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* drivers/virtio: remove depends on CONFIG_EXPERIMENTALKees Cook2013-01-111-4/+4
| | | | | | | | | | | The CONFIG_EXPERIMENTAL config item has not carried much meaning for a while now and is almost always enabled by default. As agreed during the Linux kernel summit, remove it from any "depends on" lines in Kconfigs. CC: Rusty Russell <rusty@rustcorp.com.au> CC: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
* Drivers: virtio: remove __dev* attributes.Greg Kroah-Hartman2013-01-033-9/+9
| | | | | | | | | | | | | | | | CONFIG_HOTPLUG is going away as an option. As a result, the __dev* markings need to be removed. This change removes the use of __devinit, __devexit_p, and __devexit from these drivers. Based on patches originally written by Bill Pemberton, but redone by me in order to handle some of the coding style issues better, by hand. Cc: Bill Pemberton <wfp5p@virginia.edu> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2012-12-205-76/+57
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio update from Rusty Russell: "Some nice cleanups, and even a patch my wife did as a "live" demo for Latinoware 2012. There's a slightly non-trivial merge in virtio-net, as we cleaned up the virtio add_buf interface while DaveM accepted the mq virtio-net patches." * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits) virtio_console: Add support for remoteproc serial virtio_console: Merge struct buffer_token into struct port_buffer virtio: add drv_to_virtio to make code clearly virtio: use dev_to_virtio wrapper in virtio virtio-mmio: Fix irq parsing in command line parameter virtio_console: Free buffers from out-queue upon close virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>( virtio_console: Use kmalloc instead of kzalloc virtio_console: Free buffer if splice fails virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: make virtqueue_add_buf() returning 0 on success, not capacity. virtio: console: don't rely on virtqueue_add_buf() returning capacity. virtio_net: don't rely on virtqueue_add_buf() returning capacity. virtio-net: remove unused skb_vnet_hdr->num_sg field virtio-net: correct capacity math on ring full virtio: move queue_index and num_free fields into core struct virtqueue. ...
| * virtio: add drv_to_virtio to make code clearlyWanlong Gao2012-12-181-7/+4
| | | | | | | | | | | | | | | | | | Add drv_to_virtio wrapper to get virtio_driver from device_driver. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * virtio: use dev_to_virtio wrapper in virtioWanlong Gao2012-12-181-10/+9
| | | | | | | | | | | | | | | | | | Use dev_to_virtio wrapper in virtio to make code clearly. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * virtio-mmio: Fix irq parsing in command line parameterPawel Moll2012-12-181-9/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | When the resource_size_t is 64-bit long, the sscanf() on the virtio device command line paramter string may return wrong value because its format was defined as "%u". Fixed by using an intermediate local value of a known length. Also added cleaned up the resource creation and added extra comments to make the parameters parsing easier to follow. Reported-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(Joe Perches2012-12-181-4/+3
| | | | | | | | | | | | | | | | | | dev_<level> calls take less code than dev_printk(KERN_<LEVEL> and reducing object size is good. Convert if (printk_ratelimit()) dev_printk to dev_<level>_ratelimited. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * virtio: make virtqueue_add_buf() returning 0 on success, not capacity.Rusty Russell2012-12-181-5/+2
| | | | | | | | | | | | | | | | Now noone relies on this behavior, we simplify virtqueue_add_buf() so it return 0 or -errno. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio: move queue_index and num_free fields into core struct virtqueue.Rusty Russell2012-12-183-29/+15
| | | | | | | | | | | | | | | | | | | | | | | | They're generic concepts, so hoist them. This also avoids accessor functions (though kept around for merge with DaveM's net tree). This goes even further than Jason Wang's 17bb6d4088 patch ("virtio-ring: move queue_index to vring_virtqueue") which moved the queue_index from the specific transport. Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * virtio-pci: use module_pci_driver to simplify the codeWei Yongjun2012-12-181-13/+1
| | | | | | | | | | | | | | | | | | | | | | Use the module_pci_driver() macro to make the code simpler by eliminating module_init and module_exit calls. dpatch engine is used to auto generate this patch. (https://github.com/weiyj/dpatch) Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
| * virtio: force vring descriptors to be allocated from lowmemWill Deacon2012-10-221-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Virtio devices may attempt to add descriptors to a virtqueue from atomic context using GFP_ATOMIC allocation. This is problematic because such allocations can fall outside of the lowmem mapping, causing virt_to_phys to report bogus physical addresses which are subsequently passed to userspace via the buffers for the virtual device. This patch masks out __GFP_HIGH and __GFP_HIGHMEM from the requested flags when allocating descriptors for a virtqueue. If an atomic allocation is requested and later fails, we will return -ENOSPC which will be handled by the driver. Cc: stable@kernel.org Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | virtio_balloon: introduce migration primitives to balloon pagesRafael Aquini2012-12-111-19/+132
