[Xen-devel] [PATCH] libxl: Disallow save or migrate when host devices are assigned to a guest.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

It is unhealthy. If the device is not doing any DMA operations
it would work - but if you are saving and there are DMA operations
happening the chance of corruption (outstanding DMAs) increase.

As such re-use the check migration used.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 src/libxl/libxl_domain.c    | 19 +++++++++++++++++++
 src/libxl/libxl_domain.h    |  3 +++
 src/libxl/libxl_driver.c    |  6 ++++++
 src/libxl/libxl_migration.c | 15 +--------------
 4 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 5e0ab56..c038989 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -178,6 +178,25 @@ libxlDomainObjEndJob(libxlDriverPrivatePtr driver 
ATTRIBUTE_UNUSED,
     return virObjectUnref(obj);
 }
 
+/*
+ * Checks whether the domain has host devices (PCIe) to disallow
+ * migration or saving of guest - unless they are detached.
+ *
+ * Returns true if the domain has host devices, otherwise false.
+ */
+bool
+libxlDomainHasHostDevices(virDomainDefPtr def)
+{
+    /* Migration is not allowed if definition contains any hostdevs */
+    if (def->nhostdevs > 0) {
+        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                       _("domain has assigned host devices"));
+        return true;
+    }
+
+    return false;
+}
+
 static void *
 libxlDomainObjPrivateAlloc(void)
 {
diff --git a/src/libxl/libxl_domain.h b/src/libxl/libxl_domain.h
index aa647b8..76c0c8d 100644
--- a/src/libxl/libxl_domain.h
+++ b/src/libxl/libxl_domain.h
@@ -95,6 +95,9 @@ char *
 libxlDomainManagedSavePath(libxlDriverPrivatePtr driver,
                            virDomainObjPtr vm);
 
+bool
+libxlDomainHasHostDevices(virDomainDefPtr def);
+
 int
 libxlDomainSaveImageOpen(libxlDriverPrivatePtr driver,
                          libxlDriverConfigPtr cfg,
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 9eb071e..b9faba8 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -1650,6 +1650,9 @@ libxlDomainSaveFlags(virDomainPtr dom, const char *to, 
const char *dxml,
         goto endjob;
     }
 
+    if (libxlDomainHasHostDevices(vm->def))
+        goto endjob;
+
     if (libxlDoDomainSave(driver, vm, to) < 0)
         goto endjob;
 
@@ -1876,6 +1879,9 @@ libxlDomainManagedSave(virDomainPtr dom, unsigned int 
flags)
         goto endjob;
     }
 
+    if (libxlDomainHasHostDevices(vm->def))
+        goto endjob;
+
     name = libxlDomainManagedSavePath(driver, vm);
     if (name == NULL)
         goto endjob;
diff --git a/src/libxl/libxl_migration.c b/src/libxl/libxl_migration.c
index 4010506..aaed448c 100644
--- a/src/libxl/libxl_migration.c
+++ b/src/libxl/libxl_migration.c
@@ -209,19 +209,6 @@ libxlDoMigrateSend(libxlDriverPrivatePtr driver,
     return ret;
 }
 
-static bool
-libxlDomainMigrationIsAllowed(virDomainDefPtr def)
-{
-    /* Migration is not allowed if definition contains any hostdevs */
-    if (def->nhostdevs > 0) {
-        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
-                       _("domain has assigned host devices"));
-        return false;
-    }
-
-    return true;
-}
-
 char *
 libxlDomainMigrationBegin(virConnectPtr conn,
                           virDomainObjPtr vm,
@@ -251,7 +238,7 @@ libxlDomainMigrationBegin(virConnectPtr conn,
         def = vm->def;
     }
 
-    if (!libxlDomainMigrationIsAllowed(def))
+    if (libxlDomainHasHostDevices(def))
         goto endjob;
 
     xml = virDomainDefFormat(def, VIR_DOMAIN_DEF_FORMAT_SECURE);
-- 
2.1.0


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