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authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-20 09:24:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-20 09:24:01 -0700
commit4a5bb973fa0353d25dbe854694c71bb58eb4cf78 (patch)
tree599b573d63e143df6cd1abf5dab8aae49b734a28 /drivers/block
parent709ebe6dff50405ae83551578bc08c0f78b05158 (diff)
parent5f7f77400ab5b357b5fdb7122c3442239672186c (diff)
Merge tag 'for-linus-5.10b-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull more xen updates from Juergen Gross: - A single patch to fix the Xen security issue XSA-331 (malicious guests can DoS dom0 by triggering NULL-pointer dereferences or access to stale data). - A larger series to fix the Xen security issue XSA-332 (malicious guests can DoS dom0 by sending events at high frequency leading to dom0's vcpus being busy in IRQ handling for elongated times). * tag 'for-linus-5.10b-rc1b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/events: block rogue events for some time xen/events: defer eoi in case of excessive number of events xen/events: use a common cpu hotplug hook for event channels xen/events: switch user event channels to lateeoi model xen/pciback: use lateeoi irq binding xen/pvcallsback: use lateeoi irq binding xen/scsiback: use lateeoi irq binding xen/netback: use lateeoi irq binding xen/blkback: use lateeoi irq binding xen/events: add a new "late EOI" evtchn framework xen/events: fix race in evtchn_fifo_unmask() xen/events: add a proper barrier to 2-level uevent unmasking xen/events: avoid removing an event channel while handling it
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/xen-blkback/blkback.c22
-rw-r--r--drivers/block/xen-blkback/xenbus.c5
2 files changed, 19 insertions, 8 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index adfc9352351d..501e9dacfff9 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -201,7 +201,7 @@ static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int num)
#define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
-static int do_block_io_op(struct xen_blkif_ring *ring);
+static int do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags);
static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
struct blkif_request *req,
struct pending_req *pending_req);
@@ -612,6 +612,8 @@ int xen_blkif_schedule(void *arg)
struct xen_vbd *vbd = &blkif->vbd;
unsigned long timeout;
int ret;
+ bool do_eoi;
+ unsigned int eoi_flags = XEN_EOI_FLAG_SPURIOUS;
set_freezable();
while (!kthread_should_stop()) {
@@ -636,16 +638,23 @@ int xen_blkif_schedule(void *arg)
if (timeout == 0)
goto purge_gnt_list;
+ do_eoi = ring->waiting_reqs;
+
ring->waiting_reqs = 0;
smp_mb(); /* clear flag *before* checking for work */
- ret = do_block_io_op(ring);
+ ret = do_block_io_op(ring, &eoi_flags);
if (ret > 0)
ring->waiting_reqs = 1;
if (ret == -EACCES)
wait_event_interruptible(ring->shutdown_wq,
kthread_should_stop());
+ if (do_eoi && !ring->waiting_reqs) {
+ xen_irq_lateeoi(ring->irq, eoi_flags);
+ eoi_flags |= XEN_EOI_FLAG_SPURIOUS;
+ }
+
purge_gnt_list:
if (blkif->vbd.feature_gnt_persistent &&
time_after(jiffies, ring->next_lru)) {
@@ -1121,7 +1130,7 @@ static void end_block_io_op(struct bio *bio)
* and transmute it to the block API to hand it over to the proper block disk.
*/
static int
-__do_block_io_op(struct xen_blkif_ring *ring)
+__do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags)
{
union blkif_back_rings *blk_rings = &ring->blk_rings;
struct blkif_request req;
@@ -1144,6 +1153,9 @@ __do_block_io_op(struct xen_blkif_ring *ring)
if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
break;
+ /* We've seen a request, so clear spurious eoi flag. */
+ *eoi_flags &= ~XEN_EOI_FLAG_SPURIOUS;
+
if (kthread_should_stop()) {
more_to_do = 1;
break;
@@ -1202,13 +1214,13 @@ done:
}
static int
-do_block_io_op(struct xen_blkif_ring *ring)
+do_block_io_op(struct xen_blkif_ring *ring, unsigned int *eoi_flags)
{
union blkif_back_rings *blk_rings = &ring->blk_rings;
int more_to_do;
do {
- more_to_do = __do_block_io_op(ring);
+ more_to_do = __do_block_io_op(ring, eoi_flags);
if (more_to_do)
break;
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index b9aa5d1ac10b..5e7c36d73dc6 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -246,9 +246,8 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref,
if (req_prod - rsp_prod > size)
goto fail;
- err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn,
- xen_blkif_be_int, 0,
- "blkif-backend", ring);
+ err = bind_interdomain_evtchn_to_irqhandler_lateeoi(blkif->domid,
+ evtchn, xen_blkif_be_int, 0, "blkif-backend", ring);
if (err < 0)
goto fail;
ring->irq = err;