Just hardcode $(CC) -E, it should be enough.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220517092616.1272238-2-pbonzini@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220527153603.887929-13-alex.bennee@linaro.org>
Do not rely on the detection that was done in the configure script,
since in the future we may want to cross-compile this file.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Some of the roms build with -march=i486 -m16 which is incompatible
with -fcf-protection. That in turn is can be set by default, for
example in Ubuntu [1].
That causes:
cc1: error: ‘-fcf-protection’ is not compatible with this target
This won't work on -march=i486 -m16 and no matter if set or not we can
override it to "none" if the option is known to the compiler to be
able to build reliably.
Fixes: https://gitlab.com/qemu-project/qemu/-/issues/889
[1]: https://wiki.ubuntu.com/ToolChain/CompilerFlags#A-fcf-protection
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20220323090713.1002588-1-christian.ehrhardt@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a new option rom for the multiboot loader, using DMA transfers to copy
data instead of "rep insb".
This significantly lowers QEMU's startup latency by a factor of about 40,
for example, going from 30sec to 0.8sec when loading modules of 120MB
in size.
Signed-off-by: Marcus Hähnel <marcus.haehnel@kernkonzept.com>
Signed-off-by: Adam Lackorzynski <adam@l4re.org>
[Modified to keep the non-DMA code depending on #ifdef USE_FW_CFG_DMA;
do not write below stack. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This patch enables native builds on MSYS2 with symlinks disabled.
Signed-off-by: Helge Konetzka <hk@zapateado.de>
Message-Id: <2b5ab039-8495-b55f-03f1-ecfd996907a9@zapateado.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Recent binutils changes dropping unsupported options [1] caused a build
issue in regard to the optionroms.
ld -m elf_i386 -T /<<PKGBUILDDIR>>/pc-bios/optionrom//flat.lds -no-pie \
-s -o multiboot.img multiboot.o
ld.bfd: Error: unable to disambiguate: -no-pie (did you mean --no-pie ?)
This isn't really a regression in ld.bfd, filing the bug upstream
revealed that this never worked as a ld flag [2] - in fact it seems we
were by accident setting --nmagic).
Since it never had the wanted effect this usage of LDFLAGS_NOPIE, should be
droppable without any effect. This also is the only use-case of LDFLAGS_NOPIE
in .mak, therefore we can also remove it from being added there.
[1]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=983d925d
[2]: https://sourceware.org/bugzilla/show_bug.cgi?id=27050#c5
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Message-Id: <20201214150938.1297512-1-christian.ehrhardt@canonical.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The missing "/all" suffix prevents the pc-bios/ parts of the build
from running.
In the meanwhile, -Wall has moved from QEMU_CFLAGS to CFLAGS. Simplify
everything by not passing down CFLAGS, and add -Wall in the recursive
Makefiles.
Reported-by: Miroslav Rezanina <mrezanin@redhat.com>
Reviewed-by: Miroslav Rezanina <mrezanin@redhat.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Fixes: 5e6d1573b4 ("remove Makefile.target", 2020-08-21)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make it independent from the rules.mak, and clean up to use pattern rules.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Right now the PVH option rom scans for the RSDP from 0xE0000 to
0xE1FFF. This is probobly a typo, it should scan from 0xE0000 to
0xFFFFF.
This is actually an issue on some QEMU versions/machines. For example,
when I run QEMU the RSDP is placed at 0xf5ad0 which will not be picked
up by the current implementation.
This bug still allows a Linux guest to boot (in most configurations) as
the kernel will just scan for the RSDP if one isn't provided.
Signed-off-by: Joe Richey <joerichey@google.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Fixes: 2785dc7b17 ("optionrom: add new PVH option rom")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If we found initrd through fw_cfg, we can load it and use the
first module of hvm_start_info to pass initrd address and size
to the kernel.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Based-on: <1547554687-12687-1-git-send-email-liam.merwick@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The new pvh.bin option rom can be used with SeaBIOS to boot
uncompressed kernel using the x86/HVM direct boot ABI.
pvh.S contains the entry point of the option rom. It runs
in real mode, loads the e820 table querying the BIOS, and
then it switches to 32bit protected mode and jumps to the
pvh_load_kernel() written in pvh_main.c.
pvh_load_kernel() loads the cmdline and kernel entry_point
using fw_cfg, then it looks for RSDP, fills the
hvm_start_info required by x86/HVM ABI, and finally jumps
to the kernel entry_point.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
In order to allow other option roms to use these common
useful functions and definitions, this patch put them
in two new C header files called optrom.h and
optrom_fw_cfg.h. We also add useful out*() in*()
functions for different size, and new fw_cfg functions
to use when DMA feature is not available.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
FW_CFG_DMA_CTL_* bits and struct fw_cfg_dma_access are
defined in the qemu_fw_cfg.h header file already included
in linuxboot_dma.c, so we can remove the definition of
BIOS_CFG_DMA_CTL_* and struct FWCfgDmaAccess.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Based-on: <1547554687-12687-1-git-send-email-liam.merwick@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The ROM uses the cmovne instruction, which is new in Pentium Pro and does not
work when running QEMU with "-cpu 486". Avoid producing that instruction.