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be used within a guest, thus imposing performance penalties associated with the reduced number of transparent huge pages that could be used by the guest workload. Besides making balloon pages movable at allocation time and introducing the necessary primitives to perform balloon page migration/compaction, this patch also introduces the following locking scheme, in order to enhance the syncronization methods for accessing elements of struct virtio_balloon, thus providing protection against concurrent access introduced by parallel memory migration threads. - balloon_lock (mutex) : synchronizes the access demand to elements of struct virtio_balloon and its queue operations; [yongjun_wei@trendmicro.com.cn: fix missing unlock on error in fill_balloon()] [akpm@linux-foundation.org: avoid having multiple return points in fill_balloon()] [akpm@linux-foundation.org: fix printk warning]Signed-off-by: Rafael Aquini <aquini@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <andi@firstfloor.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | virtio: Don't access index after unregister.Cornelia Huck2012-11-091-1/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | Virtio wants to release used indices after the corresponding virtio device has been unregistered. However, virtio does not hold an extra reference, giving up its last reference with device_unregister(), making accessing dev->index afterwards invalid. I actually saw problems when testing my (not-yet-merged) virtio-ccw code: - device_add virtio-net,id=xxx -> creates device virtio<n> with n>0 - device_del xxx -> deletes virtio<n>, but calls ida_simple_remove with an index of 0 - device_add virtio-net,id=xxx -> tries to add virtio0, which is still in use... So let's save the index we want to release before calling device_unregister(). Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com> Cc: stable@kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio_mmio: Don't attempt to create empty virtqueuesBrian Foley2012-09-281-0/+10
| | | | | | | | | | | | | If a virtio device reports a QueueNumMax of 0, vring_new_virtqueue() doesn't check this, and thanks to an unsigned (i < num - 1) loop guard, scribbles over memory when initialising the free list. Avoid by not trying to create zero-descriptor queues, as there's no way to do any I/O with one. Signed-off-by: Brian Foley <brian.foley@arm.com> Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio_mmio: fix off by one error allocating queueBrian Foley2012-09-281-2/+2
| | | | | | | | | | | | | vm_setup_vq fails to allow VirtQueues needing only 2 pages of storage, as it should. Found with a kernel using 64kB pages, but can be provoked if a virtio device reports QueueNumMax where the descriptor table and available ring fit in one page, and the used ring on the second (<= 227 descriptors with 4kB pages and <= 3640 with 64kB pages.) Signed-off-by: Brian Foley <brian.foley@arm.com> Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* drivers/virtio/virtio_pci.c: fix error return codePeter Senna Tschudin2012-09-281-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert a nonnegative error return code to a negative one, as returned elsewhere in the function. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> ( if@p1 (\(ret < 0\|ret != 0\)) { ... return ret; } | ret@p1 = 0 ) ... when != ret = e1 when != &ret *if(...) { ... when != ret = e2 when forall return ret; } // </smpl> Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: don't crash when device is buggyMichael S. Tsirkin2012-09-281-1/+1
| | | | | | | | | | | Because of a sanity check in virtio_dev_remove, a buggy device can crash kernel. And in case of rproc it's userspace so it's not a good idea. We are unloading a driver so how bad can it be? Be less aggressive in handling this error: if it's a driver bug, warning once should be enough. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: remove CONFIG_VIRTIO_RINGRusty Russell2012-09-282-8/+1
| | | | | | | Everyone who selects VIRTIO is also made to select VIRTIO_RING; just make them synonymous, since we removed the indirection layer some time ago. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: add help to CONFIG_VIRTIO option.Rusty Russell2012-09-281-2/+4
| | | | | | | | | | | | | Trying to enable a virtio driver (eg CONFIG_VIRTIO_BLK) is painful because it depends on CONFIG_VIRTIO. CONFIG_VIRTIO doesn't tell you how to turn it on (it's selected from anything which provides a virtio bus). This patch at least adds some documentation, visible in menuconfig, as a hint. Reported-by: Kent Overstreet <koverstreet@google.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: support reserved vqsMichael S. Tsirkin2012-09-282-1/+7
