The migration handler communicates with the hypervisor
via a shared mailbox page. The MH can perform four functions
at the behest of the HV: init, save page, restore page, and
reset.
Signed-off-by: Tobin Feldman-Fitzthum <to...@linux.ibm.com>
---
.../ConfidentialMigrationDxe.inf | 1 +
.../ConfidentialMigrationDxe.c | 74 +++++++++++++++++++
2 files changed, 75 insertions(+)
diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
index 6e3fa7e51c..cb5609271c 100644
--- a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
+++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.inf
@@ -29,6 +29,7 @@
[Pcd]
gUefiOvmfPkgTokenSpaceGuid.PcdIsConfidentialMigrationTarget
gUefiOvmfPkgTokenSpaceGuid.PcdStartConfidentialMigrationHandler
+ gUefiOvmfPkgTokenSpaceGuid.PcdConfidentialMigrationMailboxBase
[Depex]
TRUE
diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
index f0dfbd279e..a981aaeac7 100644
--- a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
+++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c
@@ -6,14 +6,88 @@
**/
#include <Library/DebugLib.h>
+#include <Library/BaseMemoryLib.h>
#include <Library/UefiLib.h>
+//
+// Functions implemented by the migration handler
+//
+#define MH_FUNC_INIT 0
+#define MH_FUNC_SAVE_PAGE 1
+#define MH_FUNC_RESTORE_PAGE 2
+#define MH_FUNC_RESET 3
+
+//
+// Return codes for MH functions
+//
+#define MH_SUCCESS 0
+#define MH_INVALID_FUNC (-1)
+#define MH_AUTH_ERR (-2)
+
+//
+// Mailbox for communication with hypervisor
+//
+typedef volatile struct {
+ UINT64 Nr;
+ UINT64 Gpa;
+ UINT32 DoPrefetch;
+ UINT32 Ret;
+ UINT32 Go;
+ UINT32 Done;
+} MH_COMMAND_PARAMETERS;
+
+
VOID
EFIAPI
MigrationHandlerMain ()
{
+ UINT64 MailboxStart;
+ MH_COMMAND_PARAMETERS *Params;
+ VOID *PageVa;
+
DebugPrint (DEBUG_INFO,"Migration Handler Started\n");
+ MailboxStart = PcdGet32 (PcdConfidentialMigrationMailboxBase);
+ Params = (VOID *)MailboxStart;
+ PageVa = (VOID *)(MailboxStart + 0x1000);
+
+ DisableInterrupts ();
+ Params->Go = 0;
+
+ while (1) {
+ while (!Params->Go) {
+ CpuPause ();
+ }
+ Params->Done = 0;
+
+ switch (Params->Nr) {
+ case MH_FUNC_INIT:
+ Params->Ret = MH_SUCCESS;
+ break;
+
+ case MH_FUNC_SAVE_PAGE:
+ CopyMem (PageVa, (VOID *)Params->Gpa, 4096);
+ Params->Ret = MH_SUCCESS;
+ break;
+
+ case MH_FUNC_RESTORE_PAGE:
+ CopyMem ((VOID *)Params->Gpa, PageVa, 4096);
+ Params->Ret = MH_SUCCESS;
+ break;
+
+ case MH_FUNC_RESET:
+ Params->Ret = MH_SUCCESS;
+ break;
+
+ default:
+ Params->Ret = MH_INVALID_FUNC;
+ break;
+ }
+
+ Params->Go = 0;
+ Params->Done = 1;
+
+ }
}
/**
--
2.20.1
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