If an NBD server advertises a size that is not a multiple of a sector,
the block layer rounds up that size, even though we set info.size to
the exact byte value sent by the server. The block layer then proceeds
to let us read or query block status on the hole that it added past
EOF, which the NBD server is unlikely to be happy with. Fortunately,
qemu as a server never advertizes an unaligned size, so we generally
don't run into this problem; but the nbdkit server makes it easy to
test:
$ printf %1000d 1 > f1
$ ~/nbdkit/nbdkit -fv file f1 & pid=$!
$ qemu-img convert -f raw nbd://localhost:10809 f2
$ kill $pid
$ qemu-img compare f1 f2
Pre-patch, the server attempts a 1024-byte read, which nbdkit
rightfully rejects as going beyond its advertised 1000 byte size; the
conversion fails and the output files differ (not even the first
sector is copied, because qemu-img does not follow ddrescue's habit of
trying smaller reads to get as much information as possible in spite
of errors). Post-patch, the client's attempts to read (and query block
status, for new enough nbdkit) are properly truncated to the server's
length, with sane handling of the hole the block layer forced on
us. Although f2 ends up as a larger file (1024 bytes instead of 1000),
qemu-img compare shows the two images to have identical contents for
display to the guest.
I didn't add iotests coverage since I didn't want to add a dependency
on nbdkit in iotests. I also did NOT patch write, trim, or write
zeroes - these commands continue to fail (usually with ENOSPC, but
whatever the server chose), because we really can't write to the end
of the file, and because 'qemu-img convert' is the most common case
where we care about being tolerant (which is read-only). Perhaps we
could truncate the request if the client is writing zeros to the tail,
but that seems like more work, especially if the block layer is fixed
in 4.1 to track byte-accurate sizing (in which case this patch would
be reverted as unnecessary).
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-5-eblake@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
The NBD spec suggests that a server should never advertise a size
inconsistent with its minimum block alignment, as that tail is
effectively inaccessible to a compliant client obeying those block
constraints. Since we have a habit of rounding up rather than
truncating, to avoid losing the last few bytes of user input, and we
cannot access the tail when the server advertises bogus block sizing,
abort the connection to alert the server to fix their bug. And
rejecting such servers matches what we already did for a min_block
that was not a power of 2 or which was larger than max_block.
Does not impact either qemu (which always sends properly aligned
sizes) or nbdkit (which does not send minimum block requirements yet);
so this is mostly aimed at new NBD server implementations, and ensures
that the rest of our code can assume the size is aligned.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190330155704.24191-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
In usb_mask_to_str() we convert a mask of USB speeds into
a human-readable string (like "full+high") for use in
tracing and error messages. However the conversion code
doesn't do anything to the string buffer if the passed in
speedmask doesn't match any of the recognized speeds,
which means that the tracing and error messages will
end up with random garbage in them. This can happen if
we're doing USB device passthrough.
Handle the "unrecognized speed" case by using the
string "unknown".
Fixes: https://bugs.launchpad.net/qemu/+bug/1603785
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20190328133503.6490-1-peter.maydell@linaro.org
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This reverts commit bd56d37884.
Turned out it isn't that simple as the device needs the pit object link.
So "-device isa-pcspk" isn't going wo work anyway. We are in freeze, so
just reverting the thing is the best way to handle this for now, trying
to come up with something better can be done in the 4.1 devel cycle.
Also add a comment noting the object link.
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20190328071121.21147-1-kraxel@redhat.com
It is desirable for 'qemu-img map' to have the same output for a file
whether it is served over file or nbd protocols. However, ever since
we implemented block status for NBD (2.12), the NBD protocol forgot to
inform the block layer that as the final layer in the chain, the
offset is valid; without an offset, the human-readable form of
qemu-img map gives up with the unhelpful:
$ nbdkit -U - data data="1" size=512 --run 'qemu-img map $nbd'
Offset Length Mapped to File
qemu-img: File contains external, encrypted or compressed clusters.
