Re: [PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls

Subject: Re: [PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Date: Tue, 3 Aug 2021 12:10:20 +0200
Cc: kvm@xxxxxxxxxxxxxxx, Sean Christopherson <seanjc@xxxxxxxxxx>, Wanpeng Li <wanpengli@xxxxxxxxxxx>, Jim Mattson <jmattson@xxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx
In-reply-to: <878s1namap.fsf@vitty.brq.redhat.com>
References: <20210730122625.112848-1-vkuznets@redhat.com> <20210730122625.112848-5-vkuznets@redhat.com> <20210730143530.GD20232@u366d62d47e3651.ant.amazon.com> <878s1namap.fsf@vitty.brq.redhat.com>
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On 30/07/21 16:50, Vitaly Kuznetsov wrote:

Should we also do WRITE_ONCE(nr_ur, 0) here?

It could probably make sense to replace 'nr_ud = 0' above with this so
compiler doesn't screw us up one day..


It should be okay with the "memory" clobber.

Paolo

References:
- [PATCH 0/4] KVM: x86: hyper-v: Check if guest is allowed to use XMM registers for hypercall input
  - From: Vitaly Kuznetsov
- [PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls
  - From: Vitaly Kuznetsov
- Re: [PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls
  - From: Siddharth Chandrasekaran
- Re: [PATCH 4/4] KVM: selftests: Test access to XMM fast hypercalls
  - From: Vitaly Kuznetsov