[RFC PATCH 0/4] KVM: SVM: Add Page Modification Logging (PML) support

[Nikunj A Dadhania <nikunj@amd.com>]

This series implements Page Modification Logging (PML) for guests, bringing
hardware-assisted dirty logging support. PML is designed to track guest
modified memory pages. PML enables the hypervisor to identify which pages in a
guest's memory have been modified since the last checkpoint or during live
migration.

The PML feature uses two new VMCB fields (PML_ADDR and PML_INDEX) and
generates a VMEXIT when the 4KB log buffer becomes full.

Patch breakdown:
1. Refactor existing VMX PML code to be shared between VMX and SVM
2. Skip SNP-safe alloc when HvInUseWrAllowed is available
3. Add AMD SVM PML CPUID
4. Implement SVM PML support using the shared infrastructure

The feature is enabled by default when hardware support is detected and
can be disabled via the 'pml' module parameter.


Nikunj A Dadhania (4):
  KVM: x86: Carve out PML flush routine
  KVM: SEV: Skip SNP-safe allocation when HvInUseWrAllowed is supported
  x86/cpufeatures: Add Page modification logging
  KVM: SVM: Add Page modification logging support

 arch/x86/include/asm/cpufeatures.h |  1 +
 arch/x86/include/asm/svm.h         |  6 +-
 arch/x86/include/uapi/asm/svm.h    |  2 +
 arch/x86/kernel/cpu/scattered.c    |  1 +
 arch/x86/kvm/svm/sev.c             |  3 +-
 arch/x86/kvm/svm/svm.c             | 99 +++++++++++++++++++++++++++++-
 arch/x86/kvm/svm/svm.h             |  4 ++
 arch/x86/kvm/vmx/vmx.c             | 26 +-------
 arch/x86/kvm/vmx/vmx.h             |  5 --
 arch/x86/kvm/x86.c                 | 31 ++++++++++
 arch/x86/kvm/x86.h                 |  7 +++
 11 files changed, 151 insertions(+), 34 deletions(-)


base-commit: 196d9e72c4b0bd68b74a4ec7f52d248f37d0f030
--
2.43.0