Some typedefs and macros are defined after the type check macros.
This makes it difficult to automatically replace their
definitions with OBJECT_DECLARE_TYPE.
Patch generated using:
$ ./scripts/codeconverter/converter.py -i \
--pattern=QOMStructTypedefSplit $(git grep -l '' -- '*.[ch]')
which will split "typdef struct { ... } TypedefName"
declarations.
Followed by:
$ ./scripts/codeconverter/converter.py -i --pattern=MoveSymbols \
$(git grep -l '' -- '*.[ch]')
which will:
- move the typedefs and #defines above the type check macros
- add missing #include "qom/object.h" lines if necessary
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20200831210740.126168-9-ehabkost@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20200831210740.126168-10-ehabkost@redhat.com>
Message-Id: <20200831210740.126168-11-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Remove superfluous breaks, as there is a "return" before them.
Signed-off-by: Liao Pingfang <liao.pingfang@zte.com.cn>
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1594631062-36341-1-git-send-email-wang.yi59@zte.com.cn>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Meson doesn't enjoy the same flexibility we have with Make in choosing
the include path. In particular the tracing headers are using
$(build_root)/$(<D).
In order to keep the include directives unchanged,
the simplest solution is to generate headers with patterns like
"trace/trace-audio.h" and place forwarding headers in the source tree
such that for example "audio/trace.h" includes "trace/trace-audio.h".
This patch is too ugly to be applied to the Makefiles now. It's only
a way to separate the changes to the tracing header files from the
Meson rewrite of the tracing logic.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
object_get_canonical_path_component() returns a malloced copy of a
property name on success, null on failure.
19 of its 25 callers immediately free the returned copy.
Change object_get_canonical_path_component() to return the property
name directly. Since modifying the name would be wrong, adjust the
return type to const char *.
Drop the free from the 19 callers become simpler, add the g_strdup()
to the other six.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200714160202.3121879-4-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Replace
error_report("...: %s", ..., error_get_pretty(err));
by
error_reportf_err(err, "...: ", ...);
One of the replaced messages lacked a colon. Add it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200505101908.6207-6-armbru@redhat.com>
The only way object_property_add() can fail is when a property with
the same name already exists. Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.
Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent. Parentage is
also under program control, so this is a programming error, too.
We have a bit over 500 callers. Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.
The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.
Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL. Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call. ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.
When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.
Drop parameter @errp and assert the preconditions instead.
There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification". Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]
Compile error reported by gcc 10.0.1:
scsi/qemu-pr-helper.c: In function ‘multipath_pr_out’:
scsi/qemu-pr-helper.c:523:32: error: array subscript <unknown> is outside array bounds of ‘struct transportid *[0]’ [-Werror=array-bounds]
523 | paramp.trnptid_list[paramp.num_transportid++] = id;
| ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from scsi/qemu-pr-helper.c:36:
/usr/include/mpath_persist.h:168:22: note: while referencing ‘trnptid_list’
168 | struct transportid *trnptid_list[];
| ^~~~~~~~~~~~
scsi/qemu-pr-helper.c:424:35: note: defined here ‘paramp’
424 | struct prout_param_descriptor paramp;
| ^~~~~~
This highlights an actual implementation issue in function multipath_pr_out.
The variable paramp is declared with type `struct prout_param_descriptor`,
which is a struct terminated by an empty array in mpath_persist.h:
struct transportid *trnptid_list[];
That empty array was filled with code that looked like that:
trnptid_list[paramp.descr.num_transportid++] = id;
This is an actual out-of-bounds access.
The fix is to malloc `paramp`.
Signed-off-by: Christophe de Dinechin <dinechin@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since we are actually testing for the newer capng library, rename the
symbol to match.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The 'r' variable was accidently shadowed, and because of this
we were always passing 0 to mpath_generic_sense, instead of original
return value, which triggers an abort()
This is an attempt to fix the
https://bugzilla.redhat.com/show_bug.cgi?id=1720047
although there might be other places in the code
that trigger qemu-pr-helper crash, and this fix might
not be the root cause.
The crash was reproduced by creating an iscsi target on a test machine,
and passing it twice to the guest like that:
-blockdev node-name=idisk0,driver=iscsi,transport=...,target=...
