From: "Liu, Jingqi" <jingqi.liu@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "rkrcmar@redhat.com" <rkrcmar@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Wang, Wei W" <wei.w.wang@intel.com>,
Robert Hoo <robert.hu@linux.intel.com>
Subject: RE: [PATCH v2] KVM: Expose the split lock detection feature to guest VM
Date: Fri, 6 Jul 2018 08:13:55 +0000 [thread overview]
Message-ID: <09D68D4CF52CAF489B702DEBDD12D3D352762245@SHSMSX103.ccr.corp.intel.com> (raw)
In-Reply-To: <7813a04b-8058-538b-8c9b-cdd01ce119ac@redhat.com>
On 04/07/2018 21:37, Paolo Bonzini wrote:
> On 04/07/2018 15:06, Jingqi Liu wrote:
> > A new control bit(bit 29) in the TEST_CTRL MSR will be introduced to
> > enable detection of split locks.
> >
> > When bit 29 of the TEST_CTRL(33H) MSR is set, the processor causes an
> > #AC exception to be issued instead of suppressing LOCK on bus(during
> > split lock access). A previous control bit (bit 31) in this MSR causes
> > the processor to disable LOCK# assertion for split locked accesses
> > when set. When bits 29 and 31 are both set, bit 29 takes precedence.
> >
> > The release document ref below link:
> > https://software.intel.com/sites/default/files/managed/c5/15/\
> > architecture-instruction-set-extensions-programming-reference.pdf
> > This patch has a dependency on https://lkml.org/lkml/2018/5/27/78.
> >
> > Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
> > ---
> > arch/x86/include/asm/kvm_host.h | 1 +
> > arch/x86/kvm/vmx.c | 77
> +++++++++++++++++++++++++++++++++++++++++
> > arch/x86/kvm/x86.c | 10 ++++++
> > arch/x86/kvm/x86.h | 5 +++
> > include/uapi/linux/kvm.h | 1 +
> > 5 files changed, 94 insertions(+)
>
> Checking for split lock is done with the MSR_TEST_CTL too, so you should not
> use a capability to expose the availability to KVM userspace.
> Instead you should expose the contents of MSR_TEST_CTL on the host, in a
> similar way to https://marc.info/?l=kvm&m=152998661713547&w=2.
>
> Please coordinate with Robert Hu on the QEMU patches too, because he's
> working on the infrastructure to use KVM_GET_MSR_FEATURE_INDEX_LIST in
> QEMU.
>
Hi Paolo,
Thanks for your review, had synced with Robert.
Need to work out a way, not impact on the old infrastructure.
Thanks
Jingqi
> Thanks,
>
> Paolo
next prev parent reply other threads:[~2018-07-06 8:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-04 13:06 [PATCH v2] KVM: Expose the split lock detection feature to guest VM Jingqi Liu
2018-07-04 13:36 ` Paolo Bonzini
2018-07-04 14:51 ` Thomas Gleixner
2018-07-04 16:21 ` Paolo Bonzini
2018-07-04 18:39 ` Thomas Gleixner
2018-07-06 8:13 ` Liu, Jingqi [this message]
2018-07-04 23:07 ` kbuild test robot
2018-07-04 23:07 ` kbuild test robot
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