Re: [PATCH] kvm:vmx: update secondary controls when disabling APICv

[Roman Kagan <rkagan@virtuozzo.com>]

On Mon, May 16, 2016 at 01:15:39PM -0700, Steve Rutherford wrote:
> After updating the secondary execution controls, the MSR bitmaps need
> to be updated to enable APIC MSR intercepts (i.e. start treating APIC
> MSRs as if the guest's APICs are back in xAPIC mode by calling
> vmx_set_msr_bitmap, given that updating the execution controls should
> disable "virtualize x2APIC mode").

Indeed.  I didn't notice that in my tests because Windows doesn't use
x2apic (they use their own apic access msrs).

> The function vmx_set_msr_bitmap needs to look at the state of APICv to
> know that "virtualize x2APIC mode" was disabled.

OK

> Also, calling vmx_secondary_exec_control clobbers /all/ dynamic bits
> in the secondary controls (including the shadow VMCS bits). Those bits
> needs to be respected (ideally this patch should just whack all of the
> APICv related secondary execution controls).

I probably misunderstood the intent of vmx_*exec_control functions.  OK
I'll clear the relevant bits in vmcs directly instead.  I wonder if I
should also do so for PIN_BASED_POSTED_INTR?

> I can put together a patch if you'd like.

I'll try myself but I won't mind if you beat me to it :)

Roman.