Commit Graph

65300 Commits (stable-3.1)

Author SHA1 Message Date
Michael Roth 920019e0e0 Update version for 3.1.1.1 release
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-10-01 17:27:10 -05:00
Michael Roth 9efdbc0224 slrip: ip_reass: Fix use after free
Using ip_deq after m_free might read pointers from an allocation reuse.

This would be difficult to exploit, but that is still related with
CVE-2019-14378 which generates fragmented IP packets that would trigger this
issue and at least produce a DoS.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(from libslirp.git commit c59279437eda91841b9d26079c70b8a540d41204)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-10-01 17:00:56 -05:00
Michael Roth 28c1dde9aa slirp: Fix heap overflow in ip_reass on big packet input
When the first fragment does not fit in the preallocated buffer, q will
already be pointing to the ext buffer, so we mustn't try to update it.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(from libslirp.git commit 126c04acbabd7ad32c2b018fe10dfac2a3bc1210)
(from libslirp.git commit e0be80430c390bce181ea04dfcdd6ea3dfa97de1)
*squash in e0be80 (clarifying comments)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-10-01 17:00:56 -05:00
Cole Robinson ab630a065a pvrdma: Fix compilation error
In function ‘create_qp’:
  hw/rdma/vmw/pvrdma_cmd.c:517:16: error: ‘rc’ undeclared

The backport of 509f57c98 in 41dd30ff6 mishandled the conflict

Signed-off-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-09-19 11:20:17 -05:00
Michael Roth 71049d2a74 Update version for 3.1.1 release
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-08-02 11:02:35 -05:00
Prasad J Pandit 03d7712b4b qemu-bridge-helper: restrict interface name to IFNAMSIZ
The network interface name in Linux is defined to be of size
IFNAMSIZ(=16), including the terminating null('\0') byte.
The same is applied to interface names read from 'bridge.conf'
file to form ACL rules. If user supplied '--br=bridge' name
is not restricted to the same length, it could lead to ACL bypass
issue. Restrict interface name to IFNAMSIZ, including null byte.

Reported-by: Riccardo Schirone <rschiron@redhat.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit 6f5d867122)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:44:36 -05:00
Kevin Wolf 4482258130 block: Fix hangs in synchronous APIs with iothreads
In the block layer, synchronous APIs are often implemented by creating a
coroutine that calls the asynchronous coroutine-based implementation and
then waiting for completion with BDRV_POLL_WHILE().

For this to work with iothreads (more specifically, when the synchronous
API is called in a thread that is not the home thread of the block
device, so that the coroutine will run in a different thread), we must
make sure to call aio_wait_kick() at the end of the operation. Many
places are missing this, so that BDRV_POLL_WHILE() keeps hanging even if
the condition has long become false.

Note that bdrv_dec_in_flight() involves an aio_wait_kick() call. This
corresponds to the BDRV_POLL_WHILE() in the drain functions, but it is
generally not enough for most other operations because they haven't set
the return value in the coroutine entry stub yet. To avoid race
conditions there, we need to kick after setting the return value.

The race window is small enough that the problem doesn't usually surface
in the common path. However, it does surface and causes easily
reproducible hangs if the operation can return early before even calling
bdrv_inc/dec_in_flight, which many of them do (trivial error or no-op
success paths).

The bug in bdrv_truncate(), bdrv_check() and bdrv_invalidate_cache() is
slightly different: These functions even neglected to schedule the
coroutine in the home thread of the node. This avoids the hang, but is
obviously wrong, too. Fix those to schedule the coroutine in the right
AioContext in addition to adding aio_wait_kick() calls.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 4720cbeea1)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:44:05 -05:00
Prasad J Pandit 41dd30ff63 pvrdma: release ring object in case of an error
create_cq and create_qp routines allocate ring object, but it's
not released in case of an error, leading to memory leakage.

Reported-by: Li Qiang <liq3ea@163.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
(cherry picked from commit 509f57c98e)
 Conflicts:
	hw/rdma/vmw/pvrdma_cmd.c
*drop dependency on 09178217
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:38:45 -05:00
Prasad J Pandit a1001760ab pvrdma: check return value from pvrdma_idx_ring_has_ routines
pvrdma_idx_ring_has_[data/space] routines also return invalid
index PVRDMA_INVALID_IDX[=-1], if ring has no data/space. Check
return value from these routines to avoid plausible infinite loops.

Reported-by: Li Qiang <liq3ea@163.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
(cherry picked from commit f1e2e38ee0)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:19:47 -05:00
Prasad J Pandit 2a0e6f1369 pvrdma: check number of pages when creating rings
When creating CQ/QP rings, an object can have up to
PVRDMA_MAX_FAST_REG_PAGES 8 pages. Check 'npages' parameter
to avoid excessive memory allocation or a null dereference.

