Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Bug 2121783

Summary: Wrong max_sectors_kb and Maximum transfer length on the pass-through device [rhel-8.7] [rhel-8.6.0.z]
Product: Red Hat Enterprise Linux 8 Reporter: RHEL Program Management Team <pgm-rhel-tools>
Component: qemu-kvmAssignee: Kevin Wolf <kwolf>
qemu-kvm sub component: virtio-blk,scsi QA Contact: qing.wang <qinwang>
Status: CLOSED ERRATA Docs Contact:
Severity: high    
Priority: high CC: bhull, coli, ehadley, jinzhao, juzhang, jwboyer, kanderso, kkiwi, kpfleming, kwolf, lijin, mgandhi, qzhang, virt-maint, xuwei, ymankad, zhguo
Version: 8.7Keywords: Triaged, ZStream
Target Milestone: rcFlags: pm-rhel: mirror+
Target Release: ---   
Hardware: x86_64   
OS: All   
Whiteboard:
Fixed In Version: qemu-kvm-6.2.0-11.module+el8.6.0+16538+01ea313d.6 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: 2120279 Environment:
Last Closed: 2022-10-25 09:32:39 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2120279    
Bug Blocks:    

Comment 2 qing.wang 2022-09-02 12:53:43 UTC 
Passed block sanity test and manually verification below:


Red Hat Enterprise Linux release 8.6 (Ootpa)
4.18.0-372.26.1.el8_6.x86_64
qemu-kvm-6.2.0-11.module+el8.6.0+16538+01ea313d.6.x86_64
seabios-bin-1.15.0-2.module+el8.6.0+14757+c25ee005.noarch
edk2-ovmf-20220126gitbb1bba3d77-2.el8.noarch



Get FC disk on HOST

/sys/block/sdb/queue/max_sectors_kb:1280
/sys/block/sdb/queue/max_segments:64

VPD INQUIRY: Block limits page (SBC)
  Maximum transfer length: 0 blocks [not reported]



pass-through to guest

[ "$1" == "" ] && disk=sdb || disk=$1

/usr/libexec/qemu-kvm \
  -name src_vm1 \
  -machine q35,accel=kvm,usb=off,dump-guest-core=off \
  -m 8G \
  -smp 2 \
  -cpu host,vmx,+kvm_pv_unhalt \
  -device pcie-root-port,id=pcie.0-root-port-2,slot=2,bus=pcie.0,multifunction=on \
  -device pcie-root-port,id=pcie.0-root-port-2-1,chassis=3,bus=pcie.0,addr=0x2.0x1 \
  -device pcie-root-port,id=pcie.0-root-port-2-2,chassis=4,bus=pcie.0,addr=0x2.0x2 \
  -device pcie-root-port,id=pcie.0-root-port-3,slot=3,bus=pcie.0 \
  -device pcie-root-port,id=pcie.0-root-port-4,slot=4,bus=pcie.0 \
  -device pcie-root-port,id=pcie.0-root-port-5,slot=5,bus=pcie.0 \
  -device pcie-root-port,id=pcie.0-root-port-7,slot=7,bus=pcie.0 \
  -device pcie-root-port,id=pcie.0-root-port-8,slot=8,bus=pcie.0 \
  -device pcie-root-port,id=pcie.0-root-port-9,slot=9,bus=pcie.0 \
  -device qemu-xhci,id=usb1,bus=pcie.0-root-port-2-1,addr=0x0 \
  -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \
  -object iothread,id=iothread0 \
  -device virtio-scsi-pci,id=scsi0,bus=pcie.0-root-port-2-2,addr=0x0,iothread=iothread0 \
  -blockdev \
  driver=qcow2,file.driver=file,cache.direct=off,cache.no-flush=on,file.filename=/home/kvm_autotest_root/images/rhel840-64-virtio-scsi.qcow2,node-name=drive_image1 \
  -device scsi-hd,id=os1,drive=drive_image1,bootindex=0 \
  \
  \
  -device virtio-scsi-pci,id=scsi1,bus=pcie.0-root-port-8,addr=0x0 \
  \
  -blockdev node-name=host_device_stg,driver=host_device,aio=native,filename=/dev/$disk,cache.direct=on,cache.no-flush=off,discard=unmap \
  -blockdev node-name=drive_stg,driver=raw,cache.direct=on,cache.no-flush=off,file=host_device_stg \
  -device scsi-block,id=stg,drive=drive_stg,rerror=stop,werror=stop \
  \
  -vnc \
  :5 \
  -qmp tcp:0:5955,server,nowait \
  -monitor stdio \
  \
  -device virtio-net-pci,mac=9a:b5:b6:b1:b2:b5,id=idMmq1jH,vectors=4,netdev=idxgXAlm,bus=pcie.0-root-port-5,addr=0x0 \
  -netdev tap,id=idxgXAlm




Get disk info in guest

/sys/block/sdb/queue/max_sectors_kb:256
/sys/block/sdb/queue/max_segments:254

  Maximum transfer length: 512 blocks


change max_sectors_kb to 64 on host then reboot guest

echo 64 > /sys/block/sdb/queue/max_sectors_kb


/sys/block/sdb/queue/max_sectors_kb:64
/sys/block/sdb/queue/max_segments:254

  Maximum transfer length: 128 blocks
  

change max_sectors_kb to 1024 on host then reboot guest
echo 1024 > /sys/block/sdb/queue/max_sectors_kb

/sys/block/sdb/queue/max_sectors_kb:256
/sys/block/sdb/queue/max_segments:254

  Maximum transfer length: 512 blocks
Comment 3 Yanan Fu 2022-09-05 02:14:21 UTC 
QE bot(pre verify): Set 'Verified:Tested,SanityOnly' as gating/tier1 test pass.
Comment 11 errata-xmlrpc 2022-10-25 09:32:39 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (virt:rhel and virt-devel:rhel bug fix update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:7122