| | | | | | | | | | | | | | | | virtio network device multiqueue support reserves vq 3 for future use (useful both for future extensions and to make it pretty - this way receive vqs have even and transmit - odd numbers). Make it possible to skip initialization for specific vq numbers by specifying NULL for name. Document this usage as well as (existing) NULL callback. Drivers using this not coded up yet, so I simply tested with virtio-pci and verified that this patch does not break existing drivers. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: introduce an API to set affinity for a virtqueueJason Wang2012-09-281-0/+46
| | | | | | | | | | | | | | | | | | | Sometimes, virtio device need to configure irq affinity hint to maximize the performance. Instead of just exposing the irq of a virtqueue, this patch introduce an API to set the affinity for a virtqueue. The api is best-effort, the affinity hint may not be set as expected due to platform support, irq sharing or irq type. Currently, only pci method were implemented and we set the affinity according to: - if device uses INTX, we just ignore the request - if device has per vq vector, we force the affinity hint - if the virtqueues share MSI, make the affinity OR over all affinities requested Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-ring: move queue_index to vring_virtqueueJason Wang2012-09-283-17/+22
| | | | | | | | | | | Instead of storing the queue index in transport-specific virtio structs, this patch moves them to vring_virtqueue and introduces an helper to get the value. This lets drivers simplify their management and tracing of virtqueues. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio_balloon: not EXPERIMENTAL any more.Rusty Russell2012-09-281-2/+2
| | | | | | | It is not experimental in any vaguely-sane sense. Reported-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-balloon: dependency fixMichael S. Tsirkin2012-09-281-2/+1
| | | | | | | | | | Devices should depend on virtio, not select it. It's supposed to be selected by the particular driver, e.g. VIRTIO_PCI. Make balloon depend on VIRTIO and EXPERIMENTAL (to match description). Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* [SCSI] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN ↵Nicholas Bellinger2012-07-201-1/+4
| | | | | | | | | | | | | | | | | | | | scanning This patch changes virtio-scsi to use a new virtio_driver->scan() callback so that scsi_scan_host() can be properly invoked once virtio_dev_probe() has set add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK) to signal active virtio-ring operation, instead of from within virtscsi_probe(). This fixes a bug where SCSI LUN scanning for both virtio-scsi-raw and virtio-scsi/tcm_vhost setups was happening before VIRTIO_CONFIG_S_DRIVER_OK had been set, causing VIRTIO_SCSI_S_BAD_TARGET to occur. This fixes a bug with virtio-scsi/tcm_vhost where LUN scan was not detecting LUNs. Tested with virtio-scsi-raw + virtio-scsi/tcm_vhost w/ IBLOCK on 3.5-rc2 code. Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* virtio-balloon: fix add/get API useMichael S. Tsirkin2012-07-091-14/+10
| | | | | | | | | | | | | | | | | Since ee7cd8981e15bcb365fc762afe3fc47b8242f630 'virtio: expose added descriptors immediately.', in virtio balloon virtqueue_get_buf might now run concurrently with virtqueue_kick. I audited both and this seems safe in practice but this is not guaranteed by the API. Additionally, a spurious interrupt might in theory make virtqueue_get_buf run in parallel with virtqueue_add_buf, which is racy. While we might try to protect against spurious callbacks it's easier to fix the driver: balloon seems to be the only one (mis)using the API like this, so let's just fix balloon. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
* virtio-mmio: Devices parameter parsingPawel Moll2012-05-222-0/+174
| | | | | | | | | | This patch adds an option to instantiate guest virtio-mmio devices basing on a kernel command line (or module) parameter, for example: virtio_mmio.devices=0x100@0x100b0000:48 Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: Use ida to allocate virtio indexAsias He2012-05-221-2/+9
| | | | | | | | | | | | | | Current index allocation in virtio is based on a monotonically increasing variable "index". This means we'll run out of numbers after a while. E.g. someone crazy doing this in host side. while(1) { hot-plug a virtio device hot-unplug the virito devcie } Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: balloon: separate out common code between remove and freeze functionsAmit Shah2012-05-221-14/+12
| | | | | | | | The remove and freeze functions have a lot of shared code; put it into a common function that gets called by both. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: balloon: drop restore_common()Amit Shah2012-05-221-6/+1
| | | | | | | | | | | | restore_common() was used when there were different thaw and freeze PM callbacks implemented. We removed thaw in commit f38f8387cbdc4138a492ce9f2a5f04fd3cd3cf33. restore_common() can be removed and virtballoon_restore() can itself do the restore ops. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: balloon: let host know of updated balloon size before module removalAmit Shah2012-05-171-0/+1
