Commit e08a9835 authored by John Snow's avatar John Snow
Browse files

ahci: correct ncq sector count 



uint16_t isn't enough to hold the real sector count, since a value of
zero implies a full 64K sectors, so we need a uint32_t here.

We *could* cheat and pretend that this value is 0-based and fit it in
a uint16_t, but I'd rather waste 2 bytes instead of a future dev's
10 minutes when they forget to +1/-1 accordingly somewhere.

See SATA 3.2, section 13.6.4.1 "READ FPDMA QUEUED".

Signed-off-by: default avatarJohn Snow <jsnow@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Message-id: 1435767578-32743-9-git-send-email-jsnow@redhat.com
parent 9364384d

hw/ide/ahci.c

+5 −2
Original line number Diff line number Diff line
@@ -1086,8 +1086,11 @@ static void process_ncq_command(AHCIState *s, int port, uint8_t *cmd_fis, 
        DPRINTF(port, "Warn: Unsupported attempt to use Rebuild Assist\n");

    }



    ncq_tfs->sector_count = ((uint16_t)ncq_fis->sector_count_high << 8) |

                                ncq_fis->sector_count_low;

    ncq_tfs->sector_count = ((ncq_fis->sector_count_high << 8) |

                             ncq_fis->sector_count_low);

    if (!ncq_tfs->sector_count) {

        ncq_tfs->sector_count = 0x10000;

    }

    size = ncq_tfs->sector_count * 512;

    ahci_populate_sglist(ad, &ncq_tfs->sglist, size, 0);

hw/ide/ahci.h

+1 −1
Original line number Diff line number Diff line
@@ -256,7 +256,7 @@ typedef struct NCQTransferState { 
    BlockAIOCB *aiocb;

    QEMUSGList sglist;

    BlockAcctCookie acct;

    uint16_t sector_count;

    uint32_t sector_count;

    uint64_t lba;

    uint8_t tag;

    uint8_t cmd;