qemu: set unpriv_sgio when starting domain and attaching disk

This ignores the default "filtered" if unpriv_sgio is not supported
by kernel, but for explicit request "filtered", it error out for
domain starting.

src/libvirt_private.syms

@@ -1284,6 +1284,7 @@ virGetDeviceUnprivSGIO;
 virGetGroupID;
 virGetGroupName;
 virGetHostname;
+virGetUnprivSGIOSysfsPath;
 virGetUserCacheDirectory;
 virGetUserConfigDirectory;
 virGetUserDirectory;

src/qemu/qemu_driver.c

@@ -5865,12 +5865,15 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
                      NULLSTR(disk->src));
     }
 
-    if (ret == 0 &&
-        disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK &&
-        disk->shared) {
-        if (qemuAddSharedDisk(driver->sharedDisks, disk->src) < 0)
-            VIR_WARN("Failed to add disk '%s' to shared disk table",
-                     disk->src);
+    if (ret == 0) {
+        if (disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK && disk->shared) {
+            if (qemuAddSharedDisk(driver->sharedDisks, disk->src) < 0)
+                VIR_WARN("Failed to add disk '%s' to shared disk table",
+                         disk->src);
+        }
+
+        if (qemuSetUnprivSGIO(disk) < 0)
+            VIR_WARN("Failed to set unpriv_sgio of disk '%s'", disk->src);
     }
 
 end:

src/qemu/qemu_process.c

@@ -3409,6 +3409,34 @@ qemuProcessReconnectAll(virConnectPtr conn, virQEMUDriverPtr driver)
     virHashForEach(driver->domains.objs, qemuProcessReconnectHelper, &data);
 }
 
+int
+qemuSetUnprivSGIO(virDomainDiskDefPtr disk)
+{
+    int val = -1;
+
+    if (disk->sgio)
+        val = (disk->sgio == VIR_DOMAIN_DISK_SGIO_UNFILTERED);
+
+    /* Ignore the setting if unpriv_sgio is not supported by the
+     * kernel, otherwise defaults to filter the SG_IO commands,
+     * I.E. Set unpriv_sgio to 0.
+     */
+    if (disk->sgio == VIR_DOMAIN_DISK_SGIO_DEFAULT &&
+        disk->device == VIR_DOMAIN_DISK_DEVICE_LUN) {
+        char *sysfs_path = NULL;
+
+        if ((sysfs_path = virGetUnprivSGIOSysfsPath(disk->src, NULL)) &&
+            virFileExists(sysfs_path))
+            val = 0;
+        VIR_FREE(sysfs_path);
+    }
+
+    if (val >= 0 && virSetDeviceUnprivSGIO(disk->src, NULL, val) < 0)
+        return -1;
+
+    return 0;
+}
+
 int qemuProcessStart(virConnectPtr conn,
                      virQEMUDriverPtr driver,
                      virDomainObjPtr vm,
@@ -3758,6 +3786,9 @@ int qemuProcessStart(virConnectPtr conn,
             if (qemuAddSharedDisk(driver->sharedDisks, disk->src) < 0)
                 goto cleanup;
         }
+
+        if (qemuSetUnprivSGIO(disk) < 0)
+            goto cleanup;
     }
 
     virCommandSetPreExecHook(cmd, qemuProcessHook, &hookData);

src/qemu/qemu_process.h

@@ -98,5 +98,6 @@ bool qemuProcessAutoDestroyActive(virQEMUDriverPtr driver,
                                   virDomainObjPtr vm);
 virBitmapPtr qemuPrepareCpumap(virQEMUDriverPtr driver,
                                virBitmapPtr nodemask);
+int qemuSetUnprivSGIO(virDomainDiskDefPtr disk);
 
 #endif /* __QEMU_PROCESS_H__ */

src/util/virutil.c

@@ -3171,7 +3171,7 @@ virGetDeviceID(const char *path ATRRIBUTE_UNUSED,
 
 #define SYSFS_DEV_BLOCK_PATH "/sys/dev/block"
 
-static char *
+char *
 virGetUnprivSGIOSysfsPath(const char *path,
                           const char *sysfs_dir)
 {

src/util/virutil.h

@@ -291,5 +291,7 @@ int virSetDeviceUnprivSGIO(const char *path,
 int virGetDeviceUnprivSGIO(const char *path,
                            const char *sysfs_dir,
                            int *unpriv_sgio);
+char * virGetUnprivSGIOSysfsPath(const char *path,
+                                 const char *sysfs_dir);
 
 #endif /* __VIR_UTIL_H__ */