Current upstream NBD documents that requests have a 16-bit flags,
followed by a 16-bit type integer; although older versions mentioned
only a 32-bit field with masking to find flags. Since the protocol
is in network order (big-endian over the wire), the ABI is unchanged;
but dealing with the flags as a separate field rather than masking
will make it easier to add support for upcoming NBD extensions that
increase the number of both flags and commands.
Improve some comments in nbd.h based on the current upstream
NBD protocol (https://github.com/yoe/nbd/blob/master/doc/proto.md),
and touch some nearby code to keep checkpatch.pl happy.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-3-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The NBD protocol allows servers to advertise a human-readable
description alongside an export name during NBD_OPT_LIST. Add
an option to pass through the user's string to the NBD client.
Doing this also makes it easier to test commit 200650d4, which
is the client counterpart of receiving the description.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1476469998-28592-2-git-send-email-eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
If the memory backend file is not large enough to hold the required 'size',
Qemu will report error and exit.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20161027042300.5929-3-haozhong.zhang@intel.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20161102010551.2723-1-haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
For '-object memory-backend-file,mem-path=foo,size=xyz', if the size of
file 'foo' does not match the given size 'xyz', the current QEMU will
truncate the file to the given size, which may corrupt the existing data
in that file. To avoid such data corruption, this patch disables
truncating non-empty backend files.
Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Message-Id: <20161027042300.5929-2-haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Implement error_vprintf to send the output of error_report to
the test log. This silences test-vmstate.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477326663-67817-3-git-send-email-pbonzini@redhat.com>
Leave the implementation of error_vprintf and error_vprintf_unless_qmp
(the latter now trivially wrapped by error_printf_unless_qmp) to
libqemustub.a and monitor.c. This has two advantages: it lets us
remove the monitor_printf and monitor_vprintf stubs, and it lets
tests provide a different implementation of the functions that uses
g_test_message.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1477326663-67817-2-git-send-email-pbonzini@redhat.com>
NBD is using the CoMutex in a way that wasn't anticipated. For example, if there are
N(N=26, MAX_NBD_REQUESTS=16) nbd write requests, so we will invoke nbd_client_co_pwritev
N times.
----------------------------------------------------------------------------------------
time request Actions
1 1 in_flight=1, Coroutine=C1
2 2 in_flight=2, Coroutine=C2
...
15 15 in_flight=15, Coroutine=C15
16 16 in_flight=16, Coroutine=C16, free_sema->holder=C16, mutex->locked=true
17 17 in_flight=16, Coroutine=C17, queue C17 into free_sema->queue
18 18 in_flight=16, Coroutine=C18, queue C18 into free_sema->queue
...
26 N in_flight=16, Coroutine=C26, queue C26 into free_sema->queue
----------------------------------------------------------------------------------------
Once nbd client recieves request No.16' reply, we will re-enter C16. It's ok, because
it's equal to 'free_sema->holder'.
----------------------------------------------------------------------------------------
time request Actions
27 16 in_flight=15, Coroutine=C16, free_sema->holder=C16, mutex->locked=false
----------------------------------------------------------------------------------------
Then nbd_coroutine_end invokes qemu_co_mutex_unlock what will pop coroutines from
free_sema->queue's head and enter C17. More free_sema->holder is C17 now.
----------------------------------------------------------------------------------------
time request Actions
28 17 in_flight=16, Coroutine=C17, free_sema->holder=C17, mutex->locked=true
----------------------------------------------------------------------------------------
In above scenario, we only recieves request No.16' reply. As time goes by, nbd client will
almostly recieves replies from requests 1 to 15 rather than request 17 who owns C17. In this
case, we will encounter assert "mutex->holder == self" failed since Kevin's commit 0e438cdc
"coroutine: Let CoMutex remember who holds it". For example, if nbd client recieves request
No.15' reply, qemu will stop unexpectedly:
----------------------------------------------------------------------------------------
time request Actions
29 15(most case) in_flight=15, Coroutine=C15, free_sema->holder=C17, mutex->locked=false
----------------------------------------------------------------------------------------
Per Paolo's suggestion "The simplest fix is to change it to CoQueue, which is like a condition
variable", this patch replaces CoMutex with CoQueue.
