KVM: nVMX: Add a helper to get highest pending from Posted Interrupt vector

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Add a helper to retrieve the highest pending vector given a Posted
Interrupt descriptor.  While the actual operation is straightforward, it's
surprisingly easy to mess up, e.g. if one tries to reuse lapic.c's
find_highest_vector(), which doesn't work with PID.PIR due to the APIC's
IRR and ISR component registers being physically discontiguous (they're
4-byte registers aligned at 16-byte intervals).

To make PIR handling more consistent with respect to IRR and ISR handling,
return -1 to indicate "no interrupt pending".

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240607172609.3205077-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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Sean Christopherson 2024-06-07 10:26:04 -07:00

parent 92c1e3cbf0

commit d83c36d822

2 changed files with 13 additions and 2 deletions

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5

arch/x86/kvm/vmx/nested.c

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10

arch/x86/kvm/vmx/posted_intr.h

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