[PATCH v3 00/17] KVM: arm64: Preliminary NV patches
Alexandru Elisei
alexandru.elisei at arm.com
Tue Jul 7 07:48:01 EDT 2020
Hi,
On 7/7/20 12:24 PM, Alexandru Elisei wrote:
> Hi,
>
> On 7/6/20 1:54 PM, Marc Zyngier wrote:
>> Hi all,
>>
>> In order not to repeat the 90+ patch series that resulted in a
>> deafening silence last time, I've extracted a smaller set of patches
>> that form the required dependencies that allow the rest of the 65 NV
>> patches to be added on top. Yes, it is that bad.
>>
>> The one real feature here is support for the ARMv8.4-TTL extension at
>> Stage-2 only. The reason to support it is that it helps the hypervisor
>> a lot when it comes to finding out how much to invalidate. It is thus
>> always "supported" with NV.
>>
>> The rest doesn't contain any functionality change. Most of it reworks
>> existing data structures and adds new accessors for the things that
>> get moved around. The reason for this is that:
>>
>> - With NV, we end-up with multiple Stage-2 MMU contexts per VM instead
>> of a single one. This requires we divorce struct kvm from the S2 MMU
>> configuration. Of course, we stick with a single MMU context for now.
>>
>> - With ARMv8.4-NV, a number of system register accesses are turned
>> into memory accesses into the so-called VNCR page. It is thus
>> convenient to make this VNCR page part of the vcpu context and avoid
>> copying data back and forth. For this to work, we need to make sure
>> that all the VNCR-aware sysregs are moved into our per-vcpu sys_regs
>> array instead of leaving in other data structures (the timers, for
>> example). The VNCR page itself isn't introduced with these patches.
>>
>> - As some of these data structures change, we need a way to isolate
>> the userspace ABI from such change.
>>
>> There is also a number of cleanups that were in the full fat series
>> that I decided to move early to get them out of the way.
>>
>> The whole this is a bit of a mix of vaguely unrelated "stuff", but it
>> all comes together if you look at the final series. This applies on
>> top of David Brazdil's series splitting the VHE and nVHE objects.
>>
>> I plan on taking this early into v5.9, and I really mean it this time!
>>
>> Catalin: How do you want to proceed for patches 2, 3, and 4? I could
>> make a stable branch that gets you pull into the arm64 tree, or the
>> other way around. Just let me know.
>>
>> Thanks,
>>
>> M.
>>
>> * From v2:
>> - Rebased on top of David's el2-obj series
> I tried to apply the patches on top of v5.8-rc1, but I get a conflict on the very
> first patch. I guess it's because I don't have the el2-obj series. Is that v4 of
> "Split off nVHE hyp code" patches from David Brazil?
Nevermind, figured it out and used your kvm-arm64/el2-obj-4.1 branch as a base.
Thanks,
Alex
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