[v5,0/7] KVM: Guest Memory Pre-Population API

Message

Paolo Bonzini July 10, 2024, 5:40 p.m. UTC

Pre-population has been requested several times to mitigate KVM page faults
during guest boot or after live migration.  It is also required by TDX
before filling in the initial guest memory with measured contents.
Introduce it as a generic API.

Paolo

v4->v5:
- add EIO as possible error
- do not introduce __kvm_mmu_do_page_fault(), instead update stats in callers
- remove goto
- fix commit message to not mention weak symbol
- return error if range->size is 0
- fix comment to explain TDP restriction
- fix guest_test_phys_mem > guest_test_virt_mem case in test

Isaku Yamahata (3):
  KVM: Document KVM_PRE_FAULT_MEMORY ioctl
  KVM: Add KVM_PRE_FAULT_MEMORY vcpu ioctl to pre-populate guest memory
  KVM: selftests: x86: Add test for KVM_PRE_FAULT_MEMORY

Paolo Bonzini (2):
  KVM: x86/mmu: Make kvm_mmu_do_page_fault() return mapped level
  KVM: x86: Implement kvm_arch_vcpu_pre_fault_memory()

Sean Christopherson (2):
  KVM: x86/mmu: Bump pf_taken stat only in the "real" page fault handler
  KVM: x86/mmu: Account pf_{fixed,emulate,spurious} in callers of "do
    page fault"

 Documentation/virt/kvm/api.rst                |  55 +++++++
 arch/x86/kvm/Kconfig                          |   1 +
 arch/x86/kvm/mmu/mmu.c                        |  96 +++++++++++-
 arch/x86/kvm/mmu/mmu_internal.h               |  26 +---
 arch/x86/kvm/x86.c                            |   3 +
 include/linux/kvm_host.h                      |   5 +
 include/uapi/linux/kvm.h                      |  10 ++
 tools/include/uapi/linux/kvm.h                |  14 +-
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/pre_fault_memory_test.c     | 146 ++++++++++++++++++
 virt/kvm/Kconfig                              |   3 +
 virt/kvm/kvm_main.c                           |  60 +++++++
 12 files changed, 394 insertions(+), 26 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/pre_fault_memory_test.c