From: Tina Zhang Date: Fri, 22 May 2026 04:00:14 +0000 (+0800) Subject: KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235) X-Git-Tag: v7.1-rc5~1^2 X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=9a12fa5213cfc391e0eed63902d3be98f0913765;p=thirdparty%2Fkernel%2Fstable.git KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235) Hygon Family 18h CPUs are derived from AMD Family 17h (Zen1) silicon and share the same erratum #1235: hardware may read a stale IsRunning=1 bit during ICR write emulation and silently fail to generate an AVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit on the sending vCPU. The absence of the VM-Exit causes KVM to miss the required wakeup of blocking target vCPUs, leading to hung vCPUs and unbounded delays in guest execution. Extend the existing AMD Family 17h erratum #1235 workaround to also cover Hygon Family 18h. With IPI virtualization disabled, KVM never sets IsRunning=1 in the Physical ID table, so every non-self IPI generates a VM-Exit and is correctly emulated. Fixes: 8de4a1c8164e ("KVM: SVM: Disable (x2)AVIC IPI virtualization if CPU has erratum #1235") Cc: Signed-off-by: Tina Zhang Message-ID: <20260522040014.3380201-1-zhang_wei@open-hieco.net> --- diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index adf211860949a..993b551180fe9 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -1300,12 +1300,14 @@ bool __init avic_hardware_setup(void) } /* - * 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. + * Disable IPI virtualization for AMD Family 17h (Zen1 and Zen2) and + * Hygon Family 18h (derived from AMD Zen1) CPUs 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. */ - enable_ipiv = enable_ipiv && boot_cpu_data.x86 != 0x17; + if (boot_cpu_data.x86 == 0x17 || boot_cpu_data.x86 == 0x18) + enable_ipiv = false; amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier);