[PATCH 0/5] armv7 BE kvm support

[Christoffer Dall]

On Thu, Dec 19, 2013 at 11:26:54PM -0800, Victor Kamensky wrote:
> Hi Guys,

Hi Victor,

> 
> Here is series that enables KVM support for V7 big endian kernels. Mostly
> it deals with BE KVM host support. Marc Zyngier showed before with his patches
> how BE guest could run on top LE host. With these patches BE guest runs on 
> top of BE host. If Marc's kvmtool is used with few additional changes I tested
> that BE host could run LE guest. Also I verified that there were no 
> regressions in BE guest on top of LE host case.

Can you please cc the kvmarm list as per the MAINTAINERS files for
patches to kvm/arm in the future?

Looking forward to reading your code!

-Christoffer

> 
> Note that posted series covers only kernel side changes. The changes were
> tested inside of bigger setup with additional changes in qemu and kvmtool.
> I will post those changes separately in proper aliases but for completeness 
> sake Appendix A gives pointers to git repositories and branches with all
> needed changes.
> 
> Please note first patch is not related to BE KVM per se. I've run
> into an issue of conflicting 'push' identifier use while trying to include 
> assembler.h into KVM .S files. Details of an issue I observed covered in
> Appendix B. The first patch is my take on solving it.
> 
> Victor Kamensky (5):
>   ARM: kvm: replace push and pop with stdmb and ldmia instrs to enable
>     assembler.h inclusion
>   ARM: fix KVM assembler files to work in BE case
>   ARM: kvm one_reg coproc set and get BE fixes
>   ARM: kvm vgic mmio should return data in BE format in BE case
>   ARM: kvm MMIO support BE host running LE code
> 
>  arch/arm/include/asm/assembler.h   |  7 +++
>  arch/arm/include/asm/kvm_asm.h     |  4 +-
>  arch/arm/include/asm/kvm_emulate.h | 22 +++++++--
>  arch/arm/kvm/coproc.c              | 94 ++++++++++++++++++++++++++++----------
>  arch/arm/kvm/init.S                |  7 ++-
>  arch/arm/kvm/interrupts.S          | 50 +++++++++++---------
>  arch/arm/kvm/interrupts_head.S     | 61 +++++++++++++++----------
>  virt/kvm/arm/vgic.c                |  4 +-
>  8 files changed, 168 insertions(+), 81 deletions(-)
> 
> -- 
> 1.8.1.4
> 
> Thanks,
> Victor
> 
>       Appendix A: Testing and Full Setup Description
>       ----------------------------------------------
> 
> I) No mixed mode setup - i.e BE guest on BE host; and LE guest
> on LE host tested to make sure no regressions.
> 
> KVM host and guest kernels:
>   TC2 on top of Linus 3.13-rc4 (this patch series):
>       git: git://git.linaro.org/people/victor.kamensky/linux-linaro-tracking-be.git
>       branch: armv7be-kvm-3.13-rc4
>       
>   TC2 and Arndale on top of Linaro BE tree:
>       git: git://git.linaro.org/people/victor.kamensky/linux-linaro-tracking-be.git
>       branch: llct-be-20131216-kvm
> 
> - TC1 kernels used as guests
> 
> qemu:
>       git: git://git.linaro.org/people/victor.kamensky/qemu-be.git 
>       branch: armv7be-v1
>       description: changes to run qemu on armeb target; and other
>       changes to work with be image on top of be host
> 
> kvmtool:
>       git: git://git.linaro.org/people/victor.kamensky/linux-linaro-tracking-be.git
>       branch: kvmtool-armv7be-v1
>       desciption: minimal changes to build kvmtool for armeb target; and
>       tiny change with virtio magic
> 
> II) Mixed mode setup all possible combinations within V7 (LE guest on BE host;
> BE guest on LE host as Marc's setup tested to make sure no regressions) only
> with kvmtool.
> 
> This work is based on Marc Zyngier's work that made BE guest to run on top
> of LE host. For this setup special version of kvmtool should be used and
> in addition I had to apply patch to guest kernel that would switch reading
> virtio configs reads to be LE only, that is made on top of previous Rusty
> Russell's changes. Effectively I just had to do very minor addition to make
> LE guest to work on BE host, most of heavy lifting was done before by Marc.
> 
> KVM host kernels: as in previous setup
> 
> Guest TC1 kernels with LE virtio config patch:
>       git: git://git.linaro.org/people/victor.kamensky/linux-linaro-tracking-be.git
>       branch: virtio-leconfig-3.13-rc4
> 
> kvmtool:
>       git: git://git.linaro.org/people/victor.kamensky/linux-linaro-tracking-be.git
>       branch: kvmtool-mixed-v1
>       description: based on git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git
>       branch kvm-arm64/kvmtool-be-on-le; adds missing include fix; above armeb target
>       build patches; and one fix related to BE mode
> 
> qemu:
>       git: git://git.linaro.org/people/victor.kamensky/qemu-be.git
>       branch: armv7be-leconfig-v1
>       description: change virtio-blk that so qemu could work with guest image
>       where virtio leconfig is made; note it does not work in mixed mode; to do
>       so qemu would need bunch of similar changes that Marc did in kvmtool
> 
> 
>       Appendix B: kvm asm file and asm/assembler.h file issue
>       -------------------------------------------------------
> 
> diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
> index ddc1553..5d3b511 100644
> --- a/arch/arm/kvm/interrupts.S
> +++ b/arch/arm/kvm/interrupts.S
> @@ -25,6 +25,7 @@
>  #include <asm/kvm_asm.h>
>  #include <asm/kvm_arm.h>
>  #include <asm/vfpmacros.h>
> +#include <asm/assembler.h>
>  #include "interrupts_head.S"
>  
>         .text
> 
> produce the following compilation errors:
> 
> /run/media/kamensky/wd/linaro/linux-linaro-core-tracking/092913/linux-linaro-tracking-be/arch/arm/kvm/interrupts.S: Assembler messages:
> /run/media/kamensky/wd/linaro/linux-linaro-core-tracking/092913/linux-linaro-tracking-be/arch/arm/kvm/interrupts.S:51: Error: ARM register expected -- `lsr {r2,r3}'
> /run/media/kamensky/wd/linaro/linux-linaro-core-tracking/092913/linux-linaro-tracking-be/arch/arm/kvm/interrupts.S:100: Error: ARM register expected -- `lsr {r2}'
> /run/media/kamensky/wd/linaro/linux-linaro-core-tracking/092913/linux-linaro-tracking-be/arch/arm/kvm/interrupts.S:100: Error: ARM register expected -- `lsr {r4-r12}'
> 

-- 
Christoffer