kernel/linux.git/drivers/virtio, branch linux-4.20.y

virtio-balloon: tweak config_changed implementation

2019-01-22T20:09:52+00:00

commit bf4dc0b2beebfd9338df7c0bcf473b356f67cf66 upstream. virtio-ccw has deadlock issues with reading the config space inside the interrupt context, so we tweak the virtballoon_changed implementation by moving the config read operations into the related workqueue contexts. The config_read_bitmap is used as a flag to the workqueue callbacks about the related config fields that need to be read. The cmd_id_received is also renamed to cmd_id_received_cache, and the value should be obtained via virtio_balloon_cmd_id_received. Reported-by: Christian Borntraeger Signed-off-by: Wei Wang Reviewed-by: Cornelia Huck Reviewed-by: Halil Pasic Signed-off-by: Michael S. Tsirkin Cc: stable@vger.kernel.org Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Tested-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman

virtio: don't allocate vqs when names[i] = NULL

2019-01-22T20:09:52+00:00

commit a229989d975eb926076307c1f2f5e4c6111768e7 upstream. Some vqs may not need to be allocated when their related feature bits are disabled. So callers may pass in such vqs with "names = NULL". Then we skip such vq allocations. Signed-off-by: Wei Wang Signed-off-by: Michael S. Tsirkin Signed-off-by: Wei Wang Signed-off-by: Wei Wang Reviewed-by: Cornelia Huck Cc: stable@vger.kernel.org Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT") Signed-off-by: Greg Kroah-Hartman

virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON

2018-10-25T00:57:55+00:00

The VIRTIO_BALLOON_F_PAGE_POISON feature bit is used to indicate if the guest is using page poisoning. Guest writes to the poison_val config field to tell host about the page poisoning value that is in use. Suggested-by: Michael S. Tsirkin Signed-off-by: Wei Wang Cc: Michael S. Tsirkin Cc: Michal Hocko Cc: Andrew Morton Signed-off-by: Michael S. Tsirkin

virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT

2018-10-25T00:57:55+00:00

Negotiation of the VIRTIO_BALLOON_F_FREE_PAGE_HINT feature indicates the support of reporting hints of guest free pages to host via virtio-balloon. Currenlty, only free page blocks of MAX_ORDER - 1 are reported. They are obtained one by one from the mm free list via the regular allocation function. Host requests the guest to report free page hints by sending a new cmd id to the guest via the free_page_report_cmd_id configuration register. When the guest starts to report, it first sends a start cmd to host via the free page vq, which acks to host the cmd id received. When the guest finishes reporting free pages, a stop cmd is sent to host via the vq. Host may also send a stop cmd id to the guest to stop the reporting. VIRTIO_BALLOON_CMD_ID_STOP: Host sends this cmd to stop the guest reporting. VIRTIO_BALLOON_CMD_ID_DONE: Host sends this cmd to tell the guest that the reported pages are ready to be freed. Why does the guest free the reported pages when host tells it is ready to free? This is because freeing pages appears to be expensive for live migration. free_pages() dirties memory very quickly and makes the live migraion not converge in some cases. So it is good to delay the free_page operation when the migration is done, and host sends a command to guest about that. Why do we need the new VIRTIO_BALLOON_CMD_ID_DONE, instead of reusing VIRTIO_BALLOON_CMD_ID_STOP? This is because live migration is usually done in several rounds. At the end of each round, host needs to send a VIRTIO_BALLOON_CMD_ID_STOP cmd to the guest to stop (or say pause) the reporting. The guest resumes the reporting when it receives a new command id at the beginning of the next round. So we need a new cmd id to distinguish between "stop reporting" and "ready to free the reported pages". TODO: - Add a batch page allocation API to amortize the allocation overhead. Signed-off-by: Wei Wang Signed-off-by: Liang Li Cc: Michael S. Tsirkin Cc: Michal Hocko Cc: Andrew Morton Cc: Linus Torvalds Signed-off-by: Michael S. Tsirkin

