Re: [PATCH v3 18/62] KVM: SVM: Disable (x2)AVIC IPI virtualization if CPU has erratum #1235
From: Sean Christopherson <seanjc@google.com>
Date: 2025-06-23 15:30:08
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kvm, kvmarm, linux-iommu, lkml
On Mon, Jun 23, 2025, Naveen N Rao wrote:
On Wed, Jun 11, 2025 at 03:45:21PM -0700, Sean Christopherson wrote:quoted
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 48c737e1200a..bf8b59556373 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c@@ -1187,6 +1187,14 @@ bool avic_hardware_setup(void) if (x2avic_enabled) pr_info("x2AVIC enabled\n"); + /* + * Disable IPI virtualization for AMD Family 17h CPUs (Zen1 and Zen2) + * due to erratum 1235, which results in missed GA log events and thus^^^^^^^^^^^^^ Not sure I understand the reference to GA log events here -- those are only for device interrupts and not IPIs.
Doh, you're absolutely right. I'll fix to this when applying: /* * Disable IPI virtualization for AMD Family 17h CPUs (Zen1 and Zen2) * due to erratum 1235, which results in missed VM-Exits on the sender * and thus missed wake events for blocking vCPUs due to the CPU * failing to see a software update to clear IsRunning. */