linux-kernel - Re: [PATCH] KVM: selftests: Wait mprotect_ro_done before write to RO in mmu_stress

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Message-ID: <Z8HBh1WR3CqcJkJQ@google.com>
Date: Fri, 28 Feb 2025 06:00:39 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Yan Zhao <yan.y.zhao@...el.com>
Cc: pbonzini@...hat.com, rick.p.edgecombe@...el.com, 
	linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH] KVM: selftests: Wait mprotect_ro_done before write to RO
 in mmu_stress_test

On Fri, Feb 28, 2025, Yan Zhao wrote:
> On Thu, Feb 27, 2025 at 02:18:02PM -0800, Sean Christopherson wrote:
> > On Thu, Feb 27, 2025, Yan Zhao wrote:
> So, I think the right one is:
> -	} while (!READ_ONCE(mprotect_ro_done));
> +	} while (!READ_ONCE(mprotect_ro_done) || !READ_ONCE(all_vcpus_hit_ro_fault));

/double facepalm

You're 100% correct.  I did most of my testing with just the all_vcpus_hit_ro_fault
check, and then botched things when adding back mprotect_ro_done.