On Tue, Feb 24, 2026 at 12:34:31PM +0000, Teddy Astie wrote: > Le 24/02/2026 à 12:16, Roger Pau Monné a écrit : > > On Tue, Feb 24, 2026 at 10:51:35AM +0000, Teddy Astie wrote: > >> It's currently possible to build Linux with CONFIG_PVH|CONFIG_XEN_PVHVM > >> and no CONFIG_XEN_PVH. That leads to inconsistent kernels that fails with > >> "Missing xen PVH initialization" when booting using PVH boot method or > >> display various errors and fail to initialize Xen PV drivers when booting > >> with PVH-GRUB. > >> > >> platform_pci_unplug: Xen Platform PCI: unrecognised magic value > >> ... > >> # modprobe xen-blkfront > >> modprobe: ERROR: could not insert 'xen_blkfront': No such device > >> # modprobe xen-netfront > >> modprobe: ERROR: could not insert 'xen_netfront': No such device > >> > >> When built without CONFIG_XEN_PVH, PVH-specific logic is disabled, hence > >> when > >> booting with e.g PVH-OVMF, Linux assumes we are a HVM guest, even when we > >> aren't > >> actually one (in the "with HVM emulated devices" sense). > >> > >> As it is actually possible to boot Xen PVH without CONFIG_PVH; and that > >> most > >> Xen-related logic exist within CONFIG_XEN_PVHVM; consider PVH guests > >> support > >> within CONFIG_XEN_PVHVM instead of CONFIG_XEN_PVH. > > > > So the current CONFIG_PVH selection done by CONFIG_XEN_PVH is moot? > > > >> Keep CONFIG_XEN_PVH as a shortcut to enable PVH boot, ACPI support and > >> PVHVM. > >> > >> Signed-off-by: Teddy Astie <[email protected]> > >> --- > >> Cc: Juergen Gross <[email protected]> > >> Cc: Boris Ostrovsky <[email protected]> > >> Cc: Oleksandr Tyshchenko <[email protected]> > >> > >> A tentative patch, I'm not sure of the way of dealing with the KConfig > >> part, > >> keeping CONFIG_XEN_PVH as a shortcut is interesting, but there may be other > >> options. > >> > >> There are widespreadly used Linux distributions that have a similar > >> configuration > >> to this one, thus exhibit this issue i.e fail to boot. > > > > Do you know the underlying cause of not enabling CONFIG_XEN_PVH? Is > > the default set to n on the defconfig? Or are distros specifically > > disabling this option on purpose? > > > > I'm observing in these distros that > > > # CONFIG_XEN_PVH is not set > > CONFIG_XEN_PVHVM_GUEST=y > > CONFIG_XEN_PVHVM=y > > Which makes CONFIG_XEN_PVH defaults to n.
We should possibly send a patch to those distros Kconfig to enable CONFIG_XEN_PVH? I think it's a bug on their side that Xen PVH is not enabled. Us trying to workaround this in our Linux Kconfig options seem wrong. Thanks, Roger.
