Re: [PATCH 07/13] x86/kconfig/64: Enable more virtualization guest options in the defconfig: enable Xen, Xen_PVH, Jailhouse, ACRN, Intel TDX and Hyper-V

[Ingo Molnar <mingo@kernel.org>]

* Michael Kelley <mhklinux@outlook.com> wrote:

> From: Ingo Molnar <mingo@kernel.org> Sent: Thursday, May 15, 2025 6:27 AM
> > 
> > Since the x86 defconfig aims to be a distro kernel work-alike with
> > fewer drivers and a shorter build time, refresh all the virtualization
> > guest Kconfig features, enabling paravirt spinlocks, and
> > enabling the guest support code for the following guests:
> > 
> >  - Xen
> >  - Xen_PVH
> >  - Jailhouse
> >  - ACRN
> >  - Intel TDX
> >  - Hyper-V
> 
> I built and tested a Hyper-V guest with defconfig.

Thank you!

> The Hyper-V storage and keyboard drivers are pulled in automatically, 
> so my previous comment about them being "missing" is moot.

Yeah. "defconfig compression" is a bit non-obvious, as the file doesn't 
carry indirect select and default-y-enabled options.

> But the Linux console for each Hyper-V guest is a synthetic graphics
> console, and that didn't work with the DRM_HYPERV driver. Missing
> the console pretty much kills any usefulness. DRM doesn't have 
> Linux console support, so it needs CONFIG_DRM_FBDEV_EMULATION
> to be set, and defconfig doesn't have it.
> 
> So either CONFIG_DRM_FBDEV_EMULATION needs to be added, or
> defconfig should switch to the older HYPERV_FB driver. I think we'd
> rather do the former. Vitaly -- any thoughts?

We can certainly enable that option, and it's likely useful for other 
guests as well - see the delta patch below I applied.

Based on your description I also added your Tested-by tag:

    Tested-by: Michael Kelley <mhklinux@outlook.com> # On Hyper-V

And pushed it all out to:

  git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git WIP.x86/kconfig

Thanks,

	Ingo

=================================>
 arch/x86/configs/x86_64_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
index df786b8b4e85..15c6b5f3b2fc 100644
--- a/arch/x86/configs/x86_64_defconfig
+++ b/arch/x86/configs/x86_64_defconfig
@@ -203,6 +203,7 @@ CONFIG_AGP=y
 CONFIG_AGP_AMD64=y
 CONFIG_AGP_INTEL=y
 CONFIG_DRM=y
+CONFIG_DRM_FBDEV_EMULATION=y
 CONFIG_DRM_I915=y
 CONFIG_DRM_VIRTIO_GPU=y
 CONFIG_DRM_HYPERV=y