Although ACPI tables come from a system BIOS on real hw,
it makes sense that the ACPI tables are coupled with the
virtual machine, since they have to abstract the x86 machine to
the OS's.
This is widely desired as a way to avoid the churn
and proliferation of QEMU-specific interfaces
associated with ACPI tables in bios code.
Notes:
As BIOS can reprogram devices prior to loading
ACPI tables, we pre-format ACPI tables but defer loading
hardware configuration there until tables are loaded.
The code structure was intentionally kept as close
to the seabios original as possible, to simplify
comparison and making sure we didn't lose anything
in translation.
Minor code duplication results, to help ensure there are no functional
regressions, I think it's better to merge it like this and do more code
changes in follow-up patches.
Cross-version compatibility concerns have been addressed:
ACPI tables are exposed to guest as FW_CFG entries.
When running with -M 1.5 and older, this patch disables ACPI
table generation, and doesn't expose ACPI
tables to guest.
As table content is likely to change over time,
the following measures are taken to simplify
cross-version migration:
- All tables besides the RSDP are packed in a single FW CFG entry.
This entry size is currently 23K. We round it up to 64K
to avoid too much churn there.
- Tables are placed in special ROM blob (not mapped into guest memory)
which is automatically migrated together with the guest, same
as BIOS code.
- Offsets where hardware configuration is loaded in ACPI tables
are also migrated, this is in case future ACPI changes make us
rearrange the tables in memory.
This patch reuses some code from SeaBIOS, which was originally under
LGPLv2 and then relicensed to GPLv3 or LGPLv3, in QEMU under GPLv2+. This
relicensing has been acked by all contributors that had contributed to the
code since the v2->v3 relicense. ACKs approving the v2+ relicensing are
listed below. The list might include ACKs from people not holding
copyright on any parts of the reused code, but it's better to err on the
side of caution and include them.
Each one of the listed people agreed to the following:
> If you allow the use of your contribution in QEMU under the
> terms of GPLv2 or later as proposed by this patch,
> please respond to this mail including the line:
>
> Acked-by: Name <email address>
This adds APIs that will be used to fill in
acpi tables, implemented using QOM,
to various ich9 components.
Some information is still missing in QOM,
so we fall back on lookups by type instead.
This adds APIs that will be used to fill in guest acpi tables.
Some required information is still lacking in QOM, so we
fall back on lookups by type and returning explicit types.
This adds a dynamic bios linker/loader.
This will be used by acpi table generation
code to:
- load each table in the appropriate memory segment
- link tables to each other
- fix up checksums after said linking
Detect presence of IASL compiler and use it
to process ASL source. If not there, use pre-compiled
files in-tree. Add script to update the in-tree files.
Note: distros are known to silently update iasl
so detect correct iasl flags for the installed version on each run as
opposed to at configure time.
Note:
This patch reuses some code from SeaBIOS, which was originally under
LGPLv2 and then relicensed to GPLv3 or LGPLv3, in QEMU under GPLv2+. This
relicensing has been acked by all contributors that had contributed to the
code since the v2->v3 relicense. ACKs approving the v2+ relicensing are
listed below. The list might include ACKs from people not holding
copyright on any parts of the reused code, but it's better to err on the
side of caution and include them.
Each one of the listed people agreed to the following:
> If you allow the use of your contribution in QEMU under the
> terms of GPLv2 or later as proposed by this patch,
> please respond to this mail including the line:
>
> Acked-by: Name <email address>
hw/pcie: AER and hot-plug events must use device's interrupt
The fields hpev_intx and aer_intx were removed because
both AER and hot-plug events must use device's interrupt.
Assert/deassert interrupts using pci irq wrappers instead.
hw/pci: add pci wrappers for allocating and asserting irqs
Interrupt pin is selected and saved into PCI_INTERRUPT_PIN
register during device initialization. Devices should not call
directly qemu_set_irq and specify the INTx pin on each call.
Added pci_* wrappers to replace qemu_set_irq, qemu_irq_raise,
qemu_irq_lower and qemu_irq_pulse, setting the irq
based on PCI_INTERRUPT_PIN.
Added pci_allocate_irq wrapper to be used by devices that
still need PCIDevice infrastructure to assert irqs.
Renamed a static method which was named already pci_set_irq.
A MemoryRegion with negative priority was created and
it spans over all the pci address space.
