On Thu, Aug 26, 2021 at 12:50:34AM +0200, Philippe Mathieu-Daudé wrote: > On 8/25/21 10:36 PM, Philippe Mathieu-Daudé wrote: > > On 8/25/21 10:09 PM, Philippe Mathieu-Daudé wrote: > >> Do not intent to access the vring MemoryRegion cache if > >> the queue is not ready (no vring available). > >> > >> This fixes issue #301: > >> > >> qemu-system-i386: include/exec/memory_ldst_cached.h.inc:77: void > >> address_space_stw_le_cached(MemoryRegionCache *, hwaddr, uint16_t, > >> MemTxAttrs, MemTxResult *): > >> Assertion `addr < cache->len && 2 <= cache->len - addr' failed. > >> Thread 1 "qemu-system-i38" received signal SIGABRT, Aborted. > >> (gdb) bt > >> #1 0x00007ffff4d1a8a4 in abort () at /lib64/libc.so.6 > >> #4 0x0000555558f2a122 in address_space_stw_le_cached > >> (cache=0x61300010bb70, addr=516, val=0, attrs=..., result=0x0) at > >> include/exec/memory_ldst_cached.h.inc:77 > >> #5 0x0000555558f2964c in stw_le_phys_cached (cache=0x61300010bb70, > >> addr=516, val=0) at include/exec/memory_ldst_phys.h.inc:109 > >> #6 0x0000555558f28da8 in virtio_stw_phys_cached (vdev=0x62d00004e680, > >> cache=0x61300010bb70, pa=516, value=0) at > >> include/hw/virtio/virtio-access.h:196 > >> #7 0x0000555558f287dc in vring_set_avail_event (vq=0x7fff5d23e800, > >> val=0) at hw/virtio/virtio.c:428 > >> #8 0x0000555558efabb7 in virtio_queue_split_set_notification > >> (vq=0x7fff5d23e800, enable=1) at hw/virtio/virtio.c:437 > >> #9 0x0000555558ef9f3c in virtio_queue_set_notification > >> (vq=0x7fff5d23e800, enable=1) at hw/virtio/virtio.c:498 > >> #10 0x0000555558c94786 in virtio_blk_handle_vq (s=0x62d00004e680, > >> vq=0x7fff5d23e800) at hw/block/virtio-blk.c:795 > >> #11 0x0000555558cb96c2 in virtio_blk_data_plane_handle_output > >> (vdev=0x62d00004e680, vq=0x7fff5d23e800) at > >> hw/block/dataplane/virtio-blk.c:165 > >> #12 0x0000555558f35937 in virtio_queue_notify_aio_vq (vq=0x7fff5d23e800) > >> at hw/virtio/virtio.c:2323 > >> #13 0x0000555558f264b3 in virtio_queue_host_notifier_aio_read > >> (n=0x7fff5d23e87c) at hw/virtio/virtio.c:3532 > >> #14 0x0000555559a9cd3e in aio_dispatch_handler (ctx=0x613000063000, > >> node=0x60d000008f40) at util/aio-posix.c:329 > >> #15 0x0000555559a963ae in aio_dispatch_handlers (ctx=0x613000063000) at > >> util/aio-posix.c:372 > >> #16 0x0000555559a95f82 in aio_dispatch (ctx=0x613000063000) at > >> util/aio-posix.c:382 > >> > >> and #302: > >> > >> qemu-system-i386: include/exec/memory_ldst_cached.h.inc:30: uint16_t > >> address_space_lduw_le_cached(MemoryRegionCache *, hwaddr, MemTxAttrs, > >> MemTxResult *): > >> Assertion `addr < cache->len && 2 <= cache->len - addr' failed. > >> Thread 1 "qemu-system-i38" received signal SIGABRT, Aborted. > >> 0x00007ffff4d312a2 in raise () from /lib64/libc.so.6 > >> (gdb) bt > >> #1 0x00007ffff4d1a8a4 in abort () at /lib64/libc.so.6 > >> #4 0x0000555558f2b8ec in address_space_lduw_le_cached > >> (cache=0x61300010a7c0, addr=134, attrs=..., result=0x0) at > >> include/exec/memory_ldst_cached.h.inc:30 > >> #5 0x0000555558f2ac6b in lduw_le_phys_cached (cache=0x61300010a7c0, > >> addr=134) at include/exec/memory_ldst_phys.h.inc:67 > >> #6 0x0000555558f2a3cd in virtio_lduw_phys_cached (vdev=0x62d00003a680, > >> cache=0x61300010a7c0, pa=134) at include/hw/virtio/virtio-access.h:166 > >> #7 0x0000555558f300ea in vring_avail_ring (vq=0x7fffdd55d8a0, i=65) at > >> hw/virtio/virtio.c:326 > >> #8 0x0000555558f33b10 in vring_get_used_event (vq=0x7fffdd55d8a0) at > >> hw/virtio/virtio.c:332 > >> #9 0x0000555558f33677 in virtio_split_should_notify > >> (vdev=0x62d00003a680, vq=0x7fffdd55d8a0) at hw/virtio/virtio.c:2471 > >> #10 0x0000555558f1859f in virtio_should_notify (vdev=0x62d00003a680, > >> vq=0x7fffdd55d8a0) at hw/virtio/virtio.c:2523 > >> #11 0x0000555558f188cc in virtio_notify (vdev=0x62d00003a680, > >> vq=0x7fffdd55d8a0) at hw/virtio/virtio.c:2565 > >> #12 0x0000555557c2bd52 in virtio_input_handle_sts (vdev=0x62d00003a680, > >> vq=0x7fffdd55d8a0) at hw/input/virtio-input.c:100 > >> #13 0x0000555558f16df7 in virtio_queue_notify (vdev=0x62d00003a680, n=1) > >> at hw/virtio/virtio.c:2363 > >> #14 0x00005555583f45c0 in virtio_pci_notify_write > >> (opaque=0x62d000032400, addr=7, val=0, size=1) at > >> hw/virtio/virtio-pci.c:1369 > >> #15 0x0000555558b80b04 in memory_region_write_accessor > >> (mr=0x62d000033190, addr=7, value=0x7fffffff8eb0, size=1, shift=0, > >> mask=255, attrs=...) at softmmu/memory.c:492 > >> > >> Reported-by: Cheolwoo Myung <cwmy...@snu.ac.kr> > >> Reported-by: Qiuhao Li <qiuhao...@outlook.com> > >> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/301 > >> BugLink: https://bugs.launchpad.net/qemu/+bug/1910941 > >> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/302 > >> BugLink: https://bugs.launchpad.net/qemu/+bug/1913510 > >> Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com> > >> --- > >> Could be more readable to use virtio_queue_ready() > >> > >> RFC because I have no clue about this hot path code, > >> I simply looked at the backtraces. > >> --- > >> hw/virtio/virtio.c | 82 +++++++++++++++++++++++++++++++++++++--------- > >> 1 file changed, 66 insertions(+), 16 deletions(-) > >> > >> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > >> index 874377f37a7..be1ec9e05ef 100644 > >> --- a/hw/virtio/virtio.c > >> +++ b/hw/virtio/virtio.c > >> @@ -289,26 +289,38 @@ static VRingMemoryRegionCaches > >> *vring_get_region_caches(struct VirtQueue *vq) > >> /* Called within rcu_read_lock(). */ > >> static inline uint16_t vring_avail_flags(VirtQueue *vq) > >> { > >> - VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); > >> - hwaddr pa = offsetof(VRingAvail, flags); > >> + VRingMemoryRegionCaches *caches; > >> + hwaddr pa; > >> > >> + if (unlikely(!vq->vring.avail)) { > >> + return 0; > >> + } > >> + > >> + caches = vring_get_region_caches(vq); > >> if (!caches) { > >> return 0; > >> } > >> > >> + pa = offsetof(VRingAvail, flags); > >> return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); > >> } > >> > >> /* Called within rcu_read_lock(). */ > >> static inline uint16_t vring_avail_idx(VirtQueue *vq) > >> { > >> - VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); > >> - hwaddr pa = offsetof(VRingAvail, idx); > >> + VRingMemoryRegionCaches *caches; > >> + hwaddr pa; > >> > >> + if (unlikely(!vq->vring.avail)) { > >> + return 0; > >> + } > >> + > >> + caches = vring_get_region_caches(vq); > >> if (!caches) { > >> return 0; > >> } > >> > >> + pa = offsetof(VRingAvail, idx); > >> vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, > >> &caches->avail, pa); > >> return vq->shadow_avail_idx; > >> } > >> @@ -316,13 +328,19 @@ static inline uint16_t vring_avail_idx(VirtQueue *vq) > >> /* Called within rcu_read_lock(). */ > >> static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) > >> { > >> - VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); > >> - hwaddr pa = offsetof(VRingAvail, ring[i]); > >> + VRingMemoryRegionCaches *caches; > >> + hwaddr pa; > >> > >> + if (unlikely(!vq->vring.avail)) { > >> + return 0; > >> + } > >> + > >> + caches = vring_get_region_caches(vq); > >> if (!caches) { > >> return 0; > >> } > >> > >> + pa = offsetof(VRingAvail, ring[i]); > >> return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); > >> } > > > > Self-NAck. > > > > While the previous part could be OK, what follows is crap (checking > > avail instead of used) so please disregard this patch. > > Previous part is also crap :/
The topic reminds me of:
commit abdd16f4681cc4d6bf84990227b5c9b98e869ccd
Author: Stefan Hajnoczi <stefa...@redhat.com>
Date: Fri Feb 7 10:46:19 2020 +0000
virtio: gracefully handle invalid region caches
Stefan
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