[PATCH v3 00/12] whpx: i386: Windows 10 and performance fixes

[Mohamed Mediouni <mohamed@unpredictable.fr>]

On Windows 10, the paravirtualisation enlightenments aren't available.
And neither is performance monitoring. Using the former as a gate to
operate in a reduced-functionality mode on Windows 10.

And on the performance side, some state is really expensive to fetch
or write with Hyper-V so switch some less-essential state to on demand.

The effect of this is magnified on Windows 10 because Hyper-V enlightenments
are not available there.

Side note: On Windows 11, use WHP with kernel-irqchip=on. On Windows 10, looks
like issues there are still lingering, with issues #289 and #346 still problematic.

v1 -> v2:
- fix x86 HVF compatibility
- small nits
- added workaround for an issue that showed up during 32-bit Linux boot
on AMD

v2 -> v3:
- Remove ad-hoc workaround in segment fetching and replace it by something
more proper.
The affected commits are "whpx: i386: fetch segments on-demand". The old
workaround separate commit is no longer present (or needed)

Issue number: https://gitlab.com/qemu-project/qemu/-/work_items/3349

Mohamed Mediouni (12):
  whpx: i386: workaround for Windows 10 support
  whpx: i386: enable exceptions VM exit only when needed
  whpx: i386: skip TSC read for MMIO exits
  whpx: i386: skip XCRs read for MMIO exits
  whpx: i386: don't restore segment registers after MMIO handling
  target/i386: emulate: add new callbacks
  whpx: i386: add implementation of new x86_emul_ops
  target/i386: emulate: indirect access to CRs
  whpx: i386: indirect access to CRs
  target/i386: emulate: segmentation rework
  whpx: i386: fetch segments on-demand
  whpx: i386: fast runtime state reads

 target/i386/emulate/x86_emu.h     |   6 +
 target/i386/emulate/x86_helpers.c |  83 +++++----
 target/i386/emulate/x86_mmu.c     |  11 +-
 target/i386/hvf/x86.c             |  11 ++
 target/i386/whpx/whpx-all.c       | 280 +++++++++++++++++++++++++-----
 5 files changed, 302 insertions(+), 89 deletions(-)

-- 
2.50.1 (Apple Git-155)