Commit Graph

20309 Commits

Author SHA1 Message Date
Paolo Bonzini
a6c5c84ae2 virtio-blk: always enable VIRTIO_BLK_F_SCSI
VIRTIO_BLK_F_SCSI is supposed to mean whether the host can *parse*
SCSI requests, not *execute* them.  You could run QEMU with scsi=on
and a file-backed disk, and QEMU would fail all SCSI requests even
though it advertises VIRTIO_BLK_F_SCSI.

Because we need to do this to fix a migration compatibility problem
related to how QEMU is invoked by management, we must do this
unconditionally even on older machine types.  This more or less assumes
that no one ever invoked QEMU with scsi=off.

Here is how testing goes:

- old QEMU, scsi=on -> new QEMU, scsi=on
- new QEMU, scsi=on -> old QEMU, scsi=on
- old QEMU, scsi=off -> new QEMU, scsi=on
- new QEMU, scsi=off -> old QEMU, scsi=on
        ok (new QEMU has VIRTIO_BLK_F_SCSI, adding host features is fine)

- old QEMU, scsi=off -> new QEMU, scsi=off
        ok (new QEMU has VIRTIO_BLK_F_SCSI, adding host features is fine)

- old QEMU, scsi=on -> new QEMU, scsi=off
        ok, bug fixed

- new QEMU, scsi=on -> old QEMU, scsi=off
        doesn't work (same as: old QEMU, scsi=on -> old QEMU, scsi=off)

- new QEMU, scsi=off -> old QEMU, scsi=off
        broken by the patch

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-05-21 15:40:50 -05:00
Paolo Bonzini
12c5674b84 virtio-blk: define VirtIOBlkConf
We will have to add another field to the virtio-blk configuration in
the next patch.  Avoid a proliferation of arguments to virtio_blk_init.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-05-21 15:40:50 -05:00
Paolo Bonzini
0e47931b88 virtio-blk: blockdev_mark_auto_del is transport-independent
Move it from virtio_blk_exit_pci to virtio_blk_exit.

This is included here because the next patch removes proxy->block.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-05-21 15:40:50 -05:00
Paolo Bonzini
f34e73cd69 virtio-blk: report non-zero status when failing SG_IO requests
Linux really looks only at scsi->errors for SG_IO requests; it does
not look at the virtio request status at all.  Because of this, when
a SG_IO request is failed early with virtio_blk_req_complete(req,
VIRTIO_BLK_S_UNSUPP), without writing hdr.status, it will look like
a success to the guest.

This is their bug, but we can make it safe for older guests now by
forcing scsi->errors to have a non-zero value whenever a request
has to be failed.

But if we fix the bug in the guest driver, we will have another problem
because QEMU returns VIRTIO_BLK_S_IOERR if the status is non-zero, and
Linux translates that to -EIO.  Rather, the guest should succeed the
request and pass the non-zero status via the userspace-provided SG_IO
structure.  So, remove the case where virtio_blk_handle_scsi can
return VIRTIO_BLK_S_IOERR.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-05-21 15:40:50 -05:00
Mark Langsdorf
80a2ba3d3c use an uint64_t for the max_sz parameter in load_image_targphys
Allow load_image_targphys to load files on systems with more than 2G of
emulated memory by changing the max_sz parameter from an int to an
uint64_t.

Reviewed-by: Andreas F=E4rber <afaerber@suse.de>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-05-21 15:40:50 -05:00
Anthony Liguori
b4f1a7ca72 Merge remote-tracking branch 'mdroth/qga-pull-5-15-12' into staging
* mdroth/qga-pull-5-15-12:
  qemu-ga: align versioning with QEMU_VERSION
  qemu-ga: fix segv after failure to open log file
  qemu-ga: guest-shutdown: use only async-signal-safe functions
  qemu-ga: guest-shutdown: become synchronous
  qemu-ga: guest-suspend: make the API synchronous
  qemu-ga: become_daemon(): reopen standard fds to /dev/null
  qemu-ga: make reopen_fd_to_null() public
  qemu-ga: guest-suspend-hybrid: don't emit a success response
  qemu-ga: guest-suspend-ram: don't emit a success response
  qemu-ga: guest-suspend-disk: don't emit a success response
  qemu-ga: guest-shutdown: don't emit a success response
  qemu-ga: don't warn on no command return
  qapi: add support for command options
2012-05-21 15:31:31 -05:00
Stefan Weil
fba0c40bb7 tests: Add rtc-test (fix test regression)
Commit 93e9eb6808 added fdc-test,
but accidentally removed rtc-test because check-qtest-i386-y was
not enhanced but set twice.