Reported-by: Li Qiang <liq3ea@163.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
(cherry picked from commit 2c858ce5da)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:19:15 -05:00
Markus Armbruster 017f271f7a device_tree: Fix integer overflowing in load_device_tree()
If the value of get_image_size() exceeds INT_MAX / 2 - 10000, the
computation of @dt_size overflows to a negative number, which then
gets converted to a very large size_t for g_malloc0() and
load_image_size().  In the (fortunately improbable) case g_malloc0()
succeeds and load_image_size() survives, we'd assign the negative
number to *sizep.  What that would do to the callers I can't say, but
it's unlikely to be good.

Fix by rejecting images whose size would overflow.

Reported-by: Kurtis Miller <kurtis.miller@nccgroup.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20190409174018.25798-1-armbru@redhat.com>
(cherry picked from commit 065e6298a7)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Peter Maydell 5149630fed device_tree.c: Don't use load_image()
The load_image() function is deprecated, as it does not let the
caller specify how large the buffer to read the file into is.
Instead use load_image_size().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20181130151712.2312-9-peter.maydell@linaro.org
(cherry picked from commit da885fe1ee)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Prasad J Pandit 59a823017a sun4u: add power_mem_read routine
Define skeleton 'power_mem_read' routine. Avoid NULL dereference.

Reported-by: Fakhri Zulkifli <mohdfakhrizulkifli@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
(cherry picked from commit ad280559c6)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Prasad J Pandit 3be7eb2f47 qxl: check release info object
When releasing spice resources in release_resource() routine,
if release info object 'ext.info' is null, it leads to null
pointer dereference. Add check to avoid it.

Reported-by: Bugs SysSec <bugs-syssec@rub.de>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-id: 20190425063534.32747-1-ppandit@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit d52680fc93)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Daniel P. Berrangé 576964bf2a seccomp: don't kill process for resource control syscalls
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>
(cherry picked from commit 9a1565a03b)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Gerd Hoffmann 4c7f4c4bbb i2c-ddc: fix oob read
Suggested-by: Michael Hanselmann <public@hansmi.ch>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael Hanselmann <public@hansmi.ch>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190108102301.1957-1-kraxel@redhat.com
(cherry picked from commit b05b267840)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Prasad J Pandit 4e74e7a867 slirp: check data length while emulating ident function
While emulating identification protocol, tcp_emu() does not check
available space in the 'sc_rcv->sb_data' buffer. It could lead to
heap buffer overflow issue. Add check to avoid it.

Reported-by: Kira <864786842@qq.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
(cherry picked from commit a7104eda7d)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Paolo Bonzini 375667af78 scsi-generic: avoid possible out-of-bounds access to r->buf
Whenever the allocation length of a SCSI request is shorter than the size of the
VPD page list, page_idx is used blindly to index into r->buf.  Even though
the stores in the insertion sort are protected against overflows, the same is not
true of the reads and the final store of 0xb0.

This basically does the same thing as commit 57dbb58d80 ("scsi-generic: avoid
out-of-bounds access to VPD page list", 2018-11-06), except that here the
allocation length can be chosen by the guest.  Note that according to the SCSI
standard, the contents of the PAGE LENGTH field are not altered based
on the allocation length.

The code was introduced by commit 6c219fc8a1 ("scsi-generic: keep VPD
page list sorted", 2018-11-06) but the overflow was already possible before.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Fixes: a71c775b24
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit e909ff9369)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Prasad J Pandit bceff528ba pvrdma: add uar_read routine
Define skeleton 'uar_read' routine. Avoid NULL dereference.

Reported-by: Li Qiang <liq3ea@163.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
(cherry picked from commit 2aa86456fb)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Prasad J Pandit 1549e3a54a pvrdma: release device resources in case of an error
If during pvrdma device initialisation an error occurs,
pvrdma_realize() does not release memory resources, leading
to memory leakage.

Reported-by: Li Qiang <liq3ea@163.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <20181212175817.815-1-ppandit@redhat.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
(cherry picked from commit cce648613b)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Niels de Vos 86d4f40141 gluster: the glfs_io_cbk callback function pointer adds pre/post stat args
The glfs_*_async() functions do a callback once finished. This callback
has changed its arguments, pre- and post-stat structures have been
added. This makes it possible to improve caching, which is useful for
Samba and NFS-Ganesha, but not so much for QEMU. Gluster 6 is the first
release that includes these new arguments.

