Re: [RFC PATCH 0/7] Support protection keys in an AMD EPYC-Milan VM

[David Edmondson <dme@dme.org>]

On Thursday, 2021-05-20 at 15:56:40 +01, David Edmondson wrote:

> AMD EPYC-Milan CPUs introduced support for protection keys, previously
> available only with Intel CPUs.
>
> AMD chose to place the XSAVE state component for the protection keys
> at a different offset in the XSAVE state area than that chosen by
> Intel.
>
> To accommodate this, modify QEMU to behave appropriately on AMD
> systems, allowing a VM to properly take advantage of the new feature.
>
> Further, avoid manipulating XSAVE state components that are not
> present on AMD systems.
>
> The code in patch 6 that changes the CPUID 0x0d leaf is mostly dumped
> somewhere that seemed to work - I'm not sure where it really belongs.

Ping - any thoughts about this approach?

> David Edmondson (7):
>   target/i386: Declare constants for XSAVE offsets
>   target/i386: Use constants for XSAVE offsets
>   target/i386: Clarify the padding requirements of X86XSaveArea
>   target/i386: Prepare for per-vendor X86XSaveArea layout
>   target/i386: Introduce AMD X86XSaveArea sub-union
>   target/i386: Adjust AMD XSAVE PKRU area offset in CPUID leaf 0xd
>   target/i386: Manipulate only AMD XSAVE state on AMD
>
>  target/i386/cpu.c            | 19 +++++----
>  target/i386/cpu.h            | 80 ++++++++++++++++++++++++++++--------
>  target/i386/kvm/kvm.c        | 57 +++++++++----------------
>  target/i386/tcg/fpu_helper.c | 20 ++++++---
>  target/i386/xsave_helper.c   | 70 +++++++++++++++++++------------
>  5 files changed, 152 insertions(+), 94 deletions(-)
>
> -- 
> 2.30.2

dme.
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