[PATCH v2] libxl: Support backend domain ID for disks

[Daniel De Graaf <dgdegra@tycho.nsa.gov>]

Allow specification of backend domains for disks, either in the config
file or via xl block-attach. This functionality was supported in xend
(via an optional command line parameter to block-attach), so should also
be supported with libxl.

In order to support named backend domains like network-attach, a valid
libxl_ctx must now be passed to xlu_cfg_init.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>

---

This patch does not include the changes to tools/libxl/libxlu_disk_l.c
and tools/libxl/libxlu_disk_l.h because the diffs contain unrelated
changes due to different generator versions.

 docs/misc/xl-disk-configuration.txt | 12 ++++++++++++
 tools/libxl/libxlu_cfg.c            |  4 +++-
 tools/libxl/libxlu_disk_l.l         |  9 +++++++++
 tools/libxl/libxlu_internal.h       |  1 +
 tools/libxl/libxlutil.h             |  3 ++-
 tools/libxl/xl.c                    |  2 +-
 tools/libxl/xl_cmdimpl.c            | 20 +++++++++-----------
 7 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/docs/misc/xl-disk-configuration.txt b/docs/misc/xl-disk-configuration.txt
index 86c16be..5bd456d 100644
--- a/docs/misc/xl-disk-configuration.txt
+++ b/docs/misc/xl-disk-configuration.txt
@@ -139,6 +139,18 @@ cdrom
 Convenience alias for "devtype=cdrom".
 
 
+backend=<domain-name>
+---------------------
+
+Description:           Designates a backend domain for the device
+Supported values:      Valid domain names
+Mandatory:             No
+
+Specifies the backend domain which this device should attach to. This
+defaults to domain 0. Specifying another domain requires setting up a
+driver domain which is outside the scope of this document.
+
+
 backendtype=<backend-type>
 --------------------------
 
diff --git a/tools/libxl/libxlu_cfg.c b/tools/libxl/libxlu_cfg.c
index 22adcb0..1d086b4 100644
--- a/tools/libxl/libxlu_cfg.c
+++ b/tools/libxl/libxlu_cfg.c
@@ -25,13 +25,15 @@
 #include "libxlu_cfg_l.h"
 #include "libxlu_cfg_i.h"
 
-XLU_Config *xlu_cfg_init(FILE *report, const char *report_source) {
+XLU_Config *xlu_cfg_init(FILE *report, const char *report_source,
+                         libxl_ctx *ctx) {
     XLU_Config *cfg;
 
     cfg= malloc(sizeof(*cfg));
     if (!cfg) return 0;
 
     cfg->report= report;
+    cfg->ctx = ctx;
     cfg->config_source= strdup(report_source);
     if (!cfg->config_source) { free(cfg); return 0; }
 
diff --git a/tools/libxl/libxlu_disk_l.l b/tools/libxl/libxlu_disk_l.l
index bee16a1..8cfc16e 100644
--- a/tools/libxl/libxlu_disk_l.l
+++ b/tools/libxl/libxlu_disk_l.l
@@ -33,6 +33,7 @@
 
 %{
 #include "libxlu_disk_i.h"
+#include "libxl_utils.h"
 
 #define YY_NO_INPUT
 
@@ -113,6 +114,13 @@ static void setbackendtype(DiskParseContext *dpc, const char *str) {
     else xlu__disk_err(dpc,str,"unknown value for backendtype");
 }
 
+/* Sets ->backend_domid from the string. */
+static void setbackend(DiskParseContext *dpc, const char *str) {
+    if (libxl_name_to_domid(dpc->cfg->ctx, str, &dpc->disk->backend_domid)) {
+        xlu__disk_err(dpc,str,"unknown domain for backend");
+    }
+}
+
 #define DEPRECATE(usewhatinstead) /* not currently reported */
 
 /* Handles a vdev positional parameter which includes a devtype. */
@@ -168,6 +176,7 @@ devtype=disk,?	{ DPC->disk->is_cdrom = 0; }
 devtype=[^,]*,?	{ xlu__disk_err(DPC,yytext,"unknown value for type"); }
 
 access=[^,]*,?	{ STRIP(','); setaccess(DPC, FROMEQUALS); }
+backend=[^,]*,? { STRIP(','); setbackend(DPC,FROMEQUALS); }
 backendtype=[^,]*,? { STRIP(','); setbackendtype(DPC,FROMEQUALS); }
 
