KVM: arm64: Check every private mapping is hyp-owned at pKVM init

fix_host_ownership() transfers only what it walks, so a hyp mapping
outside the linear map is not manipulated by the walk.

Walk the quarter of the VA space holding the private range and the
vmemmap once the transfer is done, and fail init unless every valid
leaf is hyp-owned: in the vmemmap when the page is memory, and in the
host stage-2, where hyp text may instead be mapped without write
access. A leaf that is not memory has no vmemmap entry and is checked
against the host stage-2 alone. Hyp text is matched by physical
address, since the only executable mapping in the range is the
Spectre-v3a vectors, whose VA is a private allocation, and an
executable mapping of anything else must not be host-readable. The
vmemmap can be block-mapped, so the walker checks each page of a leaf.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://patch.msgid.link/20260908110713.1540304-5-fuad.tabba@linux.dev
Signed-off-by: Oliver Upton <oupton@kernel.org>

0 files changed, 0 insertions, 0 deletions