
if (is_smmu_enabled(smmu))
break;
smmu->host_ste_base = val;
+ goto out_ret;
+ } else {
+ val = smmu->host_ste_base;
+ goto out_update_regs;
}
- mask = read_write;
- break;
case ARM_SMMU_STRTAB_BASE_CFG:
+ if (len != sizeof(u32))
+ break;
if (is_write) {
/* Must only be written when SMMU_CR0.SMMUEN == 0.*/
if (is_smmu_enabled(smmu))
break;
smmu->host_ste_cfg = val;
+ goto out_ret;
+ } else {
+ val = smmu->host_ste_cfg;
+ goto out_update_regs;
}
- mask = read_write;
- break;
+ /* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_GBPA:
mask = read_write;
break;
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 20/25] iommu/arm-smmu-v3-kvm: Share other queues
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (18 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 19/25] iommu/arm-smmu-v3-kvm: Shadow STEs Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 21/25] iommu/arm-smmu-v3-kvm: Emulate GBPA Mostafa Saleh
` (4 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Other queues as PRIQ and EVTQ doesn't need to be shadowed. However, we
need to make sure they are in a state that disallow them to be donated
to the hypervisor or guests. So, keep track of those and share them when
they get enabled.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 62 ++++++++++++++++++-
.../iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h | 4 ++
2 files changed, 64 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index d92811ef2af5..e258690384f4 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -69,6 +69,16 @@ static bool is_smmu_enabled(struct hyp_arm_smmu_v3_device *smmu)
return FIELD_GET(CR0_SMMUEN, smmu->cr0);
}
+static bool is_evtq_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_EVTQEN, smmu->cr0);
+}
+
+static bool is_priq_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_PRIQEN, smmu->cr0);
+}
+
/*
* CMDQ, STE host copies are accessed by the hypervisor, we share them to
* - Prevent the host from passing protected VM memory.
@@ -647,6 +657,14 @@ static void smmu_emulate_cmdq_disable(struct hyp_arm_smmu_v3_device *smmu)
cmdq_size(&smmu->cmdq_host)));
}
+static void smmu_emulate_queue(unsigned long q_base, size_t ent_size_shift)
+{
+ phys_addr_t base = q_base & Q_BASE_ADDR_MASK;
+ size_t size = 1UL << (FIELD_GET(Q_BASE_LOG2SIZE, q_base) + ent_size_shift);
+
+ WARN_ON(smmu_share_pages(base ,size));
+}
+
static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
struct user_pt_regs *regs,
u64 esr, u32 off)
@@ -748,12 +766,31 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
if (is_write) {
bool last_cmdq_en = is_cmdq_enabled(smmu);
bool last_smmu_en = is_smmu_enabled(smmu);
+ bool last_evtq_en = is_evtq_enabled(smmu);
+ bool last_priq_en = is_priq_enabled(smmu);
smmu->cr0 = val;
if (!last_cmdq_en && is_cmdq_enabled(smmu))
smmu_emulate_cmdq_enable(smmu);
else if (last_cmdq_en && !is_cmdq_enabled(smmu))
smmu_emulate_cmdq_disable(smmu);
+
+ /*
+ * Share PRI and EVTQ to avoid the host using them to write to
+ * protected memory. However, panic on disable for those queues
+ * as that is more complicated, unsharing from here can lead to
+ * use-after-unshare issues, and requires ordering with cr0ack.
+ * As the host never disable those queues, don't support that.
