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Message-ID: <20250227003310.367350-2-qperret@google.com>
Date: Thu, 27 Feb 2025 00:33:05 +0000
From: Quentin Perret <qperret@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
Joey Gouly <joey.gouly@....com>, Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>
Cc: Vincent Donnefort <vdonnefort@...gle.com>, Quentin Perret <qperret@...gle.com>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/6] KVM: arm64: Track SVE state in the hypervisor vcpu structure
From: Fuad Tabba <tabba@...gle.com>
When dealing with a guest with SVE enabled, make sure the host SVE
state is pinned at EL2 S1, and that the hypervisor vCPU state is
correctly initialised (and then unpinned on teardown).
Co-authored-by: Marc Zyngier <maz@...nel.org>
Signed-off-by: Fuad Tabba <tabba@...gle.com>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Signed-off-by: Quentin Perret <qperret@...gle.com>
---
arch/arm64/include/asm/kvm_host.h | 12 ++++---
arch/arm64/kvm/hyp/nvhe/hyp-main.c | 4 ---
arch/arm64/kvm/hyp/nvhe/pkvm.c | 54 +++++++++++++++++++++++++++---
3 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3a7ec98ef123..90b58f87b107 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -930,20 +930,22 @@ struct kvm_vcpu_arch {
#define vcpu_sve_zcr_elx(vcpu) \
(unlikely(is_hyp_ctxt(vcpu)) ? ZCR_EL2 : ZCR_EL1)
-#define vcpu_sve_state_size(vcpu) ({ \
+#define sve_state_size_from_vl(sve_max_vl) ({ \
size_t __size_ret; \
- unsigned int __vcpu_vq; \
+ unsigned int __vq; \
\
- if (WARN_ON(!sve_vl_valid((vcpu)->arch.sve_max_vl))) { \
+ if (WARN_ON(!sve_vl_valid(sve_max_vl))) { \
__size_ret = 0; \
} else { \
- __vcpu_vq = vcpu_sve_max_vq(vcpu); \
- __size_ret = SVE_SIG_REGS_SIZE(__vcpu_vq); \
+ __vq = sve_vq_from_vl(sve_max_vl); \
+ __size_ret = SVE_SIG_REGS_SIZE(__vq); \
} \
\
__size_ret; \
})
+#define vcpu_sve_state_size(vcpu) sve_state_size_from_vl((vcpu)->arch.sve_max_vl)
+
#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \
KVM_GUESTDBG_USE_SW_BP | \
KVM_GUESTDBG_USE_HW | \
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 2c37680d954c..59db9606e6e1 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -123,10 +123,6 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
hyp_vcpu->vcpu.arch.ctxt = host_vcpu->arch.ctxt;
- hyp_vcpu->vcpu.arch.sve_state = kern_hyp_va(host_vcpu->arch.sve_state);
- /* Limit guest vector length to the maximum supported by the host. */
- hyp_vcpu->vcpu.arch.sve_max_vl = min(host_vcpu->arch.sve_max_vl, kvm_host_sve_max_vl);
-
hyp_vcpu->vcpu.arch.mdcr_el2 = host_vcpu->arch.mdcr_el2;
hyp_vcpu->vcpu.arch.hcr_el2 &= ~(HCR_TWI | HCR_TWE);
hyp_vcpu->vcpu.arch.hcr_el2 |= READ_ONCE(host_vcpu->arch.hcr_el2) &
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 3927fe52a3dd..3ec27e12b043 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -356,13 +356,29 @@ static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu)
hyp_unpin_shared_mem(host_vcpu, host_vcpu + 1);
}
+static void unpin_host_sve_state(struct pkvm_hyp_vcpu *hyp_vcpu)
+{
+ void *sve_state;
+
+ if (!vcpu_has_feature(&hyp_vcpu->vcpu, KVM_ARM_VCPU_SVE))
+ return;
+
+ sve_state = kern_hyp_va(hyp_vcpu->vcpu.arch.sve_state);
+ hyp_unpin_shared_mem(sve_state,
+ sve_state + vcpu_sve_state_size(&hyp_vcpu->vcpu));
+}
+
static void unpin_host_vcpus(struct pkvm_hyp_vcpu *hyp_vcpus[],
unsigned int nr_vcpus)
{
int i;
- for (i = 0; i < nr_vcpus; i++)
- unpin_host_vcpu(hyp_vcpus[i]->host_vcpu);
+ for (i = 0; i < nr_vcpus; i++) {
+ struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vcpus[i];
+
+ unpin_host_vcpu(hyp_vcpu->host_vcpu);
+ unpin_host_sve_state(hyp_vcpu);
+ }
}
static void init_pkvm_hyp_vm(struct kvm *host_kvm, struct pkvm_hyp_vm *hyp_vm,
@@ -376,12 +392,40 @@ static void init_pkvm_hyp_vm(struct kvm *host_kvm, struct pkvm_hyp_vm *hyp_vm,
pkvm_init_features_from_host(hyp_vm, host_kvm);
}
-static void pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *host_vcpu)
+static int pkvm_vcpu_init_sve(struct pkvm_hyp_vcpu *hyp_vcpu, struct kvm_vcpu *host_vcpu)
{
struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;
+ unsigned int sve_max_vl;
+ size_t sve_state_size;
+ void *sve_state;
+ int ret = 0;
- if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE))
+ if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE)) {
vcpu_clear_flag(vcpu, VCPU_SVE_FINALIZED);
+ return 0;
+ }
+
+ /* Limit guest vector length to the maximum supported by the host. */
+ sve_max_vl = min(READ_ONCE(host_vcpu->arch.sve_max_vl), kvm_host_sve_max_vl);
+ sve_state_size = sve_state_size_from_vl(sve_max_vl);
+ sve_state = kern_hyp_va(READ_ONCE(host_vcpu->arch.sve_state));
+
+ if (!sve_state || !sve_state_size) {
+ ret = -EINVAL;
+ goto err;
+ }
+
+ ret = hyp_pin_shared_mem(sve_state, sve_state + sve_state_size);
+ if (ret)
+ goto err;
+
+ vcpu->arch.sve_state = sve_state;
+ vcpu->arch.sve_max_vl = sve_max_vl;
+
+ return 0;
+err:
+ clear_bit(KVM_ARM_VCPU_SVE, vcpu->kvm->arch.vcpu_features);
+ return ret;
}
static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu,
@@ -416,7 +460,7 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu,
if (ret)
goto done;
- pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);
+ ret = pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);
done:
if (ret)
unpin_host_vcpu(host_vcpu);
--
2.48.1.658.g4767266eb4-goog
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