Red Hat Bugzilla – Bug 1472131
Guest OS will down when disk enable the IOMMU for Virtio
Last modified: 2017-09-29 10:02:22 EDT
This bug has been copied from bug #1463163 and has been proposed to be backported to 7.4 z-stream (EUS).
Fix included in seabios-1.10.2-4.el7
1)Reproduced bug with:
/usr/libexec/qemu-kvm -M pc -cpu host -enable-kvm -m 2G -smp 4 -nodefconfig -rtc base=localtime,driftfix=slew -device virtio-scsi-pci,iommu_platform=on,id=scsi0,disable-legacy=on,disable-modern=off -drive file=/home/rhel74-64-virtio.qcow2,format=qcow2,if=none,id=drive-scsi0-0-0-0 -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 -vnc :1 -monitor stdio
Boot failed: could not read the boot disk
2)Verified bug with:
1. In host, add "iommu=pt intel_iommu=on" to kernel line
2. Add "intel_iommu=on" to kernel line of q35/pc guest
3. boot virtio-scsi with iommu_platform=on
Guest works well
I tested device 'virtio-blk-pci' and machine type pc/q35 as well. Guest still works well.
According to this comment4, set this bug as verified.
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, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
*** Bug 1482387 has been marked as a duplicate of this bug. ***