+ */
+ if (!last_evtq_en && is_evtq_enabled(smmu))
+ smmu_emulate_queue(smmu->evtq_base, EVTQ_ENT_SZ_SHIFT);
+ else if (last_evtq_en && !is_evtq_enabled(smmu))
+ WARN_ON(1);
+ if (!last_priq_en && is_priq_enabled(smmu))
+ smmu_emulate_queue(smmu->priq_base, PRIQ_ENT_SZ_SHIFT);
+ else if (last_priq_en && !is_priq_enabled(smmu))
+ WARN_ON(1);
+
if (!last_smmu_en && is_smmu_enabled(smmu))
smmu_emulate_enable(smmu);
else if (last_smmu_en && !is_smmu_enabled(smmu))
@@ -779,6 +816,29 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
mask = read_write;
break;
}
+ case ARM_SMMU_EVTQ_BASE:
+ if (len != sizeof(u64))
+ break;
+
+ if (is_write) {
+ if (is_evtq_enabled(smmu))
+ break;
+ smmu->evtq_base = val;
+ }
+ mask = read_write;
+ break;
+
+ case ARM_SMMU_PRIQ_BASE:
+ if (len != sizeof(u64))
+ break;
+
+ if (is_write) {
+ if (is_priq_enabled(smmu))
+ break;
+ smmu->priq_base = val;
+ }
+ mask = read_write;
+ break;
/* Allowed 32 bit registers. */
case ARM_SMMU_EVTQ_PROD + SZ_64K:
@@ -801,9 +861,7 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
mask = read_write;
break;
/* Allowed 64 bit registers. */
- case ARM_SMMU_EVTQ_BASE:
case ARM_SMMU_EVTQ_IRQ_CFG0:
- case ARM_SMMU_PRIQ_BASE:
case ARM_SMMU_PRIQ_IRQ_CFG0:
case ARM_SMMU_GERROR_IRQ_CFG0:
if (len != sizeof(u64))
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
index 6a73cf6b8873..e811d51bdfaa 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm_smmu_v3.h
@@ -30,6 +30,8 @@
* @host_ste_cfg Host stream table config
* @host_ste_base Host stream table base
* @strtab_cfg Stream table as seen by HW
+ * @evtq_base Host evtq base reg
+ * @priq_base Host priq base reg
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -52,6 +54,8 @@ struct hyp_arm_smmu_v3_device {
u64 host_ste_cfg;
u64 host_ste_base;
struct arm_smmu_strtab_cfg strtab_cfg;
+ unsigned long evtq_base;
+ unsigned long priq_base;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 21/25] iommu/arm-smmu-v3-kvm: Emulate GBPA
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (19 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 20/25] iommu/arm-smmu-v3-kvm: Share other queues Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 22/25] iommu/io-pgtable-arm: Support io-pgtable-arm in the hypervisor Mostafa Saleh
` (3 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The last bit of emulation is GBPA. it must be always set to ABORT,
as when the SMMU is disabled it’s not allowed for the host to bypass
the SMMU.
That's is done by setting the GBPA to ABORT at init time, and host
writes are always ignored and host reads always return ABORT.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 32 +++++++++++++++++--
1 file changed, 29 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index e258690384f4..1ed5ccce7849 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -126,6 +126,22 @@ static int smmu_unshare_pages(phys_addr_t addr, size_t size)
return 0;
}
+static int smmu_abort_gbpa(struct hyp_arm_smmu_v3_device *smmu)
+{
+ int ret;
+ u32 reg;
+
+ ret = smmu_wait(false,
+ (readl_relaxed(smmu->base + ARM_SMMU_GBPA) & GBPA_UPDATE) == 0);
+ if (ret)
+ return ret;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_GBPA);
+ writel_relaxed(GBPA_UPDATE | GBPA_ABORT | reg, smmu->base + ARM_SMMU_GBPA);
+ return smmu_wait(false,
+ (readl_relaxed(smmu->base + ARM_SMMU_GBPA) & GBPA_UPDATE) == 0);
+}
+
static bool smmu_cmdq_has_space(struct arm_smmu_queue *cmdq, u32 n)
{
struct arm_smmu_ll_queue *llq = &cmdq->llq;
@@ -468,6 +484,10 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (ret)
goto out_ret;
+ ret = smmu_abort_gbpa(smmu);
+ if (ret)
+ goto out_ret;
+
return 0;
out_ret:
@@ -756,10 +776,16 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
val = smmu->host_ste_cfg;
goto out_update_regs;
}
- /* Passthrough the register access for bisectiblity, handled later */
case ARM_SMMU_GBPA:
- mask = read_write;
- break;
+ if (len != sizeof(u32))
+ break;
+
+ /* Ignore write, always read to abort. */
+ if (!is_write) {
+ val = GBPA_ABORT;
+ goto out_update_regs;
+ }
+ goto out_ret;
case ARM_SMMU_CR0:
if (len != sizeof(u32))
break;
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 22/25] iommu/io-pgtable-arm: Support io-pgtable-arm in the hypervisor
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (20 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 21/25] iommu/arm-smmu-v3-kvm: Emulate GBPA Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 23/25] iommu/arm-smmu-v3-kvm: Shadow the CPU stage-2 page table Mostafa Saleh
` (2 subsequent siblings)
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
To support DMA isolation in pKVM through SMMUv3 nested trap and
emulate, io-pgtable-arm needs to be compiled for the hypervisor
to create the SMMUs page tables.