It "intercepts" the accesses to unassigned pci
address space and will follow the pci spec:
1. returns -1 on read
2. does nothing on write
Note: setting the RECEIVED MASTER ABORT bit in the STATUS register
of the device that initiated the transaction will be
implemented in another series
docs/memory: Explictly state that MemoryRegion priority is signed
When memory regions overlap, priority can be used to specify
which of them takes priority. By making the priority values signed
rather than unsigned, we make it more convenient to implement
a situation where one "background" region should appear only
where no other region exists: rather than having to explicitly
specify a high priority for all the other regions, we can let them take
the default (zero) priority and specify a negative priority for the
background region.
memory: Change MemoryRegion priorities from unsigned to signed
When memory regions overlap, priority can be used to specify
which of them takes priority. By making the priority values signed
rather than unsigned, we make it more convenient to implement
a situation where one "background" region should appear only
where no other region exists: rather than having to explicitly
specify a high priority for all the other regions, we can let them take
the default (zero) priority and specify a negative priority for the
background region.
smbios: Make multiple -smbios type= accumulate sanely
Currently, -smbios type=T,NAME=VAL,... adds one field (T,NAME) with
value VAL to fw_cfg for each unique NAME. If NAME occurs multiple
times, the last one's VAL is used (before the QemuOpts conversion, the
first one was used).
Multiple -smbios can add multiple fields with the same (T, NAME).
SeaBIOS reads all of them from fw_cfg, but uses only the first field
(T, NAME). The others are ignored.
"First one wins, subsequent ones get ignored silently" isn't nice. We
commonly let the last option win. Useful, because it lets you
-readconfig first, then selectively override with command line
options.
Clean up -smbios to work the common way. Accumulate the settings,
with later ones overwriting earlier ones. Put the result into fw_cfg
(no more useless duplicates).
Bonus cleanup: qemu_uuid_parse() no longer sets SMBIOS system uuid by
side effect.
smbios: Improve diagnostics for conflicting entries
We allow either tables or fields for the same type. Makes sense,
because SeaBIOS uses fields only when no tables are present.
We do this by searching the SMBIOS blob for a previously added table
or field. Error messages look like this:
qemu-system-x86_64: -smbios type=1,serial=42: SMBIOS type 1 table already defined, cannot add field
User needs to know that "table" is defined by -smbios file=..., and
"field" by -smbios type=...
Instead of searching the blob, record additions of interest, and check
that. Simpler, and makes better error messages possible:
qemu-system-x86_64: -smbios file=smbios_type_1.bin: Can't mix file= and type= for same type
qemu-system-x86_64: -smbios type=1,serial=42,serial=99: This is the conflicting setting
So that it can be set in config file for -readconfig.
This tightens parsing of -smbios, and makes it more consistent with
other options: unknown parameters are rejected, numbers with trailing
junk are rejected, when a parameter is given multiple times, last
rather than first wins, ...
This check is useless, as bigger addresses will be ignored when
added to 'io' MemoryRegion, which has a size of 64K.
However, some architectures don't use the 'io' MemoryRegion, like
the alpha and versatile platforms. They create a PCI I/O region
bigger than 64K, so let them handle PCI I/O BARs in the higher range.
Anthony Liguori [Wed, 11 Sep 2013 19:46:52 +0000 (14:46 -0500)]
Merge remote-tracking branch 'pmaydell/tags/pull-target-arm-20130910' into staging
ARM queue:
* aarch64 preparation patchset (excluding the defconfigs, so this
doesn't actually enable the new targets yet)
* minor bugfixes and cleanups
* disable "-cpu any" in system emulation mode
* fix ARMv7M stack alignment on reset
# gpg: Signature made Tue 10 Sep 2013 01:46:11 PM CDT using RSA key ID 14360CDE
# gpg: Can't check signature: public key not found
# By Alexander Graf (13) and others
# Via Peter Maydell
* pmaydell/tags/pull-target-arm-20130910: (28 commits)
configure: Add handling code for AArch64 targets
linux-user: Add AArch64 support
linux-user: Allow targets to specify a minimum uname release
linux-user: Add AArch64 termbits.h definitions
linux-user: Implement cpu_set_tls() and cpu_clone_regs() for AArch64
linux-user: Make sure NWFPE code is 32 bit ARM only
linux-user: Add signal handling for AArch64
linux-user: Fix up AArch64 syscall handlers
linux-user: Add syscall number definitions for AArch64
linux-user: Add cpu loop for AArch64
linux-user: Don't treat AArch64 cpu names specially
target-arm: Add AArch64 gdbstub support
target-arm: Add AArch64 translation stub
target-arm: Prepare translation for AArch64 code
target-arm: Disable 32 bit CPUs in 64 bit linux-user builds
target-arm: Add new AArch64CPUInfo base class and subclasses
target-arm: Pass DisasContext* to gen_set_pc_im()
target-arm: Fix target_ulong/uint32_t confusions
target-arm: Export cpu_env
target-arm: Extract the disas struct to a header file
...