-device scsi-block,drive=idisk0,bus=scsi0.0,bootindex=-1,scsi-id=1,lun=0,share-rw=on
-device scsi-block,drive=idisk0,bus=scsi0.0,bootindex=-1,scsi-id=1,lun=1,share-rw=on
Then in the guest, both /dev/sda and /dev/sdb were aggregated by multipath to /dev/mpatha,
which was passed to a nested guest like that
-object pr-manager-helper,id=qemu_pr_helper,path=/root/work/vm/testvm/.run/pr_helper.socket
-blockdev node-name=test,driver=host_device,filename=/dev/mapper/mpatha,pr-manager=qemu_pr_helper
-device scsi-block,drive=test,bus=scsi0.0,bootindex=-1,scsi-id=0,lun=0
The nested guest run:
sg_persist --no-inquiry -v --out --register --param-sark 0x1234 /dev/sda
Strictly speaking this is wrong configuration since qemu is where
the multipath was split, and thus the iscsi target was not aware of
multipath, and thus when libmpathpersist code rightfully tried to register
the PR key on all paths, it failed to do so.
However qemu-pr-helper should not crash in this case.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
pr_manager_worker() passes its @opaque argument to g_free(). Wrong;
it points to pr_manager_worker()'s automatic @data. Broken when
commit 2f3a7ab39b converted @data from heap- to stack-allocated. Fix
by deleting the g_free().
Fixes: 2f3a7ab39b
Cc: qemu-stable@nongnu.org
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that scsi-disk is not using scsi_sense_to_errno to separate guest-recoverable
sense codes, we can modify it to simplify iscsi's own sense handling.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When running basic operations on zoned storage from the guest via
scsi-block, the following ASCs are reported for write or read commands
due to unexpected zone status or write pointer status:
21h 04h: UNALIGNED WRITE COMMAND
21h 05h: WRITE BOUNDARY VIOLATION
21h 06h: ATTEMPT TO READ INVALID DATA
55h 0Eh: INSUFFICIENT ZONE RESOURCES
Reporting these ASCs to the guest, the user applications can handle
them to manage zone/write pointer status, or help the user application
developers to understand the failure reason and fix bugs.
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It's not really possible to fit all sense codes into errno codes,
especially in such a way that sense codes can be properly categorized as
either guest-recoverable or host-handled. Create a new function that
checks for guest recoverable sense, then scsi_sense_buf_to_errno only
needs to be called for host handled sense codes.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
No header includes qemu-common.h after this commit, as prescribed by
qemu-common.h's file comment.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190523143508.25387-5-armbru@redhat.com>
[Rebased with conflicts resolved automatically, except for
include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c
block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c
target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h
target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h
target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h
target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and
net/tap-bsd.c fixed up]
We commonly define the header guard symbol without an explicit value.
Normalize the exceptions.
Done with scripts/clean-header-guards.pl.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20190315145123.28030-8-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
This commit adds a error_init() helper which calls
g_log_set_default_handler() so that glib logs (g_log, g_warning, ...)
are handled similarly to other QEMU logs. This means they will get a
timestamp if timestamps are enabled, and they will go through the
HMP monitor if one is configured.
This commit also adds a call to error_init() to the binaries
installed by QEMU. Since error_init() also calls error_set_progname(),
this means that *-linux-user, *-bsd-user and qemu-pr-helper messages
output with error_report, info_report, ... will slightly change: they
will be prefixed by the binary name.
glib debug messages are enabled through G_MESSAGES_DEBUG similarly to
the glib default log handler.
At the moment, this change will mostly impact SPICE logging if your
spice version is >= 0.14.1. With older spice versions, this is not going
to work as expected, but will not have any ill effect, so this call is
not conditional on the SPICE version.
Signed-off-by: Christophe Fergeau <cfergeau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20190131164614.19209-3-cfergeau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
We spell out sub/dir/ in sub/dir/trace-events' comments pointing to
source files. That's because when trace-events got split up, the
comments were moved verbatim.
Delete the sub/dir/ part from these comments. Gets rid of several
misspellings.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190314180929.27722-3-armbru@redhat.com
Message-Id: <20190314180929.27722-3-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Almost all trace-events point to docs/devel/tracing.txt in a comment
right at the beginning. Touch up the ones that don't.
[Updated with Markus' new commit description wording.
--Stefan]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190314180929.27722-2-armbru@redhat.com
Message-Id: <20190314180929.27722-2-armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
No real reason to keep using the callback based mechanism here when the
rest of the file-posix driver is coroutine based. Changing it brings
ioctls more in line with how other request types work.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Some versions of Clang prior to 6.0 (and some builds of clang after,
such as 6.0.1-2.fc28) fail to recognize { 0 } as a valid initializer
for a struct with subobjects when -Wmissing-braces is enabled.
https://bugs.llvm.org/show_bug.cgi?id=21689 and
https://reviews.llvm.org/rL314499 suggests this should be fixed in 6.0,
but it might not be the case for older versions or downstream versions.
For now, follow the precedent of ebf2a499 and replace the standard { 0 }
with the accepted { } to silence this warning and allow the build to
work under clang 6.0.1-2.fc28, and builds prior to 6.0.