With an additional detection in ./configure, the new arguments can
conditionally get included in the glfs_io_cbk handler.

Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 0e3b891fef)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Prasanna Kumar Kalever 37867211d9 gluster: Handle changed glfs_ftruncate signature
New versions of Glusters libgfapi.so have an updated glfs_ftruncate()
function that returns additional 'struct stat' structures to enable
advanced caching of attributes. This is useful for file servers, not so
much for QEMU. Nevertheless, the API has changed and needs to be
adopted.

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit e014dbe74e)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Philippe Mathieu-Daudé 43a3a1b694 hw/block/pflash_cfi01: Add missing DeviceReset() handler
To avoid incoherent states when the machine resets (see bug report
below), add the device reset callback.

A "system reset" sets the device state machine in READ_ARRAY mode
and, after some delay, set the SR.7 READY bit.

Since we do not model timings, we set the SR.7 bit directly.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1678713
Reported-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
[Laszlo Ersek: Regression tested EDK2 OVMF IA32X64, ArmVirtQemu Aarch64
 https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg04373.html]
Message-Id: <20190718104837.13905-2-philmd@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
(cherry picked from commit 3a283507c0)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:15:46 -05:00
Markus Armbruster ddacb784b3 hw: Use PFLASH_CFI0{1,2} and TYPE_PFLASH_CFI0{1,2}
We have two open-coded copies of macro PFLASH_CFI01().  Move the macro
to the header, so we can ditch the copies.  Move PFLASH_CFI02() to the
header for symmetry.

We define macros TYPE_PFLASH_CFI01 and TYPE_PFLASH_CFI02 for type name
strings, then mostly use the strings.  If the macros are worth
defining, they are worth using.  Replace the strings by the macros.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20190308094610.21210-6-armbru@redhat.com>
(cherry picked from commit 81c7db723e)
*prereq for 3a283507
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:14:29 -05:00
Markus Armbruster 03f130c682 pflash: Rename *CFI_PFLASH* to *PFLASH_CFI*
pflash_cfi01.c and pflash_cfi02.c start their identifiers with
pflash_cfi01_ and pflash_cfi02_ respectively, except for
CFI_PFLASH01(), TYPE_CFI_PFLASH01, CFI_PFLASH02(), TYPE_CFI_PFLASH02.
Rename for consistency.

Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20190308094610.21210-5-armbru@redhat.com>
(cherry picked from commit e7b6274197)
*prereq for 3a283507
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:14:00 -05:00
Markus Armbruster 10b1d6070a pflash_cfi01: Log use of flawed "write to buffer"
Our implementation of "write to buffer" (command 0xE8) is flawed.
LOG_UNIMP its use, and add some FIXME comments.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20190308094610.21210-4-armbru@redhat.com>
(cherry picked from commit 4dbda935e0)
*prereq for 3a283507
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:13:29 -05:00
Markus Armbruster e634054c9d pflash_cfi01: Do not exit() on guest aborting "write to buffer"
When a guest tries to abort "write to buffer" (command 0xE8), we print
"PFLASH: Possible BUG - Write block confirm", then exit(1).  Letting
the guest terminate QEMU is not a good idea.  Instead, LOG_UNIMP we
screwed up, then reset the device.

Macro PFLASH_BUG() is now unused; delete it.

Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20190308094610.21210-3-armbru@redhat.com>
(cherry picked from commit 2d93bebf81)
*prereq for 3a283507
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:12:55 -05:00
Markus Armbruster 13cb31ce08 pflash: Rename pflash_t to PFlashCFI01, PFlashCFI02
flash.h's incomplete struct pflash_t is completed both in
pflash_cfi01.c and in pflash_cfi02.c.  The complete types are
incompatible.  This can hide type errors, such as passing a pflash_t
created with pflash_cfi02_register() to pflash_cfi01_get_memory().

Furthermore, POSIX reserves typedef names ending with _t.

Rename the two structs to PFlashCFI01 and PFlashCFI02.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190308094610.21210-2-armbru@redhat.com>
(cherry picked from commit 1643406520)
*prereq for 3a283507
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:07:50 -05:00
Stephen Checkoway d0cb440280 block/pflash_cfi02: Fix memory leak and potential use-after-free
Don't dynamically allocate the pflash's timer. But do use timer_del in
an unrealize function to make sure that the timer can't fire after the
pflash_t has been freed.

