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2010-05-03block: bdrv_has_zero_initKevin Wolf
This fixes the problem that qemu-img's use of no_zero_init only considered the no_zero_init flag of the format driver, but not of the underlying protocols. Between the raw/file split and this fix, converting to host devices is broken. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-05-03block: separate raw images from the file protocolChristoph Hellwig
We're running into various problems because the "raw" file access, which is used internally by the various image formats is entangled with the "raw" image format, which maps the VM view 1:1 to a file system. This patch renames the raw file backends to the file protocol which is treated like other protocols (e.g. nbd and http) and adds a new "raw" image format which is just a wrapper around calls to the underlying protocol. The patch is surprisingly simple, besides changing the probing logical in block.c to only look for image formats when using bdrv_open and renaming of the old raw protocols to file there's almost nothing in there. For creating images, a new bdrv_create_file is introduced which guesses the protocol to use. This allows using qemu-img create -f raw (or just using the default) for both files and host devices. Converting the other format drivers to use this function to create their images is left for later patches. The only issues still open are in the handling of the host devices. Firstly in current qemu we can specifiy the host* format names on various command line acceping images, but the new code can't do that without adding some translation. Second the layering breaks the no_zero_init flag in the BlockDriver used by qemu-img. I'm not happy how this is done per-driver instead of per-state so I'll prepare a separate patch to clean this up. There's some more cleanup opportunity after this patch, e.g. using separate lists and registration functions for image formats vs protocols and maybe even host drivers, but this can be done at a later stage. Also there's a check for protocol in bdrv_open for the BDRV_O_SNAPSHOT case that I don't quite understand, but which I fear won't work as expected - possibly even before this patch. Note that this patch requires various recent block patches from Kevin and me, which should all be in his block queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-23block.h: bdrv_create2 doesn't exist any moreKevin Wolf
The bdrv_create2 implementation has disappeared long ago. Remove its prototype from the header file, too. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-23block: get rid of the BDRV_O_FILE flagChristoph Hellwig
BDRV_O_FILE is only used to communicate between bdrv_file_open and bdrv_open. It affects two things: first bdrv_open only searches for protocols using find_protocol instead of all image formats and host drivers. We can easily move that to the caller and pass the found driver to bdrv_open. Second it is used to not force a read-write open of a snapshot file. But we never use bdrv_file_open to open snapshots and this behaviour doesn't make sense to start with. qemu-io abused the BDRV_O_FILE for it's growable option, switch it to using bdrv_file_open to make sure we only open files as growable were we can actually support that. This patch requires Kevin's "[PATCH] Replace calls of old bdrv_open" to be applied first. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-23Replace calls of old bdrv_openKevin Wolf
What is known today as bdrv_open2 becomes the new bdrv_open. All remaining callers of the old function are converted to the new one. In some places they even know the right format, so they should have used bdrv_open2 from the beginning. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-23qcow2: Trigger blkdebug eventsKevin Wolf
This adds blkdebug events to qcow2 to allow injecting I/O errors in specific places. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-04-23blkdebug: Add events and rulesKevin Wolf
Block drivers can trigger a blkdebug event whenever they reach a place where it could be useful to inject an error for testing/debugging purposes. Rules are read from a blkdebug config file and describe which action is taken when an event is triggered. For now this is only injecting an error (with a few options) or changing the state (which is an integer). Rules can be declared to be active only in a specific state; this way later rules can distiguish on which path we came to trigger their event. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-02-10block: BLOCK_IO_ERROR QMP eventLuiz Capitulino
This commit introduces the bdrv_mon_event() function, which should be called by block subsystems (eg. IDE) when a I/O error occurs, so that an QMP event is emitted. The following information is currently provided in the event: - device name - operation (ie. "read" or "write") - action taken (eg. "stop") Event example: { "event": "BLOCK_IO_ERROR", "data": { "device": "ide0-hd1", "operation": "write", "action": "stop" }, "timestamp": { "seconds": 1265044230, "microseconds": 450486 } } Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-02-09Count dirty blocks and expose an API to get dirty countLiran Schour
This will manage dirty counter for each device and will allow to get the dirty counter from above. Signed-off-by: Liran Schour <lirans@il.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-26block: kill BDRV_O_CREATChristoph Hellwig
The BDRV_O_CREAT option is unused inside qemu and partially duplicates the bdrv_create method. Remove it, and the -C option to qemu-io which isn't used in qemu-iotests anyway. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-26No need anymoe for bdrv_set_read_onlyNaphtali Sprei
Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-20Clean-up a little bit the RW related bits of BDRV_O_FLAGS. BDRV_O_RDONLY ↵Naphtali Sprei
gone (and so is BDRV_O_ACCESS). Default value for bdrv_flags (0/zero) is READ-ONLY. Need to explicitly request READ-WRITE. Instead of using the field 'readonly' of the BlockDriverState struct for passing the request, pass the request in the flags parameter to the function. Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-13block: Add bdrv_change_backing_fileKevin Wolf
