On 19/10/2016 16:30, Wanpeng Li wrote: > Cc Radim, > 2016-10-19 22:10 GMT+08:00 Paolo Bonzini <pbonz...@redhat.com>: >> >> >> On 19/10/2016 16:01, Wanpeng Li wrote: >>> 2016-10-18 8:01 GMT+08:00 Wanpeng Li <kernel...@gmail.com>: >>>> 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. >>> > > This results in undefined reference warning. > >>> >>>> >>>> If -cpu host,-x2apic we should go through mmio when writes xapic EOI. >>> >>> Any ideas? :) >> >> Make apic_set_eoi_write return the old pointer? > > Could you elaborate? :)
No, that won't work due to how struct apic works and how apic_set_eoi_write patches it. One possibility then is to add a void (*native_eoi_write)(u32 reg, u32 v); field to struct apic, and make apic_set_eoi_write set (*drv)->native_eoi_write = (*drv)->eoi_write; (*drv)->eoi_write = eoi_write; Then kvm.c can call apic->native_eoi_write(reg, v); Thanks, Paolo