The --output=json form always works, because it is reporting the
lower-level bdrv_block_status results directly rather than trying to
filter out sparse ranges for human consumption - but now it also
shows the offset member.
With this patch, the human output changes to:
Offset Length Mapped to File
0 0x200 0 nbd+unix://?socket=/tmp/nbdkitOxeoLa/socket
This change is observable to several iotests.
Fixes: 78a33ab5
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-4-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
We have a latent bug in our NBD client code, tickled by the brand new
nbdkit 1.11.10 block status support:
$ nbdkit --filter=log --filter=truncate -U - \
data data="1" size=511 truncate=64K logfile=/dev/stdout \
--run 'qemu-img convert $nbd /var/tmp/out'
...
qemu-img: block/io.c:2122: bdrv_co_block_status: Assertion `*pnum && QEMU_IS_ALIGNED(*pnum, align) && align > offset - aligned_offset' failed.
The culprit? Our implementation of .bdrv_co_block_status can return
unaligned block status for any server that operates with a lower
actual alignment than what we tell the block layer in
request_alignment, in violation of the block layer's constraints. To
date, we've been unable to trip the bug, because qemu as NBD server
always advertises block sizing (at which point it is a server bug if
the server sends unaligned status - although qemu 3.1 is such a server
and I've sent separate patches for 4.0 both to get the server to obey
the spec, and to let the client to tolerate server oddities at EOF).
But nbdkit does not (yet) advertise block sizing, and therefore is not
in violation of the spec for returning block status at whatever
boundaries it wants, and those unaligned results can occur anywhere
rather than just at EOF. While we are still wise to avoid sending
sub-sector read/write requests to a server of unknown origin, we MUST
consider that a server telling us block status without an advertised
block size is correct. So, we either have to munge unaligned answers
from the server into aligned ones that we hand back to the block
layer, or we have to tell the block layer about a smaller alignment.
Similarly, if the server advertises an image size that is not
sector-aligned, we might as well assume that the server intends to let
us access those tail bytes, and therefore supports a minimum block
size of 1, regardless of whether the server supports block status
(although we still need more patches to fix the problem that with an
unaligned image, we can send read or block status requests that exceed
EOF to the server). Again, qemu as server cannot trip this problem
(because it rounds images to sector alignment), but nbdkit advertised
unaligned size even before it gained block status support.
Solve both alignment problems at once by using better heuristics on
what alignment to report to the block layer when the server did not
give us something to work with. Note that very few NBD servers
implement block status (to date, only qemu and nbdkit are known to do
so); and as the NBD spec mentioned block sizing constraints prior to
documenting block status, it can be assumed that any future
implementations of block status are aware that they must advertise
block size if they want a minimum size other than 1.
We've had a long history of struggles with picking the right alignment
to use in the block layer, as evidenced by the commit message of
fd8d372d (v2.12) that introduced the current choice of forced 512-byte
alignment.
There is no iotest coverage for this fix, because qemu can't provoke
it, and I didn't want to make test 241 dependent on nbdkit.
Fixes: fd8d372d
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Add a test for the NBD client workaround in the previous patch. It's
not really feasible for an iotest to assume a specific tracing engine,
so we can't really probe trace_nbd_parse_blockstatus_compliance to see
if the server was fixed vs. whether the client just worked around the
server (other than by rearranging order between code patches and this
test). But having a successful exchange sure beats the previous state
of an error message. Since format probing can change alignment, we can
use that as an easy way to test several configurations.
Not tested yet, but worth adding to this test in future patches: an
NBD server that can advertise a non-sector-aligned size (such as
nbdkit) causes qemu as the NBD client to misbehave when it rounds the
size up and accesses beyond the advertised size. Qemu as NBD server
never advertises a non-sector-aligned size (since bdrv_getlength()
currently rounds up to sector boundaries); until qemu can act as such
a server, testing that flaw will have to rely on external binaries.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190329042750.14704-2-eblake@redhat.com>
Tested-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
[eblake: add forced-512 alignment, and nbdkit reproducer comment]
The NBD spec is clear that a server that advertises a minimum block
size should reply to NBD_CMD_BLOCK_STATUS with extents aligned
accordingly. However, we know that the qemu NBD server implementation
has had a corner-case bug where it is not compliant with the spec,
present since the introduction of NBD_CMD_BLOCK_STATUS in qemu 2.12
(and unlikely to be patched in time for 4.0). Namely, when qemu is
serving a file that is not a multiple of 512 bytes, it rounds the size
advertised over NBD up to the next sector boundary (someday, I'd like
to fix that to be byte-accurate, but it's a much bigger audit not
appropriate for this release); yet if the final sector contains data
prior to EOF, lseek(SEEK_HOLE) will point to the implicit hole
mid-sector which qemu then reported over NBD.
We are well within our rights to hang up on a server that can't follow
the spec, but it is more useful to try and keep the connection alive
in spite of the problem. Do so by tracing a message about the problem,
and then either truncating the request back to an aligned boundary (if
it covered more than the final sector) or widening it out to the full
boundary with a forced status of data (since truncating would result
in 0 bytes, but we have to make progress, and valid since data is a
default-safe answer). And in practice, since the problem only happens
on a sector that starts with data and ends with a hole, we are going
to want to read that full sector anyway (where qemu as the server
fills in the tail beyond EOF with appropriate NUL bytes).
Easy reproduction:
$ printf %1000d 1 > file
$ qemu-nbd -f raw -t file & pid=$!
$ qemu-img map --output=json -f raw nbd://localhost:10809
qemu-img: Could not read file metadata: Invalid argument
$ kill $pid
where the patched version instead succeeds with:
[{ "start": 0, "length": 1024, "depth": 0, "zero": false, "data": true}]
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190326171317.4036-1-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Trying 'qemu-img map -f raw nbd://localhost:10809' causes the
NBD server to output a scary message:
qemu-nbd: Disconnect client, due to: Failed to read request: Unexpected end-of-file before all bytes were read
This is because the NBD client, being remote, has no way to expose a
human-readable map (the --output=json data is fine, however). But
because we exit(1) right after the message, causing the client to
bypass all block cleanup, the server sees the abrupt exit and warns,
whereas it would be silent had the client had a chance to send
NBD_CMD_DISC. Other protocols may have similar cleanup issues, where
failure to blk_unref() could cause unintended effects.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190326184043.7544-1-eblake@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
The NBD spec is clear that when structured replies are active, a
simple error reply is acceptable to any command except for
NBD_CMD_READ. However, we were mistakenly requiring structured errors
for NBD_CMD_BLOCK_STATUS, and hanging up on a server that gave a
simple error (since qemu does not behave as such a server, we didn't
notice the problem until now). Broken since its introduction in
commit 78a33ab5 (v2.12).
Noticed while debugging a separate failure reported by nbdkit while
working out its initial implementation of BLOCK_STATUS, although it
turns out that nbdkit also chose to send structured error replies for
BLOCK_STATUS, so I had to manually provoke the situation by hacking
qemu's server to send a simple error reply:
| diff --git i/nbd/server.c w/nbd/server.c
| index fd013a2817a..833288d7c45 100644
| 00--- i/nbd/server.c
| +++ w/nbd/server.c
| @@ -2269,6 +2269,8 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
| "discard failed", errp);
|
| case NBD_CMD_BLOCK_STATUS:
| + return nbd_co_send_simple_reply(client, request->handle, ENOMEM,
| + NULL, 0, errp);
| if (!request->len) {
| return nbd_send_generic_reply(client, request->handle, -EINVAL,
| "need non-zero length", errp);
|
Signed-off-by: Eric Blake <eblake@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20190325190104.30213-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
When the server replies with a (structured [*]) error to
NBD_CMD_BLOCK_STATUS, without any extent information sent first, the
client code was blindly throwing away the server's error code and
instead telling the caller that EIO occurred. This has been broken
since its introduction in 78a33ab5 (v2.12, where we should have called:
error_setg(&local_err, "Server did not reply with any status extents");
nbd_iter_error(&iter, false, -EIO, &local_err);
to declare the situation as a non-fatal error if no earlier error had
already been flagged, rather than just blindly slamming iter.err and
iter.ret), although it is more noticeable since commit 7f86068d, which
actually tries hard to preserve the server's code thanks to a separate
iter.request_ret.