Anthony Liguori [Wed, 11 Sep 2013 19:46:26 +0000 (14:46 -0500)]
Merge remote-tracking branch 'spice/spice.v73' into staging
# By Gerd Hoffmann (2) and Christophe Fergeau (1)
# Via Gerd Hoffmann
* spice/spice.v73:
qxl: fix local renderer
qxl: trace io port name
spice-core: Use g_strdup_printf instead of snprintf
Anthony Liguori [Wed, 11 Sep 2013 19:46:21 +0000 (14:46 -0500)]
Merge remote-tracking branch 'kraxel/usb.89' into staging
# By Gerd Hoffmann (2) and Miroslav Rezanina (2)
# Via Gerd Hoffmann
* kraxel/usb.89:
ehci: save device pointer in EHCIState
Remove dev-bluetooth.c dependency from vl.c
Preparation for usb-bt-dongle conditional build
usb: sanity check setup_index+setup_len in post_load
Anthony Liguori [Wed, 11 Sep 2013 19:46:08 +0000 (14:46 -0500)]
Merge remote-tracking branch 'mdroth/qga-pull-2013-9-9' into staging
# By Tomoki Sekiyama (10) and Paul Burton (1)
# Via Michael Roth
* mdroth/qga-pull-2013-9-9:
QMP/qemu-ga-client: Make timeout longer for guest-fsfreeze-freeze command
qemu-ga: Install Windows VSS provider on `qemu-ga -s install'
qemu-ga: Call Windows VSS requester in fsfreeze command handler
qemu-ga: Add Windows VSS provider and requester as DLL
error: Add error_set_win32 and error_setg_win32
qemu-ga: Add configure options to specify path to Windows/VSS SDK
Add a script to extract VSS SDK headers on POSIX system
checkpatch.pl: Check .cpp files
Add c++ keywords to QAPI helper script
configure: Support configuring C++ compiler
mips_malta: support up to 2GiB RAM
Anthony Liguori [Wed, 11 Sep 2013 19:45:37 +0000 (14:45 -0500)]
Merge remote-tracking branch 'stefanha/block' into staging
# By Paolo Bonzini (21) and others
# Via Stefan Hajnoczi
* stefanha/block: (42 commits)
qemu-iotests: Fixed test case 026
qemu-iotests: Whitespace cleanup
dataplane: Fix startup race.
block: look for zero blocks in bs->file
block: add default get_block_status implementation for protocols
raw-posix: report unwritten extents as zero
raw-posix: return get_block_status data and flags
docs, qapi: document qemu-img map
qemu-img: add a "map" subcommand
block: return BDRV_BLOCK_ZERO past end of backing file
block: use bdrv_has_zero_init to return BDRV_BLOCK_ZERO
block: return get_block_status data and flags for formats
block: define get_block_status return value
block: introduce bdrv_get_block_status API
block: make bdrv_has_zero_init return false for copy-on-write-images
qemu-img: always probe the input image for allocated sectors
block: expect errors from bdrv_co_is_allocated
block: remove bdrv_is_allocated_above/bdrv_co_is_allocated_above distinction
block: do not use ->total_sectors in bdrv_co_is_allocated
block: make bdrv_co_is_allocated static
...
Anthony Liguori [Wed, 11 Sep 2013 19:45:18 +0000 (14:45 -0500)]
Merge remote-tracking branch 'stefanha/net' into staging
# By Brad Smith (2) and others
# Via Stefan Hajnoczi
* stefanha/net:
ne2000: mark I/O as LITTLE_ENDIAN
vmxnet3: Eliminate __packed redefined warning
e1000: add interrupt mitigation support
net: Rename send_queue to incoming_queue
tap: Use numbered tap/tun devices on all *BSD OS's
Alexander Graf [Tue, 3 Sep 2013 19:12:22 +0000 (20:12 +0100)]
configure: Add handling code for AArch64 targets
Add the necessary code to configure to handle AArch64 as a target
CPU (we already have some code for supporting it as host). Note
that this doesn't enable the AArch64 targets yet.
