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KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2

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pkvm_init_features_from_host() takes KVM_ARCH_FLAG_GUEST_HAS_SVE and
KVM_ARM_VCPU_SVE from the host separately, but pkvm_vcpu_init_sve()
tests the bit while vcpu_has_sve() reads the flag. A host that sets the
flag without the bit gets a vCPU with a NULL sve_state that the world
switch loads the guest's SVE state from.

Derive the flag from the bit, and drop the protected path's copy of the
host's flag, which is dead code since protected VMs are not allowed SVE.

Fixes: 41d6028e28 ("KVM: arm64: Convert the SVE guest vcpu flag to a vm flag")
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Link: https://patch.msgid.link/20260825085948.1674721-5-fuad.tabba@linux.dev
Signed-off-by: Oliver Upton <oupton@kernel.org>
This commit is contained in:
Fuad Tabba 2026-08-25 09:59:48 +01:00 committed by Oliver Upton
parent 0d62fbf34d
commit 4f16c5fc8d
1 changed files with 5 additions and 4 deletions
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9
arch/arm64/kvm/hyp/nvhe/pkvm.c
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@ -360,7 +360,7 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc
if (test_bit(KVM_ARCH_FLAG_WRITABLE_IMP_ID_REGS, &host_arch_flags))
hyp_vm->kvm.arch.midr_el1 = host_kvm->arch.midr_el1;
return;
goto out;
}
if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_MTE))
@ -379,13 +379,14 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc
if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC))
set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features);
if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE)) {
if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE))
set_bit(KVM_ARM_VCPU_SVE, allowed_features);
kvm->arch.flags |= host_arch_flags & BIT(KVM_ARCH_FLAG_GUEST_HAS_SVE);
}
bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features,
allowed_features, KVM_VCPU_MAX_FEATURES);
out:
__assign_bit(KVM_ARCH_FLAG_GUEST_HAS_SVE, &kvm->arch.flags,
kvm_vcpu_has_feature(kvm, KVM_ARM_VCPU_SVE));
}
static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu)