This series adds support for creating and managing AMD SEV-SNP
confidential virtual machines through the Microsoft Hypervisor root
partition driver.
The series adds fixed-size MSHV UAPI definitions, the required Microsoft
Hypervisor ABI definitions and hypercall helpers, partition ioctls,
capability discovery, processor-feature handling, ordered encrypted-memory
teardown, and nested-root SynIC handling.
Two prerequisite fixes now lead the series. The first makes memory-region
unmap ownership explicit and retains mappings, pinned pages, the partition,
and the module whenever checked hypervisor unmap cannot prove cleanup. The
second publishes and withdraws per-CPU SynIC pointers so interrupt readers
cannot observe mappings after initialization failure or CPU teardown.
The patches are based on the current hyperv-next branch.
Testing:
- Built all four affected x86 MSHV objects at every commit.
- Built the complete x86_64 kernel and the affected objects with W=1.
- Ran scripts/checkpatch.pl --strict on every patch with zero findings.
- Verified installed UAPI layouts in 64-bit and 32-bit userspace builds.
- Generated rust-vmm MSHV bindings from the installed kernel headers.
- Built the affected ARM64 objects with W=1 and no warnings.
- Passed Cloud Hypervisor's common_cvm::test_focal_simple_launch.
- Booted a four-vCPU SEV-SNP guest to login.
The development host needs two additional local runtime patches to boot
as a nested MSHV root partition: EFI HvLoader root-partition boot
enablement and the non-upstreamable nested-VMBus interrupt-vector
workaround. Neither patch is part of this series.
Changes since v3:
- Add checked memory-region unmap ownership as prerequisite patch 1. Keep
pages pinned and quarantine uncertain setup or teardown instead of
freeing memory that may remain child-accessible.
- Add SynIC pointer publication/withdrawal cleanup as prerequisite
patch 2.
- Rate-limit guest-triggerable PSP and isolated-page hypercall errors.
- Publish and consume driver readiness with release/acquire ordering.
- Make both array ioctls _IOWR interfaces with an MBZ input/completed
output
field, exact resumable progress, and defined no-rollback semantics.
- Preserve the exact asynchronous completion result, encode only bounded
repetition progress, and keep the distinct substatus out of result
bits.
- Check setup, explicit unmap, and teardown transitions; preserve list
and
kref ownership and quarantine any state whose safe release is
uncertain.
- Unmap child mappings before restoring host access for uninitialized as
well as initialized SNP partitions.
- Map hypervisor SynIC pages as decrypted shared-GPA mappings and
withdraw
per-CPU pointers before unmapping or freeing them.
- Validate VMSA and PSP GPAs before PFN conversion and retain the
existing
large-page alignment and physical-contiguity checks.
- Reject SNP isolation in intermediate commits until its complete ioctl
and
lifecycle implementation is present.
- Guard the SNP-only GPFN conversion helper so ARM64 W=1 builds do not
emit
an unused-function warning.
- Resolve additional adversarial-review findings: initialize common
region
locks for every region type, avoid mmap/remap lock inversion, validate
zero/oversized REP progress, and initialize all common copyout paths.
Two Sashiko findings were investigated and dismissed rather than papered
over.
Hyper-V consumes the PSP request input synchronously before returning
HV_STATUS_CALL_PENDING, so the shared per-CPU input page need not remain
reserved while waiting for completion. Also, MSHV's modify-SPA-host-access
operation transfers root-to-child SPA/SLAT ownership in Hyper-V; it does
not
perform an in-place SNP RMP transition on Linux-owned direct-map pages, so
kernel direct-map invalidation, encryption-attribute changes, and
shared-bit
rewrites would be incorrect here.
Link:
https://lore.kernel.org/linux-hyperv/[email protected]/
Wei Hu (3):
mshv: retain memory regions until unmap succeeds
mshv: clear SynIC mappings before freeing them
mshv: set up own SynIC registers on a nested root partition
Wei Liu (6):
mshv: add SEV-SNP UAPI definitions
mshv: add SEV-SNP PSP request hypercall
mshv: add SEV-SNP isolated page hypercalls
mshv: wire SEV-SNP partition ioctls
mshv: detect and report SEV-SNP support at init
mshv: use safe partition CPU feature defaults
drivers/hv/mshv_regions.c | 160 +++--
drivers/hv/mshv_root.h | 50 +-
drivers/hv/mshv_root_hv_call.c | 303 +++++++--
drivers/hv/mshv_root_main.c | 1045 +++++++++++++++++++++++++++++---
drivers/hv/mshv_synic.c | 172 +++---
include/hyperv/hvgdk_mini.h | 31 +
include/hyperv/hvhdk.h | 124 +++-
include/hyperv/hvhdk_mini.h | 53 ++
include/uapi/linux/mshv.h | 111 +++-
9 files changed, 1813 insertions(+), 236 deletions(-)
base-commit: be0cfab740e58b70047ef6e7e3d578f00ed5d258
--
2.43.0