Suggested-by: Richard W.M. Jones <rjones@redhat.com>
Suggested-by: Thomas Huth <thuth@redhat.com>
Reported-by: Rob Landley <rob@landley.net>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The quiet-command make rule currently takes two arguments:
the command and arguments to run, and a string to print if
the V flag is not set (ie we are not being verbose).
By convention, the string printed is of the form
" NAME some args". Unfortunately to get nicely lined up
output all the strings have to agree about what column the
arguments should start in, which means that if we add a
new quiet-command usage which wants a slightly longer CMD
name then we either put up with misalignment or change
every quiet-command string.
Split the quiet-mode string into two, the "NAME" and
the "same args" part, and use printf(1) to format the
string automatically. This means we only need to change
one place if we want to support a longer maximum name.
In particular, we can now print 7-character names lined
up properly (they are needed for the OSX "SETTOOL" invocation).
Change all the uses of quiet-command to the new syntax.
(Any which are missed or inadvertently reintroduced
via later merges will result in slightly misformatted
quiet output rather than disaster.)
A few places in the pc-bios/ makefiles are updated to use
"BUILD", "SIGN" and "STRIP" rather than "Building",
"Signing" and "Stripping" for consistency and to keep them
below 7 characters. Module .mo links now print "LD" rather
than the nonstandard "LD -r".
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1475598441-27908-1-git-send-email-peter.maydell@linaro.org
Recent compilers can detect and inline manually-written bswap code,
but GCC 4.2.1 (the last GPLv2 version) cannot and generates really
awful code. Depending on how the compiler is configured, it might
also not want to generate bswap because it was not in i386. Using
asm is fine because TCG knows about bswap and all processors with
virtualization extensions also do.
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reproducer:
CFLAGS="-g3 -O0" ./configure --target-list=aarch64-softmmu,arm-softmmu --enable-vhost-net --enable-virtfs
Here CFLAGS ends up with "-O2 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 ... -g3 -O0"
and pc-bios/optionrom/Makefile forgets to add the -O2 it needs.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The various host OSes are irritatingly variable about the name
of the linker emulation we need to pass to ld's -m option to
build the i386 option ROMs. Instead of doing this via a
CONFIG ifdef, check in configure whether any of the emulation
names we know about will work and pass the right answer through
to the makefile. If we can't find one, we fall back to not trying
to build the option ROMs, in the same way we would for a non-x86
host platform.
This is in particular necessary to unbreak the build on OpenBSD,
since it wants a different answer to FreeBSD and we don't have
an existing CONFIG_ variable that distinguishes the two.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Sean Bruno <sbruno@freebsd.org>
Message-id: 1470672688-6754-1-git-send-email-peter.maydell@linaro.org
Two fixes are needed. First, mingw does not have -D_FORTIFY_SOURCE,
hence --enable-debug disables optimization. This is not acceptable
for ROMs, which should override CFLAGS to force inclusion of -O2.
Second, PE stores global constructors and destructors using the
following linker script snippet:
___CTOR_LIST__ = .; __CTOR_LIST__ = . ;
LONG (-1);*(.ctors); *(.ctor); *(SORT(.ctors.*)); LONG (0);
___DTOR_LIST__ = .; __DTOR_LIST__ = . ;
LONG (-1); *(.dtors); *(.dtor); *(SORT(.dtors.*)); LONG (0);
The LONG directives cause the .img files to be 16 bytes too large;
the recently added check to signrom.py catches this. To fix this,
replace -T and -e options with a linker script.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When calling make with a CFLAGS=.. argument, the -g/-O filter is not
applied, which may result with build failure with ASAN for example. It
could be solved with an 'override' directive on CFLAGS, but that would
actually prevent setting different CFLAGS manually.
