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KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12

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svm_copy_lbrs() always marks VMCB_LBR dirty in the destination VMCB.
However, nested_svm_vmexit() uses it to copy LBRs to vmcb12, and
clearing clean bits in vmcb12 is not architecturally defined.

Move vmcb_mark_dirty() to callers and drop it for vmcb12.

This also facilitates incoming refactoring that does not pass the entire
VMCB to svm_copy_lbrs().

Fixes: d20c796ca3 ("KVM: x86: nSVM: implement nested LBR virtualization")
Cc: stable@vger.kernel.org
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260303003421.2185681-2-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Yosry Ahmed
2026-03-03 00:33:55 +00:00
committed by Sean Christopherson
parent d99df02ff4
commit b53ab5167a
2 changed files with 5 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/x86/kvm/svm/nested.c
+5 -2
View File
@@ -715,6 +715,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
} else {
svm_copy_lbrs(vmcb02, vmcb01);
}
vmcb_mark_dirty(vmcb02, VMCB_LBR);
svm_update_lbrv(&svm->vcpu);
}
@@ -1231,10 +1232,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);
if (unlikely(guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) &&
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK)))
(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) {
svm_copy_lbrs(vmcb12, vmcb02);
else
} else {
svm_copy_lbrs(vmcb01, vmcb02);
vmcb_mark_dirty(vmcb01, VMCB_LBR);
}
svm_update_lbrv(vcpu);
arch/x86/kvm/svm/svm.c
-2
View File
@@ -848,8 +848,6 @@ void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb)
to_vmcb->save.br_to = from_vmcb->save.br_to;
to_vmcb->save.last_excp_from = from_vmcb->save.last_excp_from;
to_vmcb->save.last_excp_to = from_vmcb->save.last_excp_to;
vmcb_mark_dirty(to_vmcb, VMCB_LBR);
}
static void __svm_enable_lbrv(struct kvm_vcpu *vcpu)