Screwed up in commit 3a55fc0f, v2.6.0.
If qemu_chr_fe_read_all() returns -EINTR the do {} statement continues and the
n accumulator used to complete reads upto sizeof(msg) is decremented by 4 (the
value of EINTR on Linux).
To avoid that, use simpler if() statements and continue if EINTR occured.
hw/misc/ivshmem.c:650:14: warning: Loss of sign in implicit conversion
} while (n < sizeof(msg));
^
Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Unlike the usual object_property_add_link() invocations in other
devices, ivshmem checks the "is mapped" state of the backend in addition
to qdev_prop_allow_set_link_before_realize. To convert it without
specializing DEFINE_PROP_LINK which always uses the qdev callback, move
the extra check to device realize time.
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170714021509.23681-12-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
link's check callback is supposed to verify/permit setting it,
however currently nothing restricts it from misusing it
and modifying target object from within.
Make sure that readonly semantics are checked by compiler
to prevent callback's misuse.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <20170714021509.23681-2-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
frontends should avoid accessing CharDriver struct where possible
Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1499342940-56739-6-git-send-email-anton.nefedov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Frontends should have an interface to setup the handler of a backend change.
The interface will be used in the next commits
Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1499342940-56739-3-git-send-email-anton.nefedov@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Instead of having its own mmap handling code, reuse the code from
exec.c.
Note: memory_region_init_ram_from_fd() adds some restrictions
(check for xen, kvm sync-mmu, etc) and changes (such as size
alignment). This may actually be more correct.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170602141229.15326-6-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move all the frontend struct and methods to a seperate unit. This avoids
accidentally mixing backend and frontend calls, and helps with readabilty.
Make qemu_chr_replay() a macro shared by both char and char-fe.
Export qemu_chr_write(), and use a macro for qemu_chr_write_all()
(nb: yes, CharBackend is for char frontend :)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
So they are all in one place. The following patch will move serial &
parallel declarations to the respective headers.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
This allows us to remove lots of includes of migration/migration.h
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This will permit its use in parse_option_size().
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)
Cc: Kevin Wolf <kwolf@redhat.com> (supporter:Block layer core)
Cc: Max Reitz <mreitz@redhat.com> (supporter:Block layer core)
Cc: qemu-block@nongnu.org (open list:Block layer core)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1487708048-2131-24-git-send-email-armbru@redhat.com>
This makes qemu_strtosz(), qemu_strtosz_mebi() and
qemu_strtosz_metric() similar to qemu_strtoi64(), except negative
values are rejected.
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)
Cc: Kevin Wolf <kwolf@redhat.com> (supporter:Block layer core)
Cc: Max Reitz <mreitz@redhat.com> (supporter:Block layer core)
Cc: qemu-block@nongnu.org (open list:Block layer core)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1487708048-2131-23-git-send-email-armbru@redhat.com>
Change the qemu_strtosz() & friends to return -EINVAL when @endptr is
null and the conversion doesn't consume the string completely.
Matches how qemu_strtol() & friends work.
Only test_qemu_strtosz_simple() passes a null @endptr. No functional
change there, because its conversion consumes the string.
Simplify callers that use @endptr only to fail when it doesn't point
to '\0' to pass a null @endptr instead.
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)
Cc: Kevin Wolf <kwolf@redhat.com> (supporter:Block layer core)
Cc: Max Reitz <mreitz@redhat.com> (supporter:Block layer core)
Cc: qemu-block@nongnu.org (open list:Block layer core)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1487708048-2131-22-git-send-email-armbru@redhat.com>
With qemu_strtosz(), no suffix means mebibytes. It's used rarely.
I'm going to add a similar function where no suffix means bytes.
Rename qemu_strtosz() to qemu_strtosz_MiB() to make the name
qemu_strtosz() available for the new function.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1487708048-2131-16-git-send-email-armbru@redhat.com>
msix_init() reports errors with error_report(), which is wrong when
it's used in realize(). The same issue was fixed for msi_init() in
commit 1108b2f. In order to make the API change as small as possible,
leave the return value check to later patch.