[*] The spec is clear that the server is also permitted to reply with
a simple error, but that's a separate fix.
I was able to provoke this scenario with a hack to the server, then
seeing whether ENOMEM makes it back to the caller:
| diff --git a/nbd/server.c b/nbd/server.c
| index fd013a2817a..29c7995de02 100644
| --- a/nbd/server.c
| +++ b/nbd/server.c
| @@ -2269,6 +2269,8 @@ static coroutine_fn int nbd_handle_request(NBDClient *client,
| "discard failed", errp);
|
| case NBD_CMD_BLOCK_STATUS:
| + return nbd_send_generic_reply(client, request->handle, -ENOMEM,
| + "no status for you today", errp);
| if (!request->len) {
| return nbd_send_generic_reply(client, request->handle, -EINVAL,
| "need non-zero length", errp);
| --
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190325190104.30213-2-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
The NBD spec states that NBD_CMD_FLAG_REQ_ONE (which we currently
always use) should not reply with an extent larger than our request,
and that the server's response should be exactly one extent. Right
now, that means that if a server sends more than one extent, we treat
the server as broken, fail the block status request, and disconnect,
which prevents all further use of the block device. But while good
software should be strict in what it sends, it should be tolerant in
what it receives.
While trying to implement NBD_CMD_BLOCK_STATUS in nbdkit, we
temporarily had a non-compliant server sending too many extents in
spite of REQ_ONE. Oddly enough, 'qemu-img convert' with qemu 3.1
failed with a somewhat useful message:
qemu-img: Protocol error: invalid payload for NBD_REPLY_TYPE_BLOCK_STATUS
which then disappeared with commit d8b4bad8, on the grounds that an
error message flagged only at the time of coroutine teardown is
pointless, and instead we should rely on the actual failed API to
report an error - in other words, the 3.1 behavior was masking the
fact that qemu-img was not reporting an error. That has since been
fixed in the previous patch, where qemu-img convert now fails with:
qemu-img: error while reading block status of sector 0: Invalid argument
But even that is harsh. Since we already partially relaxed things in
commit acfd8f7a to tolerate a server that exceeds the cap (although
that change was made prior to the NBD spec actually putting a cap on
the extent length during REQ_ONE - in fact, the NBD spec change was
BECAUSE of the qemu behavior prior to that commit), it's not that much
harder to argue that we should also tolerate a server that sends too
many extents. But at the same time, it's nice to trace when we are
being tolerant of server non-compliance, in order to help server
writers fix their implementations to be more portable (if they refer
to our traces, rather than just stderr).
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190323212639.579-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
If bdrv_block_status_above() fails, we are aborting the convert
process but failing to print an error message. Broken in commit
690c7301 (v2.4) when rewriting convert's logic.
Discovered when teaching nbdkit to support NBD_CMD_BLOCK_STATUS, and
accidentally violating the protocol by returning more than one extent
in spite of qemu asking for NBD_CMD_FLAG_REQ_ONE. The qemu NBD code
should probably handle the server's non-compliance more gracefully
than failing with EINVAL, but qemu-img shouldn't be silently
squelching any block status failures. It doesn't help that qemu 3.1
masks the qemu-img bug with extra noise that the nbd code is dumping
to stderr (that noise was cleaned up in d8b4bad8).
