Calling the MMIO_GUARD hypercall from guests which have not been
enrolled (e.g. because they are running without pvmfw) results in
-EINVAL being returned. In this case, MMIO_GUARD is not active
and so we can simply proceed with the normal ioremap() routine.

Don't fail ioremap() if MMIO_GUARD fails; instead WARN_ON_ONCE()
to highlight that the pvm environment is slightly wonky.

Fixes: 0f1269495800 ("drivers/virt: pkvm: Intercept ioremap using pKVM MMIO_GUARD hypercall")
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241202145731.6422-2-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Hook up pKVM's MMIO_GUARD hypercall so that ioremap() and friends will
register the target physical address as MMIO with the hypervisor,
allowing guest exits to that page to be emulated by the host with full
syndrome information.

Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240830130150.8568-7-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

If we detect the presence of pKVM's SHARE and UNSHARE hypercalls, then
register a backend implementation of the mem_encrypt API so that things
like DMA buffers can be shared appropriately with the host.

Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240830130150.8568-5-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

Implement a pKVM protected guest driver to probe the presence of pKVM
and determine the memory protection granule using the HYP_MEMINFO
hypercall.

Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240830130150.8568-3-will@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>