[PATCH v2 00/35] KVM: arm64: Add support for protected guest memory with pKVM

[Will Deacon]

Hi folks,

It's back and it's even bigger than before!

Although the first patch has been picked up as a fix (thanks, Oliver),
review feedback has resulted in some additional patches being included
in the series. If you'd like to see the first version, it's available
here:

  https://lore.kernel.org/kvmarm/20260105154939.11041-1-will@kernel.org/

Changes since v1 include:

  * Change hypercall order so that pKVM-specific calls are in their own
    range
  * Make 'pkvm_handle_t' a u16 and check its size at compile-time
  * Rework pte annotations to take a 4-bit type field
  * Fix a memory leak on the kvm_arch_init_vm() failure path
  * Pass KVM_PGTABLE_WALK_IGNORE_EAGAIN when mapping into the host idmap
  * Avoid host annotation when reclaiming guest pages
  * Re-instate guest pte metadata when unsharing a page
  * Extend selftests to cover guest share and unshare hypercalls
  * Drop broken MMU notifier changes
  * Documentation tweaks

As before, patches are based on v6.19-rc4 and are also available at:

  https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=kvm/protected-memory

All feedback welcome.

Cheers,

Will

Cc: Marc Zyngier <maz at kernel.org>
Cc: Oliver Upton <oupton at kernel.org>
Cc: Joey Gouly <joey.gouly at arm.com>
Cc: Suzuki K Poulose <suzuki.poulose at arm.com>
Cc: Zenghui Yu <yuzenghui at huawei.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Quentin Perret <qperret at google.com>
Cc: Fuad Tabba <tabba at google.com>
Cc: Vincent Donnefort <vdonnefort at google.com>
Cc: Mostafa Saleh <smostafa at google.com>

--->8

Fuad Tabba (1):
  KVM: arm64: Expose self-hosted debug regs as RAZ/WI for protected
    guests

Quentin Perret (2):
  KVM: arm64: Refactor enter_exception64()
  KVM: arm64: Inject SIGSEGV on illegal accesses

Will Deacon (32):
  KVM: arm64: Invert KVM_PGTABLE_WALK_HANDLE_FAULT to fix pKVM walkers
  KVM: arm64: Don't leak stage-2 page-table if VM fails to init under
    pKVM
  KVM: arm64: Move handle check into pkvm_pgtable_stage2_destroy_range()
  KVM: arm64: Rename __pkvm_pgtable_stage2_unmap()
  KVM: arm64: Don't advertise unsupported features for protected guests
  KVM: arm64: Remove is_protected_kvm_enabled() checks from hypercalls
  KVM: arm64: Ignore MMU notifier callbacks for protected VMs
  KVM: arm64: Prevent unsupported memslot operations on protected VMs
  KVM: arm64: Ignore -EAGAIN when mapping in pages for the pKVM host
  KVM: arm64: Split teardown hypercall into two phases
  KVM: arm64: Introduce __pkvm_host_donate_guest()
  KVM: arm64: Hook up donation hypercall to pkvm_pgtable_stage2_map()
  KVM: arm64: Handle aborts from protected VMs
  KVM: arm64: Introduce __pkvm_reclaim_dying_guest_page()
  KVM: arm64: Hook up reclaim hypercall to pkvm_pgtable_stage2_destroy()
  KVM: arm64: Avoid pointless annotation when mapping host-owned pages
  KVM: arm64: Generalise kvm_pgtable_stage2_set_owner()
  KVM: arm64: Introduce host_stage2_set_owner_metadata_locked()
  KVM: arm64: Change 'pkvm_handle_t' to u16
  KVM: arm64: Annotate guest donations with handle and gfn in host
    stage-2
  KVM: arm64: Introduce hypercall to force reclaim of a protected page
  KVM: arm64: Reclaim faulting page from pKVM in spurious fault handler
  KVM: arm64: Return -EFAULT from VCPU_RUN on access to a poisoned pte
  KVM: arm64: Add hvc handler at EL2 for hypercalls from protected VMs
  KVM: arm64: Implement the MEM_SHARE hypercall for protected VMs
  KVM: arm64: Implement the MEM_UNSHARE hypercall for protected VMs
  KVM: arm64: Allow userspace to create protected VMs when pKVM is
    enabled
  KVM: arm64: Add some initial documentation for pKVM
  KVM: arm64: Extend pKVM page ownership selftests to cover guest
    donation
  KVM: arm64: Register 'selftest_vm' in the VM table
  KVM: arm64: Extend pKVM page ownership selftests to cover forced
    reclaim
  KVM: arm64: Extend pKVM page ownership selftests to cover guest hvcs

 .../admin-guide/kernel-parameters.txt         |   4 +-
 Documentation/virt/kvm/arm/index.rst          |   1 +
 Documentation/virt/kvm/arm/pkvm.rst           | 103 +++
 arch/arm64/include/asm/kvm_asm.h              |  27 +-
 arch/arm64/include/asm/kvm_emulate.h          |   5 +
 arch/arm64/include/asm/kvm_host.h             |   9 +-
 arch/arm64/include/asm/kvm_pgtable.h          |  51 +-
 arch/arm64/include/asm/kvm_pkvm.h             |   4 +-
 arch/arm64/include/asm/virt.h                 |   6 +
 arch/arm64/kvm/Kconfig                        |  10 +
 arch/arm64/kvm/arm.c                          |  12 +-
 arch/arm64/kvm/hyp/exception.c                | 100 +--
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |   9 +
 arch/arm64/kvm/hyp/include/nvhe/memory.h      |   6 +
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h        |   7 +-
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 125 ++--
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 595 ++++++++++++++++--
 arch/arm64/kvm/hyp/nvhe/pkvm.c                | 224 ++++++-
 arch/arm64/kvm/hyp/nvhe/switch.c              |   1 +
 arch/arm64/kvm/hyp/nvhe/sys_regs.c            |   8 +
 arch/arm64/kvm/hyp/pgtable.c                  |  38 +-
 arch/arm64/kvm/mmu.c                          | 122 +++-
 arch/arm64/kvm/pkvm.c                         | 149 ++++-
 arch/arm64/mm/fault.c                         |  31 +-
 include/uapi/linux/kvm.h                      |   5 +
 25 files changed, 1405 insertions(+), 247 deletions(-)
 create mode 100644 Documentation/virt/kvm/arm/pkvm.rst

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2.52.0.457.g6b5491de43-goog