[Pkg-xen-devel] Bug#910946: xen-hypervisor-4.11-amd64: HVM DomU - 64-bit kernel cannot access emulated ATA devices

[Stephen Oberholtzer]

Package: xen-hypervisor-4.11-amd64
Version: 4.11.1~pre.20180911.5acdd26fdc+dfsg-3
Severity: normal

Dear Maintainer,

This mostly manifests as an "unable to access emulated CD-ROM drive", because there are no PVHVM CD-ROMs.

NOTE: I had similar issues with 4.8, so I upgraded to 4.11. This actually gave me *more* issues.

Attempting to boot an HVM domU from a CD image (to perform an install or rescue on VM data) fails when the CD uses a 64-bit kernel.
(When I use the Knoppix 'failsafe' mode, which uses a 32-bit kernel, I get different behavior.  Under 4.8, it boots; under 4.11, it hangs during ATA bus probing.)

I have tried the following ISO images:
* debian-buster-DI-alpha3-amd64-netinst.iso (tested on 4.8 only; can't use at all on 4.11)
* KNOPPIX_V8.2-2018-05-10-EN.iso
* debian-live-9.5.0-amd64-kde.iso
* gparted-live-0.32.0-1-amd64.iso

Here are some additional details (mostly gleaned from Knoppix, because that's what I was doing my testing with):
- When I try booting Knoppix in a non-accelerated VM by directly running qemu, everything works fine, so Xen is definitely a factor.
- PVHVM is working: non-CDROM drive shows up as xvbda
- With PVHVM disabled (xen_platform_pci=0), hda also fails to be detected
- Persuading libata to dump IDENTIFY data reveals that the returned page is all zeroes.


-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (900, 'testing'), (400, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.18.6 (SMP w/12 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

xen-hypervisor-4.11-amd64 depends on no packages.

Versions of packages xen-hypervisor-4.11-amd64 recommends:
ii  xen-hypervisor-common  4.11.1~pre.20180911.5acdd26fdc+dfsg-1~exp1
ii  xen-utils-4.11         4.11.1~pre.20180911.5acdd26fdc+dfsg-3

xen-hypervisor-4.11-amd64 suggests no packages.

-- no debconf information