[RFC V2 PATCH 0/8] selftests: KVM: selftests for fd-based approach of supporting private memory

Vishal Annapurve
2022-05-11T00:08:25Z

This v2 series implements selftests targeting the feature floated by Chao
via:
https://lore.kernel.org/linux-mm/20220310140911.50924-1-chao.p.peng@linux.intel.com/

Below changes aim to test the fd based approach for guest private memory
in context of normal (non-confidential) VMs executing on non-confidential
platforms.

priv_memfd_test.c file adds a suite of selftests to access private memory
from the guest via private/shared accesses and checking if the contents
can be leaked to/accessed by vmm via shared memory view.

Updates in V2:
1) Tests are added to exercise implicit/explicit memory conversion paths.
2) Test is added to exercise UPM feature without double memory allocation.

This series has dependency on following patches:
1) V5 series patches from Chao mentioned above.
2) https://github.com/vishals4gh/linux/commit/b9adedf777ad84af39042e9c19899600a4add68a
- Fixes host kernel crash with current implementation
3) https://github.com/vishals4gh/linux/commit/0577e351ee36d52c1f6cdcb1b8de7aa6b5f760fe
- Confidential platforms along with the confidentiality aware software stack
support a notion of private/shared accesses from the confidential VMs.
Generally, a bit in the GPA conveys the shared/private-ness of the access.

Non-confidential platforms don't have a notion of private or shared accesses
from the guest VMs. To support this notion, KVM_HC_MAP_GPA_RANGE is modified
to allow marking an access from a VM within a GPA range as always shared or
private. There is an ongoing discussion about adding support for
software-only confidential VMs, which should replace this patch.
4) https://github.com/vishals4gh/linux/commit/8d46aea9a7d72e4b1b998066ce0dde085fb963a7
- Temporary placeholder to be able to test memory conversion paths
till the memory conversion exit error code is finalized.
5) https://github.com/vishals4gh/linux/commit/4c36706477c62d9416d635fa6ac4ef6484014dfc
- Fixes GFN calculation during memory conversion path.

Github link for the patches posted as part of this series:
https://github.com/vishals4gh/linux/commits/priv_memfd_selftests_rfc_v2

Austin Diviness (1):
selftests: kvm: Add hugepage support to priv_memfd_test suite.

Vishal Annapurve (7):
selftests: kvm: Fix inline assembly for hypercall
selftests: kvm: Add a basic selftest to test private memory
selftests: kvm: priv_memfd_test: Add support for memory conversion
selftests: kvm: priv_memfd_test: Add shared access test
selftests: kvm: Add implicit memory conversion tests
selftests: kvm: Add KVM_HC_MAP_GPA_RANGE hypercall test
selftests: kvm: priv_memfd: Add test avoiding double allocation

tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/lib/x86_64/processor.c | 2 +-
tools/testing/selftests/kvm/priv_memfd_test.c | 1359 +++++++++++++++++
3 files changed, 1361 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/kvm/priv_memfd_test.c

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2.36.0.512.ge40c2bad7a-goog