This patch adds rtc-test again (and sorts both tests alphabetically).

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-05-21 15:31:06 -05:00
Jan Kiszka
7d37d351df virtio/vhost: Add support for KVM in-kernel MSI injection
Make use of the new vector notifier to track changes of the MSI-X
configuration of virtio PCI devices. On enabling events, we establish
the required virtual IRQ to MSI-X message route and link the signaling
eventfd file descriptor to this vIRQ line. That way, vhost-generated
interrupts can be directly delivered to an in-kernel MSI-X consumer like
the x86 APIC.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:50 +03:00
Jan Kiszka
cb697aaab9 msix: Add msix_nr_vectors_allocated
Analogously to msi_nr_vectors_allocated, add a service for MSI-X. Will
be used by the virtio-pci layer.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:50 +03:00
Jan Kiszka
bbf3b80401 kvm: Enable use of kvm_irqchip_in_kernel in hwlib code
Provide a dummy kvm_kernel_irqchip so that kvm_irqchip_in_kernel can be
used by code that is not under CONFIG_KVM protection.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:50 +03:00
Jan Kiszka
39853bbc49 kvm: Introduce kvm_irqchip_add/remove_irqfd
Add services to associate an eventfd file descriptor as input with an
IRQ line as output. Such a line can be an input pin of an in-kernel
irqchip or a virtual line returned by kvm_irqchip_add_route.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:50 +03:00
Jan Kiszka
e7b2030862 kvm: Make kvm_irqchip_commit_routes an internal service
Automatically commit route changes after kvm_add_routing_entry and
kvm_irqchip_release_virq. There is no performance relevant use case for
which collecting multiple route changes is beneficial. This makes
kvm_irqchip_commit_routes an internal service which assert()s that the
corresponding IOCTL will always succeed.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Jan Kiszka
1e2aa8be09 kvm: Publicize kvm_irqchip_release_virq
This allows to drop routes created by kvm_irqchip_add_irq/msi_route
again.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Jan Kiszka
92b4e48982 kvm: Introduce kvm_irqchip_add_msi_route
Add a service that establishes a static route from a virtual IRQ line to
an MSI message. Will be used for IRQFD and device assignment. As we will
use this service outside of CONFIG_KVM protected code, stub it properly.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Jan Kiszka
1df186df35 kvm: Rename kvm_irqchip_add_route to kvm_irqchip_add_irq_route
We will add kvm_irqchip_add_msi_route, so let's make the difference
clearer.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Jan Kiszka
2cdfe53c5f msix: Introduce vector notifiers
Vector notifiers shall be triggered by the MSI/MSI-X core whenever a
relevant configuration change is programmed by the guest. In case of
MSI-X, changes are reported when the effective mask (global &&
per-vector) alters its state. On unmask, the current vector
configuration is included in the event report. This allows users - e.g.
virtio-pci layer - to transfer this information to external MSI-X
routing subsystems - like vhost + KVM in-kernel irqchip.

This implementation only provides MSI-X support, but extension to MSI is
feasible and will be provided later on when adding support for KVM PCI
device assignment.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Jan Kiszka
5b5f1330da msix: Invoke msix_handle_mask_update on msix_mask_all
In preparation of firing vector notifiers on mask changes, call
msix_handle_mask_update also from msix_mask_all. So far, this will have
no real effect.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Jan Kiszka
bc4caf49c7 msix: Factor out msix_get_message
This helper will also be used by the upcoming config notifier.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-05-21 19:22:49 +03:00
Stefan Weil
fd4567d9a6 tests: Fix linker failure for fdc-test
When QEMU was built with the simple trace backend, linking failed:

  LINK  tests/fdc-test
oslib-posix.o: In function `trace_qemu_memalign':
qemu/bin/debug/x86/./trace.h:31: undefined reference to `trace3'
oslib-posix.o: In function `trace_qemu_vmalloc':
qemu/bin/debug/x86/./trace.h:35: undefined reference to `trace2'
oslib-posix.o: In function `trace_qemu_vfree':
qemu/bin/debug/x86/./trace.h:39: undefined reference to `trace1'
collect2: error: ld returned 1 exit status
make: *** [tests/fdc-test] Fehler 1

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-05-19 15:53:28 +00:00
Richard Sandiford
d7f66b52de mips: Fix BC1ANY[24]F instructions
There's some dodgy application of De Morgan's law in the emulation
of the MIPS BC1ANY[24]F instructions: they end up branching only
if all CCs are false, rather than if one CC is.

