[PATCH 00/15] arm64/kvm: use common sysreg definitions

[Marc Zyngier]

On Thu, Mar 09 2017 at  5:07:12 pm GMT, Mark Rutland <mark.rutland at arm.com> wrote:
> Currently we duplicate effort in maintaining system register encodings across
> arm64's <asm/sysreg.h>, KVM's sysreg tables, and other places. This redundancy
> is unfortunate, and as encodings are encoded in-place without any mnemonic,
> this ends up more painful to read than necessary.
>
> This series ameliorates this by making <asm/sysreg.h> the canonical location
> for (architected) system register encodings, with other users building atop of
> this, e.g. with KVM deriving its sysreg table values from the common mnemonics.
>
> I've only attacked AArch64-native SYS encodings, and ignored CP{15,14}
> registers for now, but these could be handled similarly. Largely, I've stuck to
> only what KVM needs, though for the debug and perfmon groups it was easier to
> take the whole group from the ARM ARM than to filter them to only what KVM
> needed today.
>
> To verify that I haven't accidentally broken KVM, I've diffed sys_regs.o and
> sys_regs_generic_v8.o on a section-by-section basis before and after the series
> is applied. The .text, .data, and .rodata sections (and most others) are
> identical. The __bug_table section, and some .debug* sections differ, and this
> appears to be due to line numbers changing due to removed lines.
>
> One thing I wasn't sure how to address was banks of registers such as
> PMEVCNTR<n>_EL0. We currently enumerate all cases for our GICv3 definitions,
> but it seemed painful to expand ~30 cases for PMEVCNTR<n>_EL0 and friends, and
> for these I've made the macros take an 'n' parameter. It would be nice to be
> consistent either way, and I'm happy to expand those cases.
>
> I've pushed thes series out to a branch [1] based on v4.11-rc1. It looks like
> git rebase is also happy to apply the patches atop of the kvm-arm-for-4.11-rc2
> tag.

I had a quick glance at this series, and this looks like a very good
piece of work - thanks for doing this.

The next question is how do we merge this. Obviously, we can't split it
between trees, and this is very likely to clash with anything that we
will merge on the KVM side (the sysreg table is a popular place).

Will, Catalin: Would it make sense to create a stable branch with these
patches, and merge it into both the arm64 and KVM trees? That'd make
things easier...

Thanks,

	M.
-- 
Jazz is not dead, it just smell funny.