From 58f423fbd5f7f435e8dc56dfa565b043d20d1e1b Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 9 Jul 2014 19:17:30 +0200 Subject: dma-helpers: Fix too long qiov If the size of the scatter/gather list isn't a multiple of 512, the number of sectors for the block layer request is rounded down, resulting in a qiov that doesn't match the request length. Truncate the qiov to the new length of the request. This fixes the IDE qtest case /x86_64/ide/bmdma/short_prdt. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- dma-helpers.c | 4 ++++ include/qemu-common.h | 1 + util/iov.c | 13 +++++++++++++ 3 files changed, 18 insertions(+) diff --git a/dma-helpers.c b/dma-helpers.c index 53cbe92..499b52b 100644 --- a/dma-helpers.c +++ b/dma-helpers.c @@ -170,6 +170,10 @@ static void dma_bdrv_cb(void *opaque, int ret) return; } + if (dbs->iov.size & ~BDRV_SECTOR_MASK) { + qemu_iovec_discard_back(&dbs->iov, dbs->iov.size & ~BDRV_SECTOR_MASK); + } + dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov, dbs->iov.size / 512, dma_bdrv_cb, dbs); assert(dbs->acb); diff --git a/include/qemu-common.h b/include/qemu-common.h index ae76197..6ef8282 100644 --- a/include/qemu-common.h +++ b/include/qemu-common.h @@ -329,6 +329,7 @@ size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, int fillc, size_t bytes); ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b); void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf); +void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes); bool buffer_is_zero(const void *buf, size_t len); diff --git a/util/iov.c b/util/iov.c index 2b4f46d..24566c8 100644 --- a/util/iov.c +++ b/util/iov.c @@ -550,3 +550,16 @@ size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, return total; } + +void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes) +{ + size_t total; + unsigned int niov = qiov->niov; + + assert(qiov->size >= bytes); + total = iov_discard_back(qiov->iov, &niov, bytes); + assert(total == bytes); + + qiov->niov = niov; + qiov->size -= bytes; +} -- cgit v1.1