Tested on mips64-linux-gnu, where it fixes the GCC MIPS3D tests.

Signed-off-by: Richard Sandiford <rdsandiford@googlemail.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-05-19 15:51:44 +00:00
Alexander Graf
77a8f1a512 linux-user: Fix stale tbs after mmap
If we execute linux-user code that does the following:

  * A = mmap()
  * execute code in A
  * munmap(A)
  * B = mmap(), but mmap returns the same address as A
  * execute code in B

we end up executing a stale cached tb that contains translated code
from A, while we want new code from B.

This patch adds a TB flush for mmap'ed regions, before we return them,
avoiding the whole issue. It also adds a flush for munmap, so that we
don't execute stale TBs instead of getting a segfault.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Riku Voipio <riku.voipio@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-05-19 15:49:40 +00:00
Blue Swirl
4636b9d146 virtio-pci: add missing 'static'
There are no outside references to virtio_portio.
Add missing 'static' specifier.

Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-05-19 15:41:14 +00:00
Blue Swirl
5f2bf0fe55 sparc64: fix initrd loading
Initrd load address is too low, it conflicts with kernel load
address:
rom: requested regions overlap (rom phdr #0: /tmp/vmlinux-debian-6.0.4-sparc64. free=0x0000000000742519, addr=0x0000000000400000)
rom loading failed

Fix by making the initrd address variable, load initrd after kernel
image. Use 64 bit variables instead of longs or 32 bit types.

Tested-by: Artyom Tarasenko <atar4qemu@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2012-05-19 15:39:04 +00:00
Roger Pau Monne
a28853871d audio: split IN_T into two separate constants
Split IN_T into BSIZE and ITYPE, to avoid expansion if the OS has
defined macros for the intX_t and uintX_t types. The IN_T constant is
then defined in mixeng_template.h so it can be used by the
functions/macros on this header file.

This change has been tested successfully under Debian Linux and NetBSD
6.0BETA.

Cc: Vassili Karpov (malc) <av1474@comtv.ru>
Signed-off-by: Roger Pau Monne <roger.pau@citrix.com>
Signed-off-by: malc <av1474@comtv.ru>
2012-05-18 15:19:28 +04:00
Peter A. G. Crosthwaite
ace2e4dad7 target-microblaze: impelemented swapx instructions
Implemented the swapb and swaph byte/halfword reversal instructions added
to microblaze v8.30

Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
2012-05-18 12:17:52 +02:00
Avi Kivity
287d55c676 kvm: update vmxcap for EPT A/D, INVPCID, RDRAND, VMFUNC
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-17 23:30:02 -03:00
John V. Baboval
180640ea07 Call xc_domain_shutdown with the reboot flag when the guest requests a reboot.
Signed-off-by: John V. Baboval <john.baboval@virtualcomputer.com>
Signed-off-by: Tom Goetz <tom.goetz@virtualcomputer.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2012-05-17 10:52:38 +00:00
Anthony PERARD
a4f1a7589a xen: Fix PV-on-HVM
In the context of PV-on-HVM under Xen, the emulated nics are supposed to be
unplug before the guest drivers are initialized, when the guest write to a
specific IO port.

Without this patch, the guest end up with two nics with the same MAC, the
emulated nic and the PV nic.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
2012-05-17 10:52:29 +00:00
Jan Beulich
ed54776643 xen_disk: properly update stats in ioreq_release()
While for the "normal" case (called from blk_send_response_all())
decrementing requests_finished is correct, doing so in the parse error
case is wrong; requests_inflight needs to be decremented instead.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
2012-05-17 10:43:33 +00:00
Stefano Stabellini
c6961b7d38 xen_disk: use bdrv_aio_flush instead of bdrv_flush
Use bdrv_aio_flush instead of bdrv_flush.

Make sure to call bdrv_aio_writev/readv after the presync bdrv_aio_flush is fully
completed and make sure to call the postsync bdrv_aio_flush after
bdrv_aio_writev/readv is fully completed.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2012-05-17 10:43:33 +00:00
Stefano Stabellini
ba1dffed63 xen_disk: remove syncwrite option
This patch removes a dead option.