Cc: Wen Congyang <wency@cn.fujitsu.com>
Reported-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Message-Id: <1476267508-19499-1-git-send-email-xiecl.fnst@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Avoid triggering on
typedef struct BlockJobDriver BlockJobDriver;
or
struct BlockJobDriver {
Cc: John Snow <jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
breaking QEMU.
-----BEGIN PGP SIGNATURE-----
iEYEABECAAYFAlgYe/IACgkQAvw66wEB28KKBwCfQqbDrsJrP321utoF1F5C7dWl
ENsAoKOVLRq8VEv3fI50dPx2JsMiqlBx
=M7GK
-----END PGP SIGNATURE-----
Merge remote-tracking branch 'remotes/gkurz/tags/for-upstream' into staging
This pull request mostly contains some more fixes to prevent buggy guests from
breaking QEMU.
# gpg: Signature made Tue 01 Nov 2016 11:26:42 GMT
# gpg: using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg: aka "Greg Kurz <groug@free.fr>"
# gpg: aka "Greg Kurz <gkurz@fr.ibm.com>"
# gpg: aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg: aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg: aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg: aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894 DBA2 02FC 3AEB 0101 DBC2
* remotes/gkurz/tags/for-upstream:
9pfs: drop excessive error message from virtfs_reset()
9pfs: don't BUG_ON() if fid is already opened
9pfs: xattrcreate requires non-opened fids
9pfs: limit xattr size in xattrcreate
9pfs: fix integer overflow issue in xattr read/write
9pfs: convert 'len/copied_len' field in V9fsXattr to the type of uint64_t
9pfs: add xattrwalk_fid field in V9fsXattr struct
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
* add guest-fstrim support for w32
* add support for using virtio-vsock as the communication channel
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJYF+gMAAoJEDNTyc7xCLWEeIAH/Agsx3ILwHSIknRY3xvO9zy3
F19ZU/pIVK0L8ykAP1vTSl/2M9REbs1koqLxpP56os0vXiibwwVAxeWGVGiBWzXk
+/VUz31Tfg1OvxiBtmsUAWmBP7lE6V+C5EQJsA+fNcXRnmCLtUBFpZTru/ZAJev1
EEA4EYeM0tqqPsXOe1N9APEDzeCNh8zFiPkC1Xqpsx19rAC44bFMZNincfJ6BwKs
84kuoQ12owK+cJFqu8ovBEjfs8cdKSbsFgtqkNpzaR7NMQSUvBDYE1RMcmPQoU+Y
W5glfrehsfyC+FR2fSHspfXiRkzKWedZslY0G7s8WTgnZryDiePZOPVGycMJbPY=
=w0WU
-----END PGP SIGNATURE-----
Merge remote-tracking branch 'remotes/mdroth/tags/qga-pull-2016-10-31-tag' into staging
qemu-ga patch queue for 2.8
* add guest-fstrim support for w32
* add support for using virtio-vsock as the communication channel
# gpg: Signature made Tue 01 Nov 2016 00:55:40 GMT
# gpg: using RSA key 0x3353C9CEF108B584
# gpg: Good signature from "Michael Roth <flukshun@gmail.com>"
# gpg: aka "Michael Roth <mdroth@utexas.edu>"
# gpg: aka "Michael Roth <mdroth@linux.vnet.ibm.com>"
# Primary key fingerprint: CEAC C9E1 5534 EBAB B82D 3FA0 3353 C9CE F108 B584
* remotes/mdroth/tags/qga-pull-2016-10-31-tag:
qga: add vsock-listen method
sockets: add AF_VSOCK support
qga: drop unnecessary GA_CHANNEL_UNIX_LISTEN checks
qga: drop unused sockaddr in accept(2) call
qga: minimal support for fstrim for Windows guests
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The virtfs_reset() function is called either when the virtio-9p device
gets reset, or when the client starts a new 9P session. In both cases,
if it finds fids from a previous session, the following is printed in
the monitor:
9pfs:virtfs_reset: One or more uncluncked fids found during reset
For example, if a linux guest with a mounted 9P share is reset from the
monitor with system_reset, the message will be printed. This is excessive
since these fids are now clunked and the state is clean.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
A buggy or malicious guest could pass the id of an already opened fid and
cause QEMU to abort. Let's return EINVAL to the guest instead.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
The xattrcreate operation only makes sense on a freshly cloned fid
actually, since any open state would be leaked because of the fid_type
change. This is indeed what the linux kernel client does:
fid = clone_fid(fid);
[...]
retval = p9_client_xattrcreate(fid, name, value_len, flags);
This patch also reverts commit ff55e94d23 since we are sure that a fid
with type P9_FID_NONE doesn't have a previously allocated xattr.