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2018-08-24T15:45:19+00:00

Pull virtio updates from Michael Tsirkin: "virtio, vhost: fixes, tweaks No new features but a bunch of tweaks such as switching balloon from oom notifier to shrinker" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost/scsi: increase VHOST_SCSI_PREALLOC_PROT_SGLS to 2048 vhost: allow vhost-scsi driver to be built-in virtio: pci-legacy: Validate queue pfn virtio: mmio-v1: Validate queue PFN virtio_balloon: replace oom notifier with shrinker virtio-balloon: kzalloc the vb struct virtio-balloon: remove BUG() in init_vqs

virtio: pci-legacy: Validate queue pfn

2018-08-21T21:56:58+00:00

Legacy PCI over virtio uses a 32bit PFN for the queue. If the queue pfn is too large to fit in 32bits, which we could hit on arm64 systems with 52bit physical addresses (even with 64K page size), we simply miss out a proper link to the other side of the queue. Add a check to validate the PFN, rather than silently breaking the devices. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Marc Zyngier Cc: Christoffer Dall Cc: Peter Maydel Cc: Jean-Philippe Brucker Signed-off-by: Suzuki K Poulose Signed-off-by: Michael S. Tsirkin

virtio: mmio-v1: Validate queue PFN

2018-08-21T21:56:56+00:00

virtio-mmio with virtio-v1 uses a 32bit PFN for the queue. If the queue pfn is too large to fit in 32bits, which we could hit on arm64 systems with 52bit physical addresses (even with 64K page size), we simply miss out a proper link to the other side of the queue. Add a check to validate the PFN, rather than silently breaking the devices. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Marc Zyngier Cc: Christoffer Dall Cc: Peter Maydel Cc: Jean-Philippe Brucker Signed-off-by: Suzuki K Poulose Signed-off-by: Michael S. Tsirkin

virtio_balloon: replace oom notifier with shrinker

2018-08-21T21:56:24+00:00

The OOM notifier is getting deprecated to use for the reasons: - As a callout from the oom context, it is too subtle and easy to generate bugs and corner cases which are hard to track; - It is called too late (after the reclaiming has been performed). Drivers with large amuont of reclaimable memory is expected to release them at an early stage of memory pressure; - The notifier callback isn't aware of oom contrains; Link: https://lkml.org/lkml/2018/7/12/314 This patch replaces the virtio-balloon oom notifier with a shrinker to release balloon pages on memory pressure. The balloon pages are given back to mm adaptively by returning the number of pages that the reclaimer is asking for (i.e. sc->nr_to_scan). Currently the max possible value of sc->nr_to_scan passed to the balloon shrinker is SHRINK_BATCH, which is 128. This is smaller than the limitation that only VIRTIO_BALLOON_ARRAY_PFNS_MAX (256) pages can be returned via one invocation of leak_balloon. But this patch still considers the case that SHRINK_BATCH or shrinker->batch could be changed to a value larger than VIRTIO_BALLOON_ARRAY_PFNS_MAX, which will need to do multiple invocations of leak_balloon. Historically, the feature VIRTIO_BALLOON_F_DEFLATE_ON_OOM has been used to release balloon pages on OOM. We continue to use this feature bit for the shrinker, so the shrinker is only registered when this feature bit has been negotiated with host. Signed-off-by: Wei Wang Cc: Michael S. Tsirkin Cc: Michal Hocko Cc: Andrew Morton Cc: Tetsuo Handa Signed-off-by: Michael S. Tsirkin

virtio-balloon: kzalloc the vb struct

2018-08-21T21:56:24+00:00

Zero all the vb fields at alloaction, so that we don't need to zero-initialize each field one by one later. Signed-off-by: Wei Wang Cc: Michael S. Tsirkin Cc: Tetsuo Handa Signed-off-by: Michael S. Tsirkin

virtio-balloon: remove BUG() in init_vqs

2018-08-21T21:56:24+00:00

It's a bit overkill to use BUG when failing to add an entry to the stats_vq in init_vqs. So remove it and just return the error to the caller to bail out nicely. Signed-off-by: Wei Wang Cc: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin