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| author | Paolo Bonzini <pbonzini@redhat.com> | 2021-11-30 13:37:45 +0100 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-12-02 10:12:11 +0100 |
| commit | ef8b4b7203682cc9adb37c8336d3f0f3b80bc382 (patch) | |
| tree | c669580c30f5a082940b346cb4ed1260c640fc86 /arch/x86/kvm/x86.c | |
| parent | KVM: x86/pmu: Fix reserved bits for AMD PerfEvtSeln register (diff) | |
| download | linux-ef8b4b7203682cc9adb37c8336d3f0f3b80bc382.tar.xz linux-ef8b4b7203682cc9adb37c8336d3f0f3b80bc382.zip | |
KVM: ensure APICv is considered inactive if there is no APIC
kvm_vcpu_apicv_active() returns false if a virtual machine has no in-kernel
local APIC, however kvm_apicv_activated might still be true if there are
no reasons to disable APICv; in fact it is quite likely that there is none
because APICv is inhibited by specific configurations of the local APIC
and those configurations cannot be programmed. This triggers a WARN:
WARN_ON_ONCE(kvm_apicv_activated(vcpu->kvm) != kvm_vcpu_apicv_active(vcpu));
To avoid this, introduce another cause for APICv inhibition, namely the
absence of an in-kernel local APIC. This cause is enabled by default,
and is dropped by either KVM_CREATE_IRQCHIP or the enabling of
KVM_CAP_IRQCHIP_SPLIT.
Reported-by: Ignat Korchagin <ignat@cloudflare.com>
Fixes: ee49a8932971 ("KVM: x86: Move SVM's APICv sanity check to common x86", 2021-10-22)
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Tested-by: Ignat Korchagin <ignat@cloudflare.com>
Message-Id: <20211130123746.293379-1-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0ee1a039b490..e0aa4dd53c7f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5740,6 +5740,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, smp_wmb(); kvm->arch.irqchip_mode = KVM_IRQCHIP_SPLIT; kvm->arch.nr_reserved_ioapic_pins = cap->args[0]; + kvm_request_apicv_update(kvm, true, APICV_INHIBIT_REASON_ABSENT); r = 0; split_irqchip_unlock: mutex_unlock(&kvm->lock); @@ -6120,6 +6121,7 @@ set_identity_unlock: /* Write kvm->irq_routing before enabling irqchip_in_kernel. */ smp_wmb(); kvm->arch.irqchip_mode = KVM_IRQCHIP_KERNEL; + kvm_request_apicv_update(kvm, true, APICV_INHIBIT_REASON_ABSENT); create_irqchip_unlock: mutex_unlock(&kvm->lock); break; @@ -8818,10 +8820,9 @@ static void kvm_apicv_init(struct kvm *kvm) { init_rwsem(&kvm->arch.apicv_update_lock); - if (enable_apicv) - clear_bit(APICV_INHIBIT_REASON_DISABLE, - &kvm->arch.apicv_inhibit_reasons); - else + set_bit(APICV_INHIBIT_REASON_ABSENT, + &kvm->arch.apicv_inhibit_reasons); + if (!enable_apicv) set_bit(APICV_INHIBIT_REASON_DISABLE, &kvm->arch.apicv_inhibit_reasons); } |