Peter Maydell [Tue, 3 Sep 2013 19:12:20 +0000 (20:12 +0100)]
linux-user: Allow targets to specify a minimum uname release
For newer target architectures, glibc can be picky about the kernel
version: for example, it will not run on an aarch64 system unless
the kernel reports itself as at least 3.8.0. Accommodate this by
enhancing the existing support for faking the kernel version so
that each target can optionally specify a minimum version: if
the user doesn't force a specific fake version then we will override
with the minimum required version only if the real host kernel
version is insufficient.
Use this facility to let aarch64 report a minimum of 3.8.0.
Peter Maydell [Tue, 3 Sep 2013 19:12:17 +0000 (20:12 +0100)]
linux-user: Make sure NWFPE code is 32 bit ARM only
On ARM, linux-user emulation includes NWFPE support for emulating the
ancient FPA floating point coprocessor. This has long since been
superseded by VFP and is only required for legacy binaries. The
AArch64 linux-user target doesn't compile in NWFPE support, so make
sure the relevant code is protected by suitable ifdefs.
Alexander Graf [Tue, 3 Sep 2013 19:12:15 +0000 (20:12 +0100)]
linux-user: Fix up AArch64 syscall handlers
Some syscall handlers have special code for ARM enabled that we don't
need on AArch64. Exclude AArch64 in those cases. In other places we
can share struct definitions with other targets or have to provide our
own.
With this patch applied, most syscall definitions in linux-user should
be sound for AArch64.
Alexander Graf [Tue, 3 Sep 2013 19:12:14 +0000 (20:12 +0100)]
linux-user: Add syscall number definitions for AArch64
The AArch64 syscall definitions are all publicly available in the Linux
kernel. Let's add them to our linux-user emulation target, so that we
can easily handle AArch64 syscalls.
Peter Maydell [Tue, 3 Sep 2013 19:12:13 +0000 (20:12 +0100)]
linux-user: Add cpu loop for AArch64
Add the main linux-user cpu loop for AArch64. Since AArch64
has a different system call interface, doesn't need to worry
about FPA emulation and may in the future keep the prefetch/data
abort information in different system registers, it's simplest
just to use a completely separate loop from the 32 bit ARM
target, rather than peppering it with ifdefs.
Alexander Graf [Tue, 3 Sep 2013 19:12:12 +0000 (20:12 +0100)]
linux-user: Don't treat AArch64 cpu names specially
32-bit ARM has a lot of different names for different types of CPUs it supports.
On AArch64, we don't have this, so we really don't want to execute the 32-bit
logic. Stub it out for AArch64 linux-user guests.
Alexander Graf [Tue, 3 Sep 2013 19:12:10 +0000 (20:12 +0100)]
target-arm: Add AArch64 translation stub
We should translate AArch64 mode separately from AArch32 mode. In AArch64 mode,
registers look vastly different, instruction encoding is completely different,
basically the system turns into a different machine.
So let's do a simple if() in translate.c to decide whether we can handle the
current code in the legacy AArch32 code or in the new AArch64 code.
So far, the translation always complains about unallocated instructions. There
is no emulator functionality in this patch!
Signed-off-by: Alexander Graf <[email protected]> Signed-off-by: John Rigby <[email protected]> Signed-off-by: Peter Maydell <[email protected]>
Message-id: 1378235544[email protected]
Message-id: 1368505980[email protected]
[PMM:
* provide no-op versions of a64 functions ifndef TARGET_AARCH64;
this lets us avoid #ifdefs in translate.c
* insert the missing call to disas_a64_insn()
* stash the insn in the DisasContext rather than reloading it in
real_unallocated_encoding()
] Signed-off-by: Peter Maydell <[email protected]>
Alexander Graf [Tue, 3 Sep 2013 19:12:09 +0000 (20:12 +0100)]
target-arm: Prepare translation for AArch64 code
This patch adds all the prerequisites for AArch64 support that didn't
fit into split up patches. It extends important bits in the core cpu
headers to also take AArch64 mode into account.
Add new ARM_TBFLAG_AARCH64_STATE translation buffer flag
indicate an ARMv8 cpu running in aarch64 mode vs aarch32 mode.
Signed-off-by: Alexander Graf <[email protected]> Signed-off-by: John Rigby <[email protected]> Signed-off-by: Peter Maydell <[email protected]>
Message-id: 1378235544[email protected]
Message-id: 1368505980[email protected]
[PMM:
* rearranged tbflags so AArch64? is bit 31 and if it is set then
30..0 are freely available for whatever makes most sense for that mode
* added version bump since we change VFP migration state
* added a comment about how VFP/Neon register state works
* physical address space is 48 bits, not 64
* added ARM_FEATURE_AARCH64 flag to identify 64-bit capable CPUs
] Signed-off-by: Peter Maydell <[email protected]>
Peter Maydell [Tue, 3 Sep 2013 19:12:08 +0000 (20:12 +0100)]
target-arm: Disable 32 bit CPUs in 64 bit linux-user builds
If we're building aarch64-linux-user then the 32 bit CPUs are
all unwanted, because they can't possibly execute the 64 bit
binaries we will be running; disable them.
Peter Maydell [Tue, 3 Sep 2013 19:12:06 +0000 (20:12 +0100)]
target-arm: Pass DisasContext* to gen_set_pc_im()
We want gen_set_pc_im() to work for both AArch64 and AArch32, but
to do this we'll need the DisasContext* so we can tell which mode
we're in, so pass it in as a parameter.
Peter Maydell [Tue, 3 Sep 2013 19:12:02 +0000 (20:12 +0100)]
target-arm: Abstract out load/store from a vaddr in AArch32
AArch32 code (ie traditional 32 bit world) expects to be
able to pass a vaddr in a TCGv_i32. However when QEMU is
compiled with TARGET_LONG_BITS=32 the TCG load/store
functions take a TCGv_i64. Abstract out load/store with
a 32 bit vaddr so we have a place to put the zero extension
of the vaddr and the extension/truncation of the data value.
Apart from the function definitions most of this patch is
a simple s/tcg_gen_qemu_/gen_aa32_/.
Peter Maydell [Tue, 10 Sep 2013 18:09:33 +0000 (19:09 +0100)]
abitypes.h: Remove incorrect ARM ABI_LLONG_ALIGNMENT
The ARM EABI specifies that 64 bit integers should be
8 aligned; remove our incorrect setting of 4 alignment.
This has no actual effect since it only set the alignment
for the 'abi_ullong' and 'abi_llong' types, which are used
only inside code which is MIPS-specific, but it will
avoid problems later if we use the types elsewhere.
Peter Maydell [Tue, 10 Sep 2013 18:09:33 +0000 (19:09 +0100)]
pl110: Clarify comment about PL110 ID on VersatilePB
Clarify a comment about the ID register value presented by
the PL110 variant present on the VersatilePB board (based
on testing what the actual hardware does), to indicate that
this is not an error in our emulation, and to remove an #if-0.
Sebastian Ottlik [Tue, 10 Sep 2013 18:09:32 +0000 (19:09 +0100)]
target-arm: fix ARMv7M stack alignment on reset
When the initial SP is loaded from the vector table on ARMv7M systems the two
least significant bits are ignored as the stack is always aligned at a four byte
boundary (see ARM DDI 0403C, B1.4.1 and B1.5.5). So far QEMU did not ignore
these bits leading to a stack alignment inconsitent with real hardware for
binaries that rely on this behaviour. This patch fixes this issue by masking the
two least significant bits when loading the SP.
Peter Maydell [Tue, 10 Sep 2013 18:09:32 +0000 (19:09 +0100)]
target-arm: Avoid "1 << 31" undefined behaviour
Avoid the undefined behaviour of "1 << 31" by using 1U to make
the shift be of an unsigned value rather than shifting into the
sign bit of a signed integer. For consistency, we make all the
CPSR_* constants unsigned, though the only one which triggers
undefined behaviour is CPSR_N.
Peter Maydell [Tue, 10 Sep 2013 18:09:32 +0000 (19:09 +0100)]
target-arm: Use sextract32() in branch decode
In the decode of ARM B and BL insns, swap the order of the
"append 2 implicit zeros to imm24" and the sign extend, and
use the new sextract32() utility function to do the latter.
This avoids a direct dependency on the undefined C behaviour
of shifting into the sign bit of an integer.
Peter Maydell [Tue, 10 Sep 2013 18:09:32 +0000 (19:09 +0100)]
target-arm: Make '-cpu any' available in linux-user mode only
Make the 'any' CPU for target-arm available only in linux-user mode.
