Re: [PATCH AUTOSEL 6.4 07/12] arm64: cpufeature: detect FEAT_HCX

[Sasha Levin]

On Mon, Jul 03, 2023 at 12:51:57PM +0100, Mark Brown wrote:
> On Sun, Jul 02, 2023 at 03:50:52PM -0400, Sasha Levin wrote:
> > From: Kristina Martsenko <kristina.martsenko@xxxxxxx>
> >
> > [ Upstream commit b0c756fe996ac930033882ca56410639e5cad1ec ]
> >
> > Detect if the system has the new HCRX_EL2 register added in ARMv8.7/9.2,
> > so that subsequent patches can check for its presence.
> >
> > KVM currently relies on the register being present on all CPUs (or
> > none), so the kernel will panic if that is not the case. Fortunately no
> > such systems currently exist, but this can be revisited if they appear.
> > Note that the kernel will not panic if CONFIG_KVM is disabled.
>
> This is a new feature, it's not clear why we'd backport it (especially
> since it's a new feature which is a dependency for other features rather
> than something that people can use outside of the kernel)?

The second paragraph (above) suggested it should be.

--
Thanks,
Sasha