Re: [PATCH v6 2/7] arm64: Introduce VA_BITS and translation level options

[Catalin Marinas]

On 15 Jul 2014, at 15:53, Jungseok Lee <jungseoklee85@xxxxxxxxx> wrote:
> On Jul 15, 2014, at 7:41 AM, Catalin Marinas wrote:
>> On Mon, Jul 14, 2014 at 09:38:59PM +0100, Joel Schopp wrote:
>>> I agree that these patches would be very useful.  I just rebased my fix
>>> for a VTTBR_BADDR_MASK bug on one of these patches that could be pulled
>>> out independently.  See
>>> https://lists.cs.columbia.edu/pipermail/kvmarm/2014-July/010480.html
>>>
>>> The original author Jungseok Lee is no longer available to work on
>>> future versions of these patches.  I was thinking that if they didn't
>>> get picked up as they are that with the original author's blessing I
>>> would pick them up and keep them forward ported/resubmitted.  I have an
>>> SOC to test them on.
>>
>> The patches are pretty good. I'll give them a try tomorrow and if there
>> isn't something fundamental missing I'll consider taking them for 3.17.
>
> Hi All,
>
> If only stage1 side is taken and merged, KVM should be disabled under 4 level
> lookups with the following configuration adjustment. I've tested it on top of
> arm64/for-next/core branch and it works fine.
>
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -18,6 +18,7 @@ if VIRTUALIZATION
>
> config KVM
>        bool "Kernel-based Virtual Machine (KVM) support"
> +       depends on !ARM64_4_LEVELS
>        select MMU_NOTIFIER
>        select PREEMPT_NOTIFIERS
>        select ANON_INODES
>
> However, I don't know whether it does make sense or not.

I added some patches on top of your series, I hope to be able to post
them tomorrow. My interim approach was to disable 4-levels if KVM is
enabled.

> In other words, stage2 side should be prepared to fully support 4 level lookups.
>
> In order to cover all combinations of host and guest, VTTBR_X should be determined
> dynamically as referring to hardware capability. At this point, the patches have
> been revised many times, but they don't have got ACKs from Christoffer and Marc yet.
>
> That is why the patches are pending now in the author's point of view.

I have some clean-up for stage 1 on top but nothing major.

Catalin

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