For some devices(like e1000e, vmxnet3, nvme) who won't fail because of
msix_init's failure, suppress the error report by passing NULL error
object.
Bonus: add comment for msix_init.
CC: Jiri Pirko <jiri@resnulli.us>
CC: Gerd Hoffmann <kraxel@redhat.com>
CC: Dmitry Fleytman <dmitry@daynix.com>
CC: Jason Wang <jasowang@redhat.com>
CC: Michael S. Tsirkin <mst@redhat.com>
CC: Hannes Reinecke <hare@suse.de>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Alex Williamson <alex.williamson@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Marcel Apfelbaum <marcel@redhat.com>
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Pick a uniform chardev type name.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If a migration is already in progress and somebody attempts
to add a migration blocker, this should rightly fail.
Add an errp parameter and a retcode return value to migrate_add_blocker.
Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Message-Id: <1484566314-3987-5-git-send-email-ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Merged with recent 'Allow invtsc migration' change
Device ivshmem property use64=0 is designed to make the device
expose a 32 bit shared memory BAR instead of 64 bit one. The
default is a 64 bit BAR, except pc-1.2 and older retain a 32 bit
BAR. A 32 bit BAR can support only up to 1 GiB of shared memory.
This worked as designed until commit 5400c02 accidentally flipped
its sense: since then, we misinterpret use64=0 as use64=1 and vice
versa. Worse, the default got flipped as well. Devices
ivshmem-plain and ivshmem-doorbell are not affected.
Fix by restoring the test of IVShmemState member not_legacy_32bit
that got messed up in commit 5400c02. Also update its
initialization for devices ivhsmem-plain and ivshmem-doorbell.
Without that, they'd regress to 32 bit BARs.
Signed-off-by: Zhuang Yanying <ann.zhuangyanying@huawei.com>
Reviewed-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1479385863-7648-1-git-send-email-ann.zhuangyanying@huawei.com>
No need to keep explicit_fe_open around if it affects only a
qemu_chr_fe_set_handlers(). Use an additional argument instead.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20161022095318.17775-24-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This also switches from qemu_chr_add_handlers() to
qemu_chr_fe_set_handlers(). Note that qemu_chr_fe_set_handlers() now
takes the focus when fe_open (qemu_chr_add_handlers() did take the
focus)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20161022095318.17775-16-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Store the property in a CharBackend instead of CharDriverState*. This
also replace systematically chr by chr.chr to access the
CharDriverState*. The following patches will replace it with calls to
qemu_chr_fe CharBackend functions.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20161022095318.17775-12-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In the past, we are doing gsi route commit for each irqchip route
update. This is not efficient if we are updating lots of routes in the
same time. This patch removes the committing phase in
kvm_irqchip_update_msi_route(). Instead, we do explicit commit after all
routes updated.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Changing the original MSIMessage parameter in kvm_irqchip_add_msi_route
into the vector number. Vector index provides more information than the
MSIMessage, we can retrieve the MSIMessage using the vector easily. This
will avoid fetching MSIMessage every time before adding MSI routes.
Meanwhile, the vector info will be used in the coming patches to further
enable gsi route update notifications.
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Currently, we use memory_region_is_mapped() to detect if the host
backend memory is being used. This works if the memory is directly
mapped into guest's address space, however, it is not true for
nvdimm as it uses aliased memory region to map the memory. This is
why this bug can happen:
https://bugzilla.redhat.com/show_bug.cgi?id=1352769
Fix it by introduce a new filed, is_mapped, to HostMemoryBackend,
we set/clear this filed accordingly when the device link/unlink to
host backend memory
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qemu/osdep.h checks whether MAP_ANONYMOUS is defined, but this check
is bogus without a previous inclusion of sys/mman.h. Include it in
sysemu/os-posix.h and remove it from everywhere else.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Remove direct uses of ram_addr_t and optimize memory_region_{get,set}_fd
now that a MemoryRegion knows its RAMBlock directly.
