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authorPaolo Bonzini <pbonzini@redhat.com>2021-04-14 19:51:48 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2021-06-25 10:54:12 +0200
commit01ef8185b809af9d287e1a03a3f9d8ea8231118a (patch)
tree3310b456ff028325cfe6b5e7bb286ab1c57ecc68 /hw/scsi
parent8ad5ab6148dca8aad297c134c09c84b0b92d45ed (diff)
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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 <pbonzini@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'hw/scsi')
-rw-r--r--hw/scsi/scsi-generic.c6
1 files changed, 4 insertions, 2 deletions
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],