db32d0f438
These quirks are necessary for GeForce, but not for Quadro/GRID/Tesla assignment. Leaving them enabled is fully functional and provides the most compatibility, but due to the unique NVIDIA MSI ACK behavior[1], it also introduces latency in re-triggering the MSI interrupt. This overhead is typically negligible, but has been shown to adversely affect some (very) high interrupt rate applications. This adds the vfio-pci device option "x-no-geforce-quirks=" which can be set to "on" to disable this additional overhead. A follow-on optimization for GeForce might be to make use of an ioeventfd to allow KVM to trigger an irqfd in the kernel vfio-pci driver, avoiding the bounce through userspace to handle this device write. [1] Background: the NVIDIA driver has been observed to issue a write to the MMIO mirror of PCI config space in BAR0 in order to allow the MSI interrupt for the device to retrigger. Older reports indicated a write of 0xff to the (read-only) MSI capability ID register, while more recently a write of 0x0 is observed at config space offset 0x704, non-architected, extended config space of the device (BAR0 offset 0x88704). Virtualization of this range is only required for GeForce. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> |
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accel | ||
audio | ||
backends | ||
block | ||
bsd-user | ||
capstone@22ead3e0bf | ||
chardev | ||
contrib | ||
crypto | ||
default-configs | ||
disas | ||
docs | ||
dtc@e54388015a | ||
fpu | ||
fsdev | ||
gdb-xml | ||
hw | ||
include | ||
io | ||
libdecnumber | ||
linux-headers | ||
linux-user | ||
migration | ||
nbd | ||
net | ||
pc-bios | ||
po | ||
qapi | ||
qga | ||
qobject | ||
qom | ||
replay | ||
roms | ||
scripts | ||
scsi | ||
slirp | ||
stubs | ||
target | ||
tcg | ||
tests | ||
trace | ||
ui | ||
util | ||
.dir-locals.el | ||
.editorconfig | ||
.exrc | ||
.gdbinit | ||
.gitignore | ||
.gitmodules | ||
.mailmap | ||
.shippable.yml | ||
.travis.yml | ||
arch_init.c | ||
balloon.c | ||
block.c | ||
blockdev-nbd.c | ||
blockdev.c | ||
blockjob.c | ||
bootdevice.c | ||
bt-host.c | ||
bt-vhci.c | ||
Changelog | ||
CODING_STYLE | ||
configure | ||
COPYING | ||
COPYING.LIB | ||
COPYING.PYTHON | ||
cpus-common.c | ||
cpus.c | ||
device_tree.c | ||
device-hotplug.c | ||
disas.c | ||
dma-helpers.c | ||
dump.c | ||
exec.c | ||
gdbstub.c | ||
HACKING | ||
hmp-commands-info.hx | ||
hmp-commands.hx | ||
hmp.c | ||
hmp.h | ||
ioport.c | ||
iothread.c | ||
LICENSE | ||
MAINTAINERS | ||
Makefile | ||
Makefile.objs | ||
Makefile.target | ||
memory_ldst.inc.c | ||
memory_mapping.c | ||
memory.c | ||
module-common.c | ||
monitor.c | ||
numa.c | ||
os-posix.c | ||
os-win32.c | ||
qapi-schema.json | ||
qdev-monitor.c | ||
qdict-test-data.txt | ||
qemu-bridge-helper.c | ||
qemu-doc.texi | ||
qemu-ga.texi | ||
qemu-img-cmds.hx | ||
qemu-img.c | ||
qemu-img.texi | ||
qemu-io-cmds.c | ||
qemu-io.c | ||
qemu-keymap.c | ||
qemu-nbd.c | ||
qemu-nbd.texi | ||
qemu-option-trace.texi | ||
qemu-options-wrapper.h | ||
qemu-options.h | ||
qemu-options.hx | ||
qemu-seccomp.c | ||
qemu-tech.texi | ||
qemu.nsi | ||
qemu.sasl | ||
qmp.c | ||
qtest.c | ||
README | ||
replication.c | ||
replication.h | ||
rules.mak | ||
thunk.c | ||
tpm.c | ||
trace-events | ||
VERSION | ||
version.rc | ||
vl.c |
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