[PATCH v16 37/45] KVM: arm64: CCA: Prevent Device mappings for realms

[Steven Price <steven.price@arm.com>]

Physical device assignment is not yet supported. RMM v2.0 does add the
relevant APIs, but device assignment is a big topic so will be handled
in a future patch series. For now prevent device mappings when the guest
is a realm.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes from v6:
 * Fix the check in user_mem_abort() to prevent all pages that are not
   guest_memfd() from being mapped into the protected half of the IPA.
Changes from v5:
 * Also prevent accesses in user_mem_abort()
---
 arch/arm64/kvm/mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 79119cb136b0..dc27f3dfb337 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1261,6 +1261,10 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 	if (is_protected_kvm_enabled())
 		return -EPERM;
 
+	/* We don't support mapping special pages into a Realm */
+	if (kvm_is_realm(kvm))
+		return -EPERM;
+
 	size += offset_in_page(guest_ipa);
 	guest_ipa &= PAGE_MASK;
 
-- 
2.43.0