From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
AND 64-BIT)), Wanpeng Li <wanpengli@tencent.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>, "H. Peter Anvin" <hpa@zytor.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Jim Mattson <jmattson@google.com>,
Sean Christopherson <seanjc@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 1/6] KVM: SVM: allow to force AVIC to be enabled
Date: Thu, 9 Dec 2021 13:54:35 +0200 [thread overview]
Message-ID: <20211209115440.394441-2-mlevitsk@redhat.com> (raw)
In-Reply-To: <20211209115440.394441-1-mlevitsk@redhat.com>
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 <mlevitsk@redhat.com>
---
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 dde0106ffc47..6fbce42b9776 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -206,6 +206,9 @@ 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);
@@ -1058,10 +1061,14 @@ 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);
}
--
2.26.3
next prev parent reply other threads:[~2021-12-09 11:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 11:54 [PATCH 0/6] RFC: KVM: SVM: Allow L1's AVIC to co-exist with nesting Maxim Levitsky
2021-12-09 11:54 ` Maxim Levitsky [this message]
2021-12-09 11:54 ` [PATCH 2/6] KVM: x86: add a tracepoint for APICv/AVIC interrupt delivery Maxim Levitsky
2021-12-09 11:54 ` [PATCH 3/6] KVM: SVM: fix AVIC race of host->guest IPI delivery vs AVIC inhibition Maxim Levitsky
2021-12-09 14:11 ` Paolo Bonzini
2021-12-09 14:26 ` Maxim Levitsky
2021-12-09 15:27 ` Sean Christopherson
2021-12-09 15:33 ` Maxim Levitsky
2021-12-09 15:35 ` Maxim Levitsky
2021-12-09 11:54 ` [PATCH 4/6] KVM: SVM: fix races in the AVIC incomplete IPI delivery to vCPUs Maxim Levitsky
2021-12-09 15:38 ` Sean Christopherson
2021-12-10 11:37 ` Paolo Bonzini
2021-12-09 11:54 ` [PATCH 5/6] KVM: x86: never clear irr_pending in kvm_apic_update_apicv Maxim Levitsky
2021-12-09 14:12 ` Paolo Bonzini
2021-12-09 15:03 ` Maxim Levitsky
2021-12-10 12:07 ` Paolo Bonzini
2021-12-10 12:20 ` Maxim Levitsky
2021-12-10 12:47 ` Maxim Levitsky
2021-12-10 13:03 ` Paolo Bonzini
2021-12-10 13:10 ` Maxim Levitsky
2021-12-09 11:54 ` [PATCH 6/6] KVM: SVM: allow AVIC to co-exist with a nested guest running Maxim Levitsky
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