LinuxPPC-Dev Archive on lore.kernel.org
 help / color / Atom feed
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	paulus@samba.org, mpe@ellerman.id.au, npiggin@gmail.com,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	kvm-ppc@vger.kernel.org
Subject: Re: [PATCH] powerpc: fix 32-bit KVM-PR lockup and panic with MacOS guest
Date: Mon, 11 Feb 2019 11:30:54 +1100
Message-ID: <c2d6938902656f2829be8077c656cee9235c21b1.camel@kernel.crashing.org> (raw)
In-Reply-To: <2ed8efb9-5cd4-31bf-6c7b-501b9d1925e6@ilande.co.uk>

On Fri, 2019-02-08 at 14:51 +0000, Mark Cave-Ayland wrote:
> 
> Indeed, but there are still some questions to be asked here:
> 
> 1) Why were these bits removed from the original bitmask in the first place without
> it being documented in the commit message?
> 
> 2) Is this the right fix? I'm told that MacOS guests already run without this patch
> on a G5 under 64-bit KVM-PR which may suggest that this is a workaround for another
> bug elsewhere in the 32-bit powerpc code.
> 
> 
> If you think that these points don't matter, then I'm happy to resubmit the patch
> as-is based upon your comments above.

We should write a test case to verify that FE0/FE1 are properly
preserved/context-switched etc... I bet if we accidentally wiped them,
we wouldn't notice 99.9% of the time.

Cheers,
Ben.


  reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-08 14:33 Mark Cave-Ayland
2019-02-08 14:45 ` Christophe Leroy
2019-02-08 14:51   ` Mark Cave-Ayland
2019-02-11  0:30     ` Benjamin Herrenschmidt [this message]
2019-02-11 21:39       ` Mark Cave-Ayland
2019-02-19  4:55         ` Michael Ellerman
2019-02-19  8:15           ` Mark Cave-Ayland
2019-02-19  4:20     ` Michael Ellerman
2019-02-19  7:55       ` Mark Cave-Ayland
2019-02-20 12:41         ` Michael Ellerman
2019-02-22  9:47 ` Michael Ellerman

Reply instructions:

You may reply publically 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=c2d6938902656f2829be8077c656cee9235c21b1.camel@kernel.crashing.org \
    --to=benh@kernel.crashing.org \
    --cc=christophe.leroy@c-s.fr \
    --cc=kvm-ppc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mark.cave-ayland@ilande.co.uk \
    --cc=mpe@ellerman.id.au \
    --cc=npiggin@gmail.com \
    --cc=paulus@samba.org \
    /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

LinuxPPC-Dev Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linuxppc-dev/0 linuxppc-dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linuxppc-dev linuxppc-dev/ https://lore.kernel.org/linuxppc-dev \
		linuxppc-dev@lists.ozlabs.org linuxppc-dev@ozlabs.org linuxppc-dev@archiver.kernel.org
	public-inbox-index linuxppc-dev


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.ozlabs.lists.linuxppc-dev


AGPL code for this site: git clone https://public-inbox.org/ public-inbox