From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joerg Roedel <jroedel@suse.de>, Joerg Roedel <joro@8bytes.org>,
stable@vger.kernel.org,
Ben Hutchings <ben.hutchings@codethink.co.uk>,
David Woodhouse <dwmw@amazon.co.uk>,
Jim Mattson <jmattson@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH stable-4.4.y] KVM: VMX: Fix x2apic check in vmx_msr_bitmap_mode()
Date: Fri, 22 Feb 2019 10:20:55 +0100 [thread overview]
Message-ID: <e56c31db-20c4-d7d1-083a-4c26fc58d5b3@redhat.com> (raw)
In-Reply-To: <20190221171541.GA7019@linux.intel.com>
On 21/02/19 18:15, Sean Christopherson wrote:
> This bug exists only in the 4.4.y backport; upstream, 4.9.y and 4.14.y
> all had the correct code from the get-go. And there is already a KVM
> unit test that *should* hit this, albeit somewhat indirectly. I'll
> verify the tests that touch the TPR actually run with x2APIC enabled.
eventinj from kvm-unit-tests should trigger it. There are other tests
that touch the TPR, but they use cr8 so they don't show the bug.
> Assuming the KVM unit test actually works, it's not a stretch for the
> bug to esacpe, e.g. if the tests weren't run on 4.4.y at all, or were
> only run on hardware with x2APIC.
Yeah, you should be able to see this with kvm_intel.enable_apicv=0 on
newer processors. But I've never run the tests for 4.4.y.
Paolo
prev parent reply other threads:[~2019-02-22 9:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-21 13:52 Joerg Roedel
2019-02-21 14:15 ` Greg Kroah-Hartman
2019-02-21 14:47 ` Joerg Roedel
2019-02-21 16:20 ` Greg Kroah-Hartman
2019-02-21 17:00 ` Ben Hutchings
2019-02-21 17:15 ` Sean Christopherson
2019-02-22 9:20 ` Paolo Bonzini [this message]
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