@@ -1228,8 +1228,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
ret = sg_get_max_segments(s->fd);
if (ret > 0) {
- bs->bl.max_transfer = MIN(bs->bl.max_transfer,
- ret * qemu_real_host_page_size);
+ bs->bl.max_iov = ret;
}
}
@@ -179,10 +179,12 @@ static void scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s)
(r->req.cmd.buf[1] & 0x01)) {
page = r->req.cmd.buf[2];
if (page == 0xb0) {
- uint32_t max_transfer =
- blk_get_max_transfer(s->conf.blk) / s->blocksize;
+ uint32_t max_transfer = blk_get_max_transfer(s->conf.blk);
+ uint32_t max_iov = blk_get_max_iov(s->conf.blk);
assert(max_transfer);
+ max_transfer = MIN_NON_ZERO(max_transfer, max_iov * qemu_real_host_page_size)
+ / s->blocksize;
stl_be_p(&r->buf[8], max_transfer);
/* Also take care of the opt xfer len. */
stl_be_p(&r->buf[12],
I/O to a disk via read/write is not limited by the number of segments allowed by the host adapter; the kernel can split requests if needed, and the limit imposed by the host adapter can be very low (256k or so) to avoid that SG_IO returns EINVAL if memory is heavily fragmented. Since this value is only interesting for SG_IO-based I/O, do not include it in the max_transfer and only take it into account when patching the block limits VPD page in the scsi-generic device. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- block/file-posix.c | 3 +-- hw/scsi/scsi-generic.c | 6 ++++-- 2 files changed, 5 insertions(+), 4 deletions(-)