The passed-through device might be an express device. In this case the
old code allocated a too small emulated config space in
pci_config_alloc() since pci_config_size() returned the size for a
non-express device. This leads to an out-of-bound write in
xen_pt_config_reg_init(), which sometimes results in crashes. So set
is_express as already done for KVM in vfio-pci.
Shortened ASan report:
==17512==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x611000041648 at pc 0x55e0fdac51ff bp 0x7ffe4af07410 sp 0x7ffe4af07408
WRITE of size 2 at 0x611000041648 thread T0
#0 0x55e0fdac51fe in memcpy /usr/include/x86_64-linux-gnu/bits/string3.h:53
#1 0x55e0fdac51fe in stw_he_p include/qemu/bswap.h:330
#2 0x55e0fdac51fe in stw_le_p include/qemu/bswap.h:379
#3 0x55e0fdac51fe in pci_set_word include/hw/pci/pci.h:490
#4 0x55e0fdac51fe in xen_pt_config_reg_init hw/xen/xen_pt_config_init.c:1991
#5 0x55e0fdac51fe in xen_pt_config_init hw/xen/xen_pt_config_init.c:2067
#6 0x55e0fdabcf4d in xen_pt_realize hw/xen/xen_pt.c:830
#7 0x55e0fdf59666 in pci_qdev_realize hw/pci/pci.c:2034
#8 0x55e0fdda7d3d in device_set_realized hw/core/qdev.c:914
[...]
0x611000041648 is located 8 bytes to the right of 256-byte region [0x611000041540,0x611000041640)
allocated by thread T0 here:
#0 0x7ff596a94bb8 in __interceptor_calloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xd9bb8)
#1 0x7ff57da66580 in g_malloc0 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x50580)
#2 0x55e0fdda7d3d in device_set_realized hw/core/qdev.c:914
[...]
Signed-off-by: Simon Gaiser <hw42@ipsumj.de>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
QEMU README
===========
QEMU is a generic and open source machine & userspace emulator and
virtualizer.
QEMU is capable of emulating a complete machine in software without any
need for hardware virtualization support. By using dynamic translation,
it achieves very good performance. QEMU can also integrate with the Xen
and KVM hypervisors to provide emulated hardware while allowing the
hypervisor to manage the CPU. With hypervisor support, QEMU can achieve
near native performance for CPUs. When QEMU emulates CPUs directly it is
capable of running operating systems made for one machine (e.g. an ARMv7
board) on a different machine (e.g. an x86_64 PC board).
QEMU is also capable of providing userspace API virtualization for Linux
and BSD kernel interfaces. This allows binaries compiled against one
architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a
different architecture ABI (e.g. the Linux x86_64 ABI). This does not
involve any hardware emulation, simply CPU and syscall emulation.
QEMU aims to fit into a variety of use cases. It can be invoked directly
by users wishing to have full control over its behaviour and settings.
It also aims to facilitate integration into higher level management
layers, by providing a stable command line interface and monitor API.
It is commonly invoked indirectly via the libvirt library when using
open source applications such as oVirt, OpenStack and virt-manager.
QEMU as a whole is released under the GNU General Public License,
version 2. For full licensing details, consult the LICENSE file.
Building
========
QEMU is multi-platform software intended to be buildable on all modern
Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety
of other UNIX targets. The simple steps to build QEMU are:
mkdir build
cd build
../configure
make
Additional information can also be found online via the QEMU website:
https://qemu.org/Hosts/Linux
https://qemu.org/Hosts/Mac
https://qemu.org/Hosts/W32
Submitting patches
==================
The QEMU source code is maintained under the GIT version control system.
git clone git://git.qemu.org/qemu.git
When submitting patches, the preferred approach is to use 'git
format-patch' and/or 'git send-email' to format & send the mail to the
qemu-devel@nongnu.org mailing list. All patches submitted must contain
a 'Signed-off-by' line from the author. Patches should follow the
guidelines set out in the HACKING and CODING_STYLE files.
Additional information on submitting patches can be found online via
the QEMU website
https://qemu.org/Contribute/SubmitAPatch
https://qemu.org/Contribute/TrivialPatches
Bug reporting
=============
The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs
found when running code built from QEMU git or upstream released sources
should be reported via:
https://bugs.launchpad.net/qemu/
If using QEMU via an operating system vendor pre-built binary package, it
is preferable to report bugs to the vendor's own bug tracker first. If
the bug is also known to affect latest upstream code, it can also be
reported via launchpad.
For additional information on bug reporting consult:
https://qemu.org/Contribute/ReportABug
Contact
=======
The QEMU community can be contacted in a number of ways, with the two
main methods being email and IRC
- qemu-devel@nongnu.org
https://lists.nongnu.org/mailman/listinfo/qemu-devel
- #qemu on irc.oftc.net
Information on additional methods of contacting the community can be
found online via the QEMU website:
https://qemu.org/Contribute/StartHere
-- End
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