historical-speck.lore.kernel.org archive mirror
 help / color / mirror / Atom feed
From: mark gross <mgross@linux.intel.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH v8 3/5] NX 3
Date: Fri, 1 Nov 2019 11:38:15 -0700	[thread overview]
Message-ID: <20191101183815.GA6582@u1904> (raw)
In-Reply-To: <91ff125b-068d-9f4a-fa3c-ca0bfec38c17@redhat.com>

On Fri, Nov 01, 2019 at 08:07:27AM +0100, speck for Paolo Bonzini wrote:
> On 01/11/19 01:24, speck for Pawan Gupta wrote:
> > On Fri, Nov 01, 2019 at 12:33:45AM +0100, speck for Paolo Bonzini wrote:
> >> From: Paolo Bonzini <pbonzini@redhat.com>
> >> Subject: [PATCH v8 3/5] kvm: mmu: ITLB_MULTIHIT mitigation
> >>  
> >> +	kvm.nx_huge_pages=
> >> +			[KVM] Controls the sw workaround for bug
> >> +			X86_BUG_ITLB_MULTIHIT.
> >> +			force	: Always deploy workaround.
> >> +			off	: Default. Never deploy workaround.
> > 
> > off is not the default in the code, so the default should be "auto" here.
> > 
> >> +			auto	: Deploy workaround based on presence of
> >> +				  X86_BUG_ITLB_MULTIHIT.
> > 
> > Also mitigations=off is not disabling this mitigation. Below patch does
> > that when mitigations=off and kvm.nx_huge_pages=auto.
> > 
> > ---
> > From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> > Date: Wed, 30 Oct 2019 21:28:24 -0700
> > Subject: [PATCH] kvm: x86: mmu: Apply global mitigations knob to ITLB_MULTIHIT
> > 
> > Problem: The global mitigation knob mitigations=off does not turn off
> > X86_BUG_ITLB_MULTIHIT mitigation.
> > 
> > Fix: Turn off the mitigation when ITLB_MULTIHIT mitigation mode is
> > "auto" and mitigations are turned off globally via cmdline
> > mitigations=off.
> > 
> > Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> 
> Thanks, I'll post v9 soon.  Are you going to post backports as bundles
> on top of Thomas's?
> 
> Paolo
We (I) have attempted the backports of this and quicly hit issues with the page
zapping changes do to code flux in the upstream.  My troubles started with with
5.2 and 4.19.  I have reached out to an internal resource who is more
knowledgable with KVM mm files to assist with that aspect of the backport.  The
engineer was at a confrence this week and we hope to make more progress next
week once he is back.

--mark

  reply	other threads:[~2019-11-01 18:38 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-31 23:33 [MODERATED] [PATCH v8 0/5] NX 0 Paolo Bonzini
2019-10-31 23:33 ` [MODERATED] [PATCH v8 1/5] NX 1 Paolo Bonzini
2019-10-31 23:33 ` [MODERATED] [PATCH v8 2/5] NX 2 Paolo Bonzini
2019-10-31 23:33 ` [MODERATED] [PATCH v8 3/5] NX 3 Paolo Bonzini
2019-11-01  0:24   ` [MODERATED] " Pawan Gupta
2019-11-01  7:07     ` Paolo Bonzini
2019-11-01 18:38       ` mark gross [this message]
2019-11-01 18:51         ` Tyler Hicks
2019-11-01 20:36           ` mark gross
2019-11-02  7:36             ` Paolo Bonzini
2019-11-01 14:58     ` Tyler Hicks
2019-11-01 15:43       ` [MODERATED] [PATCH] NX build fixup Tyler Hicks
2019-11-01 16:31         ` [MODERATED] " Josh Poimboeuf
2019-11-01 20:39           ` [MODERATED] [PATCH v2] " Tyler Hicks
2019-11-01 21:14             ` [MODERATED] " Josh Poimboeuf
2019-11-01 21:38             ` [MODERATED] Re: [PATCH v2] NX mitigations=off fix Pawan Gupta
2019-10-31 23:33 ` [MODERATED] [PATCH v8 4/5] NX 4 Paolo Bonzini
2019-10-31 23:33 ` [MODERATED] [PATCH v8 5/5] NX 5 Paolo Bonzini

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191101183815.GA6582@u1904 \
    --to=mgross@linux.intel.com \
    --cc=speck@linutronix.de \
    --subject='[MODERATED] Re: [PATCH v8 3/5] NX 3' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).