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190323212639.579-2-eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Version: GnuPG v1
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Merge remote-tracking branch 'remotes/jasowang/tags/net-pull-request' into staging
# gpg: Signature made Fri 29 Mar 2019 07:30:26 GMT
# gpg: using RSA key EF04965B398D6211
# gpg: Good signature from "Jason Wang (Jason Wang on RedHat) <jasowang@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg: It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 215D 46F4 8246 689E C77F 3562 EF04 965B 398D 6211
* remotes/jasowang/tags/net-pull-request:
net: tap: use qemu_set_nonblock
MAINTAINERS: Update the latest email address
e1000: Delay flush queue when receive RCTL
net/socket: learn to talk with a unix dgram socket
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Here's a set of bugfixes for ppc, aimed at qemu-4.0 during hard freeze.
We have one cleanup that's not strictly a bugfix, but will avoid an
ugly external interface making it to a released version.
We have one change to generic code to tweak the semantics of
qemu_getrampagesize() which fixes a bug for ppc. This does have a
possible impact on s390x which uses this function for a different
purpose. I've discussed with David Hildenbrand and Igor Mammedov,
however and we think it won't immediately break anything due to some
existing bugs in the s390 usage. David H will be following up with
some s390 fixes in that area.
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Merge remote-tracking branch 'remotes/dgibson/tags/ppc-for-4.0-20190329' into staging
ppc patch queue 2019-03-29
Here's a set of bugfixes for ppc, aimed at qemu-4.0 during hard freeze.
We have one cleanup that's not strictly a bugfix, but will avoid an
ugly external interface making it to a released version.
We have one change to generic code to tweak the semantics of
qemu_getrampagesize() which fixes a bug for ppc. This does have a
possible impact on s390x which uses this function for a different
purpose. I've discussed with David Hildenbrand and Igor Mammedov,
however and we think it won't immediately break anything due to some
existing bugs in the s390 usage. David H will be following up with
some s390 fixes in that area.
# gpg: Signature made Fri 29 Mar 2019 03:27:49 GMT
# gpg: using RSA key 75F46586AE61A66CC44E87DC6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg: aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg: aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg: aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E 87DC 6C38 CACA 20D9 B392
* remotes/dgibson/tags/ppc-for-4.0-20190329:
exec: Only count mapped memory backends for qemu_getrampagesize()
spapr/irq: Add XIVE sanity checks on non-P9 machines
spapr: Simplify handling of host-serial and host-model values
target/ppc: Fix QEMU crash with stxsdx
target/ppc: Improve comment of bcctr used for spectre v2 mitigation
target/ppc: Consolidate 64-bit server processor detection in a helper
target/ppc: Enable "decrement and test CTR" version of bcctr
target/ppc: Fix TCG temporary leaks in gen_bcond()
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The fcntl will change the flags directly, use qemu_set_nonblock()
instead.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
-net socket has a fd argument, and may be passed pre-opened sockets.
TCP sockets use framing.
UDP sockets have datagram boundaries.
When given a unix dgram socket, it will be able to read from it, but
will attempt to send on the dgram_dst, which is unset. The other end
will not receive the data.
Let's teach -net socket to recognize a UNIX DGRAM socket, and use the
regular send() command (without dgram_dst).
This makes running slirp out-of-process possible that
way (python pseudo-code):
a, b = socket.socketpair(socket.AF_UNIX, socket.SOCK_DGRAM)
subprocess.Popen('qemu -net socket,fd=%d -net user' % a.fileno(), shell=True)
subprocess.Popen('qemu ... -net nic -net socket,fd=%d' % b.fileno(), shell=True)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
qemu_getrampagesize() works out the minimum host page size backing any of
guest RAM. This is required in a few places, such as for POWER8 PAPR KVM
guests, because limitations of the hardware virtualization mean the guest
can't use pagesizes larger than the host pages backing its memory.