Signed-off-by: Stephen Checkoway <stephen.checkoway@oberlin.edu>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Wei Yang <richardw.yang@linux.intel.com>
Message-Id: <20190219153727.62279-1-stephen.checkoway@oberlin.edu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
(cherry picked from commit d80cf1eb2e)
*prereq for 16434065/3a283507
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 15:07:18 -05:00
Philippe Mathieu-Daudé 21e5c69b85 hw/display/xlnx_dp: Avoid crash when reading empty RX FIFO
In the previous commit we fixed a crash when the guest read a
register that pop from an empty FIFO.
By auditing the repository, we found another similar use with
an easy way to reproduce:

  $ qemu-system-aarch64 -M xlnx-zcu102 -monitor stdio -S
  QEMU 4.0.50 monitor - type 'help' for more information
  (qemu) xp/b 0xfd4a0134
  Aborted (core dumped)

  (gdb) bt
  #0  0x00007f6936dea57f in raise () at /lib64/libc.so.6
  #1  0x00007f6936dd4895 in abort () at /lib64/libc.so.6
  #2  0x0000561ad32975ec in xlnx_dp_aux_pop_rx_fifo (s=0x7f692babee70) at hw/display/xlnx_dp.c:431
  #3  0x0000561ad3297dc0 in xlnx_dp_read (opaque=0x7f692babee70, offset=77, size=4) at hw/display/xlnx_dp.c:667
  #4  0x0000561ad321b896 in memory_region_read_accessor (mr=0x7f692babf620, addr=308, value=0x7ffe05c1db88, size=4, shift=0, mask=4294967295, attrs=...) at memory.c:439
  #5  0x0000561ad321bd70 in access_with_adjusted_size (addr=308, value=0x7ffe05c1db88, size=1, access_size_min=4, access_size_max=4, access_fn=0x561ad321b858 <memory_region_read_accessor>, mr=0x7f692babf620, attrs=...) at memory.c:569
  #6  0x0000561ad321e9d5 in memory_region_dispatch_read1 (mr=0x7f692babf620, addr=308, pval=0x7ffe05c1db88, size=1, attrs=...) at memory.c:1420
  #7  0x0000561ad321ea9d in memory_region_dispatch_read (mr=0x7f692babf620, addr=308, pval=0x7ffe05c1db88, size=1, attrs=...) at memory.c:1447
  #8  0x0000561ad31bd742 in flatview_read_continue (fv=0x561ad69c04f0, addr=4249485620, attrs=..., buf=0x7ffe05c1dcf0 "\020\335\301\005\376\177", len=1, addr1=308, l=1, mr=0x7f692babf620) at exec.c:3385
  #9  0x0000561ad31bd895 in flatview_read (fv=0x561ad69c04f0, addr=4249485620, attrs=..., buf=0x7ffe05c1dcf0 "\020\335\301\005\376\177", len=1) at exec.c:3423
  #10 0x0000561ad31bd90b in address_space_read_full (as=0x561ad5bb3020, addr=4249485620, attrs=..., buf=0x7ffe05c1dcf0 "\020\335\301\005\376\177", len=1) at exec.c:3436
  #11 0x0000561ad33b1c42 in address_space_read (len=1, buf=0x7ffe05c1dcf0 "\020\335\301\005\376\177", attrs=..., addr=4249485620, as=0x561ad5bb3020) at include/exec/memory.h:2131
  #12 0x0000561ad33b1c42 in memory_dump (mon=0x561ad59c4530, count=1, format=120, wsize=1, addr=4249485620, is_physical=1) at monitor/misc.c:723
  #13 0x0000561ad33b1fc1 in hmp_physical_memory_dump (mon=0x561ad59c4530, qdict=0x561ad6c6fd00) at monitor/misc.c:795
  #14 0x0000561ad37b4a9f in handle_hmp_command (mon=0x561ad59c4530, cmdline=0x561ad59d0f22 "/b 0x00000000fd4a0134") at monitor/hmp.c:1082

Fix by checking the FIFO is not empty before popping from it.

The datasheet is not clear about the reset value of this register,
we choose to return '0'.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20190709113715.7761-4-philmd@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit a09ef50404)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 14:45:55 -05:00
Philippe Mathieu-Daudé e2ec206ea9 hw/ssi/mss-spi: Avoid crash when reading empty RX FIFO
Reading the RX_DATA register when the RX_FIFO is empty triggers
an abort. This can be easily reproduced:

  $ qemu-system-arm -M emcraft-sf2 -monitor stdio -S
  QEMU 4.0.50 monitor - type 'help' for more information
  (qemu) x 0x40001010
  Aborted (core dumped)

