virtio-blk-data-plane is a subset implementation of virtio-blk. It only
handles read, write, and flush requests. It does this using a dedicated
thread that executes an epoll(2)-based event loop and processes I/O
using Linux AIO.
This approach performs very well but can be used for raw image files
only. The number of IOPS achieved has been reported to be several times
higher than the existing virtio-blk implementation.
Eventually it should be possible to unify virtio-blk-data-plane with the
main body of QEMU code once the block layer and hardware emulation is
able to run outside the global mutex.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Two slightly different versions of a patch to conditionally set
VIRTIO_BLK_F_CONFIG_WCE through the "config-wce" qdev property have been
applied (ea776abca and eec7f96c2). David Gibson
<david@gibson.dropbear.id.au> noticed that the "config-wce"
property is broken as a result and fixed it recently.
The fix sets the host_features VIRTIO_BLK_F_CONFIG_WCE bit from a qdev
property. Unfortunately, the virtio device then has no chance to test
for the presence of the feature bit during virtio_blk_init().
Therefore, reinstate the VirtIOBlkConf->config_wce flag. Drop the
duplicate qdev property to set the host_features bit. The
VirtIOBlkConf->config_wce flag will be used by virtio-blk-data-plane in
a later patch.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
For the virtio-blk device (via virtio-pci) the property "config-wce" is
defined in two places. First, it's defined from the
DEFINE_VIRTIO_BLK_FEATURES macro, second it's defined directly in
virtio-pci, just two lines above the call to that macro.
The direct definition in virtio-pci.c is broken, since it operates on the
'config_wce' field of VirtIOBlkConf, which is never used anywhere else.
Therefore, this patch removes both the extra property definition and the
redundant field it works on.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Paul 'Rusty' Russell <rusty@rustcorp.com.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* kwolf/for-anthony:
virtio-blk: hide VIRTIO_BLK_F_CONFIG_WCE from old machine types
Documentation: Warn against qemu-img on active image
vmdk: Read footer for streamOptimized images
vmdk: Fix header structure
Conflicts:
hw/virtio-blk.c
QEMU has a policy of keeping a stable guest device ABI. When new guest device
features are introduced they must not change hardware info seen by existing
guests. This is important because operating systems or applications may
"fingerprint" the hardware and refuse to run when the hardware changes. To
always get the latest guest device ABI, run with x86 machine type "pc".
This patch hides the new VIRTIO_BLK_F_CONFIG_WCE virtio feature bit from
existing machine types. Only pc-1.2 and later will expose this feature
by default.
For more info on the VIRTIO_BLK_F_CONFIG_WCE feature bit, see:
commit 13e3dce068
Author: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu Aug 9 16:07:19 2012 +0200
virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE
Also rename VIRTIO_BLK_F_WCACHE to VIRTIO_BLK_F_WCE for consistency with
the spec.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Anthony Liguori <aliguori@us.ibm.com> reported:
This broke qemu-test because it changed the pc-1.0 machine type:
Setting guest RANDOM seed to 47167
*** Running tests ***
Running test /tests/finger-print.sh... OK
--- fingerprints/pc-1.0.x86_64 2011-12-18 13:08:40.000000000 -0600
+++ fingerprint.txt 2012-08-12 13:30:48.000000000 -0500
@@ -55,7 +55,7 @@
/sys/bus/pci/devices/0000:00:06.0/subsystem_device=0x0002
/sys/bus/pci/devices/0000:00:06.0/class=0x010000
/sys/bus/pci/devices/0000:00:06.0/revision=0x00
-/sys/bus/pci/devices/0000:00:06.0/virtio/host-features=0x710006d4
+/sys/bus/pci/devices/0000:00:06.0/virtio/host-features=0x71000ed4
/sys/class/dmi/id/bios_vendor=Bochs
/sys/class/dmi/id/bios_date=01/01/2007
/sys/class/dmi/id/bios_version=Bochs
Guest fingerprint changed for pc-1.0!
