qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed
From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
To: qemu-devel@nongnu.org
Cc: pbonzini@redhat.com, jsnow@redhat.com
Subject: [Qemu-devel] [PATCH 0/2] ATAPI migration fix/hack
Date: Tue,  9 Dec 2014 18:15:07 +0000	[thread overview]
Message-ID: <1418148909-19870-1-git-send-email-dgilbert@redhat.com> (raw)

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

This pair of patches fixes a problem where IDE/ATAPI cdrom
reads get lost/corrupted over migration.

The first of the patches (restore atapi_dma flag) is
a simple fix that I think is safe; it no longer causes
corruption in the case we saw, but does still trigger
a long timeout.

The second is a hack; it throws a medium error causing
the guest to retry the command in the case where migration
happens just between the IDE/ATAPI command being submitted
and the bmdma being finished.   This recovers a lot
faster than the timeout.

Only tried on Linux guests so far; I think it might be possible
to replace both of these by reparsing the command buffer for
ATAPI; I'm just not confident I know when that's safe to do,
and I wanted to see how disgusted people were by the 2nd hack.

Dave

Dr. David Alan Gilbert (2):
  Restore atapi_dma flag across migration
  atapi migration: Throw recoverable error to avoid recovery

 hw/ide/atapi.c    | 17 +++++++++++++++++
 hw/ide/core.c     |  1 +
 hw/ide/internal.h |  2 ++
 hw/ide/pci.c      | 11 +++++++++++
 4 files changed, 31 insertions(+)

-- 
2.1.0

             reply	other threads:[~2014-12-09 18:15 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-09 18:15 Dr. David Alan Gilbert (git) [this message]
2014-12-09 18:15 ` [Qemu-devel] [PATCH 1/2] Restore atapi_dma flag across migration Dr. David Alan Gilbert (git)
2014-12-10  5:04   ` John Snow
2014-12-09 18:15 ` [Qemu-devel] [PATCH 2/2] atapi migration: Throw recoverable error to avoid recovery Dr. David Alan Gilbert (git)
2014-12-10  6:14   ` John Snow
2014-12-10 12:05     ` Dr. David Alan Gilbert
2014-12-10 20:09     ` Dr. David Alan Gilbert
2014-12-10 22:04   ` Paolo Bonzini
2014-12-11 19:45     ` Dr. David Alan Gilbert
2014-12-18 19:39       ` Dr. David Alan Gilbert
2014-12-18 23:42         ` John Snow
2015-01-16 17:28   ` John Snow
2015-02-02 12:11     ` Kevin Wolf
2015-01-07 16:26 ` [Qemu-devel] [PATCH 0/2] ATAPI migration fix/hack Dr. David Alan Gilbert
2015-01-30 16:07   ` Dr. David Alan Gilbert

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=1418148909-19870-1-git-send-email-dgilbert@redhat.com \
    --to=dgilbert@redhat.com \
    --cc=jsnow@redhat.com \
    --cc=pbonzini@redhat.com \
    --cc=qemu-devel@nongnu.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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
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).