[kvm-unit-tests GIT PULL] x86: Misc changes

[Sean Christopherson]

Please pull a random set of x86 changes.  This is basically the set of things
that I could quickly/easily review, and/or were causing problems in my test
setup.

Note, "x86/run: Use separate "-accel" option to configure the accelerator"
breaks the intel_iommu test if KUT is run with ACCEL="kvm,kernel-irqchip=on"
due to the test requiring a split-IRQCHIP via "-M q35,kernel-irqchip=split".
I'm pretty sure I'm the only person that does ACCEL="kvm,kernel-irqchip=on",
and I want to unblock running KUT with notify-vmexit enabled.

Thanks!

The following changes since commit 5a221342a025948fa7d84f0c404748f6ba57f3ad:

  svm: Add SMI handler for svm_intr_intercept_mix_smi test (2026-09-08 15:33:43 +0200)

are available in the Git repository at:

  https://github.com/kvm-x86/kvm-unit-tests.git tags/kvm-x86-2026.10.02

for you to fetch changes up to 1aaec1f90618ef3cb7a4661bbec2228456050f7f:

  x86/pmu: Relax overcounting checks to allow for 1 VM-Exit per 5000 nops (2026-10-02 09:22:08 -0700)

----------------------------------------------------------------
KVM-Unit-Tests x86 changes:

 - Disable virtual PMU support when running the MSR tests as newer versions of
   QEMU will log an error when trying to create a vPMU across vendors (the test
   runs with vendor=GenuineIntel to validate SYSENTER MSRs "fun").

 - Play nice with VMMs (or hardware) that strictly adhere to the PCI spec when
   handling 0xCF8/0xCFC accesses.

 - Add a PV IPI testcase to verify KVM can deliver PV IPIs to vCPUs with APIC
   ID 255.

 - Finally add better backtraces for leaf functions on x86.

 - Add a test to verify KVM correctly handles ICEBP+TASK_SWITCH.

 - Add a testcase to validate KVM's handling of DEBUGCTL on nVMX transitions.

 - Use "-accel" instead of "-machine" to set the accelerator.

 - Add test coverage for active-low DR6 bits, and for Bus Lock Detect #DBs.

 - Apply the "PMU instructions/branches overcount" errata to all AMD CPUs and
   massage the guardrails to get the tests passing on modern CPUs without
   completely sacrificing test coverage.

 - Misc cleanups and fixes.

----------------------------------------------------------------
Chenyi Qiang (2):
      nVMX: Remove the IA32_DEBUGCTLMSR access in debugctls test
      x86/vmx: (Re)Add a nVMX test to validate load/save of DEBUGCTL

Igor Mammedov (1):
      x86/svm: work around Virtual VMLOAD/VMSAVE bug on Naples and Rome

Irene Wang (1):
      x86: pci: Support unaligned register access in PCI config read/write

Jeremiah McReynolds (1):
      x86/msr: Disable PMU for MSR tests

Jim Mattson (5):
      x86/apic: Skip PV IPI test if feature is not supported
      lib: Hoist test selection logic to library for code reuse
      x86/apic: Support subtest selection via command line
      x86/apic: Introduce send_pv_ipi()
      x86/apic: Add a test for a PV IPI boundary condition

Mathias Krause (1):
      x86: Better backtraces for leaf functions

Paolo Bonzini (1):
      taskswitch: add test for ICEBP delivery via taskgate

Sandipan Das (1):
      x86/pmu: Check for PMIs irrespective of PMU version

Sean Christopherson (6):
      x86/debug: Set all active-low DR6 bits when resetting DR6
      x86/debug: Run the "debug" test with the host CPU model
      x86/debug: Verify that KVM correctly emulates DR6 active-low and fixed-1 semantics
      x86/debug: Add actual test coverage for Bus Lock Detect #DBs
      x86/pmu: Treat all AMD CPUs as having instruction/branch overcount errata
      x86/pmu: Relax overcounting checks to allow for 1 VM-Exit per 5000 nops

Xiaoyao Li (2):
      x86: Use "accel" to require KVM for "cet" and "lam" testcases
      x86/run: Use separate "-accel" option to configure the accelerator

Yexuan Yang (1):
      x86/lam: Allocate test page from AREA_LOW instead of AREA_NORMAL

 lib/argv.c          |  14 ++++
 lib/argv.h          |   3 +
 lib/x86/asm/pci.h   |  23 ++++--
 lib/x86/msr.h       |   1 +
 lib/x86/pmu.c       |   7 ++
 lib/x86/processor.h |   1 +
 x86/Makefile.common |  22 ++++++
 x86/apic.c          | 144 +++++++++++++++++++++++++++++--------
 x86/debug.c         | 162 ++++++++++++++++++++++++++++++++----------
 x86/lam.c           |   6 +-
 x86/pmu.c           |  26 ++++---
 x86/realmode.c      |   4 ++
 x86/run             |   2 +-
 x86/svm.c           |  26 +++++++
 x86/taskswitch.c    |  46 +++++++++++-
 x86/unittests.cfg   |  24 +++++--
 x86/vmexit.c        |  15 +---
 x86/vmx_tests.c     | 199 +++++++++++++++++++++++++++++++++++++++++++---------
 18 files changed, 580 insertions(+), 145 deletions(-)