[PATCH v8 0/8] KVM: SVM: Add Page Modification Logging (PML) support

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

This series implements Page Modification Logging (PML) for guests on select
AMD Zen6 and later processors, 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. More details can be
found in the latest AMD APM Volume 2 (System Programming), section
"15.25.15 Page Modification Logging".

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

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

Changelog:
v8:
* Rebased on latest kvm/next
* Drop redundant pml_addr=0 in nested_vmcb02_prepare_control() (Yosry)
* Fix misleading comment, pml_index=-1 is hardening not stale-data
  cleanup (Yosry, Sean)
* Route nested SVM_EXIT_PML_FULL to KVM and treat it as unexpected
  exit (Sean)
* Refactor update_cpu_dirty_logging() to common code as a separate
  pre-patch (Sean)

v7: https://lore.kernel.org/kvm/20260518045916.2988667-1-nikunj@amd.com/
* Swap patch order to avoid adding @pml_page parameter only to remove it
  (Sean)
* Add Sean's prep patch to pass @vcpu to init_vmcs() instead of @vmx,
  cleaning up all vmx->vcpu usage (Sean)
* Drop guard(svm_vmcb01) patch; access vmcb01 directly in
  svm_update_cpu_dirty_logging() since VMCB is just memory (Sean, Yosry)
* Only initialize PML index on reset, leave unchanged on INIT to avoid
  discarding unflushed entries. PML_INDEX in the control area remains valid
  after intercepted SHUTDOWN (Sashiko, Sean, Kai)

Nikunj A Dadhania (7):
  KVM: x86: Move PML page to common vcpu arch structure
  KVM: x86: Carve out PML flush routine
  KVM: VMX: Use cpu_dirty_log_size instead of enable_pml for PML checks
  KVM: x86: Carve out common dirty logging update
  x86/cpufeatures: Add Page modification logging
  KVM: SVM: Use BIT_ULL for 64-bit misc_ctl bit definitions
  KVM: SVM: Add Page modification logging support

Sean Christopherson (1):
  KVM: VMX: Pass @vcpu, not @vmx to init_vmcs()

 arch/x86/include/asm/cpufeatures.h |   1 +
 arch/x86/include/asm/kvm_host.h    |   4 +-
 arch/x86/include/asm/svm.h         |  14 ++--
 arch/x86/include/uapi/asm/svm.h    |   2 +
 arch/x86/kernel/cpu/scattered.c    |   1 +
 arch/x86/kvm/svm/nested.c          |  14 ++++
 arch/x86/kvm/svm/sev.c             |   2 +-
 arch/x86/kvm/svm/svm.c             | 106 ++++++++++++++++++++++++++++-
 arch/x86/kvm/svm/svm.h             |   1 +
 arch/x86/kvm/vmx/main.c            |   4 +-
 arch/x86/kvm/vmx/vmx.c             |  82 +++++++---------------
 arch/x86/kvm/vmx/vmx.h             |   9 +--
 arch/x86/kvm/vmx/x86_ops.h         |   2 +-
 arch/x86/kvm/x86.c                 |  48 ++++++++++++-
 arch/x86/kvm/x86.h                 |   7 ++
 15 files changed, 220 insertions(+), 77 deletions(-)


base-commit: d4b7fb647204f0c81dfeae2d1a708e4d858e0c94
-- 
2.48.1