Instead, filter the CFLAGS argument from the top-level Makefile (so
you could still call make with a different CFLAGS argument on a
rom/Makefile manually)
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20160805082421.21994-2-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Recent GCC compiles linuxboot_dma.c to 921 bytes, while CentOS 6 needs
1029 and clang needs 1527. Because the size of the ROM, rounded to the
next 512 bytes, must match, this causes the API to break between a <1K
ROM and one that is bigger.
We want to make the ROM 1.5 KB in size, but it's better to make clang
produce leaner ROMs, because currently it is worryingly close to the limit.
To fix this prevent clang's happy inlining (which -Os cannot prevent).
This only requires adding a noinline attribute.
Second, the patch makes sure that the ROM has enough padding to prevent
ABI breakage on different compilers. The size is now hardcoded in the file
that is passed to signrom.py, as was the case before commit 6f71b77
("scripts/signrom.py: Allow option ROM checksum script to write the size
header.", 2016-05-23); signrom.py however will still pad the input to
the requested size. This ensures that the padding goes beyond the
next multiple of 512 if necessary, and also avoids the need for
-fno-toplevel-reorder which clang doesn't support. signrom.py can then
error out if the requested size is too small for the actual size of the
compiled ROM.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The cc-option macro runs $(CC) in -S mode (generate assembly) to avoid a
pointless run of the assembler. However, this does not work when you want
to detect support for cc->as option passthrough. clang ignores -Wa unless
-c is provided, and exits successfully even if the -Wa,-32 option is not
supported.
Reported-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1469043409-14033-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This optionrom is based on linuxboot.S.
Signed-off-by: Marc Marí <markmb@redhat.com>
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <1464027093-24073-2-git-send-email-rjones@redhat.com>
[Add -fno-toplevel-reorder, support clang without -m16. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For clang before 3.5, -fno-integrated-as does not exist,
so the workaround in 5f6f0e27fb fails to build.
Use clang's default assembler for linux-user/safe-syscall.S,
and explicitly change to use the system assembler for the
option roms.
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Much of fw_cfg.h's contents is #ifndef NO_QEMU_PROTOS. This lets a
few places include it without satisfying the dependencies of the
suppressed code. If you somehow include it with NO_QEMU_PROTOS, any
future includes are ignored. Unnecessarily unclean.
Move the stuff not under NO_QEMU_PROTOS into its own header
fw_cfg_keys.h, and include it as appropriate. Tidy up the moved code
to please checkpatch.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Old kernels that used high memory only allowed the initrd to be in the
first 896MB of memory. If you load the initrd above, they complain
that "initrd extends beyond end of memory".
In order to fix this, while not breaking machines with small amounts
of memory fixed by cdebec5 (linuxboot: compute initrd loading address,
2014-10-06), we need to distinguish two cases. If pc.c placed the
initrd at end of memory, use the new algorithm based on the e801
memory map. If instead pc.c placed the initrd at the maximum address
specified by the bzImage, leave it there.
The only interesting part is that the low-memory info block is now
loaded very early, in real mode, and thus the 32-bit address has
to be converted into a real mode segment. The initrd address is
also patched in the info block before entering real mode, it is
simpler that way.
This fixes booting the RHEL4.8 32-bit installation image with 1GB
of RAM.
Cc: qemu-stable@nongnu.org
Cc: mst@redhat.com
Cc: jsnow@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Even though hw/i386/pc.c tries to compute a valid loading address for the
initrd, close to the top of RAM, this does not take into account other
data that is malloced into that memory by SeaBIOS.
Luckily we can easily look at the memory map to find out how much memory is
used up there. This patch places the initrd in the first four gigabytes,
below the first hole (as returned by INT 15h, AX=e801h).
Without this patch:
[ 0.000000] init_memory_mapping: [mem 0x07000000-0x07fdffff]
[ 0.000000] RAMDISK: [mem 0x0710a000-0x07fd7fff]
With this patch:
[ 0.000000] init_memory_mapping: [mem 0x07000000-0x07fdffff]
[ 0.000000] RAMDISK: [mem 0x07112000-0x07fdffff]
So linuxboot is able to use the 64k that were added as padding for
QEMU <= 2.1.
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This resolves the build issue with building the ROMs on OpenBSD on x86 archs.
As of OpenBSD 5.3 the compiler builds PIE binaries by default and thus the
whole OS/packages and so forth. The ROMs need to have PIE disabled.
Check in configure whether the compiler supports the flags for disabling
PIE, and if it does then use them for building the ROMs. This fixes the
following buildbot failure:
>From the OpenBSD buildbots..
