From: Sean Christopherson <seanjc@google.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Leonardo Bras <leobras@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: Re: [PATCH 0/3] KVM: x86: Fix XSAVE related bugs
Date: Tue, 20 Sep 2022 19:19:12 +0000 [thread overview]
Message-ID: <YyoSMGSRRwratmrV@google.com> (raw)
In-Reply-To: <YwYMInTCevZ/FYNl@work-vm>
On Wed, Aug 24, 2022, Dr. David Alan Gilbert wrote:
> * Sean Christopherson (seanjc@google.com) wrote:
> > Patch 2 (from Dave) is the headliner and fixes a bug where KVM clear the
> > FP+SSE bits in user_xfeatures when XSAVE is hidden from the guest and thus
> > prevent userspace from saving/restoring FP+SSE state on XSAVE host. This
> > most visibily manifests as a failed migration (KVM_GET_XSAVE succeeds on a
> > non-XSAVE host and KVM_SET_XSAVE fails on an XSAVE host), but also causes
> > KVM_GET_SAVE on XSAVE hosts to effectively corrupt guest FP+SSE state.
> >
> > Patch 1 fixes a mostly theoretical bug, and is also a prerequisite for
> > patch 2.
> >
> > Patch 3 fixes a bug found by inspection when staring at all of this. KVM
> > fails to check CR4.OSXSAVE when emulating XSETBV (the interception case
> > gets away without the check because the intercept happens after hardware
> > checks CR4).
>
> Thanks for pulling those together; the set of 3 passes my same (light) smoke test.
Paolo, do you want to grab this series for 6.0?
next prev parent reply other threads:[~2022-09-20 19:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 3:30 [PATCH 0/3] KVM: x86: Fix XSAVE related bugs Sean Christopherson
2022-08-24 3:30 ` [PATCH 1/3] KVM: x86: Reinstate kvm_vcpu_arch.guest_supported_xcr0 Sean Christopherson
2022-08-24 3:30 ` [PATCH 2/3] KVM: x86: Always enable legacy FP/SSE in allowed user XFEATURES Sean Christopherson
2022-08-24 3:30 ` [PATCH 3/3] KVM: x86: Inject #UD on emulated XSETBV if XSAVES isn't enabled Sean Christopherson
2022-08-24 11:31 ` [PATCH 0/3] KVM: x86: Fix XSAVE related bugs Dr. David Alan Gilbert
2022-09-20 19:19 ` Sean Christopherson [this message]
2022-09-22 21:04 ` Paolo Bonzini
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