Instead of factoring out the kernel-specific code and providing
parallel implementations for the hypervisor, we directly utilize
and abstract the differences within the iommu-pages API.
This introduces a set of hypervisor-specific wrappers in iommu-pages.h
when compiled under __KVM_NVHE_HYPERVISOR__, routing allocations,
frees, virt/phys conversions, and DMA API mapping to the appropriate
pKVM hypervisor functions (kvm_iommu_donate_pages, etc). The generic
kernel definitions are now appropriately excluded in this case.
It also introduces kvm_alloc_io_pgtable_ops at the end of
io-pgtable-arm.c to instantiate the page table for pKVM and adds
the io-pgtable-arm.o object to the hypervisor Makefile.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 3 +-
drivers/iommu/io-pgtable-arm.c | 31 +++++++++++++++-
drivers/iommu/io-pgtable-arm.h | 6 +++
drivers/iommu/iommu-pages.h | 63 ++++++++++++++++++++++++++++++++
4 files changed, 100 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 8a75739db947..4e9e0f1ed2b5 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -36,7 +36,8 @@ hyp-obj-y += $(lib-objs)
HYP_SMMU_V3_DRV_PATH = ../../../../../drivers/iommu/arm/arm-smmu-v3
hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += $(HYP_SMMU_V3_DRV_PATH)/pkvm/arm-smmu-v3.o \
- $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o
+ $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o \
+ $(HYP_SMMU_V3_DRV_PATH)/../../io-pgtable-arm.o
# Path to simple_ring_buffer.c
CFLAGS_trace.nvhe.o += -I$(srctree)/kernel/trace/
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index e765021308f9..8a0ffea3ae2c 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -252,10 +252,14 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
void *cookie)
{
struct device *dev = cfg->iommu_dev;
+ int nid = NUMA_NO_NODE;
size_t alloc_size;
dma_addr_t dma;
void *pages;
+ if (dev)
+ nid = dev_to_node(dev);
+
/*
* For very small starting-level translation tables the HW requires a
* minimum alignment of at least 64 to cover all cases.
@@ -264,8 +268,7 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
if (cfg->alloc)
pages = cfg->alloc(cookie, alloc_size, gfp);
else
- pages = iommu_alloc_pages_node_sz(dev_to_node(dev), gfp,
- alloc_size);
+ pages = iommu_alloc_pages_node_sz(nid, gfp, alloc_size);
if (!pages)
return NULL;
@@ -1262,3 +1265,27 @@ struct io_pgtable_init_fns io_pgtable_arm_mali_lpae_init_fns = {
.alloc = arm_mali_lpae_alloc_pgtable,
.free = arm_lpae_free_pgtable,
};
+
+#ifdef __KVM_NVHE_HYPERVISOR__
+#include <nvhe/iommu.h>
+
+struct io_pgtable_ops *kvm_alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+ struct io_pgtable_cfg *cfg,
+ void *cookie)
+{
+ struct io_pgtable *iop;
+
+ if (fmt != ARM_64_LPAE_S2)
+ return NULL;
+
+ iop = arm_64_lpae_alloc_pgtable_s2(cfg, cookie);
+ if (!iop)
+ return NULL;
+
+ iop->fmt = fmt;
+ iop->cookie = cookie;
+ iop->cfg = *cfg;
+
+ return &iop->ops;
+}
+#endif
diff --git a/drivers/iommu/io-pgtable-arm.h b/drivers/iommu/io-pgtable-arm.h
index ba7cfdf7afa0..af3a3f1e765e 100644
--- a/drivers/iommu/io-pgtable-arm.h
+++ b/drivers/iommu/io-pgtable-arm.h
@@ -27,4 +27,10 @@
#define ARM_LPAE_TCR_PS_48_BIT 0x5ULL
#define ARM_LPAE_TCR_PS_52_BIT 0x6ULL
+#ifdef __KVM_NVHE_HYPERVISOR__
+struct io_pgtable_ops *kvm_alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+ struct io_pgtable_cfg *cfg,