Signed-off-by: Greg Kurz <groug@kaod.org>
We shouldn't allow guests to create extended attribute with arbitrary sizes.
On linux hosts, the limit is XATTR_SIZE_MAX. Let's use it.
Signed-off-by: Greg Kurz <groug@kaod.org>
The v9fs_xattr_read() and v9fs_xattr_write() are passed a guest
originated offset: they must ensure this offset does not go beyond
the size of the extended attribute that was set in v9fs_xattrcreate().
Unfortunately, the current code implement these checks with unsafe
calculations on 32 and 64 bit values, which may allow a malicious
guest to cause OOB access anyway.
Fix this by comparing the offset and the xattr size, which are
both uint64_t, before trying to compute the effective number of bytes
to read or write.
Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-By: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
The 'len' in V9fsXattr comes from the 'size' argument in setxattr()
function in guest. The setxattr() function's declaration is this:
int setxattr(const char *path, const char *name,
const void *value, size_t size, int flags);
and 'size' is treated as u64 in linux kernel client code:
int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
u64 attr_size, int flags)
So the 'len' should have an type of 'uint64_t'.
The 'copied_len' in V9fsXattr is used to account for copied bytes, it
should also have an type of 'uint64_t'.
Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Currently, 9pfs sets the 'copied_len' field in V9fsXattr
to -1 to tag xattr walk fid. As the 'copied_len' is also
used to account for copied bytes, this may make confusion. This patch
add a bool 'xattrwalk_fid' to tag the xattr walk fid.
Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Some older GCC versions (e.g. 4.4.7) report a warning on an
uninitialized variable for 'request', even though all possible code
paths that reference 'request' will be initialized. To appease
these versions, initialize the variable to 0.
Reported-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Message-id: 259818682e41b95ae60f1423b87954a3fe377639.1477950393.git.jcody@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Add AF_VSOCK (virtio-vsock) support as an alternative to virtio-serial.
$ qemu-system-x86_64 -device vhost-vsock-pci,guest-cid=3 ...
(guest)# qemu-ga -m vsock-listen -p 3:1234
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Add the AF_VSOCK address family so that qemu-ga will be able to use
virtio-vsock.
The AF_VSOCK address family uses <cid, port> address tuples. The cid is
the unique identifier comparable to an IP address. AF_VSOCK does not
use name resolution so it's easy to convert between struct sockaddr_vm
and strings.
This patch defines a VsockSocketAddress instead of trying to piggy-back
on InetSocketAddress. This is cleaner in the long run since it avoids
lots of IPv4 vs IPv6 vs vsock special casing.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* treat trailing commas as garbage when parsing (Eric Blake)
* add configure check instead of checking AF_VSOCK directly
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Throughout the code there are c->listen_channel checks which manage the
listen socket file descriptor (waiting for accept(2), closing the file
descriptor, etc). These checks are currently preceded by explicit
c->method == GA_CHANNEL_UNIX_LISTEN checks.
Explicit GA_CHANNEL_UNIX_LISTEN checks are not necessary since serial
channel types do not create the listen channel (c->listen_channel).
As more listen channel types are added, explicitly checking all of them
becomes messy. Rely on c->listen_channel to determine whether or not a
listen socket file descriptor is used.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
ga_channel_listen_accept() is currently hard-coded to support only
AF_UNIX because the struct sockaddr_un type is used. This function
should work with any address family.
Drop the sockaddr since the client address is unused and is an optional
argument to accept(2).
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Unfortunately, there is no public Windows API to start trimming the
filesystem. The only viable way here is to call 'defrag.exe /L' for
each volume.
