[PATCH v5 5/7] KVM: arm64: Don't WARN on pKVM stage-2 map failures

[Fuad Tabba <fuad.tabba@linux.dev>]

pkvm_pgtable_stage2_map() wraps the __pkvm_host_share_guest() and
__pkvm_host_donate_guest() return in WARN_ON(), but those hypercalls
fail for reasons that are not EL1 invariant violations: -EINVAL for a
pfn that is not memblock RAM (check_range_allowed_memory() rejects a
device page mapped into a non-protected guest) and -ENOMEM under
memcache pressure. Both are reachable from a guest fault, so the WARN
splats on host input.

Return the error without warning. The unshare and write-protect WARNs
stay, since a failure there does signal a broken EL1 invariant.

Fixes: 3669ddd8fa8b5 ("KVM: arm64: Add a range to pkvm_mappings")
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
---
 arch/arm64/kvm/pkvm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index ba6570e37545..1212a2c5613d 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -466,7 +466,7 @@ int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 					size / PAGE_SIZE, prot);
 	}
 
-	if (WARN_ON(ret))
+	if (ret)
 		return ret;
 
 	swap(mapping, cache->mapping);
-- 
2.39.5