Reviewed-by: Marc-André Lureau <marcandre.lureau@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
"qemu -device ivshmem-{plain,doorbell}" will crash, because the device
doesn't check that the required argument is provided. (screwed up in
commit 5400c02)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
* Chardev fix from Marc-André
* config.status tweak from David
* Header file tweaks from Markus, myself and Veronia (Outreachy candidate)
* get_ticks_per_sec() removal from Rutuja (Outreachy candidate)
* Coverity fix from myself
* PKE implementation from myself, based on rth's XSAVE support
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Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging
* Log filtering from Alex and Peter
* Chardev fix from Marc-André
* config.status tweak from David
* Header file tweaks from Markus, myself and Veronia (Outreachy candidate)
* get_ticks_per_sec() removal from Rutuja (Outreachy candidate)
* Coverity fix from myself
* PKE implementation from myself, based on rth's XSAVE support
# gpg: Signature made Thu 24 Mar 2016 20:15:11 GMT using RSA key ID 78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg: aka "Paolo Bonzini <pbonzini@redhat.com>"
* remotes/bonzini/tags/for-upstream: (28 commits)
target-i386: implement PKE for TCG
config.status: Pass extra parameters
char: translate from QIOChannel error to errno
exec: fix error handling in file_ram_alloc
cputlb: modernise the debug support
qemu-log: support simple pid substitution for logs
target-arm: dfilter support for in_asm
qemu-log: dfilter-ise exec, out_asm, op and opt_op
qemu-log: new option -dfilter to limit output
qemu-log: Improve the "exec" TB execution logging
qemu-log: Avoid function call for disabled qemu_log_mask logging
qemu-log: correct help text for -d cpu
tcg: pass down TranslationBlock to tcg_code_gen
util: move declarations out of qemu-common.h
Replaced get_tick_per_sec() by NANOSECONDS_PER_SECOND
hw: explicitly include qemu-common.h and cpu.h
include/crypto: Include qapi-types.h or qemu/bswap.h instead of qemu-common.h
isa: Move DMA_transfer_handler from qemu-common.h to hw/isa/isa.h
Move ParallelIOArg from qemu-common.h to sysemu/char.h
Move QEMU_ALIGN_*() from qemu-common.h to qemu/osdep.h
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Conflicts:
scripts/clean-includes
Move declarations out of qemu-common.h for functions declared in
utils/ files: e.g. include/qemu/path.h for utils/path.c.
Move inline functions out of qemu-common.h and into new files (e.g.
include/qemu/bcd.h)
Signed-off-by: Veronia Bahaa <veroniabahaa@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 57cb38b included qapi/error.h into qemu/osdep.h to get the
Error typedef. Since then, we've moved to include qemu/osdep.h
everywhere. Its file comment explains: "To avoid getting into
possible circular include dependencies, this file should not include
any other QEMU headers, with the exceptions of config-host.h,
compiler.h, os-posix.h and os-win32.h, all of which are doing a
similar job to this file and are under similar constraints."
qapi/error.h doesn't do a similar job, and it doesn't adhere to
similar constraints: it includes qapi-types.h. That's in excess of
100KiB of crap most .c files don't actually need.
Add the typedef to qemu/typedefs.h, and include that instead of
qapi/error.h. Include qapi/error.h in .c files that need it and don't
get it now. Include qapi-types.h in qom/object.h for uint16List.
Update scripts/clean-includes accordingly. Update it further to match
reality: replace config.h by config-target.h, add sysemu/os-posix.h,
sysemu/os-win32.h. Update the list of includes in the qemu/osdep.h
comment quoted above similarly.
