Re: [PATCH v2 00/43] KVM: Halt-polling and x86 APICv overhaul

From: Paolo Bonzini
Date: Wed Oct 27 2021 - 11:38:03 EST


On 27/10/21 17:28, Sean Christopherson wrote:
On Wed, Oct 27, 2021, Paolo Bonzini wrote:
On 27/10/21 16:41, Sean Christopherson wrote:
The other thing I don't like about having the WARN in the loop is that it suggests
that something other than the vCPU can modify the NDST and SN fields, which is
wrong and confusing (for me).

Yeah, I can agree with that. Can you add it in a comment above the cmpxchg
loop, it can be as simple as

/* The processor can set ON concurrently. */

when you respin patch 21 and the rest of the series?

I can definitely add a comment, but I think that comment is incorrect.

It's completely backwards indeed. I first had "the hardware" and then shut down my brain for a second to replace it.

So something like this?

/* ON can be set concurrently by a different vCPU or by hardware. */

Yes, of course.

Paolo