diff mbox series

[RFC,v2,13/18] guest memory protection: Move side effect out of machine_set_memory_encryption()

Message ID 20200521034304.340040-14-david@gibson.dropbear.id.au
State New, archived
Headers show
Series Refactor configuration of guest memory protection | expand

Commit Message

David Gibson May 21, 2020, 3:42 a.m. UTC
When the "memory-encryption" property is set, we also disable KSM
merging for the guest, since it won't accomplish anything.

We want that, but doing it in the property set function itself is
thereoretically incorrect, in the unlikely event of some configuration
environment that set the property then cleared it again before
constructing the guest.

But more important, it makes some other cleanups we want more
difficult.  So, instead move this logic to machine_run_board_init()
conditional on the final value of the property.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 hw/core/machine.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Comments

Richard Henderson June 2, 2020, 3:41 a.m. UTC | #1
On 5/20/20 8:42 PM, David Gibson wrote:
> When the "memory-encryption" property is set, we also disable KSM
> merging for the guest, since it won't accomplish anything.
> 
> We want that, but doing it in the property set function itself is
> thereoretically incorrect, in the unlikely event of some configuration
> environment that set the property then cleared it again before
> constructing the guest.
> 
> But more important, it makes some other cleanups we want more
> difficult.  So, instead move this logic to machine_run_board_init()
> conditional on the final value of the property.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  hw/core/machine.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
diff mbox series

Patch

diff --git a/hw/core/machine.c b/hw/core/machine.c
index bb3a7b18b1..e75f0b73d0 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -429,14 +429,6 @@  static void machine_set_memory_encryption(Object *obj, const char *value,
 
     g_free(ms->memory_encryption);
     ms->memory_encryption = g_strdup(value);
-
-    /*
-     * With memory encryption, the host can't see the real contents of RAM,
-     * so there's no point in it trying to merge areas.
-     */
-    if (value) {
-        machine_set_mem_merge(obj, false, errp);
-    }
 }
 
 static bool machine_get_nvdimm(Object *obj, Error **errp)
@@ -1129,6 +1121,15 @@  void machine_run_board_init(MachineState *machine)
         }
     }
 
+    if (machine->memory_encryption) {
+        /*
+         * With guest memory protection, the host can't see the real
+         * contents of RAM, so there's no point in it trying to merge
+         * areas.
+         */
+        machine_set_mem_merge(OBJECT(machine), false, &error_abort);
+    }
+
     machine_class->init(machine);
 }