This reduces the number of objects depending on qapi/error.h from "all
of them" to less than a third. Unfortunately, the number depending on
qapi-types.h shrinks only a little. More work is needed for that one.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
[Fix compilation without the spice devel packages. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Migration with ivshmem needs to be carefully orchestrated to work.
Exactly one peer (the "master") migrates to the destination, all other
peers need to unplug (and disconnect), migrate, plug back (and
reconnect). This is sort of documented in qemu-doc.
If peers connect on the destination before migration completes, the
shared memory can get messed up. This isn't documented anywhere. Fix
that in qemu-doc.
To avoid messing up register IVPosition on migration, the server must
assign the same ID on source and destination. ivshmem-spec.txt leaves
ID assignment unspecified, however.
Amend ivshmem-spec.txt to require the first client to receive ID zero.
The example ivshmem-server complies: it always assigns the first
unused ID.
For a bit of additional safety, enforce ID zero for the master. This
does nothing when we're not using a server, because the ID is zero for
all peers then.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-40-git-send-email-armbru@redhat.com>
Move code to more sensible places. Use the opportunity to reorder and
document IVShmemState members.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-38-git-send-email-armbru@redhat.com>
ivshmem can be configured with and without interrupt capability
(a.k.a. "doorbell"). The two configurations have largely disjoint
options, which makes for a confusing (and badly checked) user
interface. Moreover, the device can't tell the guest whether its
doorbell is enabled.
Create two new device models ivshmem-plain and ivshmem-doorbell, and
deprecate the old one.
Changes from ivshmem:
* PCI revision is 1 instead of 0. The new revision is fully backwards
compatible for guests. Guests may elect to require at least
revision 1 to make sure they're not exposed to the funny "no shared
memory, yet" state.
* Property "role" replaced by "master". role=master becomes
master=on, role=peer becomes master=off. Default is off instead of
auto.
* Property "use64" is gone. The new devices always have 64 bit BARs.
Changes from ivshmem to ivshmem-plain:
* The Interrupt Pin register in PCI config space is zero (does not use
an interrupt pin) instead of one (uses INTA).
* Property "x-memdev" is renamed to "memdev".
* Properties "shm" and "size" are gone. Use property "memdev"
instead.
* Property "msi" is gone. The new device can't have MSI-X capability.
It can't interrupt anyway.
* Properties "ioeventfd" and "vectors" are gone. They're meaningless
without interrupts anyway.
Changes from ivshmem to ivshmem-doorbell:
* Property "msi" is gone. The new device always has MSI-X capability.
* Property "ioeventfd" defaults to on instead of off.
* Property "size" is gone. The new device can only map all the shared
memory received from the server.
Guests can easily find out whether the device is configured for
interrupts by checking for MSI-X capability.
Note: some code added in sub-optimal places to make the diff easier to
review. The next commit will move it to more sensible places.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-37-git-send-email-armbru@redhat.com>
In preparation of making it a qdev property.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-36-git-send-email-armbru@redhat.com>
ivshmem_realize() puts the shared memory region in a container region.
Used to be necessary to permit delayed mapping of the shared memory.
However, we recently moved to synchronous mapping, in "ivshmem:
Receive shared memory synchronously in realize()" and the commit
following it. The container is redundant since then. Drop it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1458066895-20632-33-git-send-email-armbru@redhat.com>
ivshmem has its very own code to create and map shared memory.
Replace that with an implicitly created memory backend. Reduces the
number of ways we create BAR 2 from three to two.
The memory-backend-file is currently available only with CONFIG_LINUX,
so this adds a second Linuxism to ivshmem (the other one is eventfd).
Should we ever need to make it portable to systems where
memory-backend-file can't be made to serve, we could create a
memory-backend-shmem that allocates memory with shm_open().
