[v2] whpx: i386: x2apic emulation for kernel-irqchip=off, feature probing

[PATCH v2 0/6] whpx: i386: x2apic emulation for kernel-irqchip=off, feature probing

Mohamed Mediouni posted 6 patches 1 week, 1 day ago

Diff against v1 v3 v4
Download series mbox

Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20260402193104.56331-1-mohamed@unpredictable.fr

Maintainers: Pedro Barbuda <pbarbuda@microsoft.com>, Mohamed Mediouni <mohamed@unpredictable.fr>, Peter Maydell <peter.maydell@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Zhao Liu <zhao1.liu@intel.com>, Roman Bolshakov <rbolshakov@ddn.com>, Phil Dennis-Jordan <phil@philjordan.eu>, Wei Liu <wei.liu@kernel.org>

There is a newer version of this series

accel/whpx/whpx-common.c       |   2 +
include/system/whpx-internal.h |   4 +
target/arm/whpx/whpx-all.c     |   1 +
target/i386/cpu.c              |  25 ++++
target/i386/emulate/x86_emu.c  |   4 +-
target/i386/whpx/whpx-all.c    | 265 ++++++++++++++++++++++++++++++++-
target/i386/whpx/whpx-i386.h   |   4 +
7 files changed, 298 insertions(+), 7 deletions(-)
create mode 100644 target/i386/whpx/whpx-i386.h

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[PATCH v2 0/6] whpx: i386: x2apic emulation for kernel-irqchip=off, feature probing

Posted by Mohamed Mediouni 1 week, 1 day ago

"whpx: i386: disable TbFlushHypercalls for emulated LAPIC" is a
bugfix, and "target/i386: emulate: include name of unhandled instruction"
is a debugging aid.

"whpx: i386: x2apic emulation" makes things slightly better for Windows
10 users. But I strongly recommend *not* relying on it when possible and
using kernel-irqchip=on instead. On Windows 10 however that's more murky
because PIC interrupt injection is broken (interrupts don't wake the vCPU
from HLT) in that case.

"whpx: i386: wire up feature probing" is yet another commit adding a code path
not used on Windows 10. It'll tell the user today which CPU features they set
are incompatible with the hardware but it does not sync that to the CPUID view
that the guest has.

And then another commit to enable x2apic emulation by default even for
kernel-irqchip=off + re-introducing provided by QEMU enlightenments in a more
functional form to signal that the x2apic can be used. I'm not aware of the
actual vmware freq leaf being used though.

"whpx: x2apic emulation for kernel-irqchip=off follow-up" is rolled into this series.

Changes in v2:

- GCC warned when a variable name was re-used within a different (but overlapping)
scope in the same function. It also warned with a -Werror=maybe-uninitialized for
the MSR write case. Address those
- make the in-KVM enlightenments path available on Windows 11 too when -M hyperv=off.

Mohamed Mediouni (6):
  target/i386: emulate: include name of unhandled instruction
  whpx: i386: x2apic emulation
  whpx: i386: wire up feature probing
  whpx: i386: disable TbFlushHypercalls for emulated LAPIC
  whpx: i386: enable x2apic by default for user-mode LAPIC
  whpx: i386: reintroduce enlightenments for Windows 10

 accel/whpx/whpx-common.c       |   2 +
 include/system/whpx-internal.h |   4 +
 target/arm/whpx/whpx-all.c     |   1 +
 target/i386/cpu.c              |  25 ++++
 target/i386/emulate/x86_emu.c  |   4 +-
 target/i386/whpx/whpx-all.c    | 265 ++++++++++++++++++++++++++++++++-
 target/i386/whpx/whpx-i386.h   |   4 +
 7 files changed, 298 insertions(+), 7 deletions(-)
 create mode 100644 target/i386/whpx/whpx-i386.h

-- 
2.50.1 (Apple Git-155)