Reported-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
QEMU has a policy of keeping a stable guest device ABI. When new guest device
features are introduced they must not change hardware info seen by existing
guests. This is important because operating systems or applications may
"fingerprint" the hardware and refuse to run when the hardware changes. To
always get the latest guest device ABI, run with x86 machine type "pc".
This patch hides the new VIRTIO_BLK_F_CONFIG_WCE virtio feature bit from
existing machine types. Only pc-1.2 and later will expose this feature
by default.
For more info on the VIRTIO_BLK_F_CONFIG_WCE feature bit, see:
commit 13e3dce068
Author: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu Aug 9 16:07:19 2012 +0200
virtio-blk: support VIRTIO_BLK_F_CONFIG_WCE
Also rename VIRTIO_BLK_F_WCACHE to VIRTIO_BLK_F_WCE for consistency with
the spec.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Anthony Liguori <aliguori@us.ibm.com> reported:
This broke qemu-test because it changed the pc-1.0 machine type:
Setting guest RANDOM seed to 47167
*** Running tests ***
Running test /tests/finger-print.sh... OK
--- fingerprints/pc-1.0.x86_64 2011-12-18 13:08:40.000000000 -0600
+++ fingerprint.txt 2012-08-12 13:30:48.000000000 -0500
@@ -55,7 +55,7 @@
/sys/bus/pci/devices/0000:00:06.0/subsystem_device=0x0002
/sys/bus/pci/devices/0000:00:06.0/class=0x010000
/sys/bus/pci/devices/0000:00:06.0/revision=0x00
-/sys/bus/pci/devices/0000:00:06.0/virtio/host-features=0x710006d4
+/sys/bus/pci/devices/0000:00:06.0/virtio/host-features=0x71000ed4
/sys/class/dmi/id/bios_vendor=Bochs
/sys/class/dmi/id/bios_date=01/01/2007
/sys/class/dmi/id/bios_version=Bochs
Guest fingerprint changed for pc-1.0!
Reported-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Also rename VIRTIO_BLK_F_WCACHE to VIRTIO_BLK_F_WCE for consistency with
the spec.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This stuff doesn't belong to block layer, and was put there only
because a better home didn't exist then. Now it does.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
VIRTIO_BLK_F_SCSI is supposed to mean whether the host can *parse*
SCSI requests, not *execute* them. You could run QEMU with scsi=on
and a file-backed disk, and QEMU would fail all SCSI requests even
though it advertises VIRTIO_BLK_F_SCSI.
Because we need to do this to fix a migration compatibility problem
related to how QEMU is invoked by management, we must do this
unconditionally even on older machine types. This more or less assumes
that no one ever invoked QEMU with scsi=off.
Here is how testing goes:
- old QEMU, scsi=on -> new QEMU, scsi=on
- new QEMU, scsi=on -> old QEMU, scsi=on
- old QEMU, scsi=off -> new QEMU, scsi=on
- new QEMU, scsi=off -> old QEMU, scsi=on
ok (new QEMU has VIRTIO_BLK_F_SCSI, adding host features is fine)
- old QEMU, scsi=off -> new QEMU, scsi=off
ok (new QEMU has VIRTIO_BLK_F_SCSI, adding host features is fine)
- old QEMU, scsi=on -> new QEMU, scsi=off
ok, bug fixed
- new QEMU, scsi=on -> old QEMU, scsi=off
doesn't work (same as: old QEMU, scsi=on -> old QEMU, scsi=off)
- new QEMU, scsi=off -> old QEMU, scsi=off
broken by the patch
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
We will have to add another field to the virtio-blk configuration in
the next patch. Avoid a proliferation of arguments to virtio_blk_init.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Most changes were made using these commands:
git grep -la '__attribute__((packed))'|xargs perl -pi -e 's/__attribute__\(\(packed\)\)/QEMU_PACKED/'
git grep -la '__attribute__ ((packed))'|xargs perl -pi -e 's/__attribute__ \(\(packed\)\)/QEMU_PACKED/'
git grep -la '__attribute__((__packed__))'|xargs perl -pi -e 's/__attribute__\(\(__packed__\)\)/QEMU_PACKED/'
git grep -la '__attribute__ ((__packed__))'|xargs perl -pi -e 's/__attribute__ \(\(__packed__\)\)/QEMU_PACKED/'
git grep -la '__attribute((packed))'|xargs perl -pi -e 's/__attribute\(\(packed\)\)/QEMU_PACKED/'
Whitespace in linux-user/syscall_defs.h was fixed manually
to avoid warnings from scripts/checkpatch.pl.
