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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 1/2] Restore atapi_dma flag across migration
Date: Tue,  9 Dec 2014 18:15:08 +0000	[thread overview]
Message-ID: <1418148909-19870-2-git-send-email-dgilbert@redhat.com> (raw)
In-Reply-To: <1418148909-19870-1-git-send-email-dgilbert@redhat.com>

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

If a migration happens just after the guest has kicked
off an ATAPI command and kicked off DMA, we lose the atapi_dma
flag, and the destination tries to complete the command as PIO
rather than DMA.  This upsets Linux; modern libata based kernels
stumble and recover OK, older kernels end up passing bad data
to userspace.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 hw/ide/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index d4af5e2..ac3f015 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -2417,6 +2417,7 @@ static int ide_drive_pio_post_load(void *opaque, int version_id)
     s->end_transfer_func = transfer_end_table[s->end_transfer_fn_idx];
     s->data_ptr = s->io_buffer + s->cur_io_buffer_offset;
     s->data_end = s->data_ptr + s->cur_io_buffer_len;
+    s->atapi_dma = s->feature & 1; /* as per cmd_packet */
 
     return 0;
 }
-- 
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 [Qemu-devel] [PATCH 0/2] ATAPI migration fix/hack Dr. David Alan Gilbert (git)
2014-12-09 18:15 ` Dr. David Alan Gilbert (git) [this message]
2014-12-10  5:04   ` [Qemu-devel] [PATCH 1/2] Restore atapi_dma flag across migration 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

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