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KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid target

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[ Upstream commit 5aede752a839904059c2b5d68be0dc4501c6c15f ]

Emulate ICR writes on AVIC IPI failures due to invalid targets using the
same logic as failures due to invalid types.  AVIC acceleration fails if
_any_ of the targets are invalid, and crucially VM-Exits before sending
IPIs to targets that _are_ valid.  In logical mode, the destination is a
bitmap, i.e. a single IPI can target multiple logical IDs.  Doing nothing
causes KVM to drop IPIs if at least one target is valid and at least one
target is invalid.

Fixes: 18f40c53e10f ("svm: Add VMEXIT handlers for AVIC")
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Sean Christopherson 2023-01-06 01:12:37 +00:00 committed by Greg Kroah-Hartman
parent a78a355052
commit c5a23d43c2
1 changed files with 9 additions and 7 deletions
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16
arch/x86/kvm/svm/avic.c
View File

@ -318,14 +318,18 @@ int avic_incomplete_ipi_interception(struct kvm_vcpu *vcpu)
trace_kvm_avic_incomplete_ipi(vcpu->vcpu_id, icrh, icrl, id, index);
switch (id) {
case AVIC_IPI_FAILURE_INVALID_TARGET:
case AVIC_IPI_FAILURE_INVALID_INT_TYPE:
/*
* Emulate IPIs that are not handled by AVIC hardware, which
* only virtualizes Fixed, Edge-Triggered INTRs. The exit is
* a trap, e.g. ICR holds the correct value and RIP has been
* advanced, KVM is responsible only for emulating the IPI.
* Sadly, hardware may sometimes leave the BUSY flag set, in
* which case KVM needs to emulate the ICR write as well in
* only virtualizes Fixed, Edge-Triggered INTRs, and falls over
* if _any_ targets are invalid, e.g. if the logical mode mask
* is a superset of running vCPUs.
*
* The exit is a trap, e.g. ICR holds the correct value and RIP
* has been advanced, KVM is responsible only for emulating the
* IPI. Sadly, hardware may sometimes leave the BUSY flag set,
* in which case KVM needs to emulate the ICR write as well in
* order to clear the BUSY flag.
*/
if (icrl & APIC_ICR_BUSY)
@ -341,8 +345,6 @@ int avic_incomplete_ipi_interception(struct kvm_vcpu *vcpu)
*/
avic_kick_target_vcpus(vcpu->kvm, apic, icrl, icrh);
break;
case AVIC_IPI_FAILURE_INVALID_TARGET:
break;
case AVIC_IPI_FAILURE_INVALID_BACKING_PAGE:
WARN_ONCE(1, "Invalid backing page\n");
break;