Bonus fix: shared memory files are now created with permissions 0655
instead of 0777.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1458066895-20632-32-git-send-email-armbru@redhat.com>
If size_t is narrower than 64 bits, passing uint64_t ivshmem_size to
mmap() truncates. Reject such sizes.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-31-git-send-email-armbru@redhat.com>
Short reads from a UNIX domain sockets are exceedingly unlikely when
the other side always sends eight bytes and we always read eight
bytes. We cope with them anyway. However, the code doing that is
rather convoluted. Dumb it down radically.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-30-git-send-email-armbru@redhat.com>
The chardev must be capable of transmitting SCM_RIGHTS ancillary
messages. We check it by comparing CharDriverState member filename to
"unix:". That's almost as brittle as it is disgusting.
When the actual transmission all happened asynchronously, this check
was all we could do in realize(), and thus better than nothing. But
now we receive at least one SCM_RIGHTS synchronously in realize(),
it's not worth its keep anymore. Drop it.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-29-git-send-email-armbru@redhat.com>
The protocol specification (ivshmem-spec.txt, formerly
ivshmem_device_spec.txt) has always required the ID message to be sent
right at the beginning, and ivshmem-server has always complied. The
device, however, accepts it out of order. If an interrupt setup
arrived before it, though, it would be misinterpreted as connect
notification. Fix the latent bug by relying on the spec and
ivshmem-server's actual behavior.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-28-git-send-email-armbru@redhat.com>
This kills off the funny state described in the previous commit.
Simplify ivshmem_io_read() accordingly, and update documentation.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1458066895-20632-27-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
When configured for interrupts (property "chardev" given), we receive
the shared memory from an ivshmem server. We do so asynchronously
after realize() completes, by setting up callbacks with
qemu_chr_add_handlers().
Keeping server I/O out of realize() that way avoids delays due to a
slow server. This is probably relevant only for hot plug.
However, this funny "no shared memory, yet" state of the device also
causes a raft of issues that are hard or impossible to work around:
* The guest is exposed to this state: when we enter and leave it its
shared memory contents is apruptly replaced, and device register
IVPosition changes.
This is a known issue. We document that guests should not access
the shared memory after device initialization until the IVPosition
register becomes non-negative.
For cold plug, the funny state is unlikely to be visible in
practice, because we normally receive the shared memory long before
the guest gets around to mess with the device.
For hot plug, the timing is tighter, but the relative slowness of
PCI device configuration has a good chance to hide the funny state.
In either case, guests complying with the documented procedure are
safe.
* Migration becomes racy.
If migration completes before the shared memory setup completes on
the source, shared memory contents is silently lost. Fortunately,
migration is rather unlikely to win this race.
If the shared memory's ramblock arrives at the destination before
shared memory setup completes, migration fails.
There is no known way for a management application to wait for
shared memory setup to complete.
All you can do is retry failed migration. You can improve your
chances by leaving more time between running the destination QEMU
and the migrate command.
To mitigate silent memory loss, you need to ensure the server
initializes shared memory exactly the same on source and
destination.
These issues are entirely undocumented so far.
I'd expect the server to be almost always fast enough to hide these
issues. But then rare catastrophic races are in a way the worst kind.
This is way more trouble than I'm willing to take from any device.
Kill the funny state by receiving shared memory synchronously in
realize(). If your hot plug hangs, go kill your ivshmem server.
For easier review, this commit only makes the receive synchronous, it
doesn't add the necessary error propagation. Without that, the funny
state persists. The next commit will do that, and kill it off for
real.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-26-git-send-email-armbru@redhat.com>
close_peer_eventfds() cleans up three things: ioeventfd triggers if
they exist, eventfds, and the array to store them.
Commit 98609cd (v1.2.0) fixed it not to clean up ioeventfd triggers
when they don't exist (property ioeventfd=off, which is the default).
Unfortunately, the fix also made it skip cleanup of the eventfds and
the array then. This is a memory and file descriptor leak on unplug.
