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.in...
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/b9adedf777ad84af39042e9c19899600a... - Fixes host kernel crash with current implementation 3) https://github.com/vishals4gh/linux/commit/0577e351ee36d52c1f6cdcb1b8de7aa6b... - 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/8d46aea9a7d72e4b1b998066ce0dde085... - 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/4c36706477c62d9416d635fa6ac4ef648... - 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