KVM: Clear pv eoi pending bit only when it is set

Browse source

merge pv_eoi_get_pending and pv_eoi_clr_pending into a single
function pv_eoi_test_and_clear_pending, which returns and clear
the value of the pending bit.

This makes it possible to clear the pending bit only if the guest
had set it, and otherwise skip the call to pv_eoi_put_user().
This can save up to 300 nsec on AMD EPYC processors.

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Message-Id: <1636026974-50555-2-git-send-email-lirongqing@baidu.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

...

This commit is contained in:

Li RongQing 2021-11-04 19:56:14 +08:00 • committed by Paolo Bonzini

parent ce5977b181

commit 51b1209c61

1 changed files with 19 additions and 21 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

40

arch/x86/kvm/lapic.c

View file