Introduce the functions needed to change the backing file of an image. The function is implemented for qcow2. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2010-01-13block: Introduce BDRV_O_NO_BACKINGKevin Wolf
If an image references a backing file that doesn't exist, qemu-img info fails to open this image. Exactly in this case the info would be valuable, though: the user might want to find out which file is missing. This patch introduces a BDRV_O_NO_BACKING flag to ignore the backing file when opening the image. qemu-img info is the first user and provides info now even if the backing file is invalid. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-12-12block: Convert bdrv_info_stats() to QObjectLuiz Capitulino
Each device statistic information is stored in a QDict and the returned QObject is a QList of all devices. This commit should not change user output. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-12-12block: Convert bdrv_info() to QObjectLuiz Capitulino
Each block device information is stored in a QDict and the returned QObject is a QList of all devices. This commit should not change user output. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-12-03block migration: Increase dirty chunk size to 1MJan Kiszka
4K is too small for efficiently saving and restoring multi-GB block devices. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-12-03block migration: Rework constants APIJan Kiszka
Instead of duplicating the definition of constants or introducing trivial retrieval functions move the SECTOR constants into the public block API. This also obsoletes sector_per_block in BlkMigState. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-12-03block migration: Fix coding style and whitespacesJan Kiszka
No functional changes. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-11-17Expose a mechanism to trace block writeslirans@il.ibm.com
To support live migration without shared storage we need to be able to trace writes to disk while migrating. This Patch expose dirty block tracking per device to be polled from upper layer. Changes from v4: - Register dirty tracking for each block device. - Minor coding style issues. - Block.c will now manage a dirty bitmap per device once bdrv_set_dirty_tracking() is called. Bitmap is polled by the upper layer (block-migration.c). Signed-off-by: Liran Schour <lirans@il.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-11-09Configurable block format whitelistMarkus Armbruster
We have code for a quite a few block formats. While I trust that all of these formats are useful at least for some people in some circumstances, some of them are of a kind that friends don't let friends use in production. This patch provides an optional block format whitelist, default off. If a whitelist is configured with --block-drv-whitelist, QEMU proper can use only whitelisted formats. Other programs, like qemu-img, are not affected. Drivers for formats off the whitelist still participate in format probing, to ensure all programs probe exactly the same. Without that, QEMU proper would be prone to treat images with a format off the whitelist as raw when the image's format is probed. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-11-09Added readonly flag to -drive commandNaphtali Sprei
This is a slightly revised patch for adding readonly flag to the -drive command. Even though this patch is "stand-alone", it assumes a previous related patch (in Anthony staging tree), that passes the readonly attribute of the drive to the guest OS, applied first. This enables sharing same image between guests, with readonly access. Implementaion mark the drive as read_only and changes the flags when actually opening the file. The readonly attribute of a qcow also passed to it's base file. For ide that cannot pass the readonly attribute to the guest OS, disallow the readonly flag. Also, return error code from bdrv_truncate for readonly drive. Signed-off-by: Naphtali Sprei <nsprei@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-09-11block: add aio_flush operationChristoph Hellwig
Instead stalling the VCPU while serving a cache flush try to do it asynchronously. Use our good old helper thread pool to issue an asynchronous fdatasync for raw-posix. Note that while Linux AIO implements a fdatasync operation it is not useful for us because it isn't actually implement in asynchronous fashion. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-09-11block: add enable_write_cache flagChristoph Hellwig
Add a enable_write_cache flag in the block driver state, and use it to decide if we claim to have a volatile write cache that needs controlled flushing from the guest. The flag is off if cache=writethrough is defined because O_DSYNC guarantees that every write goes to stable storage, and it is on for cache=none and cache=writeback. Both scsi-disk and ide now use the new flage, changing from their defaults of always off (ide) or always on (scsi-disk). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-09-11Add bdrv_aio_multiwriteKevin Wolf
One performance problem of qcow2 during the initial image growth are sequential writes that are not cluster aligned. In this case, when a first requests requires to allocate a new cluster but writes only to the first couple of sectors in that cluster, the rest of the cluster is zeroed - just to be overwritten by the following second request that fills up the cluster. Let's try to merge sequential write requests to the same cluster, so we can avoid to write the zero padding to the disk in the first place. As a nice side effect, also other formats take advantage of dealing with less and larger requests. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-08-27raw-posix: add Linux native AIO supportChristoph Hellwig
