mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-09-27 21:03:32 +00:00
Code Issues Releases Wiki Activity

x86/apic: Export x2apic_mode for use by KVM in "warm" path

Browse source 
Export x2apic_mode so that KVM can query whether x2APIC is active
without having to incur the RDMSR in x2apic_enabled().  When Posted
Interrupts are in use for a guest with an assigned device, KVM ends up
checking for x2APIC at least once every time a vCPU halts.  KVM could
obviously snapshot x2apic_enabled() to avoid the RDMSR, but that's
rather silly given that x2apic_mode holds the exact info needed by KVM.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210115220354.434807-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-01-15 14:03:53 -08:00 committed by Paolo Bonzini
parent c32b1b896d
commit db7d8e4768
1 changed files with 1 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
arch/x86/kernel/apic/apic.c
View file

@ -1743,6 +1743,7 @@ void apic_ap_setup(void)
#ifdef CONFIG_X86_X2APIC
int x2apic_mode;
EXPORT_SYMBOL_GPL(x2apic_mode);
enum {
X2APIC_OFF,