On Tue, Nov 18, 2025 at 7:36 AM Zhao Liu <zhao1.liu@intel.com> wrote:
>
> Hi,
>
> This series adds APX (Advanced Performance Extensions) support in QEMU
> to enable APX in Guest based on KVM.
Thanks for sending this out, I left some comments on the patch that
adds EGPRs but otherwise it's pretty simple---good.
Paolo
> This series is based on CET v4:
>
> https://lore.kernel.org/qemu-devel/20251118034231.704240-1-zhao1.liu@intel.com/
>
> And you can also find the code here:
>
> https://gitlab.com/zhao.liu/qemu/-/commits/i386-all-for-dmr-v1.1-11-17-2025
>
> The patches for KVM side can be found at:
>
> https://lore.kernel.org/kvm/20251110180131.28264-1-chang.seok.bae@intel.com/
>
>
> Thanks for your review!
>
>
> Overview
> ========
>
> Intel Advanced Performance Extensions (Intel APX) expands the Intel 64
> instruction set architecture with access to more registers (16
> additional general-purpose registers (GPRs) R16–R31) and adds various
> new features that improve general-purpose performance. The extensions
> are designed to provide efficient performance gains across a variety of
> workloads without significantly increasing silicon area or power
> consumption of the core.
>
> APX spec link (rev.07) is:
> https://cdrdv2.intel.com/v1/dl/getContent/861610
>
> At QEMU side, the enabling work mainly includes two parts:
>
> 1. save/restore/migrate the xstate of APX.
> * APX xstate is a user xstate, but it reuses MPX xstate area in
> un-compacted XSAVE buffer.
> * To address this, QEMU will reject both APX and MPX if their CPUID
> feature bits are set at the same (in Patch 1).
>
> 2. add related CPUIDs support in feature words.
>
> Thanks and Best Regards,
> Zhao
> ---
> Zhao Liu (2):
> i386/cpu: Support APX CPUIDs
> i386/cpu: Mark apx xstate as migratable
>
> Zide Chen (3):
> i386/cpu: Add APX EGPRs into xsave area
> i386/cpu: Cache EGPRs in CPUX86State
> i386/cpu: Add APX migration support
>
> target/i386/cpu.c | 68 ++++++++++++++++++++++++++++++++++++--
> target/i386/cpu.h | 26 +++++++++++++--
> target/i386/machine.c | 24 ++++++++++++++
> target/i386/xsave_helper.c | 14 ++++++++
> 4 files changed, 128 insertions(+), 4 deletions(-)
>
> --
> 2.34.1
>