However, it currently checks against *every* memory backend, whether or not
it is actually mapped into guest memory at the moment. This is incorrect.
This can cause a problem attempting to add memory to a POWER8 pseries KVM
guest which is configured to allow hugepages in the guest (e.g.
-machine cap-hpt-max-page-size=16m). If you attempt to add non-hugepage,
you can (correctly) create a memory backend, however it (correctly) will
throw an error when you attempt to map that memory into the guest by
'device_add'ing a pc-dimm.
What's not correct is that if you then reset the guest a startup check
against qemu_getrampagesize() will cause a fatal error because of the new
memory object, even though it's not mapped into the guest.
This patch corrects the problem by adjusting find_max_supported_pagesize()
(called from qemu_getrampagesize() via object_child_foreach) to exclude
non-mapped memory backends.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
On non-P9 machines, the XIVE interrupt mode is not advertised, see
spapr_dt_ov5_platform_support(). Add a couple of checks on the machine
configuration to filter bogus setups and prevent OS failures :
Interrupt modes
CPU/Compat XICS XIVE dual
P8/P8 OK QEMU failure (1) OK (3)
P9/P8 OK QEMU failure (2) OK (3)
P9/P9 OK OK OK
(1) CPU exception model is incompatible with XIVE and the presenters
will fail to realize.
(2) CPU exception model is compatible with XIVE, but the XIVE CAS
advertisement is dropped when in POWER8 mode. So we could ended up
booting with the XIVE DT properties but without the HCALLs. Avoid
confusing Linux with such settings and fail under QEMU.
(3) force XICS in machine init
Remove the check on XIVE-only machines in spapr_machine_init(), which
has now become redundant.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190328100044.11408-1-clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
27461d69a0 "ppc: add host-serial and host-model machine attributes
(CVE-2019-8934)" introduced 'host-serial' and 'host-model' machine
properties for spapr to explicitly control the values advertised to the
guest in device tree properties with the same names.
The previous behaviour on KVM was to unconditionally populate the device
tree with the real host serial number and model, which leaks possibly
sensitive information about the host to the guest.
To maintain compatibility for old machine types, we allowed those props
to be set to "passthrough" to take the value from the host as before. Or
they could be set to "none" to explicitly omit the device tree items.
Special casing specific values on what's otherwise a user supplied string
is very ugly. So, this patch simplifies things by implementing the
backwards compatibility in a different way: we have a machine class flag
set for the older machines, and we only load the host values into the
device tree if A) they're not set by the user and B) we have that flag set.
This does mean that the "passthrough" functionality is no longer available
with the current machine type. That's ok though: if a user or management
layer really wants the information passed through they can read it
themselves (OpenStack Nova already does something similar for x86).
It also means the user can't explicitly ask for the values to be omitted
on the old machine types. I think that's an acceptable trade-off: if you
care enough about not leaking the host information you can either move to
the new machine type, or use a dummy value for the properties.
For the new machine type, this also removes an odd inconsistency
between running on a POWER and non-POWER (or non-Linux) hosts: if the
host information couldn't be read from where we expect (in the host's
device tree as exposed by Linux), we'd fallback to omitting the guest
device tree items.
While we're there, improve some poorly worded comments, and the help text
for the properties.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
I've been hitting several QEMU crashes while running a fedora29 ppc64le
guest under TCG. Each time, this would occur several minutes after the
guest reached login:
Fedora 29 (Twenty Nine)
Kernel 4.20.6-200.fc29.ppc64le on an ppc64le (hvc0)
Web console: https://localhost:9090/
localhost login:
tcg/tcg.c:3211: tcg fatal error
This happens because a bug crept up in the gen_stxsdx() helper when it
was converted to use VSR register accessors by commit 8b3b2d75c7
"target/ppc: introduce get_cpu_vsr{l,h}() and set_cpu_vsr{l,h}() helpers
for VSR register access".
