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Commit 3ec7a1b2 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: SVM: Fix a benign off-by-one bug in AVIC physical table mask



Define the "physical table max index mask" as bits 8:0, not 9:0.  x2AVIC
currently supports a max of 512 entries, i.e. the max index is 511, and
the inputs to GENMASK_ULL() are inclusive.  The bug is benign as bit 9 is
reserved and never set by KVM, i.e. KVM is just clearing bits that are
guaranteed to be zero.

Note, as of this writing, APM "Rev. 3.39-October 2022" incorrectly states
that bits 11:8 are reserved in Table B-1. VMCB Layout, Control Area.  I.e.
that table wasn't updated when x2AVIC support was added.

Opportunistically fix the comment for the max AVIC ID to align with the
code, and clean up comment formatting too.

Fixes: 4d1d7942 ("KVM: SVM: Introduce logic to (de)activate x2AVIC mode")
Cc: stable@vger.kernel.org
Cc: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Tested-by: default avatarSuravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Message-Id: <20230207002156.521736-2-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3dc40cf8
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