KVM: selftests: Update private_mem_conversions_test for in-place conversions

Update private_mem_conversions_test for in-place conversions. In-place
conversions support is detected in selftests with kvm_has_gmem_attributes.

With in-place conversions, specifying userspace_addr from some other memory
provider that is not the guest_memfd associated with the memslot is a user
error, since KVM will only use both shared and private memory from the
guest_memfd.

Hence, when kvm_has_gmem_attributes, only test in-place conversions with
single backing, where guest_memfd provides both shared and private memory.

For single backing, guest_memfd must be created with
GUEST_MEMFD_FLAG_MMAP. Initialize the guest_memfd as shared to align with
how memory would default to shared when shared/private state was tracked at
the VM level (the test expects this, it was written for
non-in-place-conversions).

When handling a hypercall to set attributes, use
vm_mem_set_memory_attributes() to send the ioctl to the guest_memfd instead
of the VM.

When testing in-place conversions (single-backing), don't allow the user to
configure src_type, since src_type will be ignored. Don't use src_type to
determine alignment for rounding up per-cpu test memory size, since
guest_memfd's backing page size is always the system PAGE_SIZE.

Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://patch.msgid.link/20260910-gmem-inplace-conversion-v13-43-dd6fbf94f4e1@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

0 files changed, 0 insertions, 0 deletions