| | | | | | | | | | | | | When the balloon module is removed, we deflate the balloon, reclaiming all the pages that were given to the host. However, we don't update the config values for the new balloon size, resulting in the host showing outdated balloon values. The size update is done after each leak and fill operation, only the module removal case was left out. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio_balloon: fix handling of PAGE_SIZE != 4kMichael S. Tsirkin2012-04-151-10/+41
| | | | | | | | | | | | | | | | | | | As reported by David Gibson, current code handles PAGE_SIZE != 4k completely wrong which can lead to guest memory corruption errors: - page_to_balloon_pfn is wrong: e.g. on system with 64K page size it gives the same pfn value for 16 different pages. - we also need to convert back to linux pfns when we free. - for each linux page we need to tell host about multiple balloon pages, but code only adds one pfn to the array. This patch fixes all that, tested with a 64k ppc64 kernel. Reported-by: David Gibson <david@gibson.dropbear.id.au> Tested-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio_balloon: Fix endian bugDavid Gibson2012-04-151-2/+5
| | | | | | | | | | | | | | Although virtio config space fields are usually in guest-native endian, the spec for the virtio balloon device explicitly states that both fields in its config space are little-endian. However, the current virtio_balloon driver does not have a suitable endian swap for the 'num_pages' field, although it does have one for the 'actual' field. This patch corrects the bug, adding sparse annotation while we're at it. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-pci: switch to PM ops macro to initialise PM functionsAmit Shah2012-03-311-6/+1
| | | | | | | Use the SET_SYSTEM_SLEEP_PM_OPS macro to initialise the suspend/resume functions in the new PM API. Signed-off-by: Amit Shah <amit.shah@redhat.com>
* virtio-pci: S3 supportAmit Shah2012-03-311-21/+3
| | | | | | | | | There's no difference in supporting S3 and S4 for virtio devices: the vqs have to be re-created as the device has to be assumed to be reset at restore-time. Since S4 already handles this situation, we can directly use the same code and callbacks for S3 support. Signed-off-by: Amit Shah <amit.shah@redhat.com>
* virtio-pci: drop restore_common()Amit Shah2012-03-311-16/+7
| | | | | | | restore_common() was shared between restore and thaw callbacks. With thaw gone, we don't need restore_common() anymore. Signed-off-by: Amit Shah <amit.shah@redhat.com>
* virtio: drop thaw PM operationAmit Shah2012-03-312-33/+1
| | | | | | | The thaw operation was used by the balloon driver, but after the last commit there's no reason to have separate thaw and restore callbacks. Signed-off-by: Amit Shah <amit.shah@redhat.com>
* virtio: balloon: Allow stats update after restore from S4Amit Shah2012-03-311-8/+0
| | | | | | | | | There's no reason stats update after restore can't work. If a host requested for stats, and before servicing the request, the guest entered S4, upon restore, the stats request can still be processed and sent off to the host. Signed-off-by: Amit Shah <amit.shah@redhat.com>
* Remove all #inclusions of asm/system.hDavid Howells2012-03-281-1/+0
| | | | | | | | | Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *` Signed-off-by: David Howells <dhowells@redhat.com>
* virtio: balloon: leak / fill balloon across S4Amit Shah2012-03-011-11/+22
| | | | | | | | | | | | | | | | | | | | | | commit e562966dbaf49e7804097cd991e5d3a8934fc148 added support for S4 to the balloon driver. The freeze function did nothing to free the pages, since reclaiming the pages from the host to immediately give them back (if S4 was successful) seemed wasteful. Also, if S4 wasn't successful, the guest would have to re-fill the balloon. On restore, the pages were supposed to be marked freed and the free page counters were incremented to reflect the balloon was totally deflated. However, this wasn't done right. The pages that were earlier taken away from the guest during a balloon inflation operation were just shown as used pages after a successful restore from S4. Just a fancy way of leaking lots of memory. Instead of trying that, just leak the balloon on freeze and fill it on restore/thaw paths. This works properly now. The optimisation to not leak can be added later on after a bit of refactoring of the code. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: correct the memory barrier in virtqueue_kick_prepare()Jason Wang2012-01-281-3/+3
| | | | | | | | | | | | | Use virtio_mb() to make sure the available index to be exposed before checking the the avail event. Otherwise we may get stale value of avail event in guest and never kick the host after. Note: this fixes a bug introduced by ee7cd8981e15bcb365fc762afe3fc47b8242f630. Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: stable@kernel.org
* virtio: fix typos of memory barriersJason Wang2012-01-281-1/+1
