A number of files were including dirent.h but not using any
of the functions it provides
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

A number of files were including assert.h but not using any
of the functions it provides
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Many source files have doubled words (eg "the the", "to to",
and so on). Most of these can simply be removed, but a couple
were actual mis-spellings (eg "to to" instead of "to do").
There was even one triple word score "to to to" :-)
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

A number of source files have statements accidentally
terminated by a double semicolon - eg 'foo = bar;;'.
This is harmless but a mistake none the less.

The tcg/ia64/tcg-target.c file is whitelisted because
it has valid use of ';;' in a comment containing assembly
code.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

We use muldiv64() to compute the time to wait:

    timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000);

but get_ticks_per_sec() is 10^9 (30 bit value) and timeout
is a 35 bit value.

Whereas muldiv64 is:

    uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)

So we loose 3 bits of timeout.

Swapping get_ticks_per_sec() and timeout fixes it.

We can also replace it by a multiplication by 30 ns,
but this changes PCI clock frequency from 33MHz to 33.333333MHz
and we need to do this on all the QEMU PCI devices (later...)
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Fix obvious typo in printed help for qemu-nbd.
Signed-off-by: NAndrey Korolyov <andrey@xdel.ru>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>

xen-2015-09-10

# gpg: Signature made Thu 10 Sep 2015 17:52:08 BST using RSA key ID 70E1AE90
# gpg: Good signature from "Stefano Stabellini <stefano.stabellini@eu.citrix.com>"

* remotes/sstabellini/tags/xen-2015-09-10-tag: (29 commits)
  xen/pt: Don't slurp wholesale the PCI configuration registers
  xen/pt: Check for return values for xen_host_pci_[get|set] in init
  xen/pt: Move bulk of xen_pt_unregister_device in its own routine.
  xen/pt: Make xen_pt_unregister_device idempotent
  xen/pt: Log xen_host_pci_get/set errors in MSI code.
  xen/pt: Log xen_host_pci_get in two init functions
  xen/pt: Remove XenPTReg->data field.
  xen/pt: Check if reg->init function sets the 'data' past the reg->size
  xen/pt: Sync up the dev.config and data values.
  xen/pt: Use xen_host_pci_get_[byte|word] instead of dev.config
  xen/pt: Use XEN_PT_LOG properly to guard against compiler warnings.
  xen/pt/msi: Add the register value when printing logging and error messages
  xen: use errno instead of rc for xc_domain_add_to_physmap
  xen/pt: xen_host_pci_config_read returns -errno, not -1 on failure
  xen/pt: Make xen_pt_msi_set_enable static
  xen/pt: Update comments with proper function name.
  xen/HVM: atomically access pointers in bufioreq handling
  xen-hvm: When using xc_domain_add_to_physmap also include errno when reporting
  xen, gfx passthrough: add opregion mapping
  xen, gfx passthrough: register host bridge specific to passthrough
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

Instead we have the emulation registers ->init functions which
consult the host values to see what the initial value should be
and they are responsible for populating the dev.config.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

and if we have failures we call xen_pt_destroy introduced in
'xen/pt: Move bulk of xen_pt_unregister_device in its own routine.'
and free all of the allocated structures.
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

This way we can call it if we fail during init.

This code movement introduces no changes.
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

To deal with xen_host_pci_[set|get]_ functions returning error values
and clearing ourselves in the init function we should make the
.exit (xen_pt_unregister_device) function be idempotent in case
the generic code starts calling .exit (or for fun does it before
calling .init!).
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

We seem to only use these functions when de-activating the
MSI - so just log errors.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

To help with troubleshooting in the field.
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

We do not want to have two entries to cache the guest configuration
registers: XenPTReg->data and dev.config. Instead we want to use
only the dev.config.

To do without much complications we rip out the ->data field
and replace it with an pointer to the dev.config. This way we
have the type-checking (uint8_t, uint16_t, etc) and as well
and pre-computed location.

Alternatively we could compute the offset in dev.config by
using the XenPTRRegInfo and XenPTRegGroup every time but
this way we have the pre-computed values.