+ void *cookie);
+#endif
+
#endif /* IO_PGTABLE_ARM_H_ */
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
index e1945193ad7f..749f0f4f870c 100644
--- a/drivers/iommu/iommu-pages.h
+++ b/drivers/iommu/iommu-pages.h
@@ -10,6 +10,7 @@
#include <linux/dma-mapping.h>
#include <linux/iommu.h>
+#ifndef __KVM_NVHE_HYPERVISOR__
/**
* struct ioptdesc - Memory descriptor for IOMMU page tables
* @iopt_freelist_elm: List element for a struct iommu_pages_list
@@ -181,4 +182,66 @@ static inline void iommu_pages_dma_unmap(struct device *dev, dma_addr_t dma, siz
dma_unmap_single(dev, dma, size, DMA_TO_DEVICE);
}
+#else /* __KVM_NVHE_HYPERVISOR__ */
+
+#include <nvhe/memory.h>
+#include <nvhe/iommu.h>
+
+static inline void *iommu_alloc_pages_node_sz(int nid, gfp_t gfp, size_t size)
+{
+ return kvm_iommu_donate_pages(get_order(size));
+}
+
+static inline void iommu_free_pages(void *virt)
+{
+ kvm_iommu_reclaim_pages(virt);
+}
+
+static inline void *iommu_alloc_data(size_t size, gfp_t gfp)
+{
+ return kvm_iommu_donate_pages(get_order(size));
+}
+
+static inline void iommu_free_data(void *p)
+{
+ kvm_iommu_reclaim_pages(p);
+}
+
+#undef WARN_ONCE
+#define WARN_ONCE(condition, format...) WARN_ON(condition)
+
+static inline phys_addr_t iommu_virt_to_phys(void *virt)
+{
+ return hyp_virt_to_phys(virt);
+}
+
+static inline void *iommu_phys_to_virt(phys_addr_t phys)
+{
+ return hyp_phys_to_virt(phys);
+}
+
+static inline void iommu_pages_flush_incoherent(struct device *dma_dev,
+ void *virt, size_t offset,
+ size_t len)
+{
+ kvm_flush_dcache_to_poc(virt + offset, len);
+}
+
+static inline dma_addr_t iommu_pages_dma_map(struct device *dev, void *virt, size_t size)
+{
+ kvm_flush_dcache_to_poc(virt, size);
+ return (dma_addr_t)hyp_virt_to_phys(virt);
+}
+
+static inline int iommu_pages_dma_mapping_error(struct device *dev, dma_addr_t dma)
+{
+ return 0;
+}
+
+static inline void iommu_pages_dma_unmap(struct device *dev, dma_addr_t dma, size_t size)
+{
+}
+
+#endif /* __KVM_NVHE_HYPERVISOR__ */
+
#endif /* __IOMMU_PAGES_H */
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 23/25] iommu/arm-smmu-v3-kvm: Shadow the CPU stage-2 page table
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (21 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 22/25] iommu/io-pgtable-arm: Support io-pgtable-arm in the hypervisor Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 24/25] iommu/arm-smmu-v3-kvm: Enable nesting Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 25/25] KVM: arm64: Add documentation for pKVM DMA isolation Mostafa Saleh
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Based on the callbacks from the hypervisor, update the SMMUv3
Identity mapped page table.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 197 +++++++++++++++++-
1 file changed, 195 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 1ed5ccce7849..b73a2462f0dd 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -13,6 +13,9 @@
#include "arm_smmu_v3.h"
+#include <linux/io-pgtable.h>
+#include "../../../io-pgtable-arm.h"
+
size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
@@ -59,6 +62,9 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
__ret; \
})
+/* Protected by host_mmu.lock from core code. */
+static struct io_pgtable *idmap_pgtable;
+
static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
