On 11/02/16 19:07, Christoffer Dall wrote:

On Thu, Feb 11, 2016 at 06:39:41PM +0000, Marc Zyngier wrote:

quoted

ARMv8.1 comes with the "Virtualization Host Extension" (VHE for
short), which enables simpler support of Type-2 hypervisors.

This extension allows the kernel to directly run at EL2, and
significantly reduces the number of system registers shared between
host and guest, reducing the overhead of virtualization.

In order to have the same kernel binary running on all versions of the
architecture, this series makes heavy use of runtime code patching.

The first 22 patches massage the KVM code to deal with VHE and enable
Linux to run at EL2. The last patch catches an ugly case when VHE
capable CPUs are paired with some of their less capable siblings. This
should never happen, but hey...

I have deliberately left out some of the more "advanced"
optimizations, as they are likely to distract the reviewer from the
core infrastructure, which is what I care about at the moment.

Note: GDB is currently busted on VHE systems, as it checks for version
      6 on the debug architecture, while VHE is version 7. The
      binutils people are on the case.

This has been tested on the FVP_Base_SLV-V8-A model, and based on
v4.5-rc3 + kvmarm/master. I've put a branch out on:

git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/vhe

I'm happy with this series as it stands, we just need someone to take a
look at that debug patch and be happy with it.

I think Will is planning to have a go at it shortly. Once he and Catalin
are happy with the thing, I'll throw it into -next for a good shake.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...