  (gdb) bt
  #1  0x00007f035874f895 in abort () at /lib64/libc.so.6
  #2  0x00005628686591ff in fifo8_pop (fifo=0x56286a9a4c68) at util/fifo8.c:66
  #3  0x00005628683e0b8e in fifo32_pop (fifo=0x56286a9a4c68) at include/qemu/fifo32.h:137
  #4  0x00005628683e0efb in spi_read (opaque=0x56286a9a4850, addr=4, size=4) at hw/ssi/mss-spi.c:168
  #5  0x0000562867f96801 in memory_region_read_accessor (mr=0x56286a9a4b60, addr=16, value=0x7ffeecb0c5c8, size=4, shift=0, mask=4294967295, attrs=...) at memory.c:439
  #6  0x0000562867f96cdb in access_with_adjusted_size (addr=16, value=0x7ffeecb0c5c8, size=4, access_size_min=1, access_size_max=4, access_fn=0x562867f967c3 <memory_region_read_accessor>, mr=0x56286a9a4b60, attrs=...) at memory.c:569
  #7  0x0000562867f99940 in memory_region_dispatch_read1 (mr=0x56286a9a4b60, addr=16, pval=0x7ffeecb0c5c8, size=4, attrs=...) at memory.c:1420
  #8  0x0000562867f99a08 in memory_region_dispatch_read (mr=0x56286a9a4b60, addr=16, pval=0x7ffeecb0c5c8, size=4, attrs=...) at memory.c:1447
  #9  0x0000562867f38721 in flatview_read_continue (fv=0x56286aec6360, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4, addr1=16, l=4, mr=0x56286a9a4b60) at exec.c:3385
  #10 0x0000562867f38874 in flatview_read (fv=0x56286aec6360, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4) at exec.c:3423
  #11 0x0000562867f388ea in address_space_read_full (as=0x56286aa3e890, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4) at exec.c:3436
  #12 0x0000562867f389c5 in address_space_rw (as=0x56286aa3e890, addr=1073745936, attrs=..., buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4, is_write=false) at exec.c:3466
  #13 0x0000562867f3bdd7 in cpu_memory_rw_debug (cpu=0x56286aa19d00, addr=1073745936, buf=0x7ffeecb0c7c0 "\340ǰ\354\376\177", len=4, is_write=0) at exec.c:3976
  #14 0x000056286811ed51 in memory_dump (mon=0x56286a8c32d0, count=1, format=120, wsize=4, addr=1073745936, is_physical=0) at monitor/misc.c:730
  #15 0x000056286811eff1 in hmp_memory_dump (mon=0x56286a8c32d0, qdict=0x56286b15c400) at monitor/misc.c:785
  #16 0x00005628684740ee in handle_hmp_command (mon=0x56286a8c32d0, cmdline=0x56286a8caeb2 "0x40001010") at monitor/hmp.c:1082

From the datasheet "Actel SmartFusion Microcontroller Subsystem
User's Guide" Rev.1, Table 13-3 "SPI Register Summary", this
register has a reset value of 0.

Check the FIFO is not empty before accessing it, else log an
error message.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20190709113715.7761-3-philmd@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit c0bccee9b4)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 14:45:15 -05:00
Philippe Mathieu-Daudé 1f30e35861 hw/ssi/xilinx_spips: Avoid out-of-bound access to lqspi_buf[]
Both lqspi_read() and lqspi_load_cache() expect a 32-bit
aligned address.

>From UG1085 datasheet [*] chapter on 'Quad-SPI Controller':

  Transfer Size Limitations

    Because of the 32-bit wide TX, RX, and generic FIFO, all
    APB/AXI transfers must be an integer multiple of 4-bytes.
    Shorter transfers are not possible.

Set MemoryRegionOps.impl values to force 32-bit accesses,
this way we are sure we do not access the lqspi_buf[] array
out of bound.

[*] https://www.xilinx.com/support/documentation/user_guides/ug1085-zynq-ultrascale-trm.pdf

Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Tested-by: Francisco Iglesias <frasse.iglesias@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 526668c734)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 14:44:36 -05:00
Philippe Mathieu-Daudé 19f55e7ab5 target/m68k: Fix a tcg_temp leak
The function gen_get_ccr() returns a tcg_temp created with
tcg_temp_new(). Free it with tcg_temp_free().

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190310003428.11723-4-f4bug@amsat.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
(cherry picked from commit 44c64e9095)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 14:33:20 -05:00
Michael S. Tsirkin c6b77a64b4 virtio-balloon: free pbp more aggressively
Previous patches switched to a temporary pbp but that does not go far
enough: after device uses a buffer, guest is free to reuse it, so
tracking the page and freeing it later is wrong.

Free and reset the pbp after we push each element.