{
return FIELD_GET(CR0_CMDQEN, smmu->cr0);
@@ -210,7 +216,6 @@ static int smmu_sync_cmd(struct hyp_arm_smmu_v3_device *smmu)
smmu_cmdq_empty(&smmu->cmdq));
}
-__maybe_unused
static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
struct arm_smmu_cmdq_ent *cmd)
{
@@ -222,6 +227,78 @@ static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
return smmu_sync_cmd(smmu);
}
+static void __smmu_add_cmd(void *__opaque, struct arm_smmu_cmdq_batch *unused,
+ struct arm_smmu_cmdq_ent *cmd)
+{
+ struct hyp_arm_smmu_v3_device *smmu = (struct hyp_arm_smmu_v3_device *)__opaque;
+
+ WARN_ON(smmu_add_cmd(smmu, cmd));
+}
+
+static int smmu_tlb_inv_range_smmu(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmdq_ent *cmd,
+ unsigned long iova, size_t size, size_t granule)
+{
+ arm_smmu_tlb_inv_build(cmd, iova, size, granule,
+ PAGE_SHIFT, smmu->features & ARM_SMMU_FEAT_RANGE_INV,
+ smmu, __smmu_add_cmd, NULL);
+ return smmu_sync_cmd(smmu);
+}
+
+static void smmu_tlb_inv_range(unsigned long iova, size_t size, size_t granule,
+ bool leaf)
+{
+ struct arm_smmu_cmdq_ent cmd_s1 = {
+ .opcode = CMDQ_OP_TLBI_NH_ALL,
+ .tlbi = {
+ .vmid = 0,
+ },
+ };
+ struct hyp_arm_smmu_v3_device *smmu;
+
+ for_each_smmu(smmu) {
+ struct arm_smmu_cmdq_ent cmd = {
+ .opcode = CMDQ_OP_TLBI_S2_IPA,
+ .tlbi = {
+ .leaf = leaf,
+ .vmid = 0,
+ },
+ };
+
+ hyp_spin_lock(&smmu->lock);
+ /*
+ * Don't bother if SMMU is disabled, this would be useful for the case
+ * when RPM is supported to avoid touching the SMMU MMIO when disabled.
+ * The hypervisor also asserts CMDQEN is enabled before the SMMU is
+ * enabled. As otherwise the host can prevent the hypervisor from doing
+ * TLB invalidations.
+ */
+ if (is_smmu_enabled(smmu)) {
+ WARN_ON(smmu_tlb_inv_range_smmu(smmu, &cmd, iova, size, granule));
+ WARN_ON(smmu_send_cmd(smmu, &cmd_s1));
+ }
+ hyp_spin_unlock(&smmu->lock);
+ }
+}
+
+static void smmu_tlb_flush_walk(unsigned long iova, size_t size,
+ size_t granule, void *cookie)
+{
+ smmu_tlb_inv_range(iova, size, granule, false);
+}
+
+static void smmu_tlb_add_page(struct iommu_iotlb_gather *gather,
+ unsigned long iova, size_t granule,
+ void *cookie)
+{
+ smmu_tlb_inv_range(iova, granule, granule, true);
+}
+
+static const struct iommu_flush_ops smmu_tlb_ops = {
+ .tlb_flush_walk = smmu_tlb_flush_walk,
+ .tlb_add_page = smmu_tlb_add_page,
+};
+
/* Put the device in a state that can be probed by the host driver. */
static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
{
@@ -495,6 +572,37 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
return ret;
}
+static int smmu_init_pgt(void)
+{
+ /* Default values overridden based on SMMUs common features. */
+ struct io_pgtable_cfg cfg = (struct io_pgtable_cfg) {
+ .tlb = &smmu_tlb_ops,
+ .pgsize_bitmap = -1,
+ .ias = 48,
+ .oas = 48,
+ .coherent_walk = true,
+ };
+ struct hyp_arm_smmu_v3_device *smmu;
+ struct io_pgtable_ops *ops;
+
+ for_each_smmu(smmu) {
+ cfg.ias = min(cfg.ias, smmu->oas);
+ cfg.oas = min(cfg.oas, smmu->oas);
+ cfg.pgsize_bitmap &= smmu->pgsize_bitmap;
+ cfg.coherent_walk &= !!(smmu->features & ARM_SMMU_FEAT_COHERENCY);
+ }
+
+ /* At least PAGE_SIZE must be supported by all SMMUs*/
+ if ((cfg.pgsize_bitmap & PAGE_SIZE) == 0)
+ return -EINVAL;
+
+ ops = kvm_alloc_io_pgtable_ops(ARM_64_LPAE_S2, &cfg, NULL);
+ if (!ops)
+ return -ENOMEM;
