[PULL,10/41] target/i386: sev: Use ram_block_discard_disable()

Commit Message

Michael S. Tsirkin July 3, 2020, 9:03 a.m. UTC

From: David Hildenbrand <[e-mail]>

AMD SEV will pin all guest memory, mark discarding of RAM broken. At the
time this is called, we cannot have anyone active that relies on discards
to work properly - let's still implement error handling.

Reviewed-by: Dr. David Alan Gilbert <[e-mail]>
Cc: "Michael S. Tsirkin" <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Cc: Richard Henderson <[e-mail]>
Cc: Eduardo Habkost <[e-mail]>
Signed-off-by: David Hildenbrand <[e-mail]>
Message-Id: <[e-mail]>
Reviewed-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>
---
 target/i386/sev.c | 7 +++++++
 1 file changed, 7 insertions(+)

Patch

diff --git a/target/i386/sev.c b/target/i386/sev.c
index d273174ad3..f100a53231 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -680,6 +680,12 @@  sev_guest_init(const char *id)
     uint32_t host_cbitpos;
     struct sev_user_data_status status = {};
 
+    ret = ram_block_discard_disable(true);
+    if (ret) {
+        error_report("%s: cannot disable RAM discard", __func__);
+        return NULL;
+    }
+
     sev = lookup_sev_guest_info(id);
     if (!sev) {
         error_report("%s: '%s' is not a valid '%s' object",
@@ -751,6 +757,7 @@  sev_guest_init(const char *id)
     return sev;
 err:
     sev_guest = NULL;
+    ram_block_discard_disable(false);
     return NULL;
 }