The ARM target provides a CPU named "any", which turns on support for
all user-level instruction set extensions we know about. This is
intended for linux-user emulation mode, where it is the default CPU type.
It makes no sense to try to use this for system emulation, since we don't
initialize it with any system-level information like feature register
values or implementation specific cp15 registers. (Unsurprisingly, some
boards won't boot at all, though you might get lucky in some cases where
the guest doesn't happen to prod things that aren't there.)
Prevent users from making this command line error by removing the
CPU definition from the softmmu build.
Cole Robinson [Sat, 31 Aug 2013 22:36:17 +0000 (18:36 -0400)]
qapi-types.py: Fix enum struct sizes on i686
Unlike other list types, enum wasn't adding any padding, which caused
a mismatch between the generated struct size and GenericList struct
size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21
This crashed qemu if calling qmp query-tpm-types for example, which
upsets libvirt capabilities probing. Reproducer on i686:
To allow disable usb-bt-dongle device using CONFIG_BLUETOOTH option, some of
functions in vl.c file has to be made accessible in dev-bluetooth.c. This is
pure code moving.
The local spice renderer assumes the primary surface is located at the
start of the "ram" bar. This used to be a requirement in qxl hardware
revision 1. In revision 2+ this is relaxed. Nevertheless guest drivers
continued to use the traditional location, for historical and backward
compatibility reasons. The qxl kms driver doesn't though as it depends
on qxl revision 4+ anyway.
Result is that local rendering is hosed for recent linux guests, you'll
get pixel garbage with non-spice ui (gtk, sdl, vnc) and when doing
screendumps. Fix that by doing a proper mapping of the guest-specified
memory location.
Tomoki Sekiyama [Wed, 7 Aug 2013 15:40:39 +0000 (11:40 -0400)]
QMP/qemu-ga-client: Make timeout longer for guest-fsfreeze-freeze command
guest-fsfreeze-freeze command can take longer than 3 seconds when heavy
disk I/O is running. To avoid unexpected timeout, this changes the timeout
to 60 seconds (timeout of pre-commit phase of VSS).
Tomoki Sekiyama [Wed, 7 Aug 2013 15:40:32 +0000 (11:40 -0400)]
qemu-ga: Install Windows VSS provider on `qemu-ga -s install'
Register QGA VSS provider library into Windows when qemu-ga is installed as
Windows service ('-s install' option). It is deregistered when the service
is uninstalled ('-s uninstall' option).
Tomoki Sekiyama [Wed, 7 Aug 2013 15:40:25 +0000 (11:40 -0400)]
qemu-ga: Call Windows VSS requester in fsfreeze command handler
Support guest-fsfreeze-freeze and guest-fsfreeze-thaw commands for Windows
guests. When fsfreeze command is issued, it calls the VSS requester to
freeze filesystems and applications. On thaw command, it again tells the VSS
requester to thaw them.
This also adds calling of initialize functions for the VSS requester.
Tomoki Sekiyama [Wed, 7 Aug 2013 15:40:18 +0000 (11:40 -0400)]
qemu-ga: Add Windows VSS provider and requester as DLL
Adds VSS provider and requester as a qga-vss.dll, which is loaded by
Windows VSS service as well as by qemu-ga.
"provider.cpp" implements a basic stub of a software VSS provider.
Currently, this module only relays a frozen event from VSS service to the
agent, and thaw event from the agent to VSS service, to block VSS process
to keep the system frozen while snapshots are taken at the host.
To register the provider to the guest system as COM+ application, the type
library (.tlb) for qga-vss.dll is required. To build it from COM IDL (.idl),
VisualC++, MIDL and stdole2.tlb in Windows SDK are required. This patch also
adds pre-compiled .tlb file in the repository in order to enable
cross-compile qemu-ga.exe for Windows with VSS support.
"requester.cpp" provides the VSS requester to kick the VSS snapshot process.
Qemu-ga.exe works without the DLL, although fsfreeze features are disabled.
These functions are only supported in Windows 2003 or later. In older
systems, fsfreeze features are disabled.
In several versions of Windows which don't support attribute
VSS_VOLSNAP_ATTR_NO_AUTORECOVERY, DoSnapshotSet fails with error
VSS_E_OBJECT_NOT_FOUND. In this patch, we just ignore this error.
To solve this fundamentally, we need a framework to handle mount writable
snapshot on guests, which is required by VSS auto-recovery feature
(cleanup phase after a snapshot is taken).