Now that do have a nicer interface to work against we can add Linux native AIO support. It's an extremly thing layer just setting up an iocb for the io_submit system call in the submission path, and registering an eventfd with the qemu poll handler to do complete the iocbs directly from there. This started out based on Anthony's earlier AIO patch, but after estimated 42,000 rewrites and just as many build system changes there's not much left of it. To enable native kernel aio use the aio=native sub-command on the drive command line. I have also added an option to qemu-io to test the aio support without needing a guest. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-07-16replace bdrv_{get, put}_buffer with bdrv_{load, save}_vmstateChristoph Hellwig
The VM state offset is a concept internal to the image format. Replace the old bdrv_{get,put}_buffer method that require an index into the image file that is constructed from the VM state offset and an offset into the vmstate with the bdrv_{load,save}_vmstate that just take an offset into the VM state. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-07-09Revert "support colon in filenames"Anthony Liguori
This reverts commit 707c0dbc97cddfe8d2441b8259c6c526d99f2dd8. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-07-09qcow2: Make cache=writethrough defaultKevin Wolf
The performance of qcow2 has improved meanwhile, so we don't need to special-case it any more. Switch the default to write-through caching like all other block drivers. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-06-29support colon in filenamesRam Pai
Problem: It is impossible to feed filenames with the character colon because qemu interprets such names as a protocol. For example filename scsi:0, is interpreted as a protocol by name "scsi". This patch allows user to espace colon characters. For example the above filename can now be expressed either as 'scsi\:0' or as file:scsi:0 anything following the "file:" tag is interpreted verbatin. However if "file:" tag is omitted then any colon characters in the string must be escaped using backslash. Here are couple of examples: scsi\:0\:abc is a local file scsi:0:abc http\://myweb is a local file by name http://myweb file:scsi:0:abc is a local file scsi:0:abc file:http://myweb is a local file by name http://myweb Signed-off-by: Ram Pai <linuxram@us.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-06-16Prevent CD-ROM media eject while device is lockedMark McLoughlin
Section 10.8.25 ("START/STOP UNIT Command") of SFF-8020i states that if the device is locked we should refuse to eject if the device is locked. ASC_MEDIA_REMOVAL_PREVENTED is the appropriate return in this case. In order to stop itself from ejecting the media it is running from, Fedora's installer (anaconda) requires the CDROMEJECT ioctl() to fail if the drive has been previously locked. See also https://bugzilla.redhat.com/501412 Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-05-22Convert all block drivers to new bdrv_createKevin Wolf
Now we can make use of the newly introduced option structures. Instead of having bdrv_create carry more and more parameters (which are format specific in most cases), just pass a option structure as defined by the driver itself. bdrv_create2() contains an emulation of the old interface to simplify the transition. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-05-14Convert block infrastructure to use new module init functionalityAnthony Liguori
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-04-21Introduce bdrv_check (Kevin Wolf)aliguori
From: Kevin Wolf <kwolf@redhat.com> Introduce a new bdrv_check function pointer for block drivers. Modify qcow2 to return an error status in check_refcounts(), so it can implement bdrv_check. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7214 c046a42c-6fe2-441c-8c8c-71466251a162
2009-04-07remove bdrv_aio_read/bdrv_aio_write (Christoph Hellwig)aliguori
Always use the vectored APIs to reduce code churn once we switch the BlockDriver API to be vectored. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7019 c046a42c-6fe2-441c-8c8c-71466251a162
2009-04-05Fix savevm after BDRV_FILE size enforcementaliguori
We now enforce that you cannot write beyond the end of a non-growable file. qcow2 files are not growable but we rely on them being growable to do savevm/loadvm. Temporarily allow them to be growable by introducing a new API specifically for savevm read/write operations. Reported-by: malc Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6994 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-28block: support known backing format for image create and open (Uri Lublin)aliguori
Added a backing_format field to BlockDriverState. Added bdrv_create2 and drv->bdrv_create2 to create an image with a known backing file format. Upon bdrv_open2 if backing format is known use it, instead of probing the (backing) image. Signed-off-by: Uri Lublin <uril@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6908 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-28new scsi-generic abstraction, use SG_IO (Christoph Hellwig)aliguori
Okay, I started looking into how to handle scsi-generic I/O in the new world order. I think the best is to use the SG_IO ioctl instead of the read/write interface as that allows us to support scsi passthrough on disk/cdrom devices, too. See Hannes patch on the kvm list from August for an example. Now that we always do ioctls we don't need another abstraction than bdrv_ioctl for the synchronous requests for now, and for asynchronous requests I've added a aio_ioctl abstraction keeping it simple. Long-term we might want to move the ops to a higher-level abstraction and let the low-level code fill out the request header, but I'm lazy enough to leave that to the people trying to support scsi-passthrough on a non-Linux OS. Tested lightly by issuing various sg_ commands from sg3-utils in a guest to a host CDROM device. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6895 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-12Add specialized block driver scsi generic API (Avi Kivity)aliguori