+ idmap_pgtable = io_pgtable_ops_to_pgtable(ops);
+ return 0;
+}
+
/* Called while is the host is still trusted. */
static int smmu_init(void)
{
@@ -520,7 +628,10 @@ static int smmu_init(void)
BUILD_BUG_ON(sizeof(hyp_spinlock_t) != sizeof(u32));
- return 0;
+ ret = smmu_init_pgt();
+ if (ret)
+ goto out_reclaim_smmu;
+ return ret;
out_reclaim_smmu:
while (smmu != kvm_hyp_arm_smmu_v3_smmus)
@@ -950,8 +1061,90 @@ static bool smmu_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr)
return false;
}
+static size_t smmu_pgsize_idmap(size_t size, u64 paddr, size_t pgsize_bitmap)
+{
+ size_t pgsizes;
+
+ /* Remove page sizes that are larger than the current size */
+ pgsizes = pgsize_bitmap & GENMASK_ULL(__fls(size), 0);
+
+ /* Remove page sizes that the address is not aligned to. */
+ if (likely(paddr))
+ pgsizes &= GENMASK_ULL(__ffs(paddr), 0);
+
+ WARN_ON(!pgsizes);
+
+ /* Return the largest page size that fits. */
+ return BIT(__fls(pgsizes));
+}
+
static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
{
+ size_t pgsize = PAGE_SIZE, pgcount, size;
+ struct io_pgtable *pgtable = idmap_pgtable;
+ int ret = 0;
+
+ end = min(end, BIT(pgtable->cfg.oas));
+ if (start >= end)
+ return 0;
+
+ size = end - start;
+ if (prot) {
+ size_t mapped;
+
+ if (!(prot & IOMMU_MMIO))
+ prot |= IOMMU_CACHE;
+
+ while (size) {
+ mapped = 0;
+ /*
+ * We handle pages size for memory and MMIO differently:
+ * - memory: Map everything with PAGE_SIZE, that is guaranteed to
+ * find memory as we allocated enough pages to cover the entire
+ * memory, we do that as io-pgtable-arm doesn't support
+ * split_blk_unmap logic any more, so we can't break blocks once
+ * mapped to tables.
+ * - MMIO: Unlike memory, pKVM allocate 1G to for all MMIO, while
+ * the MMIO space can be large, as it is assumed to cover the
+ * whole IAS that is not memory, we have to use block mappings,
+ * that is fine for MMIO as it is never donated at the moment,
+ * so we never need to unmap MMIO at the run time triggereing
+ * split block logic.
+ */
+ if (prot & IOMMU_MMIO)
+ pgsize = smmu_pgsize_idmap(size, start, pgtable->cfg.pgsize_bitmap);
+
+ pgcount = size / pgsize;
+ ret = pgtable->ops.map_pages(&pgtable->ops, start, start,
+ pgsize, pgcount, prot, 0, &mapped);
+ size -= mapped;
+ start += mapped;
+ /* Map failures doesn't impact security, tolerate it. */
+ if (!mapped || ret)
+ break;
+ }
+ } else {
+ struct iommu_iotlb_gather gather;
+ size_t unmapped;
+
+ while (size) {
+ pgcount = size / pgsize;
+ iommu_iotlb_gather_init(&gather);
+ unmapped = pgtable->ops.unmap_pages(&pgtable->ops, start,
+ pgsize, pgcount, &gather);
+ size -= unmapped;
+ start += unmapped;
+ if (!unmapped)
+ break;
+ }
+ }
+
+ if (ret)
+ return ret;
+
+ if (WARN_ON(size))
+ return -EINVAL;
+
return 0;
}
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 24/25] iommu/arm-smmu-v3-kvm: Enable nesting
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (22 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 23/25] iommu/arm-smmu-v3-kvm: Shadow the CPU stage-2 page table Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
2026-05-01 11:19 ` [PATCH v6 25/25] KVM: arm64: Add documentation for pKVM DMA isolation Mostafa Saleh
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Now, as the hypervisor controls the command queue, stream table,
and shadows the stage-2 page table.
