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| author | Liran Alon <liran.alon@oracle.com> | 2018-03-21 02:50:31 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-03-21 14:16:44 +0100 |
| commit | e40ff1d6608dd9a5e07d7bc3079c64d9d676fe15 (patch) | |
| tree | bc58f4634f5f5b99e32c5b414eb73c7b30fb8938 /arch/x86/kvm/x86.c | |
| parent | 35060ed6a1ffc92106904f5e4b5823ca4facfc73 (diff) | |
| download | lwn-e40ff1d6608dd9a5e07d7bc3079c64d9d676fe15.tar.gz lwn-e40ff1d6608dd9a5e07d7bc3079c64d9d676fe15.zip | |
KVM: nVMX: Do not load EOI-exitmap while running L2
When L1 IOAPIC redirection-table is written, a request of
KVM_REQ_SCAN_IOAPIC is set on all vCPUs. This is done such that
all vCPUs will now recalc their IOAPIC handled vectors and load
it to their EOI-exitmap.
However, it could be that one of the vCPUs is currently running
L2. In this case, load_eoi_exitmap() will be called which would
write to vmcs02->eoi_exit_bitmap, which is wrong because
vmcs02->eoi_exit_bitmap should always be equal to
vmcs12->eoi_exit_bitmap. Furthermore, at this point
KVM_REQ_SCAN_IOAPIC was already consumed and therefore we will
never update vmcs01->eoi_exit_bitmap. This could lead to remote_irr
of some IOAPIC level-triggered entry to remain set forever.
Fix this issue by delaying the load of EOI-exitmap to when vCPU
is running L1.
One may wonder why not just delay entire KVM_REQ_SCAN_IOAPIC
processing to when vCPU is running L1. This is done in order to handle
correctly the case where LAPIC & IO-APIC of L1 is pass-throughed into
L2. In this case, vmcs12->virtual_interrupt_delivery should be 0. In
current nVMX implementation, that results in
vmcs02->virtual_interrupt_delivery to also be 0. Thus,
vmcs02->eoi_exit_bitmap is not used. Therefore, every L2 EOI cause
a #VMExit into L0 (either on MSR_WRITE to x2APIC MSR or
APIC_ACCESS/APIC_WRITE/EPT_MISCONFIG to APIC MMIO page).
In order for such L2 EOI to be broadcasted, if needed, from LAPIC
to IO-APIC, vcpu->arch.ioapic_handled_vectors must be updated
while L2 is running. Therefore, patch makes sure to delay only the
loading of EOI-exitmap but not the update of
vcpu->arch.ioapic_handled_vectors.
Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.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 | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 26a8cd93be0c..9d19e6a31ed4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7110,8 +7110,6 @@ void kvm_make_scan_ioapic_request(struct kvm *kvm) static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) { - u64 eoi_exit_bitmap[4]; - if (!kvm_apic_hw_enabled(vcpu->arch.apic)) return; @@ -7124,6 +7122,20 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) kvm_x86_ops->sync_pir_to_irr(vcpu); kvm_ioapic_scan_entry(vcpu, vcpu->arch.ioapic_handled_vectors); } + + if (is_guest_mode(vcpu)) + vcpu->arch.load_eoi_exitmap_pending = true; + else + kvm_make_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu); +} + +static void vcpu_load_eoi_exitmap(struct kvm_vcpu *vcpu) +{ + u64 eoi_exit_bitmap[4]; + + if (!kvm_apic_hw_enabled(vcpu->arch.apic)) + return; + bitmap_or((ulong *)eoi_exit_bitmap, vcpu->arch.ioapic_handled_vectors, vcpu_to_synic(vcpu)->vec_bitmap, 256); kvm_x86_ops->load_eoi_exitmap(vcpu, eoi_exit_bitmap); @@ -7238,6 +7250,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) } if (kvm_check_request(KVM_REQ_SCAN_IOAPIC, vcpu)) vcpu_scan_ioapic(vcpu); + if (kvm_check_request(KVM_REQ_LOAD_EOI_EXITMAP, vcpu)) + vcpu_load_eoi_exitmap(vcpu); if (kvm_check_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu)) kvm_vcpu_reload_apic_access_page(vcpu); if (kvm_check_request(KVM_REQ_HV_CRASH, vcpu)) { |