This change also exposes some mis-use:
 - In 'xen_pt_status_reg_init' we used u32 for the Capabilities Pointer
   register, but said register is an an u16.
 - In 'xen_pt_msgdata_reg_write' we used u32 but should have only use u16.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

It should never happen, but in case it does (an developer adds
a new register and the 'init_val' expands past the register
size) we want to report. The code will only write up to
reg->size so there is no runtime danger of the register spilling
across other ones - however to catch this sort of thing
we still return an error.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

For a passthrough device we maintain a state of emulated
registers value contained within d->config. We also consult
the host registers (and apply ro and write masks) whenever
the guest access the registers. This is done in xen_pt_pci_write_config
and xen_pt_pci_read_config.

Also in this picture we call pci_default_write_config which
updates the d->config and if the d->config[PCI_COMMAND] register
has PCI_COMMAND_MEMORY (or PCI_COMMAND_IO) acts on those changes.

On startup the d->config[PCI_COMMAND] are the host values, not
what the guest initial values should be, which is exactly what
we do _not_ want to do for 64-bit BARs when the guest just wants
to read the size of the BAR. Huh you say?

To get the size of 64-bit memory space BARs,  the guest has
to calculate ((BAR[x] & 0xFFFFFFF0) + ((BAR[x+1] & 0xFFFFFFFF) << 32))
which means it has to do two writes of ~0 to BARx and BARx+1.

prior to this patch and with XSA120-addendum patch (Linux kernel)
the PCI_COMMAND register is copied from the host it can have
PCI_COMMAND_MEMORY bit set which means that QEMU will try to
update the hypervisor's P2M with BARx+1 value to ~0 (0xffffffff)
(to sync the guest state to host) instead of just having
xen_pt_pci_write_config and xen_pt_bar_reg_write apply the
proper masks and return the size to the guest.

To thwart this, this patch syncs up the host values with the
guest values taking into account the emu_mask (bit set means
we emulate, PCI_COMMAND_MEMORY and PCI_COMMAND_IO are set).
That is we copy the host values - masking out any bits which
we will emulate. Then merge it with the initial emulation register
values. Lastly this value is then copied both in
dev.config _and_ XenPTReg->data field.

There is also reg->size accounting taken into consideration
that ends up being used in patch.
 xen/pt: Check if reg->init function sets the 'data' past the reg->size

This fixes errors such as these:

(XEN) memory_map:add: dom2 gfn=fffe0 mfn=fbce0 nr=20
(DEBUG) 189 pci dev 04:0 BAR16 wrote ~0.
(DEBUG) 200 pci dev 04:0 BAR16 read 0x0fffe0004.
(XEN) memory_map:remove: dom2 gfn=fffe0 mfn=fbce0 nr=20
(DEBUG) 204 pci dev 04:0 BAR16 wrote 0x0fffe0004.
(DEBUG) 217 pci dev 04:0 BAR16 read upper 0x000000000.
(XEN) memory_map:add: dom2 gfn=ffffffff00000 mfn=fbce0 nr=20
(XEN) p2m.c:883:d0v0 p2m_set_entry failed! mfn=ffffffffffffffff rc:-22
(XEN) memory_map:fail: dom2 gfn=ffffffff00000 mfn=fbce0 nr=20 ret:-22
(XEN) memory_map:remove: dom2 gfn=ffffffff00000 mfn=fbce0 nr=20
(XEN) p2m.c:920:d0v0 gfn_to_mfn failed! gfn=ffffffff00000 type:4
(XEN) p2m.c:920:d0v0 gfn_to_mfn failed! gfn=ffffffff00001 type:4
..
(XEN) memory_map: error -22 removing dom2 access to [fbce0,fbcff]
(DEBUG) 222 pci dev 04:0 BAR16 read upper 0x0ffffffff.
(XEN) memory_map:remove: dom2 gfn=ffffffff00000 mfn=fbce0 nr=20
(XEN) memory_map: error -22 removing dom2 access to [fbce0,fbcff]

[The DEBUG is to illustate what the hvmloader was doing]

Also we swap from xen_host_pci_long to using xen_host_pci_get_[byte,word,long].

Otherwise we get:

xen_pt_config_reg_init: Offset 0x0004 mismatch! Emulated=0x0000, host=0x2300017, syncing to 0x2300014.
xen_pt_config_reg_init: Error: Offset 0x0004:0x2300014 expands past register size(2)!

which is not surprising. We read the value as an 32-bit (from host),
then operate it as a 16-bit - and the remainder is left unchanged.

