blackbird-op-linux/drivers/virtio, branch v4.4.25

virtio: fix memory leak in virtqueue_add()

2016-09-07T06:32:36+00:00

commit 58625edf9e2515ed41dac2a24fa8004030a87b87 upstream. When using the indirect buffers feature, 'desc' is allocated in virtqueue_add() but isn't freed before leaving on a ring full error, causing a memory leak. For example, it seems rather clear that this can trigger with virtio net if mergeable buffers are not used. Signed-off-by: Wei Yongjun Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

balloon: check the number of available pages in leak balloon

2016-08-20T16:09:23+00:00

commit 37cf99e08c6fb4dcea0f9ad2b13b6daa8c76a711 upstream. The balloon has a special mechanism that is subscribed to the oom notification which leads to deflation for a fixed number of pages. The number is always fixed even when the balloon is fully deflated. But leak_balloon did not expect that the pages to deflate will be more than taken, and raise a "BUG" in balloon_page_dequeue when page list will be empty. So, the simplest solution would be to check that the number of releases pages is less or equal to the number taken pages. Signed-off-by: Konstantin Neumoin Signed-off-by: Denis V. Lunev CC: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_balloon: fix PFN format for virtio-1

2016-07-27T16:47:34+00:00

commit 87c9403b0d1de4676b0bd273eea68fcf6de68e68 upstream. Everything should be LE when using virtio-1, but the linux balloon driver does not seem to care about that. Reported-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Tested-by: Cornelia Huck Reviewed-by: Cornelia Huck Signed-off-by: Greg Kroah-Hartman

virtio: virtio 1.0 cs04 spec compliance for reset

2016-04-20T06:42:10+00:00

commit 05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c upstream. The spec says: after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Greg Kroah-Hartman

virtio_pci: fix use after free on release

2016-03-03T23:07:18+00:00

commit 2989be09a8a9d62a785137586ad941f916e08f83 upstream. KASan detected a use-after-free error in virtio-pci remove code. In virtio_pci_remove(), vp_dev is still used after being freed in unregister_virtio_device() (in virtio_pci_release_dev() more precisely). To fix, keep a reference until cleanup is done. Fixes: 63bd62a08ca4 ("virtio_pci: defer kfree until release callback") Reported-by: Jerome Marchand Cc: Sasha Levin Signed-off-by: Michael S. Tsirkin Tested-by: Jerome Marchand Signed-off-by: Greg Kroah-Hartman

virtio_balloon: fix race by fill and leak

2016-03-03T23:07:17+00:00

commit f68b992bbb474641881932c61c92dcfa6f5b3689 upstream. During my compaction-related stuff, I encountered a bug with ballooning. With repeated inflating and deflating cycle, guest memory( ie, cat /proc/meminfo | grep MemTotal) is decreased and couldn't be recovered. The reason is balloon_lock doesn't cover release_pages_balloon so struct virtio_balloon fields could be overwritten by race of fill_balloon(e,g, vb->*pfns could be critical). This patch fixes it in my test. Signed-off-by: Minchan Kim Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

virtio_ring: shadow available ring flags & index

2015-12-07T15:28:11+00:00

Improves cacheline transfer flow of available ring header. Virtqueues are implemented as a pair of rings, one producer->consumer avail ring and one consumer->producer used ring; preceding the avail ring in memory are two contiguous u16 fields -- avail->flags and avail->idx. A producer posts work by writing to avail->idx and a consumer reads avail->idx. The flags and idx fields only need to be written by a producer CPU and only read by a consumer CPU; when the producer and consumer are running on different CPUs and the virtio_ring code is structured to only have source writes/sink reads, we can continuously transfer the avail header cacheline between 'M' states between cores. This flow optimizes core -> core bandwidth on certain CPUs. (see: "Software Optimization Guide for AMD Family 15h Processors", Section 11.6; similar language appears in the 10h guide and should apply to CPUs w/ exclusive caches, using LLC as a transfer cache) Unfortunately the existing virtio_ring code issued reads to the avail->idx and read-modify-writes to avail->flags on the producer. This change shadows the flags and index fields in producer memory; the vring code now reads from the shadows and only ever writes to avail->flags and avail->idx, allowing the cacheline to transfer core -> core optimally. In a concurrent version of vring_bench, the time required for 10,000,000 buffer checkout/returns was reduced by ~2% (average across many runs) on an AMD Piledriver (15h) CPU: (w/o shadowing): Performance counter stats for './vring_bench': 5,451,082,016 L1-dcache-loads ... 2.221477739 seconds time elapsed (w/ shadowing): Performance counter stats for './vring_bench': 5,405,701,361 L1-dcache-loads ... 2.168405376 seconds time elapsed The further away (in a NUMA sense) virtio producers and consumers are from each other, the more we expect to benefit. Physical implementations of virtio devices and implementations of virtio where the consumer polls vring avail indexes (vhost) should also benefit. Signed-off-by: Venkatesh Srinivas Signed-off-by: Michael S. Tsirkin

virtio: Do not drop __GFP_HIGH in alloc_indirect

2015-12-07T15:28:11+00:00

b92b1b89a33c ("virtio: force vring descriptors to be allocated from lowmem") tried to exclude highmem pages for descriptors so it cleared __GFP_HIGHMEM from a given gfp mask. The patch also cleared __GFP_HIGH which doesn't make much sense for this fix because __GFP_HIGH only controls access to memory reserves and it doesn't have any influence on the zone selection. Some of the call paths use GFP_ATOMIC and dropping __GFP_HIGH will reduce their changes for success because the lack of access to memory reserves. Signed-off-by: Michal Hocko Signed-off-by: Michael S. Tsirkin Acked-by: Will Deacon Reviewed-by: Mel Gorman

virtio: fix memory leak of virtio ida cache layers

2015-12-07T15:28:01+00:00

The virtio core uses a static ida named virtio_index_ida for assigning index numbers to virtio devices during registration. The ida core may allocate some internal idr cache layers and an ida bitmap upon any ida allocation, and all these layers are truely freed only upon the ida destruction. The virtio_index_ida is not destroyed at present, leading to a memory leak when using the virtio core as a module and atleast one virtio device is registered and unregistered. Fix this by invoking ida_destroy() in the virtio core module exit. Cc: stable@vger.kernel.org Signed-off-by: Suman Anna Signed-off-by: Michael S. Tsirkin

virtio_balloon: do not change memory amount visible via /proc/meminfo

2015-09-08T10:32:11+00:00

Balloon device is frequently used as a mean of cooperative memory control in between guest and host to manage memory overcommitment. This is the typical case for any hosting workload when KVM guest is provided for end-user. Though there is a problem in this setup. The end-user and hosting provider have signed SLA agreement in which some amount of memory is guaranted for the guest. The good thing is that this memory will be given to the guest when the guest will really need it (f.e. with OOM in guest and with VIRTIO_BALLOON_F_DEFLATE_ON_OOM configuration flag set). The bad thing is that end-user does not know this. Balloon by default reduce the amount of memory exposed to the end-user each time when the page is stolen from guest or returned back by using adjust_managed_page_count and thus /proc/meminfo shows reduced amount of memory. Fortunately the solution is simple, we should just avoid to call adjust_managed_page_count with VIRTIO_BALLOON_F_DEFLATE_ON_OOM set. Signed-off-by: Denis V. Lunev CC: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin