KVM: x86: Allow APICv APIC ID inhibit to be cleared

Browse source

Legacy kernels prior to commit 4399c03c67 ("x86/apic: Remove
verify_local_APIC()") write the APIC ID of the boot CPU twice to verify
a functioning local APIC.  This results in APIC acceleration inhibited
on these kernels for reason APICV_INHIBIT_REASON_APIC_ID_MODIFIED.

Allow the APICV_INHIBIT_REASON_APIC_ID_MODIFIED inhibit reason to be
cleared if/when all APICs in xAPIC mode set their APIC ID back to the
expected vcpu_id value.

Fold the functionality previously in kvm_lapic_xapic_id_updated() into
kvm_recalculate_apic_map(), as this allows examining all APICs in one
pass.

Fixes: 3743c2f025 ("KVM: x86: inhibit APICv/AVIC on changes to APIC ID or APIC base")
Signed-off-by: Greg Edwards <gedwards@ddn.com>
Link: https://lore.kernel.org/r/20221117183247.94314-1-gedwards@ddn.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230106011306.85230-33-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

...

This commit is contained in:

Greg Edwards 2023-01-06 01:13:05 +00:00 • committed by Paolo Bonzini

parent b3f257a846

commit d471bd853d

1 changed files with 15 additions and 26 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

41

arch/x86/kvm/lapic.c

View file