[PATCH v2 15/43] arm64: RME: Support for the VGIC in realms

Steven Price
2024-04-12T08:43:53Z

The RMM provides emulation of a VGIC to the realm guest but delegates
much of the handling to the host. Implement support in KVM for
saving/restoring state to/from the REC structure.

Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/arm64/kvm/arm.c | 15 +++++++++++---
arch/arm64/kvm/vgic/vgic-v3.c | 9 +++++++--
arch/arm64/kvm/vgic/vgic.c | 37 +++++++++++++++++++++++++++++++++--
3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index d70c511e16a0..f8daf478114f 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -534,17 +534,22 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
+ kvm_timer_vcpu_put(vcpu);
+ kvm_vgic_put(vcpu);
+
+ vcpu->cpu = -1;
+
+ if (vcpu_is_rec(vcpu))
+ return;
+
kvm_arch_vcpu_put_debug_state_flags(vcpu);
kvm_arch_vcpu_put_fp(vcpu);
if (has_vhe())
kvm_vcpu_put_vhe(vcpu);
- kvm_timer_vcpu_put(vcpu);
- kvm_vgic_put(vcpu);
kvm_vcpu_pmu_restore_host(vcpu);
kvm_arm_vmid_clear_active();

vcpu_clear_on_unsupported_cpu(vcpu);
- vcpu->cpu = -1;
}

static void __kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu)
@@ -758,6 +763,10 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
}

if (!irqchip_in_kernel(kvm)) {
+ /* Userspace irqchip not yet supported with Realms */
+ if (kvm_is_realm(vcpu->kvm))
+ return -EOPNOTSUPP;
+
/*
* Tell the rest of the code that there are userspace irqchip
* VMs in the wild.
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index 4ea3340786b9..75ae98b0f700 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -7,9 +7,11 @@
#include <linux/kvm.h>
#include <linux/kvm_host.h>
#include <kvm/arm_vgic.h>
+#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_asm.h>
+#include <asm/rmi_smc.h>

#include "vgic.h"

@@ -667,7 +669,8 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
(unsigned long long)info->vcpu.start);
} else if (kvm_get_mode() != KVM_MODE_PROTECTED) {
kvm_vgic_global_state.vcpu_base = info->vcpu.start;
- kvm_vgic_global_state.can_emulate_gicv2 = true;
+ if (!static_branch_unlikely(&kvm_rme_is_available))
+ kvm_vgic_global_state.can_emulate_gicv2 = true;
ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
if (ret) {
kvm_err("Cannot register GICv2 KVM device.\n");
@@ -742,7 +745,9 @@ void vgic_v3_vmcr_sync(struct kvm_vcpu *vcpu)
{
struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;

- if (likely(cpu_if->vgic_sre))
+ if (vcpu_is_rec(vcpu))
+ cpu_if->vgic_vmcr = vcpu->arch.rec.run->exit.gicv3_vmcr;
+ else if (likely(cpu_if->vgic_sre))
cpu_if->vgic_vmcr = kvm_call_hyp_ret(__vgic_v3_read_vmcr);
}

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index 4ec93587c8cd..02561d4e6447 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -10,7 +10,9 @@
#include <linux/list_sort.h>
#include <linux/nospec.h>

+#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>
+#include <asm/rmi_smc.h>

#include "vgic.h"

@@ -845,10 +847,23 @@ static inline bool can_access_vgic_from_kernel(void)
return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has_vhe();
}

+static inline void vgic_rmm_save_state(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+ int i;
+
+ for (i = 0; i < kvm_vgic_global_state.nr_lr; i++) {
+ cpu_if->vgic_lr[i] = vcpu->arch.rec.run->exit.gicv3_lrs[i];
+ vcpu->arch.rec.run->entry.gicv3_lrs[i] = 0;
+ }
+}
+
static inline void vgic_save_state(struct kvm_vcpu *vcpu)
{
if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
vgic_v2_save_state(vcpu);
+ else if (vcpu_is_rec(vcpu))
+ vgic_rmm_save_state(vcpu);
else
__vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
}
@@ -875,10 +890,28 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
vgic_prune_ap_list(vcpu);
}

+static inline void vgic_rmm_restore_state(struct kvm_vcpu *vcpu)
+{
+ struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+ int i;
+
+ for (i = 0; i < kvm_vgic_global_state.nr_lr; i++) {
+ vcpu->arch.rec.run->entry.gicv3_lrs[i] = cpu_if->vgic_lr[i];
+ /*
+ * Also populate the rec.run->exit copies so that a late
+ * decision to back out from entering the realm doesn't cause
+ * the state to be lost
+ */
+ vcpu->arch.rec.run->exit.gicv3_lrs[i] = cpu_if->vgic_lr[i];
+ }
+}
+
static inline void vgic_restore_state(struct kvm_vcpu *vcpu)
{
if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
vgic_v2_restore_state(vcpu);
+ else if (vcpu_is_rec(vcpu))
+ vgic_rmm_restore_state(vcpu);
else
__vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
}
@@ -919,7 +952,7 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)

void kvm_vgic_load(struct kvm_vcpu *vcpu)
{
- if (unlikely(!vgic_initialized(vcpu->kvm)))
+ if (unlikely(!vgic_initialized(vcpu->kvm)) || vcpu_is_rec(vcpu))
return;

if (kvm_vgic_global_state.type == VGIC_V2)
@@ -930,7 +963,7 @@ void kvm_vgic_load(struct kvm_vcpu *vcpu)

void kvm_vgic_put(struct kvm_vcpu *vcpu)
{
- if (unlikely(!vgic_initialized(vcpu->kvm)))
+ if (unlikely(!vgic_initialized(vcpu->kvm)) || vcpu_is_rec(vcpu))
return;

if (kvm_vgic_global_state.type == VGIC_V2)
--
2.34.1