The same can be achieved removing BDRV_O_NOCACHE and BDRV_O_CACHE_WB
from the flags passed to bdrv_open.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2012-05-17 10:43:33 +00:00
Stefano Stabellini
95d5d75ede xen: disable rtc_clock
rtc_clock is only used by the RTC emulator (mc146818rtc.c), however Xen
has its own RTC emulator in the hypervisor so we can disable it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2012-05-17 10:43:32 +00:00
Stefano Stabellini
c2d8d311c1 xen: do not initialize the interval timer and PCSPK emulator
PIT and PCSPK are emulated by the hypervisor so we don't need to emulate
them in Qemu: this patch prevents Qemu from waking up needlessly at
PIT_FREQ on Xen.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2012-05-17 10:43:32 +00:00
Jan Kiszka
a24b9106fa kvm: Enable in-kernel irqchip support by default
As MSI is now fully supported by KVM (/wrt available features in
upstream), we can finally enable the in-kernel irqchip by default.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:45 -03:00
Jan Kiszka
4a3adebb18 kvm: Add support for direct MSI injections
If the kernel supports KVM_SIGNAL_MSI, we can avoid the route-based
MSI injection mechanism.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:45 -03:00
Jan Kiszka
80a3eb10fe kvm: Update kernel headers
Corresponding kvm.git hash: f2569053e0

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:45 -03:00
Jan Kiszka
ffb8d4296e kvm: x86: Wire up MSI support for in-kernel irqchip
Catch writes to the MSI MMIO region in the KVM APIC and forward them to
the kernel. Provide the kernel support GSI routing, this allows to
enable MSI support also for in-kernel irqchip mode.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:45 -03:00
Jan Kiszka
08a82ac01c pc: Enable MSI support at APIC level
Push msi_supported enabling to the APIC implementations where we can
encapsulate the decision more cleanly, hiding the details from the
generic code.

Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:44 -03:00
Jan Kiszka
04fa27f5ae kvm: Introduce basic MSI support for in-kernel irqchips
This patch basically adds kvm_irqchip_send_msi, a service for sending
arbitrary MSI messages to KVM's in-kernel irqchip models.

As the original KVM API requires us to establish a static route from a
pseudo GSI to the target MSI message and inject the MSI via toggling
that virtual IRQ, we need to play some tricks to make this interface
transparent. We create those routes on demand and keep them in a hash
table. Succeeding messages can then search for an existing route in the
table first and reuse it whenever possible. If we should run out of
limited GSIs, we simply flush the table and rebuild it as messages are
sent.

This approach is rather simple and could be optimized further. However,
latest kernels contains a more efficient MSI injection interface that
will obsolete the GSI-based dynamic injection.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:44 -03:00
Jan Kiszka
14de9bab9e Introduce MSIMessage structure
Will be used for generating and distributing MSI messages, both in
emulation mode and under KVM.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:44 -03:00
Jan Kiszka
4e2e4e6355 kvm: Refactor KVMState::max_gsi to gsi_count
Instead of the bitmap size, store the maximum of GSIs the kernel
support. Move the GSI limit assertion to the API function
kvm_irqchip_add_route and make it stricter.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-05-16 18:04:44 -03:00
Michael Roth
8efacc43ae qemu-ga: align versioning with QEMU_VERSION
Previously qemu-ga version was defined seperately. Since it is aligned
with QEMU releases, use QEMU_VERSION instead. This also implies the
version bump for 1.1[-rcN] release of qemu-ga.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Acked-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:17:06 -05:00
Michael Roth
6c615ec57e qemu-ga: fix segv after failure to open log file
Currently, if we fail to open the specified log file (generally due to a
permissions issue), we'll assign NULL to the logfile handle (stderr,
initially) used by the logging routines, which can cause a segfault to
occur when we attempt to report the error before exiting.

Instead, only re-assign if the open() was successful.

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:16:55 -05:00
Luiz Capitulino
3674838cd0 qemu-ga: guest-shutdown: use only async-signal-safe functions
POSIX mandates[1] that a child process of a multi-thread program uses
only async-signal-safe functions before exec(). We consider qemu-ga
to be multi-thread, because it uses glib.

