[PATCH 31/89] KVM: arm64: Disallow dirty logging and RO memslots with pKVM

[Will Deacon]

From: Quentin Perret <qperret at google.com>

The current implementation of pKVM doesn't support dirty logging or
read-only memslots. Although support for these features is desirable,
this will require future work, so let's cleanly report the limitations
to userspace by failing the ioctls until then.

Signed-off-by: Quentin Perret <qperret at google.com>
---
 arch/arm64/kvm/mmu.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 67cac3340d49..df92b5f7ac63 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1679,11 +1679,17 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	hva_t hva, reg_end;
 	int ret = 0;
 
-	/* In protected mode, cannot modify memslots once a VM has run. */
-	if (is_protected_kvm_enabled() &&
-	    (change == KVM_MR_DELETE || change == KVM_MR_MOVE) &&
-	    kvm->arch.pkvm.shadow_handle) {
-		return -EPERM;
+	if (is_protected_kvm_enabled()) {
+		/* In protected mode, cannot modify memslots once a VM has run. */
+		if ((change == KVM_MR_DELETE || change == KVM_MR_MOVE) &&
+		    kvm->arch.pkvm.shadow_handle) {
+			return -EPERM;
+		}
+
+		if (new &&
+		    new->flags & (KVM_MEM_LOG_DIRTY_PAGES | KVM_MEM_READONLY)) {
+			return -EPERM;
+		}
 	}
 
 	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
-- 
2.36.1.124.g0e6072fb45-goog