From 01ef8185b809af9d287e1a03a3f9d8ea8231118a Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 14 Apr 2021 19:51:48 +0200 Subject: scsi-generic: pass max_segments via max_iov field in BlockLimits 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 Reviewed-by: Max Reitz --- hw/scsi/scsi-generic.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'hw') diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c index 40e0398..b6c4143 100644 --- a/hw/scsi/scsi-generic.c +++ b/hw/scsi/scsi-generic.c @@ -179,10 +179,12 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len) (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], -- cgit v1.1