[PATCH v4 26/28] iommu/arm-smmu-v3-kvm: Support io-pgtable

Mostafa Saleh
2025-08-19T21:52:50Z

Add hooks needed to support io-pgtable-arm, mostly about
memory allocation.

Also add a function to allocate s2 64 bit page table.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 4 +-
.../arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c | 64 +++++++++++++++++++
drivers/iommu/io-pgtable-arm.c | 2 +-
drivers/iommu/io-pgtable-arm.h | 11 ++++
4 files changed, 79 insertions(+), 2 deletions(-)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c

diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index c71c96262378..10090be6b067 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -34,7 +34,9 @@ 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-hyp.o
+ $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-hyp.o \
+ $(HYP_SMMU_V3_DRV_PATH)/pkvm/io-pgtable-arm-hyp.o \
+ $(HYP_SMMU_V3_DRV_PATH)/../../io-pgtable-arm.o

##
## Build rules for compiling nVHE hyp code
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c
new file mode 100644
index 000000000000..6cf9e5bb76e7
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Arm Ltd.
+ */
+#include <nvhe/iommu.h>
+
+#include "../../../io-pgtable-arm.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);
+ iop->fmt = fmt;
+ iop->cookie = cookie;
+ iop->cfg = *cfg;
+
+ return &iop->ops;
+}
+
+void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
+ struct io_pgtable_cfg *cfg, void *cookie)
+{
+ void *addr;
+
+ addr = kvm_iommu_donate_pages(get_order(size));
+
+ if (addr && !cfg->coherent_walk)
+ kvm_flush_dcache_to_poc(addr, size);
+
+ return addr;
+}
+
+void __arm_lpae_free_pages(void *addr, size_t size, struct io_pgtable_cfg *cfg,
+ void *cookie)
+{
+ if (!cfg->coherent_walk)
+ kvm_flush_dcache_to_poc(addr, size);
+
+ kvm_iommu_reclaim_pages(addr);
+}
+
+void __arm_lpae_sync_pte(arm_lpae_iopte *ptep, int num_entries,
+ struct io_pgtable_cfg *cfg)
+{
+ if (!cfg->coherent_walk)
+ kvm_flush_dcache_to_poc(ptep, sizeof(*ptep) * num_entries);
+}
+
+/* At the moment this is only used once, so rounding up to a page is not really a problem. */
+void *__arm_lpae_alloc_data(size_t size, gfp_t gfp)
+{
+ return kvm_iommu_donate_pages(get_order(size));
+}
+
+void __arm_lpae_free_data(void *p)
+{
+ return kvm_iommu_reclaim_pages(p);
+}
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 2ca09081c3b0..211f6d54b902 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -947,7 +947,7 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
return NULL;
}

-static struct io_pgtable *
+struct io_pgtable *
arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
{
u64 sl;
diff --git a/drivers/iommu/io-pgtable-arm.h b/drivers/iommu/io-pgtable-arm.h
index 7d9f0b759275..194c3e975288 100644
--- a/drivers/iommu/io-pgtable-arm.h
+++ b/drivers/iommu/io-pgtable-arm.h
@@ -78,8 +78,19 @@ void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
void *cookie);
void *__arm_lpae_alloc_data(size_t size, gfp_t gfp);
void __arm_lpae_free_data(void *p);
+struct io_pgtable *
+arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie);
#ifndef __KVM_NVHE_HYPERVISOR__
#define __arm_lpae_virt_to_phys __pa
#define __arm_lpae_phys_to_virt __va
+#else
+#include <nvhe/memory.h>
+#define __arm_lpae_virt_to_phys hyp_virt_to_phys
+#define __arm_lpae_phys_to_virt hyp_phys_to_virt
+#undef WARN_ONCE
+#define WARN_ONCE(condition, format...) WARN_ON(1)
+struct io_pgtable_ops *kvm_alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+ struct io_pgtable_cfg *cfg,
+ void *cookie);
#endif /* !__KVM_NVHE_HYPERVISOR__ */
#endif /* IO_PGTABLE_ARM_H_ */
--
2.51.0.rc1.167.g924127e9c0-goog