We end up writing the value as 16-bit (so 0014) to dev.config
(as we use proper xen_set_host_[byte,word,long] so we don't spill
to other registers) but in XenPTReg->data it is as 32-bit (0x2300014)!

It is harmless as the read/write functions end up using an size mask
and never modify the bits past 16-bit (reg->size is 2).

This patch fixes the warnings by reading the value using the
proper size.

Note that the check for size is still left in-case the developer
sets bits past the reg->size in the ->init routines. The author
tried to fiddle with QEMU_BUILD_BUG to make this work but failed.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reported-by: NSander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

During init time we treat the dev.config area as a cache
of the host view. However during execution time we treat it
as guest view (by the generic PCI API). We need to sync Xen's
code to the generic PCI API view. This is the first step
by replacing all of the code that uses dev.config or
pci_get_[byte|word] to get host value to actually use the
xen_host_pci_get_[byte|word] functions.

Interestingly in 'xen_pt_ptr_reg_init' we also needed to swap
reg_field from uint32_t to uint8_t - since the access is only
for one byte not four bytes. We can split this as a seperate
patch however we would have to use a cast to thwart compiler
warnings in the meantime.

We also truncated 'flags' to 'flag' to make the code fit within
the 80 characters.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

error: On abort, report where the error was created

# gpg: Signature made Thu 10 Sep 2015 13:01:39 BST using RSA key ID EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>"

* remotes/armbru/tags/pull-error-2015-09-10:
  error: On abort, report where the error was created
  error: Revamp interface documentation
  error: error_set_errno() is unused, drop
  qga/vss-win32: Document the DLL requires non-null errp
  qga: Clean up unnecessarily dirty casts
  error: Make error_setg() a function
  error: De-duplicate code creating Error objects
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

If XEN_PT_LOGGING_ENABLED is enabled the XEN_PT_LOG macros start
using the first argument. Which means if within the function there
is only one user of the argument ('d') and XEN_PT_LOGGING_ENABLED
is not set, we get compiler warnings. This is not the case now
but with the "xen/pt: Use xen_host_pci_get_[byte|word] instead of dev.config"
we will hit - so this sync up the function to the rest of them.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

We would like to know what the MSI register value is to help
in troubleshooting in the field. As such modify the logging
logic to include such details in xen_pt_msgctrl_reg_write.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

In Xen 4.6 commit cd2f100f0f61b3f333d52d1737dd73f02daee592
"libxc: Fix do_memory_op to return negative value on errors"
made the libxc API less odd-ball: On errors, return value is
-1 and error code is in errno. On success the return value
is either 0 or an positive value.

Since we could be running with an old toolstack in which the
Exx value is in rc or the newer, we add an wrapper around
the xc_domain_add_to_physmap (called xen_xc_domain_add_to_physmap)
which will always return the EXX.

Xen 4.6 did not change the libxc functions mentioned (same parameters)
so we piggyback on the fact that Xen 4.6 has a new function:
commit 504ed2053362381ac01b98db9313454488b7db40 "tools/libxc: Expose
new hypercall xc_reserved_device_memory_map" and check for that.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Suggested-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

However the init routines assume that on errors the return
code is -1 (as the libxc API is) - while those xen_host_* routines follow
another paradigm - negative errno on return, 0 on success.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

As we do not use it outside our code.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

It has changed but the comments still refer to the old names.
Reviewed-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The number of slots per page being 511 (i.e. not a power of two) means
that the (32-bit) read and write indexes going beyond 2^32 will likely
disturb operation. The hypervisor side gets I/O req server creation
extended so we can indicate that we're using suitable atomic accesses
where needed, allowing it to atomically canonicalize both pointers when
both have gone through at least one cycle.

The Xen side counterpart (which is not a functional prereq to this
change, albeit a build one) went in already (commit b7007bc6f9).
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

.errors - as it will most likely have the proper error value.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

The OpRegion shouldn't be mapped 1:1 because the address in the host
can't be used in the guest directly.

This patch traps read and write access to the opregion of the Intel
GPU config space (offset 0xfc).