The code creates a temporary, passes it directly to gen_qemu_st64_i64()
and then to set_cpu_vrsh()... which looks like this was mistakenly
coded as a load instead of a store.
Reverse the logic: read the VSR to the temporary first and then store
it to memory.
Fixes: 8b3b2d75c7
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <155371035249.2038502.12364252604337688538.stgit@bahia.lan>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <155359567174.1794128.3183997593369465355.stgit@bahia.lan>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
We use PPC_SEGMENT_64B in various places to guard code that is specific
to 64-bit server processors compliant with arch 2.x. Consolidate the
logic in a helper macro with an explicit name.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <155327783157.1283071.3747129891004927299.stgit@bahia.lan>
Tested-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Even if all ISAs up to v3 indeed mention:
If the "decrement and test CTR" option is specified (BO2=0), the
instruction form is invalid.
The UMs of all existing 64-bit server class processors say:
If BO[2] = 0, the contents of CTR (before any update) are used as the
target address and for the test of the contents of CTR to resolve the
branch. The contents of the CTR are then decremented and written back
to the CTR.
The linux kernel has spectre v2 mitigation code that relies on a
BO[2] = 0 variant of bcctr, which is now activated by default on
spapr, even with TCG. This causes linux guests to panic with
the default machine type under TCG.
Since any CPU model can provide its own behaviour for invalid forms,
we could possibly introduce a new instruction flag to handle this.
In practice, since the behaviour is shared by all 64-bit server
processors starting with 970 up to POWER9, let's reuse the
PPC_SEGMENT_64B flag. Caveat: this may have to be fixed later if
POWER10 introduces a different behaviour.
The existing behaviour of throwing a program interrupt is kept for
all other CPU models.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <155327782604.1283071.10640596307206921951.stgit@bahia.lan>
Tested-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
A single patch updating the MAINTAINERS file for 4.0.
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Merge remote-tracking branch 'remotes/alistair/tags/pull-device-tree-20190327' into staging
Device Tree Pull Request for 4.0
A single patch updating the MAINTAINERS file for 4.0.
# gpg: Signature made Wed 27 Mar 2019 17:02:00 GMT
# gpg: using RSA key F6C4AC46D4934868D3B8CE8F21E10D29DF977054
# gpg: Good signature from "Alistair Francis <alistair@alistair23.me>" [full]
# Primary key fingerprint: F6C4 AC46 D493 4868 D3B8 CE8F 21E1 0D29 DF97 7054
* remotes/alistair/tags/pull-device-tree-20190327:
MAINTAINERS: Update the device tree maintainers
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Remove Alex as a Device Tree maintainer as requested by him. Add myself
as a maintainer to avoid it being orphaned. Also add David as a
Reviewer (R) as he is the libfdt and DTC maintainer.
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alexander Graf <agraf@csgraf.de>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Most of the seccomp functions return errnos as a negative return
value. The code is currently ignoring these and reporting a generic
error message for all seccomp failure scenarios making debugging
painful. Report a more precise error from each failed call and include
errno if it is available.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Eduardo Otubo <otubo@redhat.com>
The Mesa library tries to set process affinity on some of its threads in
order to optimize its performance. Currently this results in QEMU being
immediately terminated when seccomp is enabled.
Mesa doesn't consider failure of the process affinity settings to be
fatal to its operation, but our seccomp policy gives it no choice in
gracefully handling this denial.
It is reasonable to consider that malicious code using the resource
control syscalls to be a less serious attack than if they were trying
to spawn processes or change UIDs and other such things. Generally
speaking changing the resource control setting will "merely" affect
quality of service of processes on the host. With this in mind, rather
than kill the process, we can relax the policy for these syscalls to
return the EPERM errno value. This allows callers to detect that QEMU
does not want them to change resource allocations, and apply some
reasonable fallback logic.