Enable stage-2 in case the host puts an STE in bypass or stage-1.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 108 ++++++++++++++++--
1 file changed, 101 insertions(+), 7 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index b73a2462f0dd..3d727d6dfbf0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -411,6 +411,57 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+static int smmu_attach_stage_2(struct arm_smmu_ste *ste)
+{
+ unsigned long vttbr;
+ unsigned long ts, sl, ic, oc, sh, tg, ps;
+ unsigned long cfg;
+ struct io_pgtable_cfg *pgt_cfg = &idmap_pgtable->cfg;
+
+ cfg = FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(ste->data[0]));
+ if (!FIELD_GET(STRTAB_STE_0_V, le64_to_cpu(ste->data[0])) ||
+ (cfg == STRTAB_STE_0_CFG_ABORT)) {
+ ste->data[2] = 0;
+ ste->data[3] = 0;
+ return 0;
+ }
+ /* S2 is not advertised, that should never be attempted. */
+ if (cfg == STRTAB_STE_0_CFG_NESTED)
+ return -EINVAL;
+ vttbr = pgt_cfg->arm_lpae_s2_cfg.vttbr;
+ ps = pgt_cfg->arm_lpae_s2_cfg.vtcr.ps;
+ tg = pgt_cfg->arm_lpae_s2_cfg.vtcr.tg;
+ sh = pgt_cfg->arm_lpae_s2_cfg.vtcr.sh;
+ oc = pgt_cfg->arm_lpae_s2_cfg.vtcr.orgn;
+ ic = pgt_cfg->arm_lpae_s2_cfg.vtcr.irgn;
+ sl = pgt_cfg->arm_lpae_s2_cfg.vtcr.sl;
+ ts = pgt_cfg->arm_lpae_s2_cfg.vtcr.tsz;
+
+ ste->data[1] &= ~cpu_to_le64(STRTAB_STE_1_SHCFG);
+ ste->data[1] |= cpu_to_le64(FIELD_PREP(STRTAB_STE_1_SHCFG, STRTAB_STE_1_SHCFG_INCOMING));
+
+ /* The host shouldn't write dwords 2 and 3, overwrite them. */
+ ste->data[2] = cpu_to_le64(FIELD_PREP(STRTAB_STE_2_VTCR,
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2PS, ps) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2TG, tg) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2SH0, sh) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2OR0, oc) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2IR0, ic) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2SL0, sl) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2T0SZ, ts)) |
+ FIELD_PREP(STRTAB_STE_2_S2VMID, 0) |
+ STRTAB_STE_2_S2AA64 | STRTAB_STE_2_S2R |
+ #ifdef __BIG_ENDIAN
+ STRTAB_STE_2_S2ENDI |
+#endif
+ STRTAB_STE_2_S2PTW);
+
+ ste->data[3] = cpu_to_le64(vttbr & STRTAB_STE_3_S2TTB_MASK);
+ /* Convert S1 => nested and bypass => S2 */
+ ste->data[0] |= cpu_to_le64(FIELD_PREP(STRTAB_STE_0_CFG, cfg | BIT(1)));
+ return 0;
+}
+
static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
struct arm_smmu_ste *host_ste_out)
{
@@ -440,9 +491,18 @@ static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool leaf)
{
struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
- struct arm_smmu_ste *hyp_ste_ptr, *host_ste_ptr, host_ste_copy;
+ struct arm_smmu_ste *hyp_ste_ptr;
u64 *hyp_ste_base = strtab_hyp_base(smmu);
- int ret;
+ struct arm_smmu_ste target = {};
+ struct arm_smmu_cmdq_ent cfgi_cmd = {
+ .opcode = CMDQ_OP_CFGI_STE,
+ .cfgi = {
+ .sid = sid,
+ .leaf = true,
+ },
+ };
+ bool cur_valid, target_valid;
+ int i, ret;
/*
* Linux only uses leaf = 1, when leaf is 0, we need to verify that this
@@ -463,7 +523,7 @@ static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool
return -E2BIG;
hyp_ste_ptr = &hyp_table[sid];
- host_ste_ptr = &host_table[sid];
+ memcpy(target.data, host_table[sid].data, STRTAB_STE_DWORDS << 3);
} else {
struct arm_smmu_strtab_l1 *l1tab = (struct arm_smmu_strtab_l1 *)hyp_ste_base;
u32 l1_idx = arm_smmu_strtab_l1_idx(sid);
@@ -472,8 +532,7 @@ static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool
if (l1_idx >= cfg->l2.num_l1_ents)
return -E2BIG;
- host_ste_ptr = &host_ste_copy;
- ret = smmu_get_host_l2_ste(smmu, sid, host_ste_ptr);
+ ret = smmu_get_host_l2_ste(smmu, sid, &target);
if (ret)
return ret;
@@ -491,9 +550,44 @@ static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool
hyp_ste_ptr = &l2ptr->stes[arm_smmu_strtab_l2_idx(sid)];
}
- memcpy(hyp_ste_ptr->data, host_ste_ptr->data, STRTAB_STE_DWORDS << 3);
- return 0;
+ /*
+ * Summary of each host emulated state vs real HW.
