From: Sean Christopherson <seanjc@google.com>
To: "Chang S. Bae" <chang.seok.bae@intel.com>
Cc: kvm@vger.kernel.org, pbonzini@redhat.com,
linux-kernel@vger.kernel.org, yang.zhong@intel.com
Subject: Re: [RFC PATCH 1/2] KVM: x86: Add a new system attribute for dynamic XSTATE component
Date: Thu, 25 Aug 2022 16:19:56 +0000 [thread overview]
Message-ID: <YwehLNws0WBNRDgN@google.com> (raw)
In-Reply-To: <08e59f2d-24cb-dca8-b1b8-9e80f8a85398@intel.com>
On Wed, Aug 24, 2022, Chang S. Bae wrote:
> On 8/24/2022 2:42 PM, Sean Christopherson wrote:
> Maybe this is a policy decision. I don't think that
> ARCH_REQ_XCOMP_GUEST_PERM goes away with this. Userspace may still use the
> arch_prctl() set. But then it makes more sense and consistent to use
> ARCH_GET_XCOMP_SUPP in first place, instead of KVM_X86_XCOMP_GUEST_SUPP, no?
KVM_X86_XCOMP_GUEST_SUPP is needed so that userspace understands what _KVM_
supports.
> > If QEMU wants to assert that it didn't misconfigure itself, it can assert on the
> > config in any number of ways, e.g. assert that ARCH_GET_XCOMP_GUEST_PERM is a
> > subset of KVM_X86_XCOMP_GUEST_SUPP at the end of kvm_request_xsave_components().
>
> Yes, but I guess the new attribute can make it simple.
Adding new uAPI and new exports to eliminate one line of userspace code is not a
good tradeoff. Am I missing something? This really seems like solution looking
for a problem.
next prev parent reply other threads:[~2022-08-25 16:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-23 23:14 [RFC PATCH 0/2] KVM: x86: Add a new attribute to control dynamic XSTATE components Chang S. Bae
2022-08-23 23:14 ` [RFC PATCH 1/2] KVM: x86: Add a new system attribute for dynamic XSTATE component Chang S. Bae
2022-08-24 21:42 ` Sean Christopherson
2022-08-24 22:49 ` Chang S. Bae
2022-08-25 16:19 ` Sean Christopherson [this message]
2022-08-25 20:45 ` Chang S. Bae
2022-08-25 21:54 ` Sean Christopherson
2022-08-23 23:14 ` [RFC PATCH 2/2] selftests: kvm: Use the KVM API to enable dynamic XSTATE features Chang S. Bae
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