Additionally, the reset of nb_eventfds is skipped. Doesn't matter on
unplug. On peer disconnect, however, this permanently wedges the
interrupt vectors used for that peer's ID. The eventfds stay behind,
but aren't connected to a peer anymore. When the ID gets recycled for
a new peer, the new peer's eventfds get assigned to vectors after the
old ones. Commonly, the device's number of vectors matches the
server's, so the new ones get dropped with a "Too many eventfd
received" message. Interrupts either don't work (common case) or go
to the wrong vector.
Fix by narrowing the conditional to just the ioeventfd trigger
cleanup.
While there, move the "invalid" peer check to the only caller where it
can actually happen, and tighten it to reject own ID.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-25-git-send-email-armbru@redhat.com>
ivshmem_read() processes server messages. These are 64 bit signed
integers. -1 is shared memory setup, 16 bit unsigned is a peer ID,
anything else is invalid.
ivshmem_read() rejects invalid negative messages right away, silently.
Invalid positive messages get rejected only in resize_peers(), and
ivshmem_read() then prints the rather cryptic message "failed to
resize peers array".
Extend the first check to cover all invalid messages, make it report
"server sent invalid message", and drop the second check.
Now resize_peers() can't fail anymore; simplify.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-23-git-send-email-armbru@redhat.com>
An interrupt is set up when the interrupt's file descriptor is
received. Each message applies to the next interrupt vector.
Therefore, each vector cannot be set up more than once.
ivshmem_add_kvm_msi_virq() half-heartedly tries not to rely on this by
doing nothing then, but that's not going to recover from this error
should it become possible in the future. watch_vector_notifier()
doesn't even try.
Simply assert what is the case, so we get alerted if we ever screw it
up.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <1458066895-20632-22-git-send-email-armbru@redhat.com>
The ivshmem device can either use MSI-X or legacy INTx for interrupts.
With MSI-X enabled, peer interrupt events trigger an MSI as they
should. But software can still raise INTx via interrupt status and
mask register in BAR 0. This is explicitly prohibited by PCI Local
Bus Specification Revision 3.0, section 6.8.3.3:
While enabled for MSI or MSI-X operation, a function is prohibited
from using its INTx# pin (if implemented) to request service (MSI,
MSI-X, and INTx# are mutually exclusive).
Fix the device model to leave INTx alone when using MSI-X.
Document that we claim to use INTx in config space even when we don't.
Unlike other devices, ivshmem does *not* use INTx when configured for
MSI-X and MSI-X isn't enabled by software.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1458066895-20632-21-git-send-email-armbru@redhat.com>
There are three predicates related to MSI-X:
* ivshmem_has_feature(s, IVSHMEM_MSI) is true unless the non-MSI-X
variant of the device is selected with msi=off.
* msix_present() is true when the device has the PCI capability MSI-X.
It's initially false, and becomes true during successful realize of
the MSI-X variant of the device. Thus, it's the same as
ivshmem_has_feature(s, IVSHMEM_MSI) for realized devices.
* msix_enabled() is true when msix_present() is true and guest software
has enabled MSI-X.
Code that differs between the non-MSI-X and the MSI-X variant of the
device needs to be guarded by ivshmem_has_feature(s, IVSHMEM_MSI) or
by msix_present(), except the latter works only for realized devices.
Code that depends on whether MSI-X is in use needs to be guarded with
msix_enabled().
Code review led me to two minor messes:
* ivshmem_vector_notify() calls msix_notify() even when
!msix_enabled(), unlike most other MSI-X-capable devices. As far as
I can tell, msix_notify() does nothing when !msix_enabled(). Add
the guard anyway.
* Most callers of ivshmem_use_msix() guard it with
ivshmem_has_feature(s, IVSHMEM_MSI). Not necessary, because
ivshmem_use_msix() does nothing when !msix_present(). That's
ivshmem's only use of msix_present(), though. Guard it
consistently, and drop the now redundant msix_present() check.
While there, rename ivshmem_use_msix() to ivshmem_msix_vector_use().
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <1458066895-20632-20-git-send-email-armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