This is working since Win8 and Win2k12.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
CC: Michael Roth <mdroth@linux.vnet.ibm.com>
CC: Stefan Weil <sw@weilnetz.de>
CC: Marc-André Lureau <marcandre.lureau@gmail.com>
* check g_utf16_to_utf8() return value for GError handling instead
of GError directly (Marc-André)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
The functions that these generate are no longer used.
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>
The cpu is allowed to require stricter alignment on these 8- and 16-byte
operations, and the OS is required to fix up the accesses as necessary,
so the previous code was not wrong.
However, we can easily handle this misalignment for all direct 8-byte
operations and for direct 16-byte loads.
We must retain 16-byte alignment for 16-byte stores, so that we don't have
to probe for writability of a second page before performing the first of
two 8-byte stores. We also retain 8-byte alignment for no-fault loads,
since they are rare and it's not worth extending the helpers for this.
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>
At the same time, fix a problem with stqf_asi, when
a write might access two pages.
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Now that we never call out to helpers when direct accesses can
handle an asi, remove the corresponding code in those helpers.
For ldda, this removes the entire helper.
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Print a warning when mixing [+-]foo and foo=(on|off) in the -cpu
argument in a way that will break in the future.
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)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=Hglo
-----END PGP SIGNATURE-----
Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer patches
# gpg: Signature made Mon 31 Oct 2016 16:10:07 GMT
# gpg: using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* remotes/kevin/tags/for-upstream: (29 commits)
qapi: allow blockdev-add for NFS
block/nfs: Introduce runtime_opts in NFS
block: Mention replication in BlockdevDriver enum docs
qemu-iotests: test 'offset' and 'size' options in raw driver
raw_bsd: add offset and size options
qemu-iotests: Test the 'base-node' parameter of 'block-stream'
block: Add 'base-node' parameter to the 'block-stream' command
qemu-iotests: Test streaming to a Quorum child
qemu-iotests: Add iotests.supports_quorum()
qemu-iotests: Test block-stream and block-commit in parallel
qemu-iotests: Test overlapping stream and commit operations
qemu-iotests: Test block-stream operations in parallel
qemu-iotests: Test streaming to an intermediate layer
docs: Document how to stream to an intermediate layer
block: Add QMP support for streaming to an intermediate layer
block: Support streaming to an intermediate layer
block: Block all intermediate nodes in commit_active_start()
block: Block all nodes involved in the block-commit operation
block: Check blockers in all nodes involved in a block-commit job
block: Use block_job_add_bdrv() in backup_start()
...
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Some tests use the "-vnc none" option without any clear reason,
making those tests break when --disable-vnc is specified on
./configure. Remove the unnecessary option.
Reviewed-by: John Snow <jsnow@redhat.com>
Tested-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Now the kernel commit 05f0c03fbac1 ("vfio-pci: Allow to mmap
sub-page MMIO BARs if the mmio page is exclusive") allows VFIO
to mmap sub-page BARs. This is the corresponding QEMU patch.
With those patches applied, we could passthrough sub-page BARs
to guest, which can help to improve IO performance for some devices.
In this patch, we expand MemoryRegions of these sub-page
MMIO BARs to PAGE_SIZE in vfio_pci_write_config(), so that
the BARs could be passed to KVM ioctl KVM_SET_USER_MEMORY_REGION
with a valid size. The expanding size will be recovered when
the base address of sub-page BAR is changed and not page aligned
any more in guest. And we also set the priority of these BARs'
memory regions to zero in case of overlap with BARs which share
the same page with sub-page BARs in guest.
Signed-off-by: Yongji Xie <xyjxie@linux.vnet.ibm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
When a PCI device is reset, pci_do_device_reset resets all BAR addresses
in the relevant PCIDevice's config buffer.
The VFIO configuration space stays untouched, so the guest OS may choose
to skip restoring the BAR addresses as they would seem intact. The PCI
device may be left non-operational.
One example of such a scenario is when the guest exits S3.
Fix this by resetting the BAR addresses in the VFIO configuration space
as well.
Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
As reported in the link below, user has a PCI device with a 4KB BAR
which contains the MSI-X table. This seems to hit a corner case in
the kernel where the region reports being mmap capable, but the sparse
mmap information reports a zero sized range. It's not entirely clear
that the kernel is incorrect in doing this, but regardless, we need
to handle it. To do this, fill our mmap array only with non-zero
sized sparse mmap entries and add an error return from the function
so we can tell the difference between nr_mmaps being zero based on
sparse mmap info vs lack of sparse mmap info.
NB, this doesn't actually change the behavior of the device, it only
removes the scary "Failed to mmap ... Performance may be slow" error
message. We cannot currently create an mmap over the MSI-X table.
Link: http://lists.nongnu.org/archive/html/qemu-discuss/2016-10/msg00009.html
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
With a vfio assigned device we lay down a base MemoryRegion registered
as an IO region, giving us read & write accessors. If the region
supports mmap, we lay down a higher priority sub-region MemoryRegion
on top of the base layer initialized as a RAM device pointer to the
mmap. Finally, if we have any quirks for the device (ie. address
ranges that need additional virtualization support), we put another IO
sub-region on top of the mmap MemoryRegion. When this is flattened,
we now potentially have sub-page mmap MemoryRegions exposed which
cannot be directly mapped through KVM.
This is as expected, but a subtle detail of this is that we end up
with two different access mechanisms through QEMU. If we disable the
mmap MemoryRegion, we make use of the IO MemoryRegion and service
accesses using pread and pwrite to the vfio device file descriptor.
If the mmap MemoryRegion is enabled and results in one of these
sub-page gaps, QEMU handles the access as RAM, using memcpy to the
mmap. Using either pread/pwrite or the mmap directly should be
correct, but using memcpy causes us problems. I expect that not only
does memcpy not necessarily honor the original width and alignment in
performing a copy, but it potentially also uses processor instructions
not intended for MMIO spaces. It turns out that this has been a
problem for Realtek NIC assignment, which has such a quirk that
creates a sub-page mmap MemoryRegion access.
To resolve this, we disable memory_access_is_direct() for ram_device
regions since QEMU assumes that it can use memcpy for those regions.
Instead we access through MemoryRegionOps, which replaces the memcpy
with simple de-references of standard sizes to the host memory.
With this patch we attempt to provide unrestricted access to the RAM
device, allowing byte through qword access as well as unaligned
access. The assumption here is that accesses initiated by the VM are
driven by a device specific driver, which knows the device
capabilities. If unaligned accesses are not supported by the device,
we don't want them to work in a VM by performing multiple aligned
accesses to compose the unaligned access. A down-side of this
philosophy is that the xp command from the monitor attempts to use
the largest available access weidth, unaware of the underlying
device. Using memcpy had this same restriction, but at least now an
operator can dump individual registers, even if blocks of device
memory may result in access widths beyond the capabilities of a
given device (RTL NICs only support up to dword).
Reported-by: Thorsten Kohfeldt <thorsten.kohfeldt@gmx.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Setting skip_dump on a MemoryRegion allows us to modify one specific
code path, but the restriction we're trying to address encompasses
more than that. If we have a RAM MemoryRegion backed by a physical
device, it not only restricts our ability to dump that region, but
also affects how we should manipulate it. Here we recognize that
MemoryRegions do not change to sometimes allow dumps and other times
not, so we replace setting the skip_dump flag with a new initializer
so that we know exactly the type of region to which we're applying
this behavior.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Introduce new object 'BlockdevOptionsNFS' in qapi/block-core.json to
support blockdev-add for NFS network protocol driver. Also make a new
struct NFSServer to support tcp connection.
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Make NFS block driver use various fine grained runtime_opts.
Set .bdrv_parse_filename() to nfs_parse_filename() and introduce two
new functions nfs_parse_filename() and nfs_parse_uri() to help parsing
the URI.
Add a new option "server" which then accepts a new struct NFSServer.
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
[ kwolf: Fixed client->path ]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Added two new options 'offset' and 'size'. This makes it possible to use
only part of the file as a device. This can be used e.g. to limit the
access only to single partition in a disk image or use a disk inside a
tar archive (like OVA).
When 'size' is specified we do our best to honour it.
Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The block-stream command has traditionally used the 'base' parameter
to indicate the image to copy the data from. This test checks that the
'base-node' parameter can also be used for the same purpose.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
