From: Greg KH <gregkh@linuxfoundation.org>
To: speck@linutronix.de
Subject: [MODERATED] Re: [patch V4 09/11] x86/speculation/mds: Add mitigation mode VMWERV
Date: Sat, 23 Feb 2019 10:52:28 +0100 [thread overview]
Message-ID: <20190223095228.GB11354@kroah.com> (raw)
In-Reply-To: <20190222224149.881444221@linutronix.de>
On Fri, Feb 22, 2019 at 11:24:27PM +0100, speck for Thomas Gleixner wrote:
> From: Thomas Gleixner <tglx@linutronix.de>
>
> In virtualized environments it can happen that the host has the microcode
> update which utilizes the VERW instruction to clear CPU buffers, but the
> hypervisor is not yet updated to expose the X86_FEATURE_MD_CLEAR CPUID bit
> to guests.
>
> Introduce an internal mitigation mode VWWERV which enables the invocation
> of the CPU buffer clearing even if X86_FEATURE_MD_CLEAR is not set. If the
> system has no updated microcode this results in a pointless execution of
> the VERW instruction wasting a few CPU cycles. If the microcode is updated,
> but not exposed to a guest then the CPU buffers will be cleared.
>
> That said: Virtual Machines Will Eventually Receive Vaccine
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Thanks for the documentation update here, looks good.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
next prev parent reply other threads:[~2019-02-23 9:52 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-22 22:24 [patch V4 00/11] MDS basics Thomas Gleixner
2019-02-22 22:24 ` [patch V4 01/11] x86/msr-index: Cleanup bit defines Thomas Gleixner
2019-02-22 22:24 ` [patch V4 02/11] x86/speculation/mds: Add basic bug infrastructure for MDS Thomas Gleixner
2019-02-23 1:28 ` [MODERATED] " Linus Torvalds
2019-02-23 7:42 ` Thomas Gleixner
2019-02-27 13:04 ` Thomas Gleixner
2019-02-22 22:24 ` [patch V4 03/11] x86/kvm: Expose X86_FEATURE_MD_CLEAR to guests Thomas Gleixner
2019-02-22 22:24 ` [patch V4 04/11] x86/speculation/mds: Add mds_clear_cpu_buffer() Thomas Gleixner
2019-02-25 16:06 ` [MODERATED] " Frederic Weisbecker
2019-02-26 14:19 ` Josh Poimboeuf
2019-03-01 20:58 ` [MODERATED] Encrypted Message Jon Masters
2019-03-01 22:14 ` Jon Masters
2019-02-26 15:00 ` [MODERATED] Re: [patch V4 04/11] x86/speculation/mds: Add mds_clear_cpu_buffer() David Woodhouse
2019-02-22 22:24 ` [patch V4 05/11] x86/speculation/mds: Clear CPU buffers on exit to user Thomas Gleixner
2019-02-25 21:04 ` [MODERATED] " Greg KH
2019-02-26 15:20 ` Josh Poimboeuf
2019-02-26 20:26 ` Thomas Gleixner
2019-02-22 22:24 ` [patch V4 06/11] x86/speculation/mds: Conditionally clear CPU buffers on idle entry Thomas Gleixner
2019-02-25 21:09 ` [MODERATED] " Greg KH
2019-02-26 15:31 ` Josh Poimboeuf
2019-02-26 20:20 ` Thomas Gleixner
2019-02-22 22:24 ` [patch V4 07/11] x86/speculation/mds: Add mitigation control for MDS Thomas Gleixner
2019-02-25 20:17 ` [MODERATED] " mark gross
2019-02-26 15:50 ` Josh Poimboeuf
2019-02-26 20:16 ` Thomas Gleixner
2019-02-22 22:24 ` [patch V4 08/11] x86/speculation/mds: Add sysfs reporting " Thomas Gleixner
2019-02-22 22:24 ` [patch V4 09/11] x86/speculation/mds: Add mitigation mode VMWERV Thomas Gleixner
2019-02-23 9:52 ` Greg KH [this message]
2019-02-25 20:31 ` [MODERATED] " mark gross
2019-02-26 0:34 ` Andrew Cooper
2019-02-26 18:51 ` mark gross
2019-02-26 19:29 ` Thomas Gleixner
2019-02-22 22:24 ` [patch V4 10/11] Documentation: Move L1TF to separate directory Thomas Gleixner
2019-02-23 8:41 ` [MODERATED] " Greg KH
2019-02-22 22:24 ` [patch V4 11/11] Documentation: Add MDS vulnerability documentation Thomas Gleixner
2019-02-23 9:58 ` [MODERATED] " Greg KH
2019-02-26 20:11 ` Thomas Gleixner
2019-02-25 18:02 ` [MODERATED] " Dave Hansen
2019-02-26 20:10 ` Thomas Gleixner
2019-02-23 0:53 ` [MODERATED] Re: [patch V4 00/11] MDS basics Andrew Cooper
2019-02-23 14:12 ` Peter Zijlstra
2019-02-25 16:38 ` mark gross
2019-02-26 19:58 ` Thomas Gleixner
2019-02-26 16:28 ` [MODERATED] " Tyler Hicks
2019-02-26 19:58 ` Thomas Gleixner
2019-02-26 18:58 ` [MODERATED] " Kanth Ghatraju
2019-02-26 19:59 ` Thomas Gleixner
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