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| author | Sean Christopherson <seanjc@google.com> | 2024-09-05 21:34:07 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-09-09 20:14:57 -0700 |
| commit | a194a3a13ce0b4cce4b52f328405891ef3a85cb9 (patch) | |
| tree | 4dfd600c1f2ef8fddb056aef58fde305ae58005c /arch/x86/kvm/lapic.h | |
| parent | KVM: VMX: Also clear SGX EDECCSSA in KVM CPU caps when SGX is disabled (diff) | |
| download | linux-a194a3a13ce0b4cce4b52f328405891ef3a85cb9.tar.gz linux-a194a3a13ce0b4cce4b52f328405891ef3a85cb9.zip | |
KVM: x86: Move "ack" phase of local APIC IRQ delivery to separate API
Split the "ack" phase, i.e. the movement of an interrupt from IRR=>ISR,
out of kvm_get_apic_interrupt() and into a separate API so that nested
VMX can acknowledge a specific interrupt _after_ emulating a VM-Exit from
L2 to L1.
To correctly emulate nested posted interrupts while APICv is active, KVM
must:
1. find the highest pending interrupt.
2. check if that IRQ is L2's notification vector
3. emulate VM-Exit if the IRQ is NOT the notification vector
4. ACK the IRQ in L1 _after_ VM-Exit
When APICv is active, the process of moving the IRQ from the IRR to the
ISR also requires a VMWRITE to update vmcs01.GUEST_INTERRUPT_STATUS.SVI,
and so acknowledging the interrupt before switching to vmcs01 would result
in marking the IRQ as in-service in the wrong VMCS.
KVM currently fudges around this issue by doing kvm_get_apic_interrupt()
smack dab in the middle of emulating VM-Exit, but that hack doesn't play
nice with nested posted interrupts, as notification vector IRQs don't
trigger a VM-Exit in the first place.
Cc: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240906043413.1049633-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/lapic.h')
| -rw-r--r-- | arch/x86/kvm/lapic.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 7ef8ae73e82d..db80a2965b9c 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -88,6 +88,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu); void kvm_free_lapic(struct kvm_vcpu *vcpu); int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu); +void kvm_apic_ack_interrupt(struct kvm_vcpu *vcpu, int vector); int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu); int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu); int kvm_apic_accept_events(struct kvm_vcpu *vcpu); |