The original patch is from Jean Guyader <jean.guyader@eu.citrix.com>
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Just register that pci host bridge specific to passthrough.
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Currently we just register this isa bridge when we use IGD
passthrough in Xen side.
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Currently IGD drivers always need to access PCH by 1f.0. But we
don't want to poke that directly to get ID, and although in real
world different GPU should have different PCH. But actually the
different PCH DIDs likely map to different PCH SKUs. We do the
same thing for the GPU. For PCH, the different SKUs are going to
be all the same silicon design and implementation, just different
features turn on and off with fuses. The SW interfaces should be
consistent across all SKUs in a given family (eg LPT). But just
same features may not be supported.

Most of these different PCH features probably don't matter to the
Gfx driver, but obviously any difference in display port connections
will so it should be fine with any PCH in case of passthrough.

So currently use one PCH version, 0x8c4e, to cover all HSW(Haswell)
scenarios, 0x9cc3 for BDW(Broadwell).
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

Now we retrieve VGA bios like kvm stuff in qemu but we need to
fix Device Identification in case if its not matched with the
real IGD device since Seabios is always trying to compare this
ID to work out VGA BIOS.
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

basic gfx passthrough support:
- add a vga type for gfx passthrough
- register/unregister legacy VGA I/O ports and MMIOs for passthrough GFX
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Signed-off-by: NYang Zhang <yang.z.zhang@Intel.com>
Acked-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

We will try to reuse assign_dev_load_option_rom in xen side, and
especially its a good beginning to unify pci assign codes both on
kvm and xen in the future.

[Fix build for Windows]
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

Implement a pci host bridge specific to passthrough. Actually
this just inherits the standard one. And we also just expose
a minimal real host bridge pci configuration subset.

[Replace pread with lseek and read to fix Windows build]
Signed-off-by: NTiejun Chen <tiejun.chen@intel.com>
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>

This is particularly useful when we abort in error_propagate(),
because there the stack backtrace doesn't lead to where the error was
created.  Looks like this:

    Unexpected error in parse_block_error_action() at .../qemu/blockdev.c:322:
    qemu-system-x86_64: -drive if=none,werror=foo: 'foo' invalid write error action
    Aborted (core dumped)

Note: to get this example output, I monkey-patched drive_new() to pass
&error_abort to blockdev_init().

To keep the error handling boiler plate from growing even more, all
error_setFOO() become macros expanding into error_setFOO_internal()
with additional __FILE__, __LINE__, __func__ arguments.  Not exactly
pretty, but it works.

The macro trickery breaks down when you take the address of an
error_setFOO().  Fortunately, we do that in just one place: qemu-ga's
Windows VSS provider and requester DLL wants to call
error_setg_win32() through a function pointer "to avoid linking glib
to the DLL".  Use error_setg_win32_internal() there.  The use of the
function pointer is already wrapped in a macro, so the churn isn't
bad.

Code size increases by some 35KiB for me (0.7%).  Tolerable.  Could be
less if we passed relative rather than absolute source file names to
the compiler, or forwent reporting __func__.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Acked-by: NLaszlo Ersek <lersek@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

requester.cpp uses this pattern to receive an error and pass it on to
the caller (err_is_set() macro peeled off for clarity):

    ... code that may set errset->errp ...
    if (errset->errp && *errset->errp) {
        ... handle error ...
    }

This breaks when errset->errp is null.  As far as I can tell, it
currently isn't, so this is merely fragile, not actually broken.

The robust way to do this is to receive the error in a local variable,
then propagate it up, like this:

    Error *err = NULL;

    ... code that may set err ...
    if (err)
        ... handle error ...
        error_propagate(errset->errp, err);
    }

See also commit 5e54769c, 0f230bf7, a903f40c.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

qga_vss_fsfreeze() casts error_set_win32() from

    void (*)(Error **, int, ErrorClass, const char *, ...)

to

    void (*)(void **, int, int, const char *, ...)

The result is later called.  Since the two types are not compatible,
the call is undefined behavior.  It works in practice anyway.

However, there's no real need for trickery here.  Clean it up as
follows:

* Declare struct Error, and fix the first parameter.

* Switch to error_setg_win32().  This gets rid of the troublesome
  ErrorClass parameter.  Requires converting error_setg_win32() from
  macro to function, but that's trivially easy, because this is the
  only user of error_set_win32().
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>