However, qmp_guest_shutdown() uses functions that are not
async-signal-safe. Fix it the following way:

- fclose() -> reopen_fd_to_null()
- execl() -> execle()
- exit() -> _exit()
- drop slog() usage (which is not safe)

  [1] http://pubs.opengroup.org/onlinepubs/009695399/functions/fork.html

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
d5dd3498eb qemu-ga: guest-shutdown: become synchronous
Last commit dropped qemu-ga's SIGCHLD handler, used to automatically
reap terminated children processes. This introduced a bug to
qmp_guest_shutdown(): it will generate zombies.

This problem probably doesn't matter in the success case, as the VM
will shutdown anyway, but let's do the right thing and reap the
created process. This ultimately means that guest-shutdown is now a
synchronous command.

An interesting side effect is that guest-shutdown is now able to
report an error to the client if shutting down fails.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
dc8764f061 qemu-ga: guest-suspend: make the API synchronous
Currently, qemu-ga has a SIGCHLD handler that automatically reaps terminated
children processes. The idea is to avoid having qemu-ga commands blocked
waiting for children to terminate.

That approach has two problems:

 1. qemu-ga is unable to detect errors in the child, meaning that qemu-ga
    returns success even if the child fails to perform its task

 2. if a command does depend on the child exit status, the command has to
    play tricks to bypass the automatic reaper

Case 2 impacts the guest-suspend-* API, because it has to execute an external
program to check for suspend support. Today, to bypass the automatic reaper,
suspend code has to double fork and pass exit status information through a
pipe. Besides being complex, this is prone to race condition bugs. Indeed,
the current code does have such bugs.

Making the guest-suspend-* API synchronous (ie. by dropping the SIGCHLD
handler and calling waitpid() from commands) is a much simpler approach,
which fixes current race conditions bugs and enables commands to detect
errors in the child.

This commit does just that. There's a side effect though, guest-shutdown
will generate zombies if shutting down fails. This will be fixed by the
next commit.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
226a48949c qemu-ga: become_daemon(): reopen standard fds to /dev/null
This fixes a bug where qemu-ga doesn't suspend the guest because it
fails to detect suspend support even when the guest does support
suspend. This happens because of the way qemu-ga fds are managed in
daemon mode.

When starting qemu-ga with --daemon, become_daemon() will close all
standard fds. This will cause qemu-ga to end up with the following
fds (if started with 'qemu-ga --daemon'):

    0 -> /dev/vport0p1
    3 -> /run/qemu-ga.pid

Then a guest-suspend-* function is issued. They call bios_supports_mode(),
which will call pipe(), and qemu-ga's fd will be:

    0 -> /dev/vport0p1
    1 -> pipe:[16247]
    2 -> pipe:[16247]
    3 -> /run/qemu-ga.pid

bios_supports_mode() forks off a child and blocks waiting for the child
to write something to the pipe. The child, however, closes its reading
end of the pipe _and_ reopen all standard fds to /dev/null. This will
cause the child's fds to be:

    0 -> /dev/null
    1 -> /dev/null
    2 -> /dev/null
    3 -> /run/qemu-ga.pid

In other words, the child's writing end of the pipe is now /dev/null.
It writes there and exits. The parent process (blocked on read()) will
get an EOF and interpret this as "something unexpected happened in
the child, let's assume the guest doesn't support suspend". And suspend
will fail.

To solve this problem we have to reopen standard fds to /dev/null
in become_daemon(), instead of closing them.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
04b4e75f33 qemu-ga: make reopen_fd_to_null() public
The next commit wants to use it.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
d9fcd2a1c8 qemu-ga: guest-suspend-hybrid: don't emit a success response
Today, qemu-ga may not be able to emit a success response when
guest-suspend-hybrid completes. This happens because the VM may
suspend before qemu-ga is able to emit a response.

This semantic is a bit confusing, as it's not clear for clients if
they should wait for a response or how they should check for success.

This commit solves that problem by changing guest-suspend-hybrid to
never emit a success response and suggests in the documentation
what clients should do to check for success.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00
Luiz Capitulino
432d29db0d qemu-ga: guest-suspend-ram: don't emit a success response
Today, qemu-ga may not be able to emit a success response when
guest-suspend-ram completes. This happens because the VM may
suspend before qemu-ga is able to emit a response.

This semantic is a bit confusing, as it's not clear for clients if
they should wait for a response or how they should check for success.

This commit solves that problem by changing guest-suspend-ram to
never emit a success response and suggests in the documentation
what clients should do to check for success.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2012-05-15 09:15:16 -05:00