[Qemu-devel] [PULL for-2.9 0/1] Block patches

[Qemu-devel] [PULL for-2.9 0/1] Block patches

[Stefan Hajnoczi]

The following changes since commit d84f714eafedd8bb9d4aaec8b76417bef8e3535e:

  Update version for v2.9.0-rc0 release (2017-03-14 19:18:23 +0000)

are available in the git repository at:

  git://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to 9dc44aa5829eb3131a01378a738dee28a382bbc1:

  os: don't corrupt pre-existing memory-backend data with prealloc (2017-03-15 11:55:41 +0800)

----------------------------------------------------------------

----------------------------------------------------------------

Daniel P. Berrange (1):
  os: don't corrupt pre-existing memory-backend data with prealloc

 util/oslib-posix.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

-- 
2.9.3

[Qemu-devel] [PULL for-2.9 1/1] os: don't corrupt pre-existing memory-backend data with prealloc

[Stefan Hajnoczi]

From: "Daniel P. Berrange" <berrange@redhat.com>

When using a memory-backend object with prealloc turned on, QEMU
will memset() the first byte in every memory page to zero. While
this might have been acceptable for memory backends associated
with RAM, this corrupts application data for NVDIMMs.

Instead of setting every page to zero, read the current byte
value and then just write that same value back, so we are not
corrupting the original data. Directly write the value instead
of memset()ing it, since there's no benefit to memset for a
single byte write.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Message-id: 20170303113255.28262-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/oslib-posix.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 956f66a..94d81b9 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -361,7 +361,19 @@ static void *do_touch_pages(void *arg)
         memset_thread_failed = true;
     } else {
         for (i = 0; i < numpages; i++) {
-            memset(addr, 0, 1);
+            /*
+             * Read & write back the same value, so we don't
+             * corrupt existing user/app data that might be
+             * stored.
+             *
+             * 'volatile' to stop compiler optimizing this away
+             * to a no-op
+             *
+             * TODO: get a better solution from kernel so we
+             * don't need to write at all so we don't cause
+             * wear on the storage backing the region...
+             */
+            *(volatile char *)addr = *addr;
             addr += hpagesize;
         }
     }
-- 
2.9.3

Re: [Qemu-devel] [PULL for-2.9 0/1] Block patches

[no-reply]

Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Subject: [Qemu-devel] [PULL for-2.9 0/1] Block patches
Message-id: 20170315050602.7750-1-stefanha@redhat.com

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

# Useful git options
git config --local diff.renamelimit 0
git config --local diff.renames True

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/20170315050602.7750-1-stefanha@redhat.com -> patchew/20170315050602.7750-1-stefanha@redhat.com
Switched to a new branch 'test'
1562711 os: don't corrupt pre-existing memory-backend data with prealloc

=== OUTPUT BEGIN ===
Checking PATCH 1/1: os: don't corrupt pre-existing memory-backend data with prealloc...
ERROR: Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt
#45: FILE: util/oslib-posix.c:376:
+            *(volatile char *)addr = *addr;

total: 1 errors, 0 warnings, 20 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


---
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Please send your feedback to patchew-devel@freelists.org

Re: [Qemu-devel] [PULL for-2.9 0/1] Block patches

[Peter Maydell]

On 15 March 2017 at 05:06, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> The following changes since commit d84f714eafedd8bb9d4aaec8b76417bef8e3535e:
>
>   Update version for v2.9.0-rc0 release (2017-03-14 19:18:23 +0000)
>
> are available in the git repository at:
>
>   git://github.com/stefanha/qemu.git tags/block-pull-request
>
> for you to fetch changes up to 9dc44aa5829eb3131a01378a738dee28a382bbc1:
>
>   os: don't corrupt pre-existing memory-backend data with prealloc (2017-03-15 11:55:41 +0800)
>
> ----------------------------------------------------------------
>
> ----------------------------------------------------------------
>
> Daniel P. Berrange (1):
>   os: don't corrupt pre-existing memory-backend data with prealloc
>
>  util/oslib-posix.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)

Applied, thanks.

-- PMM

Re: [Qemu-devel] [PULL for-2.9 0/1] Block patches

[Peter Maydell]

On 28 March 2017 at 11:07, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> The following changes since commit eb06c9e2d3c8f026a206e8402b0ffa201060ec8e:
>
>   Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging (2017-03-27 17:34:50 +0100)
>
> are available in the git repository at:
>
>   git://github.com/stefanha/qemu.git tags/block-pull-request
>
> for you to fetch changes up to dc62da88b5d17477227a3563a6ad466129d416d6:
>
>   parallels: wrong call to bdrv_truncate (2017-03-28 11:06:00 +0100)
>
> ----------------------------------------------------------------
>
> ----------------------------------------------------------------
>
> Denis V. Lunev (1):
>   parallels: wrong call to bdrv_truncate
>
>  block/parallels.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied, thanks.

-- PMM

[Qemu-devel] [PULL for-2.9 0/1] Block patches

[Stefan Hajnoczi]

The following changes since commit eb06c9e2d3c8f026a206e8402b0ffa201060ec8e:

  Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging (2017-03-27 17:34:50 +0100)

are available in the git repository at:

  git://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to dc62da88b5d17477227a3563a6ad466129d416d6:

  parallels: wrong call to bdrv_truncate (2017-03-28 11:06:00 +0100)

----------------------------------------------------------------

----------------------------------------------------------------

Denis V. Lunev (1):
  parallels: wrong call to bdrv_truncate

 block/parallels.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

-- 
2.9.3

Re: [Qemu-devel] [PULL for-2.9 0/1] Block patches

[Peter Maydell]

On 22 March 2017 at 12:54, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> The following changes since commit 940a8ce075e3408742a4edcabfd6c2a15e2539eb:
>
>   Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging (2017-03-20 16:34:26 +0000)
>
> are available in the git repository at:
>
>   git://github.com/stefanha/qemu.git tags/block-pull-request
>
> for you to fetch changes up to ff5bbe56c6f9a74c2d77389a21d5d2368458c939:
>
>   parallels: fix default options parsing (2017-03-21 10:02:36 +0000)
>
> ----------------------------------------------------------------
>
> ----------------------------------------------------------------
>
> Edgar Kaziahmedov (1):
>   parallels: fix default options parsing
>
>  block/parallels.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied, thanks.

-- PMM

[Qemu-devel] [PULL for-2.9 0/1] Block patches

[Stefan Hajnoczi]

The following changes since commit 940a8ce075e3408742a4edcabfd6c2a15e2539eb:

  Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging (2017-03-20 16:34:26 +0000)

are available in the git repository at:

  git://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to ff5bbe56c6f9a74c2d77389a21d5d2368458c939:

  parallels: fix default options parsing (2017-03-21 10:02:36 +0000)

----------------------------------------------------------------

----------------------------------------------------------------

Edgar Kaziahmedov (1):
  parallels: fix default options parsing

 block/parallels.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.9.3