[PATCH v4 2/7] qemu: tpm: Allow offline migration with TPM_EMULATOR only with shared storage

[Stefan Berger <stefanb@xxxxxxxxxxxxx>]

Allow migration with TPM_EMULATOR (swtpm) only if shared storage has been
set up for the TPM state directory.

Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
---
 src/qemu/qemu_migration.c |  6 ++++++
 src/qemu/qemu_tpm.c       | 28 ++++++++++++++++++++++++++++
 src/qemu/qemu_tpm.h       |  5 +++++
 3 files changed, 39 insertions(+)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 33105cf07b..16bf7ac178 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -38,6 +38,7 @@
 #include "qemu_security.h"
 #include "qemu_slirp.h"
 #include "qemu_block.h"
+#include "qemu_tpm.h"
 
 #include "domain_audit.h"
 #include "virlog.h"
@@ -2579,6 +2580,11 @@ qemuMigrationSrcBeginPhase(virQEMUDriver *driver,
                            _("tunnelled offline migration does not make sense"));
             return NULL;
         }
+        if (qemuTPMHasSharedStorage(driver, vm->def) != 1) {
+            virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                           _("offline migration requires TPM state directory to be on shared storage"));
+            return NULL;
+        }
     }
 
     if (flags & VIR_MIGRATE_ZEROCOPY && !(flags & VIR_MIGRATE_PARALLEL)) {
diff --git a/src/qemu/qemu_tpm.c b/src/qemu/qemu_tpm.c
index dc09c94a4d..5f89a6bb18 100644
--- a/src/qemu/qemu_tpm.c
+++ b/src/qemu/qemu_tpm.c
@@ -954,6 +954,34 @@ qemuTPMEmulatorStart(virQEMUDriver *driver,
 }
 
 
+int
+qemuTPMHasSharedStorage(virQEMUDriver *driver,
+                        virDomainDef *def)
+{
+    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
+    size_t i;
+
+    for (i = 0; i < def->ntpms; i++) {
+        virDomainTPMDef *tpm = def->tpms[i];
+
+        switch (tpm->type) {
+        case VIR_DOMAIN_TPM_TYPE_EMULATOR:
+            if (qemuTPMEmulatorInitPaths(tpm,
+                                         cfg->swtpmStorageDir,
+                                         cfg->swtpmLogDir,
+                                         def->name,
+                                         def->uuid) < 0)
+                return -1;
+            return virFileIsSharedFS(tpm->data.emulator.storagepath);
+        case VIR_DOMAIN_TPM_TYPE_PASSTHROUGH:
+        case VIR_DOMAIN_TPM_TYPE_LAST:
+        }
+    }
+
+    return 0;
+}
+
+
 /* ---------------------
  *  Module entry points
  * ---------------------
diff --git a/src/qemu/qemu_tpm.h b/src/qemu/qemu_tpm.h
index f068f3ca5a..531d93846b 100644
--- a/src/qemu/qemu_tpm.h
+++ b/src/qemu/qemu_tpm.h
@@ -56,3 +56,8 @@ int qemuExtTPMSetupCgroup(virQEMUDriver *driver,
                           virCgroup *cgroup)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3)
     G_GNUC_WARN_UNUSED_RESULT;
+
+int qemuTPMHasSharedStorage(virQEMUDriver *driver,
+                            virDomainDef *def)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
+    G_GNUC_WARN_UNUSED_RESULT;
-- 
2.37.3