KVM: Add support for read-only usage of gfn_to_page()

Rework gfn_to_page() to support read-only accesses so that it can be used
by arm64 to get MTE tags out of guest memory.

Opportunistically rewrite the comment to be even more stern about using
gfn_to_page(), as there are very few scenarios where requiring a struct
page is actually the right thing to do (though there are such scenarios).
Add a FIXME to call out that KVM probably should be pinning pages, not
just getting pages.

Tested-by: Alex Bennée <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Tested-by: Dmitry Osipenko <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Message-ID: <[email protected]>

0 files changed, 0 insertions, 0 deletions