Manual changes were also applied to hw/pc.c.
I did not fix indentation with tabs in block/vvfat.c.
The patch will show 4 errors with scripts/checkpatch.pl.
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
It needs to be a qdev property, because it belongs to the drive's
guest part. Precedence: commit a0fef654 and 6ced55a5.
Bonus: info qtree now shows the serial number.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This patch adds the final missing bits for support of
passing a serial/id string to a virtio-blk guest driver.
The guest-side component already exists in the virtio
driver, and has recently been reworked by Ryan to export
a /sys interface for retrieval of the id from guest userland.
Signed-off-by: john cooper <john.cooper@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Add a logical block size attribute as various guest side tools only
increase the filesystem sector size based on it, not the advisory
physical block size.
For scsi we already have support for a different logical block size
in place for CDROMs that we can built upon. Only my recent block
device characteristics VPD page needs some fixups. Note that we
leave the logial block size for CDROMs hardcoded as the 2k value
is expected for it in general.
For virtio-blk we already have a feature flag claiming to support
a variable logical block size that was added for the s390 kuli
hypervisor. Interestingly it does not actually change the units
in which the protocol works, which is still fixed at 512 bytes,
but only communicates a different minimum I/O granularity. So
all we need to do in virtio is to add a trap for unaligned I/O
and round down the device size to the next multiple of the logical
block size.
IDE does not support any other logical block size than 512 bytes.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Export all topology information in the block config structure,
guarded by a new VIRTIO_BLK_F_TOPOLOGY feature flag.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The addition of the whole ATA IDENTIY page caused the config space to
go above the allowed size in the PCI spec, and thus the feature was
already reverted in the Linux guest driver and disabled by default in
qemu.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add feature bits as properties to virtio. This makes it possible to e.g. define
machine without indirect buffer support, which is required for 0.10
compatibility, or without hardware checksum support, which is required for 0.11
compatibility. Since default values for optional features are now set by qdev,
get_features callback has been modified: it sets non-optional bits, and clears
bits not supported by host.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Add a new VIRTIO_BLK_F_WCACHE feature to virtio-blk to indicate that we have
a volatile write cache that needs controlled flushing. Implement a
VIRTIO_BLK_T_FLUSH operation to flush it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
[brought forward to current qemu-kvm.git]
This patch implements the missing qemu logic to
interpret a '-drive .. serial=XYZ ..' flag for
a virtio_blk device.
The serial number string is contained in a
skeletal IDENTIFY DEVICE data structure and
this structure is made available to the guest
virtio_blk driver via pci i/o region 0.
Signed-off-by: john cooper <john.cooper@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
The inhdr is at the end of the S/G list, not the beginning.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
[had the qemu list address wrong the first time, reply to this message,
not the previous if you were on Cc]
Add support for SG_IO passthru (packet commands) to the virtio-blk
backend. Conceptually based on an older patch from Hannes Reinecke
but largely rewritten to match the code structure and layering in
virtio-blk.
Note that currently we issue the hose SG_IO synchronously. We could
easily switch to async I/O, but that would required either bloating
the VirtIOBlockReq by the size of struct sg_io_hdr or an additional
memory allocation for each SG_IO request.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Use the defines added by the previous patch in the virtio drivers.
Also remove the pointless vendor and device args from the
virtio_blk_init() function.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5987 c046a42c-6fe2-441c-8c8c-71466251a162
Virtio-blk is a paravirtual block device based on VirtIO. It can be used by
specifying the if=virtio parameter to the -drive parameter.
When using -enable-kvm, it can achieve very good performance compared to IDE or
SCSI.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5870 c046a42c-6fe2-441c-8c8c-71466251a162
