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KVM: arm64: Track SVE state in the hypervisor vcpu structure

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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@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20250416152648.2982950-2-qperret@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Fuad Tabba 2025-04-16 15:26:41 +00:00 committed by Marc Zyngier
parent b4432656b3
commit 5db1bef933
3 changed files with 51 additions and 12 deletions
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12
arch/arm64/include/asm/kvm_host.h
View File

@ -971,20 +971,22 @@ 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 | \

4
arch/arm64/kvm/hyp/nvhe/hyp-main.c
View File

@ -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) &

47
arch/arm64/kvm/hyp/nvhe/pkvm.c
View File

@ -372,6 +372,18 @@ 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)
{
@ -384,6 +396,7 @@ static void unpin_host_vcpus(struct pkvm_hyp_vcpu *hyp_vcpus[],
continue;
unpin_host_vcpu(hyp_vcpu->host_vcpu);
unpin_host_sve_state(hyp_vcpu);
}
}
@ -398,12 +411,40 @@ 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,
@ -432,7 +473,7 @@ 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);