When a scsi device is backed by a scsi generic device instead of an ordinary host block device, the block API is abused in a couple of annoying ways: - nb_sectors is negative, and specifies a byte count instead of a sector count - offset is ignored, since scsi-generic is essentially a packet protocol This overloading makes hacking the block layer difficult. Remove it by introducing a new explicit API for scsi-generic devices. The new API is still backed by the old implementation, but at least the users are insulated. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6822 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-11Revert r6405aliguori
This series is broken by design as it requires expensive IO operations at open time causing very long delays when starting a virtual machine for the first time. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6815 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-11Revert r6407aliguori
This series is broken by design as it requires expensive IO operations at open time causing very long delays when starting a virtual machine for the first time. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6813 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-05monitor: Rework API (Jan Kiszka)aliguori
Refactor the monitor API and prepare it for decoupled terminals: term_print functions are renamed to monitor_* and all monitor services gain a new parameter (mon) that will once refer to the monitor instance the output is supposed to appear on. However, the argument remains unused for now. All monitor command callbacks are also extended by a mon parameter so that command handlers are able to pass an appropriate reference to monitor output services. For the case that monitor outputs so far happen without clearly identifiable context, the global variable cur_mon is introduced that shall once provide a pointer either to the current active monitor (while processing commands) or to the default one. On the mid or long term, those use case will be obsoleted so that this variable can be removed again. Due to the broad usage of the monitor interface, this patch mostly deals with converting users of the monitor API. A few of them are already extended to pass 'mon' from the command handler further down to internal functions that invoke monitor_printf. At this chance, monitor-related prototypes are moved from console.h to a new monitor.h. The same is done for the readline API. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6711 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-05monitor: Rework early disk password inquiry (Jan Kiszka)aliguori
Reading the passwords for encrypted hard disks during early startup is broken (I guess for quiet a while now): - No monitor terminal is ready for input at this point - Forcing all mux'ed terminals into monitor mode can confuse other users of that channels To overcome these issues and to lay the ground for a clean decoupling of monitor terminals, this patch changes the initial password inquiry as follows: - Prevent autostart if there is some encrypted disk - Once the user tries to resume the VM, prompt for all missing passwords - Only resume if all passwords were accepted Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6707 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-05block: Introduce bdrv_get_encrypted_filename (Jan Kiszka)aliguori
Introduce bdrv_get_encrypted_filename service to allow more informative password prompting. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6704 c046a42c-6fe2-441c-8c8c-71466251a162
2009-03-05block: Improve bdrv_iterate (Jan Kiszka)aliguori
Make bdrv_iterate more useful by passing the BlockDriverState to the iterator instead of the device name. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6703 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-22qcow2 format: keep 'num_free_bytes', and show it upon 'info blockstats' (Uri ↵aliguori
Lublin) 'num_free_bytes' is the number of non-allocated bytes below highest-allocation. It's useful, together with the highest-allocation, to figure out how fragmented the image is, and how likely it will run out-of-space soon. For example when the highest allocation is high (almost end-of-disk), but many bytes (clusters) are free, and can be re-allocated when neeeded, than we know it's probably not going to reach end-of-disk-space soon. Added bookkeeping to block-qcow2.c Export it using BlockDeviceInfo Show it upon 'info blockstats' if BlockDeviceInfo exists Signed-off-by: Uri Lublin <uril@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6407 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-22block-qcow2: export highest_allocated through BlockDriverInfo and get_info() ↵aliguori
(Uri Lublin) Signed-off-by: Uri Lublin <uril@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6405 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-22Vectored block device API (Avi Kivity)aliguori
Most devices that are capable of DMA are also capable of scatter-gather. With the memory mapping API, this means that the device code needs to be able to access discontiguous host memory regions. For block devices, this translates to vectored I/O. This patch implements an aynchronous vectored interface for the qemu block devices. At the moment all I/O is bounced and submitted through the non-vectored API; in the future we will convert block devices to natively support vectored I/O wherever possible. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6397 c046a42c-6fe2-441c-8c8c-71466251a162
2008-12-04Use writeback caching by default with qcow2aliguori
qcow2 writes a cluster reference count on every cluster update. This causes performance to crater when using anything but cache=writeback. This is most noticeable when using savevm. Right now, qcow2 isn't a reliable format regardless of the type of cache your using because metadata is not updated in the correct order. Considering this, I think it's somewhat reasonable to use writeback caching by default with qcow2 files. It at least avoids the massive performance regression for users until we sort out the issues in qcow2. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5879 c046a42c-6fe2-441c-8c8c-71466251a162
2008-11-25Abstract out geometry detection code from IDE for reusealiguori
Virtio will want to use the geometry detection code. It doesn't belong in ide.c anyway. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5797 c046a42c-6fe2-441c-8c8c-71466251a162