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20181127184929.20065-1-jsnow@redhat.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The generated qapi_event_send_FOO() take an Error ** argument. They
can't actually fail, because all they do with the argument is passing it
to functions that can't fail: the QObject output visitor, and the
@qmp_emit callback, which is either monitor_qapi_event_queue() or
event_test_emit().
Drop the argument, and pass &error_abort to the QObject output visitor
and @qmp_emit instead.
Suggested-by: Eric Blake <eblake@redhat.com>
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180815133747.25032-4-peterx@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message rewritten, update to qapi-code-gen.txt corrected]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
After commit b3f1c8c413 "qemu-pr-helper: use new
libmultipath API", QEMU started using new libmultipath API, which is not
available on CentOS 7.x.
This fixes that by probing the new libmultipath API in configure. If it fails,
then try probing the old API. If it fails, then consider libmultipath not
available.
With this, configure script defines CONFIG_MPATH_NEW_API that is used in
scsi/qemu-pr-helper.c to use the new libmultipath API.
Fixes: b3f1c8c413
BugLink: https://bugs.launchpad.net/qemu/+bug/1786343
Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Message-Id: <20180810141116.24016-1-muriloo@linux.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When reviewing Paolo's pr-helper patches I've noticed couple of
problems:
1) socket_path needs to be calculated at two different places
(one for printing out help, the other if socket activation is NOT
used),
2) even though the default socket_path is allocated in
compute_default_paths() it is the only default path the function
handles. For instance, pidfile is allocated outside of this
function. And yet again, at different places than 1)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <c791ba035f26ea957e8f3602e3009b621769b1ba.1530611283.git.mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After reading a PR IN command with zero request size in prh_read_request,
the resp->result field will be uninitialized and the resp.sz field will
be also uninitialized when returning to prh_co_entry.
If resp->result == GOOD (from a previous successful reply or just luck),
then the assert in prh_write_response might not be triggered and
uninitialized response will be sent.
The fix is to remove the whole handling of sz == 0 in prh_co_entry.
Those errors apply only to PR OUT commands and it's perfectly okay to
catch them later in do_pr_out and multipath_pr_out; the check for
too-short parameters in fact doesn't apply in the easy SG_IO case, as
it can be left to the target firmware even.
The result is that prh_read_request does not fail requests anymore and
prh_co_entry becomes simpler.
Reported-by: Dima Stepanov <dimastep@yandex-team.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Let management know if there were any problems communicating with
qemu-pr-helper. The event is edge-triggered, and is sent every time
the connection status of the pr-manager-helper object changes.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When writing to the qemu-pr-helper socket failed, the persistent
reservation manager was correctly disconnecting the socket, but it
did not clear pr_mgr->ioc. So the rest of the code did not know
that the socket had been disconnected, accessed pr_mgr->ioc and
happily caused a crash.
To reproduce, it is enough to stop qemu-pr-helper between QEMU
startup and executing e.g. sg_persist -k /dev/sdb.
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The response size is expected to be zero if the SCSI status is not
"GOOD", but nothing was resetting it.
This can be reproduced simply by "sg_persist -s /dev/sdb" where /dev/sdb
in the guest is a scsi-block device corresponding to a multipath device
on the host.
Before:
PR in (Read full status): Aborted command
and on the host:
prh_write_response: Assertion `resp->sz == 0' failed.
After:
PR in (Read full status): bad field in cdb or parameter list
(perhaps unsupported service action)
Reported-by: Jiri Belka <jbelka@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Currently --help shows "(default '(null)')" for the -k/--socket-path
option. Fix it by getting the default path in /var/run.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Let's write pidfile even if user did not request --daemon but
they requested just --pidfile. Libvirt will use exactly this.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After we've dropped privileges it might be not possible to write
pidfile. For instance, if this binary is run as root (because
user wants it to write pidfile to some privileged location)
writing pidfile fails because privileges are dropped before we
even get to that.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Due to wrong specification of arguments to getopt_long() any
attempt to set pidfile resulted in:
1) the default to be leaked
2) the @pidfile variable to be set to NULL (because optarg is
NULL without this patch).
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Message-Id: <6f10cd53d361a395aa0e85a9311ec4e9a8fc11e5.1521868451.git.mprivozn@redhat.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Since commit 67a1de0d19 there is no space anymore between the
version number and the parentheses when running configure with
--with-pkgversion=foo :
$ qemu-system-s390x --version
QEMU emulator version 2.11.50(foo)
But the space is included when building without that option
when building from a git checkout:
$ qemu-system-s390x --version
QEMU emulator version 2.11.50 (v2.11.0-1494-gbec9c64-dirty)
The same confusion exists with the "query-version" QMP command.
