From f99b052256f16224687e5947772f0942bff73fc1 Mon Sep 17 00:00:00 2001 From: Ravi Bangoria Date: Wed, 5 Jun 2024 11:48:10 +0000 Subject: [PATCH] KVM: SNP: Fix LBR Virtualization for SNP guest SEV-ES and thus SNP guest mandates LBR Virtualization to be _always_ ON. Although commit b7e4be0a224f ("KVM: SEV-ES: Delegate LBR virtualization to the processor") did the correct change for SEV-ES guests, it missed the SNP. Fix it. Reported-by: Srikanth Aithal Fixes: b7e4be0a224f ("KVM: SEV-ES: Delegate LBR virtualization to the processor") Signed-off-by: Ravi Bangoria Message-ID: <20240605114810.1304-1-ravi.bangoria@amd.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/sev.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 113243daa3d6..df8818759698 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2402,6 +2402,14 @@ static int snp_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp) } svm->vcpu.arch.guest_state_protected = true; + /* + * SEV-ES (and thus SNP) guest mandates LBR Virtualization to + * be _always_ ON. Enable it only after setting + * guest_state_protected because KVM_SET_MSRS allows dynamic + * toggling of LBRV (for performance reason) on write access to + * MSR_IA32_DEBUGCTLMSR when guest_state_protected is not set. + */ + svm_enable_lbrv(vcpu); } return 0;