This patchset allows userspace to be a fallback for handling emulation errors.
v1 -> v2:
- Added additional documentation for KVM_CAP_EXIT_ON_EMULATION_FAILURE.
- In prepare_emulation_failure_exit():
- Created a local variable for vcpu->run.
- Cleared the flags, emulation_failure.flags.
- Or'd the instruction bytes flag on to emulation_failure.flags.
- Updated the comment for KVM_INTERNAL_ERROR_EMULATION flags on how they are
to be used.
- Updated the comment for struct emulation_failure.
v2 -> v3:
- Update documentation for KVM_CAP_EXIT_ON_EMULATION_FAILURE.
- Fix spacing in prepare_emulation_failure_exit().
v3 -> v4:
- In prepare_emulation_failure_exit():
- Clear instruction bytes to 0x90.
- Copy over insn_size bytes rather than sizeof(ctxt->fetch.data).
- set_page_table_entry() takes a pte rather than mask.
- In _vm_get_page_table_entry():
- Removed check for page aligned addresses only.
- Added canonical check.
- Added a check to make sure no reserved bits are set along the walk except
for the final pte (the pte cannot have the reserved bits checked otherwise
the test would fail).
- Added check to ensure superpage bits are clear.
- Added check in test for 'allow_smaller_maxphyaddr' module parameter.
- If the is_flds() check fails, only look at the first byte.
- Don't use labels to increment the RIP. Decode the instruction well enough to
ensure it is only 2-bytes.
v4 -> v5:
- Switch 'insn_size' to u32.
- Add documentation for how the flags are used.
- Remove 'max_insn_size' and use 'sizeof(run->emulation_failure.insn_bytes)' instead.
- Fix typos.
- Fix canonical check.
- Add reserved check for bit-7 of PML4E.
- Add reserved check for bit-63 of all page table levels if EFER.NXE = 0.
- Remove opcode check (it might be a prefix).
- Remove labels.
- Remove detritus (rogue cpuid entry in the test).
Aaron Lewis (2):
kvm: x86: Allow userspace to handle emulation errors
selftests: kvm: Allows userspace to handle emulation errors.
Documentation/virt/kvm/api.rst | 21 ++
arch/x86/include/asm/kvm_host.h | 6 +
arch/x86/kvm/x86.c | 37 ++-
include/uapi/linux/kvm.h | 23 ++
tools/include/uapi/linux/kvm.h | 23 ++
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/include/x86_64/processor.h | 4 +
.../selftests/kvm/lib/x86_64/processor.c | 94 ++++++++
.../kvm/x86_64/emulator_error_test.c | 219 ++++++++++++++++++
10 files changed, 425 insertions(+), 4 deletions(-)
create mode 100644 tools/testing/selftests/kvm/x86_64/emulator_error_test.c
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2.31.1.527.g47e6f16901-goog
