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2f295167e0
The q35 machine type currently lets the guest firmware select a 1MB, 2MB
or 8MB TSEG (basically, SMRAM) size. In edk2/OVMF, we use 8MB, but even
that is not enough when a lot of VCPUs (more than approx. 224) are
configured -- SMRAM footprint scales largely proportionally with VCPU
count.
Introduce a new property for "mch" called "extended-tseg-mbytes", which
expresses (in megabytes) the user's choice of TSEG (SMRAM) size.
Invent a new, QEMU-specific register in the config space of the DRAM
Controller, at offset 0x50, in order to allow guest firmware to query the
TSEG (SMRAM) size.
According to Intel Document Number 316966-002, Table 5-1 "DRAM Controller
Register Address Map (D0:F0)":
Warning: Address locations that are not listed are considered Intel
Reserved registers locations. Reads to Reserved registers may
return non-zero values. Writes to reserved locations may
cause system failures.
All registers that are defined in the PCI 2.3 specification,
but are not necessary or implemented in this component are
simply not included in this document. The
reserved/unimplemented space in the PCI configuration header
space is not documented as such in this summary.
Offsets 0x50 and 0x51 are not listed in Table 5-1. They are also not part
of the standard PCI config space header. And they precede the capability
list as well, which starts at 0xe0 for this device.
When the guest writes value 0xffff to this register, the value that can be
read back is that of "mch.extended-tseg-mbytes" -- unless it remains
0xffff. The guest is required to write 0xffff first (as opposed to a
read-only register) because PCI config space is generally not cleared on
QEMU reset, and after S3 resume or reboot, new guest firmware running on
old QEMU could read a guest OS-injected value from this register.
After reading the available "extended" TSEG size, the guest firmware may
actually request that TSEG size by writing pattern 11b to the ESMRAMC
register's TSEG_SZ bit-field. (The Intel spec referenced above defines
only patterns 00b (1MB), 01b (2MB) and 10b (8MB); 11b is reserved.)
On the QEMU command line, the value can be set with
-global mch.extended-tseg-mbytes=N
The default value for 2.10+ q35 machine types is 16. The value is limited
to 0xfff (4095) at the moment, purely so that the product (4095 MB) can be
stored to the uint32_t variable "tseg_size" in mch_update_smram(). Users
are responsible for choosing sensible TSEG sizes.
On 2.9 and earlier q35 machine types, the default value is 0. This lets
the 11b bit pattern in ESMRAMC.TSEG_SZ, and the register at offset 0x50,
keep their original behavior.
When "extended-tseg-mbytes" is nonzero, the new register at offset 0x50 is
set to that value on reset, for completeness.
PCI config space is migrated automatically, so no VMSD changes are
necessary.
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1447027
Ref: https://lists.01.org/pipermail/edk2-devel/2017-May/010456.html
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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| audio | ||
| backends | ||
| block | ||
| bsd-user | ||
| chardev | ||
| contrib | ||
| crypto | ||
| default-configs | ||
| disas | ||
| docs | ||
| dtc@558cd81bdd | ||
| fpu | ||
| fsdev | ||
| gdb-xml | ||
| hw | ||
| include | ||
| io | ||
| libdecnumber | ||
| linux-headers | ||
| linux-user | ||
| migration | ||
| nbd | ||
| net | ||
| pc-bios | ||
| pixman@87eea99e44 | ||
| po | ||
| qapi | ||
| qga | ||
| qobject | ||
| qom | ||
| replay | ||
| roms | ||
| scripts | ||
| slirp | ||
| stubs | ||
| target | ||
| tcg | ||
| tests | ||
| trace | ||
| ui | ||
| util | ||
| .dir-locals.el | ||
| .exrc | ||
| .gdbinit | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| .shippable.yml | ||
| .travis.yml | ||
| accel.c | ||
| arch_init.c | ||
| atomic_template.h | ||
| 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 | ||
| cpu-exec-common.c | ||
| cpu-exec.c | ||
| cpus-common.c | ||
| cpus.c | ||
| cputlb.c | ||
| device-hotplug.c | ||
| device_tree.c | ||
| disas.c | ||
| dma-helpers.c | ||
| dump.c | ||
| exec.c | ||
| gdbstub.c | ||
| HACKING | ||
| hax-stub.c | ||
| hmp-commands-info.hx | ||
| hmp-commands.hx | ||
| hmp.c | ||
| hmp.h | ||
| ioport.c | ||
| iothread.c | ||
| kvm-all.c | ||
| kvm-stub.c | ||
| LICENSE | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.objs | ||
| Makefile.target | ||
| memory.c | ||
| memory_ldst.inc.c | ||
| memory_mapping.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-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 | ||
| softmmu_template.h | ||
| tcg-runtime.c | ||
| tci.c | ||
| thunk.c | ||
| tpm.c | ||
| trace-events | ||
| translate-all.c | ||
| translate-all.h | ||
| translate-common.c | ||
| user-exec-stub.c | ||
| user-exec.c | ||
| 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:
http://qemu-project.org/Hosts/Linux
http://qemu-project.org/Hosts/Mac
http://qemu-project.org/Hosts/W32
Submitting patches
==================
The QEMU source code is maintained under the GIT version control system.
git clone git://git.qemu-project.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
http://qemu-project.org/Contribute/SubmitAPatch
http://qemu-project.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:
http://qemu-project.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
http://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:
http://qemu-project.org/Contribute/StartHere
-- End