Fixes: ed48c59875 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size")
Cc: qemu-stable@nongnu.org #v4.0.0
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 1b47b37c33)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:46:52 -05:00
David Hildenbrand 0965d5583e virtio-balloon: don't track subpages for the PBP
As ramblocks cannot get removed/readded while we are processing a bulk
of inflation requests, there is no more need to track the page size
in form of the number of subpages.

Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190725113638.4702-8-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 9a7ca8a7c9)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:46:46 -05:00
David Hildenbrand 14d9028a7d virtio-balloon: Use temporary PBP only
We still have multiple issues in the current code
- The PBP is not freed during unrealize()
- The PBP is not reset on device resets: After a reset, the PBP is stale.
- We are not indicating VIRTIO_BALLOON_F_MUST_TELL_HOST, therefore
  guests (esp. legacy guests) will reuse pages without deflating,
  turning the PBP stale. Adding that would require compat handling.

Instead, let's use the PBP only temporarily, when processing one bulk of
inflation requests. This will keep guest_page_size > 4k working (with
Linux guests). There is nothing to do for deflation requests anymore.
The pbp is only used for a limited amount of time.

Fixes: ed48c59875 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size")
Cc: qemu-stable@nongnu.org #v4.0.0
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-7-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit a8cd64d488)
*drop context dependency on qemu_4_0_config_size changes
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:45:53 -05:00
David Hildenbrand 2aa5009412 virtio-balloon: Rework pbp tracking data
Using the address of a RAMBlock to test for a matching pbp is not really
safe. Instead, let's use the guest physical address of the base page
along with the page size (via the number of subpages).

Also, let's allocate the bitmap separately. This makes the code
easier to read and maintain - we can reuse bitmap_new().

Prepare the code to move the PBP out of the device.

Fixes: ed48c59875 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size")
Fixes: b27b323914 ("virtio-balloon: Fix possible guest memory corruption with inflates & deflates")
Cc: qemu-stable@nongnu.org #v4.0.0
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-6-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 1c5cfc2b71)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:41:34 -05:00
David Hildenbrand 46275f9091 virtio-balloon: Better names for offset variables in inflate/deflate code
"host_page_base" is really confusing, let's make this clearer, also
rename the other offsets to indicate to which base they apply.

offset -> mr_offset
ram_offset -> rb_offset
host_page_base -> rb_aligned_offset

While at it, use QEMU_ALIGN_DOWN() instead of a handcrafted computation
and move the computation to the place where it is needed.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-5-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit e6129b271b)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:41:24 -05:00
David Hildenbrand b0d6feca99 virtio-balloon: Simplify deflate with pbp
Let's simplify this - the case we are optimizing for is very hard to
trigger and not worth the effort. If we're switching from inflation to
deflation, let's reset the pbp.

Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-4-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 2ffc49eea1)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:41:18 -05:00
David Hildenbrand 07026c30c3 virtio-balloon: Fix QEMU crashes on pagesize > BALLOON_PAGE_SIZE
We are using the wrong functions to set/clear bits, effectively touching
multiple bits, writing out of range of the bitmap, resulting in memory
corruptions. We have to use set_bit()/clear_bit() instead.

Can easily be reproduced by starting a qemu guest on hugetlbfs memory,
inflating the balloon. QEMU crashes. This never could have worked
properly - especially, also pages would have been discarded when the
first sub-page would be inflated (the whole bitmap would be set).

While testing I realized, that on hugetlbfs it is pretty much impossible
to discard a page - the guest just frees the 4k sub-pages in random order
most of the time. I was only able to discard a hugepage a handful of
times - so I hope that now works correctly.

Fixes: ed48c59875 ("virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size")
Fixes: b27b323914 ("virtio-balloon: Fix possible guest memory corruption with inflates & deflates")
Cc: qemu-stable@nongnu.org #v4.0.0
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-3-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 483f13524b)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:38:57 -05:00
David Hildenbrand 11dd808dc0 virtio-balloon: Fix wrong sign extension of PFNs
If we directly cast from int to uint64_t, we will first sign-extend to
an int64_t, which is wrong. We actually want to treat the PFNs like
unsigned values.

As far as I can see, this dates back to the initial virtio-balloon
commit, but wasn't triggered as fairly big guests would be required.

Cc: qemu-stable@nongnu.org
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-2-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit ffa207d082)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:38:33 -05:00
David Gibson f8364784f0 virtio-balloon: Restore MADV_WILLNEED hint on balloon deflate
Prior to f6deb6d9 "virtio-balloon: Remove unnecessary MADV_WILLNEED on
deflate", the balloon device issued an madvise() MADV_WILLNEED on
pages removed from the balloon.  That would hint to the host kernel
that the pages were likely to be needed by the guest in the near
future.

