FROMGIT: KVM: arm64: Fix __pkvm_init_switch_pgd call ABI

Fix the mismatch between the (incorrect) C signature, C call site, and
asm implementation by aligning all three on an API passing the
parameters (pgd and SP) separately, instead of as a bundled struct.

Remove the now unnecessary memory accesses while the MMU is off from the
asm, which simplifies the C caller (as it does not need to convert a VA
struct pointer to PA) and makes the code slightly more robust by
offsetting the struct fields from C and properly expressing the call to
the C compiler (e.g. type checker and kCFI).

Bug: 278010198
Bug: 278749606
(cherry picked from commit ea9d7c83
 https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git

 )
Change-Id: Iefee4c3e1ec7821b60feedc78236b28f02d2f3b2
Fixes: f320bc74 ("KVM: arm64: Prepare the creation of s1 mappings at EL2")
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240610063244.2828978-3-ptosi@google.com


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>