From: David Woodhouse <dwmw2@infradead.org>
To: speck@linutronix.de
Subject: [MODERATED] Re: L1D-Fault KVM mitigation
Date: Tue, 24 Apr 2018 10:48:12 +0100 [thread overview]
Message-ID: <1524563292.8691.38.camel@infradead.org> (raw)
In-Reply-To: <20180424093537.GC4064@hirez.programming.kicks-ass.net>
On Tue, 2018-04-24 at 11:35 +0200, speck for Peter Zijlstra wrote:
>
> Another option, that is being explored, is to co-schedule siblings.
> So ensure all siblings either run vcpus of the _same_ VM or idle.
>
> Of course, this is all rather intrusive and ugly and brings with it
> setup costs as well, because you'd have to sync up on VMENTER, VMEXIT
> and interrupts (on the idle CPUs).
I hate to suggest more microcode hacks but... if there was an MSR bit
which, when set, would pause any HT sibling that was currently in VMX
non-root mode, then we could set that up to be automatically set on
vmexit and it would automatically pause the problematic siblings.
Meaning that co-ordinating vmexits with them might actually be
feasible?
The precise definition of 'pause' in the above could survive some
bikeshedding, but basically it shouldn't run any more guest
instructions, but it *should* be allowed to vmexit on interrupts, etc.
next prev parent reply other threads:[~2018-04-24 9:48 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-24 9:06 [MODERATED] L1D-Fault KVM mitigation Joerg Roedel
2018-04-24 9:35 ` [MODERATED] " Peter Zijlstra
2018-04-24 9:48 ` David Woodhouse [this message]
2018-04-24 11:04 ` Peter Zijlstra
2018-04-24 11:16 ` David Woodhouse
2018-04-24 15:10 ` Jon Masters
2018-05-23 9:45 ` David Woodhouse
2018-05-24 9:45 ` Peter Zijlstra
2018-05-24 14:14 ` Jon Masters
2018-05-24 15:04 ` Thomas Gleixner
2018-05-24 15:33 ` Thomas Gleixner
2018-05-24 15:38 ` [MODERATED] " Jiri Kosina
2018-05-24 17:22 ` Dave Hansen
2018-05-24 17:30 ` Linus Torvalds
2018-05-24 23:18 ` [MODERATED] Encrypted Message Tim Chen
2018-05-24 23:28 ` [MODERATED] Re: L1D-Fault KVM mitigation Linus Torvalds
2018-05-25 8:31 ` Thomas Gleixner
2018-05-28 14:43 ` [MODERATED] " Paolo Bonzini
2018-05-25 18:22 ` [MODERATED] Encrypted Message Tim Chen
2018-05-26 19:14 ` L1D-Fault KVM mitigation Thomas Gleixner
2018-05-26 20:43 ` [MODERATED] " Andi Kleen
2018-05-26 20:48 ` Linus Torvalds
2018-05-27 18:25 ` Andi Kleen
2018-05-27 18:49 ` Linus Torvalds
2018-05-27 18:57 ` Thomas Gleixner
2018-05-27 19:13 ` [MODERATED] " Andrew Cooper
2018-05-27 19:26 ` Linus Torvalds
2018-05-27 19:41 ` Thomas Gleixner
2018-05-27 22:26 ` [MODERATED] " Andrew Cooper
2018-05-28 6:47 ` Thomas Gleixner
2018-05-28 12:26 ` [MODERATED] " Andrew Cooper
2018-05-28 14:40 ` Paolo Bonzini
2018-05-28 15:56 ` Thomas Gleixner
2018-05-28 17:15 ` [MODERATED] " Paolo Bonzini
2018-05-27 15:42 ` Thomas Gleixner
2018-05-27 16:26 ` [MODERATED] " Linus Torvalds
2018-05-27 18:31 ` Andi Kleen
2018-05-29 19:29 ` [MODERATED] Encrypted Message Tim Chen
2018-05-29 21:14 ` L1D-Fault KVM mitigation Thomas Gleixner
2018-05-30 16:38 ` [MODERATED] Encrypted Message Tim Chen
2018-05-24 15:44 ` [MODERATED] Re: L1D-Fault KVM mitigation Andi Kleen
2018-05-24 15:38 ` Linus Torvalds
2018-05-24 15:59 ` David Woodhouse
2018-05-24 16:35 ` Linus Torvalds
2018-05-24 16:51 ` David Woodhouse
2018-05-24 16:57 ` Linus Torvalds
2018-05-25 11:29 ` David Woodhouse
2018-04-24 10:30 ` [MODERATED] Re: ***UNCHECKED*** " Joerg Roedel
2018-04-24 11:09 ` Thomas Gleixner
2018-04-24 16:06 ` [MODERATED] " Andi Kleen
2018-04-24 12:53 ` Paolo Bonzini
2018-05-03 16:20 ` Konrad Rzeszutek Wilk
2018-05-07 17:11 ` Paolo Bonzini
2018-05-16 8:51 ` Jiri Kosina
2018-05-16 8:53 ` Paolo Bonzini
2018-05-21 10:06 ` David Woodhouse
2018-05-21 13:40 ` Thomas Gleixner
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