Paolo Bonzini <pbonzini@xxxxxxxxxx> writes: > On 03/02/21 07:40, Kechen Lu wrote: >> From the above observations, trying to see if there's a way for >> enabling AVIC while also having the most optimized clock source for >> windows guest. >> > > You would have to change KVM, so that AVIC is only disabled if Auto-EOI > interrupts are used. > (I vaguely recall having this was discussed already but apparently no changes were made since) Hyper-V TLFS defines the following bit: CPUID 0x40000004.EAX Bit 9: Recommend deprecating AutoEOI. But this is merely a recommendation and older Windows versions may not know about the bit and still use it. We need to make sure the bit is set/exposed to Windows guests but we also must track AutoEOI usage and inhibit AVIC when detected. -- Vitaly
