[Xen-devel] [PATCH V4 22/24] xl: update domain configuration when we hotplug a device

[Wei Liu <wei.liu2@xxxxxxxxxx>]

A convenient macro is written to accomplish following tasks:

1. load domain configuration
2. allocate a new device structure NEW
3. copy the parsed device strcture PARSED to NEW
4. call libxl_device_TYPE_add(PARSED)
5. pull from PARSED any fields that might be touched by libxl to NEW
6. store domain configuration

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxl/xl_cmdimpl.c |   85 +++++++++++++++++++++++++++++++++++++---------
 1 file changed, 69 insertions(+), 16 deletions(-)

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 83f058e..91172c5 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -381,6 +381,36 @@ static void *xrealloc(void *ptr, size_t sz) {
         &(array)[array_extend_old_count];                               \
     })
 
+#define ARRAY_EXTEND_INIT_NODEVID(array,count,initfn)                   \
+    ({                                                                  \
+        typeof((count)) array_extend_old_count = (count);               \
+        (count)++;                                                      \
+        (array) = xrealloc((array), sizeof(*array) * (count));          \
+        (initfn)(&(array)[array_extend_old_count]);                     \
+        &(array)[array_extend_old_count];                               \
+    })
+
+/* Add a device and update the stored configuration */
+#define ADD_DEVICE(devtype,domid,dev,d_config,ptr,allocate,maybe_fixup) \
+    do {                                                                \
+        libxl_domain_config_init((d_config));                           \
+        load_domain_config((domid), (d_config));                        \
+                                                                        \
+        allocate;                                                       \
+                                                                        \
+        libxl_device_ ## devtype ## _copy(ctx,(ptr),&(dev));            \
+                                                                        \
+        if (libxl_device_ ## devtype ## _add(ctx,(domid),&(dev), 0)) {  \
+            fprintf(stderr, "libxl_device_%s_add failed.\n", #devtype); \
+            exit(1);                                                    \
+        }                                                               \
+                                                                        \
+        maybe_fixup;                                                    \
+                                                                        \
+        store_domain_config((domid), (d_config));                       \
+        libxl_domain_config_dispose((d_config));                        \
+    } while (0)
+
 #define LOG(_f, _a...)   dolog(__FILE__, __LINE__, __func__, _f "\n", ##_a)
 
 static void dolog(const char *file, int line, const char *func, char *fmt, ...)
@@ -3047,7 +3077,8 @@ int main_pcidetach(int argc, char **argv)
 }
 static void pciattach(uint32_t domid, const char *bdf, const char *vs)
 {
-    libxl_device_pci pcidev;
+    libxl_domain_config d_config;
+    libxl_device_pci pcidev, *ppcidev;
     XLU_Config *config;
 
     libxl_device_pci_init(&pcidev);
@@ -3059,7 +3090,12 @@ static void pciattach(uint32_t domid, const char *bdf, 
const char *vs)
         fprintf(stderr, "pci-attach: malformed BDF specification \"%s\"\n", 
bdf);
         exit(2);
     }
-    libxl_device_pci_add(ctx, domid, &pcidev, 0);
+
+    ADD_DEVICE(pci, domid, pcidev, &d_config, ppcidev, {
+            ppcidev = ARRAY_EXTEND_INIT_NODEVID(d_config.pcidevs,
+                                                d_config.num_pcidevs,
+                                                libxl_device_pci_init);
+        }, {});
 
     libxl_device_pci_dispose(&pcidev);
     xlu_cfg_destroy(config);
@@ -5959,7 +5995,8 @@ int main_networkattach(int argc, char **argv)
 {
     uint32_t domid;
     int opt;
-    libxl_device_nic nic;
+    libxl_domain_config d_config;
+    libxl_device_nic nic, *pnic;
     XLU_Config *config = 0;
     char *endptr, *oparg;
     const char *tok;
@@ -6040,10 +6077,16 @@ int main_networkattach(int argc, char **argv)
         return 0;
     }
 
-    if (libxl_device_nic_add(ctx, domid, &nic, 0)) {
-        fprintf(stderr, "libxl_device_nic_add failed.\n");
-        return 1;
-    }
+    /* libxl allocates devid and may generate mac */
+    ADD_DEVICE(nic, domid, nic, &d_config, pnic, {
+            pnic = ARRAY_EXTEND_INIT(d_config.nics,
+                                     d_config.num_nics,
+                                     libxl_device_nic_init);
+        }, {
+            pnic->devid = nic.devid;
+            libxl_mac_copy(ctx, &pnic->mac, &nic.mac);
+        });
+
     libxl_device_nic_dispose(&nic);
     xlu_cfg_destroy(config);
     return 0;
@@ -6123,7 +6166,8 @@ int main_blockattach(int argc, char **argv)
 {
     int opt;
     uint32_t fe_domid;
-    libxl_device_disk disk;
+    libxl_domain_config d_config;
+    libxl_device_disk disk, *pdisk;
     XLU_Config *config = 0;
 
     SWITCH_FOREACH_OPT(opt, "", NULL, "block-attach", 2) {
@@ -6147,9 +6191,12 @@ int main_blockattach(int argc, char **argv)
         return 0;
     }
 
-    if (libxl_device_disk_add(ctx, fe_domid, &disk, 0)) {
-        fprintf(stderr, "libxl_device_disk_add failed.\n");
-    }
+    ADD_DEVICE(disk, fe_domid, disk, &d_config, pdisk, {
+            pdisk = ARRAY_EXTEND_INIT_NODEVID(d_config.disks,
+                                              d_config.num_disks,
+                                              libxl_device_disk_init);
+        }, {});
+
     return 0;
 }
 
@@ -6218,7 +6265,8 @@ int main_blockdetach(int argc, char **argv)
 int main_vtpmattach(int argc, char **argv)
 {
     int opt;
-    libxl_device_vtpm vtpm;
+    libxl_domain_config d_config;
+    libxl_device_vtpm vtpm, *pvtpm;
     char *oparg;
     uint32_t domid;
 
@@ -6256,10 +6304,15 @@ int main_vtpmattach(int argc, char **argv)
        return 0;
     }
 
-    if (libxl_device_vtpm_add(ctx, domid, &vtpm, 0)) {
-        fprintf(stderr, "libxl_device_vtpm_add failed.\n");
-        return 1;
-    }
+    /* libxl may generates UUID for vtpm */
+    ADD_DEVICE(vtpm, domid, vtpm, &d_config, pvtpm, {
+            pvtpm  = ARRAY_EXTEND_INIT(d_config.vtpms,
+                                       d_config.num_vtpms,
+                                       libxl_device_vtpm_init);
+        }, {
+            libxl_uuid_copy(&pvtpm->uuid, &vtpm.uuid);
+        });
+
     libxl_device_vtpm_dispose(&vtpm);
     return 0;
 }
-- 
1.7.10.4


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