+ * | Host | HW |
+ * ==============================
+ * | V=0 | V=0 |
+ * | Abort | Abort |
+ * | Bypass | S2 |
+ * | S1 | S1+S2 |
+ *
+ * For the host, any V=0 transition is not hitless, all other permutations of
+ * (abort, bypass, S1) transitions are hitless.
+ * For the HW state, any V=0 transition is not hitless, as all the S2 config is
+ * always the same (ttbr, vtcr...), all other transitions should be hitless too.
+ * However, the host is not trusted, which means that any V=0 <=> V=1 transitions
+ * we need to enforce writing order of the STE and add CFGI.
+ */
+ cur_valid = FIELD_GET(STRTAB_STE_0_V, le64_to_cpu(hyp_ste_ptr->data[0]));
+ ret = smmu_attach_stage_2(&target);
+ if (ret)
+ return ret;
+ target_valid = FIELD_GET(STRTAB_STE_0_V, le64_to_cpu(target.data[0]));
+ if (cur_valid && !target_valid) {
+ WRITE_ONCE(hyp_ste_ptr->data[0], target.data[0]);
+ WARN_ON(smmu_send_cmd(smmu, &cfgi_cmd));
+ for (i = 1; i < STRTAB_STE_DWORDS; i++)
+ WRITE_ONCE(hyp_ste_ptr->data[i], target.data[i]);
+ } else if (!cur_valid && target_valid) {
+ for (i = 1; i < STRTAB_STE_DWORDS; i++)
+ WRITE_ONCE(hyp_ste_ptr->data[i], target.data[i]);
+ WARN_ON(smmu_send_cmd(smmu, &cfgi_cmd));
+ WRITE_ONCE(hyp_ste_ptr->data[0], target.data[0]);
+ } else {
+ for (i = 0; i < STRTAB_STE_DWORDS; i++)
+ WRITE_ONCE(hyp_ste_ptr->data[i], target.data[i]);
+ }
+
+ return smmu_send_cmd(smmu, &cfgi_cmd);
}
static int smmu_init_strtab(struct hyp_arm_smmu_v3_device *smmu)
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread* [PATCH v6 25/25] KVM: arm64: Add documentation for pKVM DMA isolation
2026-05-01 11:19 [PATCH v6 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (23 preceding siblings ...)
2026-05-01 11:19 ` [PATCH v6 24/25] iommu/arm-smmu-v3-kvm: Enable nesting Mostafa Saleh
@ 2026-05-01 11:19 ` Mostafa Saleh
24 siblings, 0 replies; 38+ messages in thread
From: Mostafa Saleh @ 2026-05-01 11:19 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jean-philippe, jgg, mark.rutland,
qperret, tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Populate the section for DMA isolation in pKVM with the newly
added KVM IOMMU and pKVM SMMUv3 driver details.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
Documentation/virt/kvm/arm/pkvm.rst | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/Documentation/virt/kvm/arm/pkvm.rst b/Documentation/virt/kvm/arm/pkvm.rst
index 514992a79a83..46e5c553646b 100644
--- a/Documentation/virt/kvm/arm/pkvm.rst
+++ b/Documentation/virt/kvm/arm/pkvm.rst
@@ -77,7 +77,24 @@ Status: **Unimplemented.**
DMA isolation using an IOMMU
----------------------------
-Status: **Unimplemented.**
+Status: Supported for devices behind SMMUv3 supporting dual stages
+of translation.
+
+With ``CONFIG_ARM_SMMU_V3_PKVM``, the hypervisor will take over the SMMUs
+on the system and provide an architectural emulation to the kernel SMMUv3
+driver transparently.
+
+If some devices are not behind an IOMMU or behind another IOMMU architecture,
+DMA isolation is not supported, as a driver must be provided for that.
+
+DMA isolation is enforced by dual stage of translation; similar to the CPU
+where a driver can register their ops through ``kvm_iommu_register_driver``
+and implement ``host_stage2_idmap`` to shadow the CPU page table.
+
+This implementation trusts the systems firmware not to allow the untrusted
+host kernel to bypass the SMMUv3.
+For example by resetting the power. In that case, it is the firmware
+responsibility to save/restore the SMMUv3 state.
Proxying of Trustzone services
------------------------------
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 38+ messages in thread