| | | | | | | | | Note: this fixes a bug introduced recently in 7b21e34fd1c272e3a8c3846168f2f6287a4cd72b. Signed-off-by: Jason Wang <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: balloon: Add freeze, restore handlers to support S4Amit Shah2012-01-121-0/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Handling balloon hibernate / restore is tricky. If the balloon was inflated before going into the hibernation state, upon resume, the host will not have any memory of that. Any pages that were passed on to the host earlier would most likely be invalid, and the host will have to re-balloon to the previous value to get in the pre-hibernate state. So the only sane thing for the guest to do here is to discard all the pages that were put in the balloon. When to discard the pages is the next question. One solution is to deflate the balloon just before writing the image to the disk (in the freeze() PM callback). However, asking for pages from the host just to discard them immediately after seems wasteful of resources. Hence, it makes sense to do this by just fudging our counters soon after wakeup. This means we don't deflate the balloon before sleep, and also don't put unnecessary pressure on the host. This also helps in the thaw case: if the freeze fails for whatever reason, the balloon should continue to remain in the inflated state. This was tested by issuing 'swapoff -a' and trying to go into the S4 state. That fails, and the balloon stays inflated, as expected. Both the host and the guest are happy. Finally, in the restore() callback, we empty the list of pages that were previously given off to the host, add the appropriate number of pages to the totalram_pages counter, reset the num_pages counter to 0, and all is fine. As a last step, delete the vqs on the freeze callback to prepare for hibernation, and re-create them in the restore and thaw callbacks to resume normal operation. The kthread doesn't race with any operations here, since it's frozen before the freeze() call and is thawed after the thaw() and restore() callbacks, so we're safe with that. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: balloon: Move vq initialization into separate functionAmit Shah2012-01-121-18/+30
| | | | | | | The probe and PM restore functions will share this code. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: pci: add PM notification handlers for restore, freeze, thaw, poweroffAmit Shah2012-01-121-2/+92
| | | | | | | | | | | | | | Handle thaw, restore and freeze notifications from the PM core. Expose these to individual virtio drivers that can quiesce and resume vq operations. For drivers not implementing the thaw() method, use the restore method instead. These functions also save device-specific data so that the device can be put in pre-suspend state after resume, and disable and enable the PCI device in the freeze and resume functions, respectively. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: pci: switch to new PM APIAmit Shah2012-01-121-4/+12
| | | | | | | | The older PM API doesn't have a way to get notifications on hibernate events. Switch to the newer one that gives us those notifications. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: add debugging if driver doesn't kick.Rusty Russell2012-01-121-0/+31
| | | | | | | | | | | Under the existing #ifdef DEBUG, check that they don't have more than 1/10 of a second between an add_buf() and a virtqueue_notify()/virtqueue_kick_prepare() call. We could get false positives on a really busy system, but good for development. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: expose added descriptors immediately.Rusty Russell2012-01-121-6/+14
| | | | | | | | | | | | | | | | A virtio driver does virtqueue_add_buf() multiple times before finally calling virtqueue_kick(); previously we only exposed the added buffers in the virtqueue_kick() call. This means we don't need a memory barrier in virtqueue_add_buf(), but it reduces concurrency as the device (ie. host) can't see the buffers until the kick. In the unusual (but now possible) case where a driver does add_buf() and get_buf() without doing a kick, we do need to insert one before our counter wraps. Otherwise we could wrap num_added, and later on not realize that we have passed the marker where we should have kicked. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: avoid modulus operation.Rusty Russell2012-01-121-4/+6
| | | | | | | Since we know vq->vring.num is a power of 2, modulus is lazy (it's asserted in vring_new_virtqueue()). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: support unlocked queue kickRusty Russell2012-01-121-12/+48
| | | | | | | | | | | | | | | | | | | | Based on patch by Christoph for virtio_blk speedup: Split virtqueue_kick to be able to do the actual notification outside the lock protecting the virtqueue. This patch was originally done by Stefan Hajnoczi, but I can't find the original one anymore and had to recreated it from memory. Pointers to the original or corrections for the commit message are welcome. Stefan's patch was here: https://github.com/stefanha/linux/commit/a6d06644e3a58e57a774e77d7dc34c4a5a2e7496 http://www.spinics.net/lists/linux-virtualization/msg14616.html Third time's the charm! Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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