diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-01-06 04:12:56 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-01-13 18:45:31 +0300 |
| commit | 5063c41bebac8d18a83ac7b5d54782d73a9ab5f7 (patch) | |
| tree | ea2ba91d40500855f925a9dd00a3b172a7e42903 /arch/x86/include/asm/kvm_host.h | |
| parent | 5b84b0291702ea84db2c9e55696cdcdd95f9cf1a (diff) | |
| download | linux-5063c41bebac8d18a83ac7b5d54782d73a9ab5f7.tar.xz | |
KVM: x86: Inhibit APICv/AVIC if the optimized physical map is disabled
Inhibit APICv/AVIC if the optimized physical map is disabled so that KVM
KVM provides consistent APIC behavior if xAPIC IDs are aliased due to
vcpu_id being truncated and the x2APIC hotplug hack isn't enabled. If
the hotplug hack is disabled, events that are emulated by KVM will follow
architectural behavior (all matching vCPUs receive events, even if the
"match" is due to truncation), whereas APICv and AVIC will deliver events
only to the first matching vCPU, i.e. the vCPU that matches without
truncation.
Note, the "extra" inhibit is needed because KVM deliberately ignores
mismatches due to truncation when applying the APIC_ID_MODIFIED inhibit
so that large VMs (>255 vCPUs) can run with APICv/AVIC.
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-24-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/kvm_host.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 732421a0ad02..5865bad08a23 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1175,6 +1175,12 @@ enum kvm_apicv_inhibit { APICV_INHIBIT_REASON_BLOCKIRQ, /* + * APICv is disabled because not all vCPUs have a 1:1 mapping between + * APIC ID and vCPU, _and_ KVM is not applying its x2APIC hotplug hack. + */ + APICV_INHIBIT_REASON_PHYSICAL_ID_ALIASED, + + /* * For simplicity, the APIC acceleration is inhibited * first time either APIC ID or APIC base are changed by the guest * from their reset values. |