2016-10-17 18:08 GMT+08:00 Paolo Bonzini <pbonz...@redhat.com>: [...] >> > Something like the below avoids all that. Paravirt will still need fixing. >> >> kvm_guest_apic_eoi_write >> -> native_apic_msr_write > > kvm_guest_apic_eoi_write can use native_apic_msr_eoi_write too: > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index f5aaf6c83222..9769d76a62c4 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -174,7 +174,7 @@ static inline void disable_local_APIC(void) { } > static inline void lapic_update_tsc_freq(void) { } > #endif /* !CONFIG_X86_LOCAL_APIC */ > > -#ifdef CONFIG_X86_X2APIC > +#if defined CONFIG_X86_X2APIC || defined CONFIG_KVM_GUEST
If CONFIG_X86_X2APIC is undefined and CONFIG_KVM_GUEST is defined, there are undefined reference warning for x2apic_mode and check_x2apic etc since they are extern variables and just define under CONFIG_X86_X2APIC. > /* > * Make previous memory operations globally visible before > * sending the IPI through x2apic wrmsr. We need a serializing instruction or > diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c > index edbbfc854e39..61cc6a5e3f44 100644 > --- a/arch/x86/kernel/kvm.c > +++ b/arch/x86/kernel/kvm.c > @@ -319,7 +319,7 @@ static void kvm_guest_apic_eoi_write(u32 reg, u32 val) > */ > if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi))) > return; > - apic_write(APIC_EOI, APIC_EOI_ACK); > + native_apic_msr_eoi_write(APIC_EOI, APIC_EOI_ACK); > } If -cpu host,-x2apic we should go through mmio when writes xapic EOI. Regards, Wanpeng Li