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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 5p1AZa2f0Ztocgdnv08V5TkUJQ9TcdshwgVL3jvORnw+PXe4oVJsxs3GV6lEVr8rr/ZIN8McT4GzZ9ta1/V1z+ObvJHGaWlwKBKDnoGTCwyDL6fz13t/VpR88f66n6NZ92bWILcXmGrZ4TQETjQkzqFBtoxWwVDc7dVkJpeih0Mee24pCChq7jsa4gEmQ6aQm9Z7lgAH+GHxPKhSO8jFU3VbXPHgOrGoyAs7cBauifoiXd+Azs9s4n5mxOdbkgXaBXw2/Q5pZoAU7OeRlKBkp4O/H6IqW25knE8YU7bgxs3+eNRKHEFhja9h8p1E06FC/0WMqD4RALaupHAKVNJG5mIPVzl+hKqfnW66fGm7rryLrCCEf2X8X9cFgyXbJHyUBK8gFWy0k4l/QWE4wkrusqyKB7CH1SpdtiRPx6GyoSZbL8qDulusv7lAA89vp6v+ X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Mar 2026 04:54:18.3532 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: d49a298b-0df8-4e1d-0e67-08de7f2a40b5 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SN1PEPF00026369.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR12MB6580 On 3/11/2026 2:48 AM, Sean Christopherson wrote: > Don't set the CR8 write intercept when disabling AVIC for SEV-ES vCPUs, as > attempting to intercept CR8 will generate a #VC and in all likelihood kill > the VM. > > Note! At first glance, one might think KVM's handling of CR8 write traps > for SEV-ES is flawed, as KVM traps CR8 writes even when AVIC is enabled, > despite the fact that hardware updates the AVIC backing page as well. But > KVM unconditionally inhibits AVIC for SEV-ES guests as current hardware > apparently can't support it (see c538dc792ff7 ("KVM: SVM: Do not activate > AVIC for SEV-enabled guest")). > > However, KVM's overall handling of CR8 _is_ broken, as sync_cr8_to_lapic() > will clobber with stale information from the unencrypted VMCB. That issue > will be fixed separately. > > Reported-by: Srikanth Aithal > Closes: https://lore.kernel.org/all/19935696-36cf-411b-af90-aabe6a98d7e7@amd.com > Fixes: e992bf67bcba ("KVM: SVM: Set/clear CR8 write interception when AVIC is (de)activated") > Cc: stable@vger.kernel.org > Acked-by: Naveen N Rao (AMD) > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/svm/avic.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c > index 13a4a8949aba..f7ec7914e3c4 100644 > --- a/arch/x86/kvm/svm/avic.c > +++ b/arch/x86/kvm/svm/avic.c > @@ -226,7 +226,8 @@ static void avic_deactivate_vmcb(struct vcpu_svm *svm) > vmcb->control.int_ctl &= ~(AVIC_ENABLE_MASK | X2APIC_MODE_MASK); > vmcb->control.avic_physical_id &= ~AVIC_PHYSICAL_MAX_INDEX_MASK; > > - svm_set_intercept(svm, INTERCEPT_CR8_WRITE); > + if (!sev_es_guest(svm->vcpu.kvm)) > + svm_set_intercept(svm, INTERCEPT_CR8_WRITE); > > /* > * If running nested and the guest uses its own MSR bitmap, there This fixes the SEV-ES boot issue. Thank you. Tested-by: Srikanth Aithal