It's unclear if this is actually valuable or not, and so f6deb6d9
removed this, essentially ignoring balloon deflate requests.  However,
concerns have been raised that this might cause a performance
regression by causing extra latency for the guest in certain
configurations.

So, until we can get actual benchmark data to see if that's the case,
this restores the old behaviour, issuing a MADV_WILLNEED when a page is
removed from the balloon.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190306030601.21986-4-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 596546fe9e)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:36:15 -05:00
David Gibson 38e8e9007d virtio-balloon: Fix possible guest memory corruption with inflates & deflates
This fixes a balloon bug with a nasty consequence - potentially
corrupting guest memory - but which is extremely unlikely to be
triggered in practice.

The balloon always works in 4kiB units, but the host could have a
larger page size on certain platforms.  Since ed48c59 "virtio-balloon:
Safely handle BALLOON_PAGE_SIZE < host page size" we've handled this
by accumulating requests to balloon 4kiB subpages until they formed a
full host page.  Since f6deb6d "virtio-balloon: Remove unnecessary
MADV_WILLNEED on deflate" we essentially ignore deflate requests.

Suppose we have a host with 8kiB pages, and one host page has subpages
A & B.  If we get this sequence of events -
	inflate A
	deflate A
	inflate B
- the current logic will discard the whole host page.  That's
incorrect because the guest has deflated subpage A, and could have
written important data to it.

This patch fixes the problem by adjusting our state information about
partially ballooned host pages when deflate requests are received.

Fixes: ed48c59 "virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size"

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190306030601.21986-3-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
(cherry picked from commit b27b323914)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:35:14 -05:00
David Gibson 80c96a7b60 virtio-balloon: Don't mismatch g_malloc()/free (CID 1399146)
ed48c59875 "virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host
page size" introduced a new temporary data structure which tracks 4kiB
chunks which have been inserted into the balloon by the guest but
don't yet form a full host page which we can discard.

Unfortunately, I had a thinko and allocated that structure with
g_malloc0() but freed it with a plain free() rather than g_free().
This corrects the problem.

Fixes: ed48c59875
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190306030601.21986-2-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
(cherry picked from commit 301cf2a8dd)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:34:38 -05:00
David Gibson 118112024d virtio-balloon: Safely handle BALLOON_PAGE_SIZE < host page size
The virtio-balloon always works in units of 4kiB (BALLOON_PAGE_SIZE), but
we can only actually discard memory in units of the host page size.

Now, we handle this very badly: we silently ignore balloon requests that
aren't host page aligned, and for requests that are host page aligned we
discard the entire host page.  The latter can corrupt guest memory if its
page size is smaller than the host's.

The obvious choice would be to disable the balloon if the host page size is
not 4kiB.  However, that would break the special case where host and guest
have the same page size, but that's larger than 4kiB.  That case currently
works by accident[1] - and is used in practice on many production POWER
systems where 64kiB has long been the Linux default page size on both host
and guest.

To make the balloon safe, without breaking that useful special case, we
need to accumulate 4kiB balloon requests until we have a whole contiguous
host page to discard.

We could in principle do that across all guest memory, but it would require
a large bitmap to track.  This patch represents a compromise: we track
ballooned subpages for a single contiguous host page at a time.  This means
that if the guest discards all 4kiB chunks of a host page in succession,
we will discard it.  This is the expected behaviour in the (host page) ==
(guest page) != 4kiB case we want to support.

If the guest scatters 4kiB requests across different host pages, we don't
discard anything, and issue a warning.  Not ideal, but at least we don't
corrupt guest memory as the previous version could.

Warning reporting is kind of a compromise here.  Determining whether we're
in a problematic state at realize() time is tricky, because we'd have to
look at the host pagesizes of all memory backends, but we can't really know
if some of those backends could be for special purpose memory that's not
subject to ballooning.

Reporting only when the guest tries to balloon a partial page also isn't
great because if the guest page size happens to line up it won't indicate
that we're in a non ideal situation.  It could also cause alarming repeated
warnings whenever a migration is attempted.

So, what we do is warn the first time the guest attempts balloon a partial
host page, whether or not it will end up ballooning the rest of the page
immediately afterwards.

[1] Because when the guest attempts to balloon a page, it will submit
    requests for each 4kiB subpage.  Most will be ignored, but the one
    which happens to be host page aligned will discard the whole lot.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Message-Id: <20190214043916.22128-6-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit ed48c59875)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:34:09 -05:00
David Gibson 83cddbaadf virtio-balloon: Use ram_block_discard_range() instead of raw madvise()
Currently, virtio-balloon uses madvise() with MADV_DONTNEED to actually
discard RAM pages inserted into the balloon.  This is basically a Linux
only interface (MADV_DONTNEED exists on some other platforms, but doesn't
always have the same semantics).  It also doesn't work on hugepages and has
some other limitations.