Let's fix this by introducing a proper QEMU_FULL_VERSION definition
that includes the space and parentheses, while the QEMU_PKGVERSION
should just cleanly contain the package version string itself.
Note that this also changes the behavior of the "query-version" QMP
command (the space and parentheses are not included there anymore),
but that's supposed to be OK since the strings there are not meant
to be parsed by other tools.
Fixes: 67a1de0d19
Buglink: https://bugs.launchpad.net/qemu/+bug/1673373
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1518692807-25859-1-git-send-email-thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Clean up includes so that osdep.h is included first and headers
which it implies are not included manually.
This commit was created with scripts/clean-includes, with the change
to target/s390x/gen-features.c manually reverted, and blank lines
around deletions collapsed.
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20180201111846.21846-3-armbru@redhat.com>
scsi_disk_emulate_command passes in_buf == NULL when sent a REQUEST
SENSE command. Check for in_len == 0 before dereferencing in_buf.
Fixes: f68d98b21f
Reported-by: Roman Kagan <rkagan@virtuozzo.com>
Tested-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sense keys have nice #defines in scsi/constants.h, use them.
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Extract the common parts of scsi_sense_buf_to_errno, scsi_convert_sense
and scsi_target_send_command's REQUEST SENSE handling into two new
functions scsi_parse_sense_buf and scsi_build_sense_buf.
Fix a bug in scsi_target_send_command along the way; the length was
written in buf[10] rather than buf[7].
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Fixes: b07fbce634 ("scsi-bus: correct responses for INQUIRY and REQUEST SENSE")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1) Return a generic sense if TEST UNIT READY does not provide one;
2) Fix two mistakes in copying from the spec.
Cc: qemu-stable@nongnu.org
Reported-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
libmultipath has recently changed its API. The new API supports multi-threaded
clients better. Unfortunately there is no backwards-compatibility, so we just
switch to the new one. Running QEMU compiled with the new library on the old
library will likely crash, while doing the opposite will cause QEMU not to
start at all (because udev, get_multipath_config and put_multipath_config
are undefined).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Proper support of persistent reservation for multipath devices requires
communication with the multipath daemon, so that the reservation is
registered and applied when a path comes up. The device mapper
utilities provide a library to do so; this patch makes qemu-pr-helper.c
detect multipath devices and, when one is found, delegate the operation
to libmpathpersist.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Introduce a privileged helper to run persistent reservation commands.
This lets virtual machines send persistent reservations without using
CAP_SYS_RAWIO or out-of-tree patches. The helper uses Unix permissions
and SCM_RIGHTS to restrict access to processes that can access its socket
and prove that they have an open file descriptor for a raw SCSI device.
The next patch will also correct the usage of persistent reservations
with multipath devices.
It would also be possible to support for Linux's IOC_PR_* ioctls in
the future, to support NVMe devices. For now, however, only SCSI is
supported.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It is a common requirement for virtual machine to send persistent
reservations, but this currently requires either running QEMU with
CAP_SYS_RAWIO, or using out-of-tree patches that let an unprivileged
QEMU bypass Linux's filter on SG_IO commands.
As an alternative mechanism, the next patches will introduce a
privileged helper to run persistent reservation commands without
expanding QEMU's attack surface unnecessarily.
The helper is invoked through a "pr-manager" QOM object, to which
file-posix.c passes SG_IO requests for PERSISTENT RESERVE OUT and
PERSISTENT RESERVE IN commands. For example:
$ qemu-system-x86_64
-device virtio-scsi \
-object pr-manager-helper,id=helper0,path=/var/run/qemu-pr-helper.sock
-drive if=none,id=hd,driver=raw,file.filename=/dev/sdb,file.pr-manager=helper0
-device scsi-block,drive=hd
or:
$ qemu-system-x86_64
-device virtio-scsi \
-object pr-manager-helper,id=helper0,path=/var/run/qemu-pr-helper.sock
-blockdev node-name=hd,driver=raw,file.driver=host_device,file.filename=/dev/sdb,file.pr-manager=helper0
-device scsi-block,drive=hd
Multiple pr-manager implementations are conceivable and possible, though
only one is implemented right now. For example, a pr-manager could:
- talk directly to the multipath daemon from a privileged QEMU
(i.e. QEMU links to libmpathpersist); this makes reservation work
properly with multipath, but still requires CAP_SYS_RAWIO
- use the Linux IOC_PR_* ioctls (they require CAP_SYS_ADMIN though)
- more interestingly, implement reservations directly in QEMU
through file system locks or a shared database (e.g. sqlite)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
