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Re: [Qemu-devel] HEAD is failing virt-test on migration tests
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] HEAD is failing virt-test on migration tests |
Date: |
Mon, 16 Feb 2015 18:57:56 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* Alexander Graf (address@hidden) wrote:
<snip>
> Can you please test whether the patch below makes things work for you again?
The patch below fixes RDMA migration (same host); however, see comments.
> Alex
>
> From ef6fde21007e62529799264f57a65c6bb3d0d414 Mon Sep 17 00:00:00 2001
> From: Alexander Graf <address@hidden>
> Date: Sat, 14 Feb 2015 00:21:01 +0100
> Subject: [PATCH] migration: Read JSON VM description on incoming migration
>
> One of the really nice things about the VM description format is that it
> goes
> over the wire when live migration is happening. Unfortunately QEMU today
> closes
> any socket once it sees VM_EOF coming, so we never give the VMDESC the
> chance to
> actually land on the wire.
>
> This patch makes QEMU read the description as well. This way we ensure that
> anything wire tapping us in between will get the chance to also
> interpret the
> stream.
>
> Along the way we also fix virt tests that assume that number_bytes_sent
> on the
> sender side is equal to number_bytes_read which was true before the VMDESC
> patches and is true again with this patch.
>
> Signed-off-by: Alexander Graf <address@hidden>
>
> diff --git a/savevm.c b/savevm.c
> index 8040766..ff4bead 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -929,6 +929,7 @@ int qemu_loadvm_state(QEMUFile *f)
> uint8_t section_type;
> unsigned int v;
> int ret;
> + int file_error_after_eof = -1;
>
> if (qemu_savevm_state_blocked(&local_err)) {
> error_report("%s", error_get_pretty(local_err));
> @@ -1034,6 +1035,22 @@ int qemu_loadvm_state(QEMUFile *f)
> }
> }
>
> + file_error_after_eof = qemu_file_get_error(f);
> +
> + /*
> + * Try to read in the VMDESC section as well, so that dumping tools
> that
> + * intercept our migration stream have the chance to see it.
> + */
> + if (qemu_get_byte(f) == QEMU_VM_VMDESCRIPTION) {
You could use qemu_peek_byte for that?
> + uint32_t size = qemu_get_be32(f);
> + uint8_t *buf = g_malloc(size);
> +
> + if (buf) {
> + qemu_get_buffer(f, buf, size);
> + g_free(buf);
> + }
This is slightly dangerous; a malformed file could send you a huge
value and get you to allocate lots of memory for no good reason.
You could do some clever; but personally I'd just loop around a
nice small buffer until it's gone.
As mentioned on IRC; I'm still worried though that this is only
a fix for loading on newer versions; migration to an older QEMU
with the same machine type would fail.
(Yes I know mythically that no one cares about this; but I do).
Dave
> + }
> +
> cpu_synchronize_all_post_init();
>
> ret = 0;
> @@ -1045,7 +1062,8 @@ out:
> }
>
> if (ret == 0) {
> - ret = qemu_file_get_error(f);
> + /* We may not have a VMDESC section, so ignore relative errors */
> + ret = file_error_after_eof;
> }
>
> return ret;
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, (continued)
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Lucas Meneghel Rodrigues, 2015/02/12
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Lucas Meneghel Rodrigues, 2015/02/12
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Lucas Meneghel Rodrigues, 2015/02/12
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Lucas Meneghel Rodrigues, 2015/02/12
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Alexander Graf, 2015/02/12
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Dr. David Alan Gilbert, 2015/02/13
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Alexander Graf, 2015/02/13
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Dr. David Alan Gilbert, 2015/02/13
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Lucas Meneghel Rodrigues, 2015/02/13
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Alexander Graf, 2015/02/13
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests,
Dr. David Alan Gilbert <=
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Alexander Graf, 2015/02/16
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Paolo Bonzini, 2015/02/16
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Alexander Graf, 2015/02/16
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Paolo Bonzini, 2015/02/16
- Re: [Qemu-devel] HEAD is failing virt-test on migration tests, Lucas Meneghel Rodrigues, 2015/02/13