[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240605114810.1304-1-ravi.bangoria@amd.com>
Date: Wed, 5 Jun 2024 11:48:10 +0000
From: Ravi Bangoria <ravi.bangoria@....com>
To: <seanjc@...gle.com>, <pbonzini@...hat.com>, <nikunj.dadhania@....com>,
<sraithal@....com>
CC: <ravi.bangoria@....com>, <thomas.lendacky@....com>, <tglx@...utronix.de>,
<mingo@...hat.com>, <bp@...en8.de>, <dave.hansen@...ux.intel.com>,
<x86@...nel.org>, <hpa@...or.com>, <michael.roth@....com>,
<pankaj.gupta@....com>, <kvm@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <santosh.shukla@....com>
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 <sraithal@....com>
Fixes: b7e4be0a224f ("KVM: SEV-ES: Delegate LBR virtualization to the processor")
Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
---
- SNP support was not present while I prepared the original patches and
that lead to this confusion. Sorry about that.
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 7d401f8a3001..57291525e084 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2395,6 +2395,14 @@ 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;
--
2.45.1
Powered by blists - more mailing lists