It turns out that postcopy also needs to discard chunks of memory, and uses
a better interface for it: ram_block_discard_range().  It doesn't cover
every case, but it covers more than going direct to madvise() and this
gives us a single place to update for more possibilities in future.

There are some subtleties here to maintain the current balloon behaviour:

* For now, we just ignore requests to balloon in a hugepage backed region.
  That matches current behaviour, because MADV_DONTNEED on a hugepage would
  simply fail, and we ignore the error.

* If host page size is > BALLOON_PAGE_SIZE we can frequently call this on
  non-host-page-aligned addresses.  These would also fail in madvise(),
  which we then ignored.  ram_block_discard_range() error_report()s calls
  on unaligned addresses, so we explicitly check that case to avoid
  spamming the logs.

* We now call ram_block_discard_range() with the *host* page size, whereas
  we previously called madvise() with BALLOON_PAGE_SIZE.  Surprisingly,
  this also matches existing behaviour.  Although the kernel fails madvise
  on unaligned addresses, it will round unaligned sizes *up* to the host
  page size.  Yes, this means that if BALLOON_PAGE_SIZE < guest page size
  we can incorrectly discard more memory than the guest asked us to.  I'm
  planning to address that soon.

Errors other than the ones discussed above, will now be reported by
ram_block_discard_range(), rather than silently ignored, which means we
have a much better chance of seeing when something is going wrong.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20190214043916.22128-5-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit dbe1a27745)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:33:57 -05:00
David Gibson 89b0e359bc virtio-balloon: Rework ballon_page() interface
This replaces the balloon_page() internal interface with
ballon_inflate_page(), with a slightly different interface.  The new
interface will make future alterations simpler.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20190214043916.22128-4-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit e9550234d7)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:33:48 -05:00
David Gibson b260cdec21 virtio-balloon: Corrections to address verification
The virtio-balloon device's verification of the address given to it by the
guest has a number of faults:
    * The addresses here are guest physical addresses, which should be
      'hwaddr' rather than 'ram_addr_t' (the distinction is admittedly
      pretty subtle and confusing)
    * We don't check for section.mr being NULL, which is the main way that
      memory_region_find() reports basic failures.  We really need to check
      that before looking at any other section fields, because
      memory_region_find() doesn't initialize them on the failure path
    * We're passing a length of '1' to memory_region_find(), but really the
      guest is requesting that we put the entire page into the balloon,
      so it makes more sense to call it with BALLOON_PAGE_SIZE

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20190214043916.22128-3-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit b218a70e6a)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:33:37 -05:00
David Gibson 7a31a0af31 virtio-balloon: Remove unnecessary MADV_WILLNEED on deflate
When the balloon is inflated, we discard memory place in it using madvise()
with MADV_DONTNEED.  And when we deflate it we use MADV_WILLNEED, which
sounds like it makes sense but is actually unnecessary.

The misleadingly named MADV_DONTNEED just discards the memory in question,
it doesn't set any persistent state on it in-kernel; all that's necessary
to bring the memory back is to touch it.  MADV_WILLNEED in contrast
specifically says that the memory will be used soon and faults it in.

This patch simplify's the balloon operation by dropping the madvise()
on deflate.  This might have an impact on performance - it will move a
delay at deflate time until that memory is actually touched, which
might be more latency sensitive.  However:

  * Memory that's being given back to the guest by deflating the
    balloon *might* be used soon, but it equally could just sit around
    in the guest's pools until needed (or even be faulted out again if
    the host is under memory pressure).

  * Usually, the timescale over which you'll be adjusting the balloon
    is long enough that a few extra faults after deflation aren't
    going to make a difference.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20190214043916.22128-2-david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit f6deb6d95a)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:33:30 -05:00
Peter Maydell f0a334345b hw/virtio/virtio-balloon: zero-initialize the virtio_balloon_config struct
In virtio_balloon_get_config() we initialize a struct virtio_balloon_config
which we then copy to guest memory. However, the local variable is not
zero initialized. This works OK at the moment because we initialize
all the fields in it; however an upcoming kernel header change will
add some new fields. If we don't zero out the whole struct then we
will start leaking a small amount of the contents of QEMU's stack
to the guest as soon as we update linux-headers/ to a set of headers
that includes the new fields.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190118183603.24757-1-peter.maydell@linaro.org
(cherry picked from commit 5385a5988c)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2019-07-30 12:31:44 -05:00