From 1d8c11d631545ee43aff16b0763aff7181b61f20 Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Tue, 17 Nov 2015 15:06:25 -0500 Subject: [PATCH] ide: add support for IDEBufferedRequest this patch adds a new aio readv compatible function which copies all data through a bounce buffer. These buffered requests can be flagged as orphaned which means that their original callback has already been invoked and the request has just not been completed by the backend storage. The bounce buffer guarantees that guest memory corruption is avoided when such a orphaned request is completed by the backend at a later stage. This trick only works for read requests as a write request completed at a later stage might corrupt data as there is no way to control if and what data has already been written to the storage. Signed-off-by: Peter Lieven Reviewed-by: Fam Zheng Message-id: 1447345846-15624-4-git-send-email-pl@kamp.de Signed-off-by: John Snow --- hw/ide/core.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ hw/ide/internal.h | 14 ++++++++++++++ 2 files changed, 61 insertions(+) diff --git a/hw/ide/core.c b/hw/ide/core.c index 2725dd3b81..1470737e34 100644 --- a/hw/ide/core.c +++ b/hw/ide/core.c @@ -561,6 +561,53 @@ static bool ide_sect_range_ok(IDEState *s, return true; } +static void ide_buffered_readv_cb(void *opaque, int ret) +{ + IDEBufferedRequest *req = opaque; + if (!req->orphaned) { + if (!ret) { + qemu_iovec_from_buf(req->original_qiov, 0, req->iov.iov_base, + req->original_qiov->size); + } + req->original_cb(req->original_opaque, ret); + } + QLIST_REMOVE(req, list); + qemu_vfree(req->iov.iov_base); + g_free(req); +} + +#define MAX_BUFFERED_REQS 16 + +BlockAIOCB *ide_buffered_readv(IDEState *s, int64_t sector_num, + QEMUIOVector *iov, int nb_sectors, + BlockCompletionFunc *cb, void *opaque) +{ + BlockAIOCB *aioreq; + IDEBufferedRequest *req; + int c = 0; + + QLIST_FOREACH(req, &s->buffered_requests, list) { + c++; + } + if (c > MAX_BUFFERED_REQS) { + return blk_abort_aio_request(s->blk, cb, opaque, -EIO); + } + + req = g_new0(IDEBufferedRequest, 1); + req->original_qiov = iov; + req->original_cb = cb; + req->original_opaque = opaque; + req->iov.iov_base = qemu_blockalign(blk_bs(s->blk), iov->size); + req->iov.iov_len = iov->size; + qemu_iovec_init_external(&req->qiov, &req->iov, 1); + + aioreq = blk_aio_readv(s->blk, sector_num, &req->qiov, nb_sectors, + ide_buffered_readv_cb, req); + + QLIST_INSERT_HEAD(&s->buffered_requests, req, list); + return aioreq; +} + static void ide_sector_read(IDEState *s); static void ide_sector_read_cb(void *opaque, int ret) diff --git a/hw/ide/internal.h b/hw/ide/internal.h index e4629b023a..2d1e2d2d2f 100644 --- a/hw/ide/internal.h +++ b/hw/ide/internal.h @@ -343,6 +343,16 @@ enum ide_dma_cmd { #define ide_cmd_is_read(s) \ ((s)->dma_cmd == IDE_DMA_READ) +typedef struct IDEBufferedRequest { + QLIST_ENTRY(IDEBufferedRequest) list; + struct iovec iov; + QEMUIOVector qiov; + QEMUIOVector *original_qiov; + BlockCompletionFunc *original_cb; + void *original_opaque; + bool orphaned; +} IDEBufferedRequest; + /* NOTE: IDEState represents in fact one drive */ struct IDEState { IDEBus *bus; @@ -396,6 +406,7 @@ struct IDEState { BlockAIOCB *pio_aiocb; struct iovec iov; QEMUIOVector qiov; + QLIST_HEAD(, IDEBufferedRequest) buffered_requests; /* ATA DMA state */ uint64_t io_buffer_offset; int32_t io_buffer_size; @@ -572,6 +583,9 @@ void ide_set_inactive(IDEState *s, bool more); BlockAIOCB *ide_issue_trim(BlockBackend *blk, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockCompletionFunc *cb, void *opaque); +BlockAIOCB *ide_buffered_readv(IDEState *s, int64_t sector_num, + QEMUIOVector *iov, int nb_sectors, + BlockCompletionFunc *cb, void *opaque); /* hw/ide/atapi.c */ void ide_atapi_cmd(IDEState *s); -- GitLab