diff options
Diffstat (limited to 'hw/ide/pci.c')
| -rw-r--r-- | hw/ide/pci.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/hw/ide/pci.c b/hw/ide/pci.c index 4afd0cfe8c..d31ff885b7 100644 --- a/hw/ide/pci.c +++ b/hw/ide/pci.c @@ -53,10 +53,14 @@ static void bmdma_start_dma(IDEDMA *dma, IDEState *s, } /** - * Return the number of bytes successfully prepared. - * -1 on error. + * Prepare an sglist based on available PRDs. + * @limit: How many bytes to prepare total. + * + * Returns the number of bytes prepared, -1 on error. + * IDEState.io_buffer_size will contain the number of bytes described + * by the PRDs, whether or not we added them to the sglist. */ -static int32_t bmdma_prepare_buf(IDEDMA *dma, int is_write) +static int32_t bmdma_prepare_buf(IDEDMA *dma, int32_t limit) { BMDMAState *bm = DO_UPCAST(BMDMAState, dma, dma); IDEState *s = bmdma_active_if(bm); @@ -75,7 +79,7 @@ static int32_t bmdma_prepare_buf(IDEDMA *dma, int is_write) /* end of table (with a fail safe of one page) */ if (bm->cur_prd_last || (bm->cur_addr - bm->addr) >= BMDMA_PAGE_SIZE) { - return s->io_buffer_size; + return s->sg.size; } pci_dma_read(pci_dev, bm->cur_addr, &prd, 8); bm->cur_addr += 8; @@ -90,7 +94,14 @@ static int32_t bmdma_prepare_buf(IDEDMA *dma, int is_write) } l = bm->cur_prd_len; if (l > 0) { - qemu_sglist_add(&s->sg, bm->cur_prd_addr, l); + uint64_t sg_len; + + /* Don't add extra bytes to the SGList; consume any remaining + * PRDs from the guest, but ignore them. */ + sg_len = MIN(limit - s->sg.size, bm->cur_prd_len); + if (sg_len) { + qemu_sglist_add(&s->sg, bm->cur_prd_addr, sg_len); + } /* Note: We limit the max transfer to be 2GiB. * This should accommodate the largest ATA transaction |