[PATCH v3 25/49] i386/sev: Skip RAMBlock notifiers for SNP

[Michael Roth]

SEV uses these notifiers to register/pin pages prior to guest use, since
they could potentially be used for private memory where page migration
is not supported. But SNP only uses guest_memfd-provided pages for
private memory, which has its own kernel-internal mechanisms for
registering/pinning memory.

Signed-off-by: Michael Roth <michael.roth@amd.com>
---
 target/i386/sev.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index 61af312a11..774262d834 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -982,7 +982,15 @@ static int sev_kvm_init(ConfidentialGuestSupport *cgs, 
Error **errp)
         goto err;
     }
 
-    ram_block_notifier_add(&sev_ram_notifier);
+    if (!sev_snp_enabled()) {
+        /*
+         * SEV uses these notifiers to register/pin pages prior to guest use,
+         * but SNP relies on guest_memfd for private pages, which has it's
+         * own internal mechanisms for registering/pinning private memory.
+         */
+        ram_block_notifier_add(&sev_ram_notifier);
+    }
+
     qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
     qemu_add_vm_change_state_handler(sev_vm_state_change, sev_common);
 
-- 
2.25.1