Building optionrom/multiboot.img
ld: multiboot.o: relocation R_X86_64_16 can not be used when making a shared object; recompile with -fPIC
Signed-off by: Brad Smith <brad@comstyle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The upper_mem field of the Multiboot information struct doesn't really
contain the RAM size - 1 MB like we used to calculate it, but only the
memory from 1 MB up to the first (upper) memory hole.
In order to correctly retrieve this information, the multiboot ROM now
looks at the mmap it creates anyway and tries to find the size of
contiguous usable memory from 1 MB.
Drop the multiboot.c definition of lower_mem and upper_mem because both
are queried at runtime now.
Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Message-id: 1372018066-21822-3-git-send-email-mail@kevin-wolf.de
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
When the BIOS returns ebx = 0, the current entry is still valid and
needs to be included in the Multiboot memory map.
Fixing this meant that using bx as the entry index doesn't work any
more because it's 0 on the last entry (and it was SeaBIOS-specific
anyway), so the whole loop had to change a bit and should be more
generic as a result (ebx can be an arbitrary continuation number now,
and the entry size returned by the BIOS is used instead of hard-coding
20 bytes).
Signed-off-by: Kevin Wolf <mail@kevin-wolf.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Message-id: 1372018066-21822-2-git-send-email-mail@kevin-wolf.de
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Many of these should be cleaned up with proper qdev-/QOM-ification.
Right now there are many catch-all headers in include/hw/ARCH depending
on cpu.h, and this makes it necessary to compile these files per-target.
However, fixing this does not belong in these patches.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The e801 memory sizes in the multiboot structures hard-code the available
low memory to 640. However, the value should not include the size of the
EBDA. Fill the value in the option ROM, getting the size of low memory
from the BIOS.
Cc: Alexander Graf <agraf@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Now that we have a hard dependency on python anyway, we can replace the
slow shell script to calculate the option ROM checksum with a fast AND
portable python version. Tested both with python 2.7 and 3.1.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Use OPTION_ROM_START/END from the common header file, add comment to
init code.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Always add a byte before the final 512-bytes alignment to reserve the
space for the ROM checksum.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The CH registers is only written, never read. So we can remove these
operations and, in case of up_set_tpr, also the ECX push/pop.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This imports and builds the original VAPIC option ROM of qemu-kvm.
Its interaction with QEMU is described in the commit that introduces the
corresponding device model.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
The build process of optionroms spits out an "rm ..." line. Moreover, it
removes all .o files that can be handy for debugging purposes. So
disable automatic intermediate removal.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
accidently->accidentally
annother->another
choosen->chosen
consideres->considers
decriptor->descriptor
developement->development
paramter->parameter
preceed->precede
preceeding->preceding
priviledge->privilege
propogation->propagation
substraction->subtraction
throught->through
upto->up to
usefull->useful
Fix also grammar in posix-aio-compat.c
Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Currently linuxboot.bin and multiboot.bin option roms override int19
vector to intercept boot process. No sane option rom should do that.
Provide bev entry instead that will be called by BIOS if option rom
is selected for booting.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
signrom.sh has multiple bugs:
- the last byte is considered when calculating the existing checksum, but not
when computing the correction
- apprently the 'expr' expression overflows and produces incorrect results with
larger roms
- if the checksum happened to be zero, we calculated the correction byte to be
256
Instead of rewriting this in half a line of python, this patch fixes the bugs.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Commit dd4239d657 broke multiboot. It replaced the
instruction "rep insb (%dx), %es:(%edi)" by the binary output of
"addr32 rep insb (%dx), %es:(%di)".
Linuxboot calls the respective helper function in a code16 section. So the
original instruction was automatically translated to its "addr32" equivalent.
For multiboot, we're running in code32 so gcc didn't add the "addr32" which
breaks the instruction.
This patch splits that helper function in one which uses addr32 and one which
does not, so everyone's happy.
The good news is that nobody probably cared so far. The bundled multiboot.bin
binary was built before the change and is thus correct.
Please also put this patch into -stable.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
The gdt address calculation in linuxboot.bin is broken in two ways: first
it loads %cs into %eax, but that instruction leaves the high bits of %eax
undefined and we did not clear them. Secondly, we completely ignore the
incorrect %eax, and use the undefined %ebx instead.
With these issues fixed, linuxboot works again.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The vpath directive has two advantages over the VPATH variable:
1) it allows to skip searching of .o files; 2) the default semantics
are to append to the vpath, so there is no confusion between "VPATH=xyz"
and "VPATH+=xyz".
Since "vpath %.c %.h PATH" is not valid, I'm introducing a wrapper
macro to append one or more directories to the vpath.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The %gs segment that was used was not matching the comments.
I just moved the GDT descriptor on the stack instead.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>