From 83be2d9a01ff9715fcf728f1c3cfb7d631c690bf Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Tue, 1 Mar 2022 16:36:49 +0200 Subject: [PATCH] KVM: x86: SVM: allow to force AVIC to be enabled Apparently on some systems AVIC is disabled in CPUID but still usable. Allow the user to override the CPUID if the user is willing to take the risk. Signed-off-by: Maxim Levitsky Message-Id: <20220301143650.143749-7-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/svm.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 653a7bf93bb3f..e7e5084908a77 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -202,6 +202,9 @@ module_param(tsc_scaling, int, 0444); static bool avic; module_param(avic, bool, 0444); +static bool force_avic; +module_param_unsafe(force_avic, bool, 0444); + bool __read_mostly dump_invalid_vmcb; module_param(dump_invalid_vmcb, bool, 0644); @@ -4821,10 +4824,14 @@ static __init int svm_hardware_setup(void) nrips = false; } - enable_apicv = avic = avic && npt_enabled && boot_cpu_has(X86_FEATURE_AVIC); + enable_apicv = avic = avic && npt_enabled && (boot_cpu_has(X86_FEATURE_AVIC) || force_avic); if (enable_apicv) { - pr_info("AVIC enabled\n"); + if (!boot_cpu_has(X86_FEATURE_AVIC)) { + pr_warn("AVIC is not supported in CPUID but force enabled"); + pr_warn("Your system might crash and burn"); + } else + pr_info("AVIC enabled\n"); amd_iommu_register_ga_log_notifier(&avic_ga_log_notifier); } else { -- 2.50.1