The main downside to this is for code which uses these syscalls but does
not check the return value, blindly assuming they will always
succeeed. Returning an errno could result in sub-optimal behaviour.
Arguably though such code is already broken & needs fixing regardless.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Eduardo Otubo <otubo@redhat.com>
- Fix slow pre-zeroing in qemu-img convert
- Test case for block job pausing on I/O errors
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Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer patches:
- Fix slow pre-zeroing in qemu-img convert
- Test case for block job pausing on I/O errors
# gpg: Signature made Tue 26 Mar 2019 15:28:00 GMT
# gpg: using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* remotes/kevin/tags/for-upstream:
qemu-io: Add write -n for BDRV_REQ_NO_FALLBACK
qemu-img: Use BDRV_REQ_NO_FALLBACK for pre-zeroing
file-posix: Support BDRV_REQ_NO_FALLBACK for zero writes
block: Advertise BDRV_REQ_NO_FALLBACK in filter drivers
block: Add BDRV_REQ_NO_FALLBACK
block: Remove error messages in bdrv_make_zero()
iotests: add 248: test resume mirror after auto pause on ENOSPC
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The vCont packet accepts a series of actions, each being applied on a
given thread ID. Giving no thread ID for an action is valid and means
"all threads".
This commit fixes vCont packets being incorrectly rejected when no
thread ID was given for an action.
In multiprocess mode, the GDB Remote Protocol specification is unclear
on what "all threads" means. We choose to apply the action on all
threads of all attached processes.
This commit is based on the initial fix by Lucien Murray-Pitts.
Fixes: e40e5204af
Reported-by: Lucien Murray-Pitts <lucienmp_antispam@yahoo.com>
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Luc Michel <luc.michel@greensocs.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190325110452.6756-1-luc.michel@greensocs.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Coverity (CID 1399700) found that this was wrong so instead of trying
to do it by hand use existing access functions that should work better.
Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Message-id: 20190318223842.427CB7456B2@zero.eik.bme.hu
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This makes the new BDRV_REQ_NO_FALLBACK flag available in the qemu-io
write command.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
If qemu-img convert sees that the target image isn't zero-initialised
yet, it tries to do an efficient zero write for the whole image first
to save the overhead of repeated explicit zero writes during the
conversion. Obviously, this provides only an advantage if the
pre-zeroing is actually efficient. Otherwise, we can end up writing
zeroes slowly while zeroing out the whole image, and then overwrite the
same blocks again with real data, potentially doubling the written data.
Pass BDRV_REQ_NO_FALLBACK to blk_make_zero() to avoid this case. If we
can't efficiently zero out, we'll instead write explicit zeroes only if
there is no data to be written to a block.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
We know that the kernel implements a slow fallback code path for
BLKZEROOUT, so if BDRV_REQ_NO_FALLBACK is given, we shouldn't call it.
The other operations we call in the context of .bdrv_co_pwrite_zeroes
should usually be quick, so no modification should be needed for them.
If we ever notice that there are additional problematic cases, we can
still make these conditional as well.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
Filter drivers that support .bdrv_co_pwrite_zeroes can safely advertise
BDRV_REQ_NO_FALLBACK because they just forward the request flags to
their child node.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
For qemu-img convert, we want an operation that zeroes out the whole
image if this can be done efficiently, but that returns an error
otherwise so we don't write explicit zeroes and immediately overwrite
them with the real data, potentially doubling the amount of data to be
written.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
There is only a single caller of bdrv_make_zero(), which is qemu-img
convert. If the function fails, we just fall back to a different method
of zeroing out blocks on the target image. There is no good reason to
print error messages on stderr when the higher level operation will
actually succeed.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Eric Blake <eblake@redhat.com>
Test that mirror job actually resume on resume command after being
automatically paused on ENOSPC error.
It's a follow-up test for 8d9648cbf3
"blockjob: fix user pause in block_job_error_action"
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Tested-by: John Snow <jsnow@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
