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

[David Edmondson <dme@dme.org>]

On Thursday, 2021-07-01 at 16:24:51 -05, Babu Moger wrote:

> David, Are you still working on v2 of these series? I was going to test
> and review. Thanks

Yes. I have something that works, but it's messy in places. I hope to
get it out in a couple of days.

>> -----Original Message-----
>> From: David Edmondson <dme@dme.org>
>> Sent: Tuesday, June 8, 2021 3:25 AM
>> To: qemu-devel@nongnu.org
>> Cc: kvm@vger.kernel.org; Eduardo Habkost <ehabkost@redhat.com>; Paolo
>> Bonzini <pbonzini@redhat.com>; Marcelo Tosatti <mtosatti@redhat.com>;
>> Richard Henderson <richard.henderson@linaro.org>; Moger, Babu
>> <Babu.Moger@amd.com>
>> Subject: Re: [RFC PATCH 0/7] Support protection keys in an AMD EPYC-Milan
>> VM
>> 
>> 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.
>> --
>> You know your green from your red.

dme.
-- 
When you were the brightest star, who were the shadows?