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KVM: nSVM: Ensure AVIC is inhibited when restoring a vCPU to guest mode

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On nested VMRUN, KVM ensures AVIC is inhibited by requesting
KVM_REQ_APICV_UPDATE, triggering a check of inhibit reasons, finding
APICV_INHIBIT_REASON_NESTED, and disabling AVIC.

However, when KVM_SET_NESTED_STATE is performed on a vCPU not in guest
mode with AVIC enabled, KVM_REQ_APICV_UPDATE is not requested, and AVIC
is not inhibited.

Request KVM_REQ_APICV_UPDATE in the KVM_SET_NESTED_STATE path if AVIC is
active, similar to the nested VMRUN path.

Fixes: f44509f849 ("KVM: x86: SVM: allow AVIC to co-exist with a nested guest running")
Cc: stable@vger.kernel.org
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260224225017.3303870-1-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Yosry Ahmed 2026-02-24 22:50:17 +00:00 committed by Sean Christopherson
parent e63fb1379f
commit 24f7d36b82
1 changed files with 3 additions and 0 deletions
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3
arch/x86/kvm/svm/nested.c
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@ -1928,6 +1928,9 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
svm->nested.force_msr_bitmap_recalc = true;
if (kvm_vcpu_apicv_active(vcpu))
kvm_make_request(KVM_REQ_APICV_UPDATE, vcpu);
kvm_make_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
ret = 0;
out_free: