From: Sean Christopherson Date: Fri, 15 Jan 2021 22:03:53 +0000 (-0800) Subject: x86/apic: Export x2apic_mode for use by KVM in "warm" path X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=db7d8e476821df85dce0cfd1e654c72c7db879dc;p=linux.git x86/apic: Export x2apic_mode for use by KVM in "warm" path 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 Message-Id: <20210115220354.434807-2-seanjc@google.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 6bd20c0de8bc6..dea2b44966ca3 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1743,6 +1743,7 @@ void apic_ap_setup(void) #ifdef CONFIG_X86_X2APIC int x2apic_mode; +EXPORT_SYMBOL_GPL(x2apic_mode); enum { X2APIC_OFF,