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From: "Luck, Tony" <tony.luck@intel.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH 1/2] v3 more sampling fun 1
Date: Thu, 12 Mar 2020 09:02:24 -0700	[thread overview]
Message-ID: <20200312160224.GA17609@agluck-desk2.amr.corp.intel.com> (raw)
In-Reply-To: <20200312152501.GA16899@agluck-desk2.amr.corp.intel.com>

On Thu, Mar 12, 2020 at 08:25:01AM -0700, speck for Luck, Tony wrote:
> On Thu, Mar 12, 2020 at 01:34:50AM +0000, speck for Andrew Cooper wrote:
> > Particularly with this issue where it seems that no hypervisor is
> > interested in offering the knob to guest kernels (so could at least
> > infer based on SRBDS_CTRL), nor is there an ARCH_CAPS_$FOO_NO bit which
> > could be filled in by a hypervisor on unaffected or mitigated hardware.
> 
> Maybe that is the solution?  We allocated a s/w (VMM) bit in
> ARCH_CAPABILITIES for the TLB DoS issue for the nested hypervisor case.
> Should we do that again for this issue?

Bah, memory fail. I was actually thinking of bit 3 SKIP_L1DFL_VMENTRY
that told a nested VMM it didn't need to flush L1D again for L1TF as
an outer VMM was already handling that.

> If you think so, then we can take this discussion to Keybase so
> that the other VMM vendors who hang out there can chime in.
> 
> [Note that it isn't my call to allocate a bit in ARCH_CAPABILITIES,
> but I can campaign for it if folks want it].
> 
> -Tony

  reply	other threads:[~2020-03-12 16:02 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 15:39 [MODERATED] [PATCH 0/2] v3 more sampling fun 0 mark gross
2020-01-16 22:16 ` [MODERATED] [PATCH 1/2] v3 more sampling fun 1 mark gross
2020-01-30 19:12 ` [MODERATED] [PATCH 2/2] v3 more sampling fun 2 mark gross
     [not found] ` <5e690bea.1c69fb81.16d6d.4b78SMTPIN_ADDED_BROKEN@mx.google.com>
2020-03-11 17:21   ` [MODERATED] Re: [PATCH 1/2] v3 more sampling fun 1 Greg KH
2020-03-11 23:09     ` mark gross
2020-03-11 20:02 ` Thomas Gleixner
2020-03-17 18:56   ` [MODERATED] " mark gross
2020-03-11 20:26 ` [PATCH 2/2] v3 more sampling fun 2 Thomas Gleixner
2020-03-11 20:38   ` [MODERATED] " Andrew Cooper
2020-03-11 23:23   ` mark gross
2020-03-12 22:04   ` mark gross
2020-03-13 15:21     ` Thomas Gleixner
2020-03-11 20:28 ` [MODERATED] Re: [PATCH 1/2] v3 more sampling fun 1 Andrew Cooper
2020-03-11 23:18   ` mark gross
2020-03-12  0:25     ` Luck, Tony
2020-03-12  1:34       ` Andrew Cooper
2020-03-12 15:25         ` Luck, Tony
2020-03-12 16:02           ` Luck, Tony [this message]
2020-03-12 16:45             ` Andrew Cooper

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