 vdev=[^,]*,?	{ STRIP(','); SAVESTRING("vdev", vdev, FROMEQUALS); }
diff --git a/tools/libxl/libxlu_internal.h b/tools/libxl/libxlu_internal.h
index 7579158..5a9cf6d 100644
--- a/tools/libxl/libxlu_internal.h
+++ b/tools/libxl/libxlu_internal.h
@@ -39,6 +39,7 @@ struct XLU_Config {
     XLU_ConfigSetting *settings;
     FILE *report;
     char *config_source;
+    libxl_ctx *ctx;
 };
 
 typedef struct {
diff --git a/tools/libxl/libxlutil.h b/tools/libxl/libxlutil.h
index 0333e55..1de23e7 100644
--- a/tools/libxl/libxlutil.h
+++ b/tools/libxl/libxlutil.h
@@ -24,7 +24,8 @@
 typedef struct XLU_Config XLU_Config;
 typedef struct XLU_ConfigList XLU_ConfigList;
 
-XLU_Config *xlu_cfg_init(FILE *report, const char *report_filename);
+XLU_Config *xlu_cfg_init(FILE *report, const char *report_filename,
+                         libxl_ctx *ctx);
   /* 0 means we got ENOMEM. */
   /* report_filename is copied; report is saved and must remain valid
    *  until the Config is destroyed. */
diff --git a/tools/libxl/xl.c b/tools/libxl/xl.c
index f31e836..32a5c32 100644
--- a/tools/libxl/xl.c
+++ b/tools/libxl/xl.c
@@ -56,7 +56,7 @@ static void parse_global_config(const char *configfile,
     int e;
     const char *buf;
 
-    config = xlu_cfg_init(stderr, configfile);
+    config = xlu_cfg_init(stderr, configfile, ctx);
     if (!config) {
         fprintf(stderr, "Failed to allocate for configuration\n");
         exit(1);
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 2d6ab97..eaebbeb 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -427,7 +427,7 @@ static void parse_disk_config_multistring(XLU_Config **config,
     libxl_device_disk_init(disk);
 
     if (!*config) {
-        *config = xlu_cfg_init(stderr, "command line");
+        *config = xlu_cfg_init(stderr, "command line", ctx);
         if (!*config) { perror("xlu_cfg_init"); exit(-1); }
     }
 
@@ -583,7 +583,7 @@ static void parse_config_data(const char *config_source,
     libxl_domain_create_info *c_info = &d_config->c_info;
     libxl_domain_build_info *b_info = &d_config->b_info;
 
-    config= xlu_cfg_init(stderr, config_source);
+    config= xlu_cfg_init(stderr, config_source, ctx);
     if (!config) {
         fprintf(stderr, "Failed to allocate for configuration\n");
         exit(1);
@@ -2473,7 +2473,7 @@ static void pcidetach(const char *dom, const char *bdf, int force)
 
     libxl_device_pci_init(&pcidev);
     
-    config = xlu_cfg_init(stderr, "command line");
+    config = xlu_cfg_init(stderr, "command line", ctx);
     if (!config) { perror("xlu_cfg_inig"); exit(-1); }
 
     if (xlu_pci_parse_bdf(config, &pcidev, bdf)) {
@@ -2520,7 +2520,7 @@ static void pciattach(const char *dom, const char *bdf, const char *vs)
 
     libxl_device_pci_init(&pcidev);
 
-    config = xlu_cfg_init(stderr, "command line");
+    config = xlu_cfg_init(stderr, "command line", ctx);
     if (!config) { perror("xlu_cfg_inig"); exit(-1); }
 
     if (xlu_pci_parse_bdf(config, &pcidev, bdf)) {
@@ -2586,7 +2586,7 @@ static void pciassignable_add(const char *bdf, int rebind)
 
     libxl_device_pci_init(&pcidev);
 
-    config = xlu_cfg_init(stderr, "command line");
+    config = xlu_cfg_init(stderr, "command line", ctx);
     if (!config) { perror("xlu_cfg_init"); exit(-1); }
 
     if (xlu_pci_parse_bdf(config, &pcidev, bdf)) {
@@ -2624,7 +2624,7 @@ static void pciassignable_remove(const char *bdf, int rebind)
 
     libxl_device_pci_init(&pcidev);
 
-    config = xlu_cfg_init(stderr, "command line");
+    config = xlu_cfg_init(stderr, "command line", ctx);
     if (!config) { perror("xlu_cfg_init"); exit(-1); }
 
     if (xlu_pci_parse_bdf(config, &pcidev, bdf)) {
@@ -5321,7 +5321,7 @@ int main_networkattach(int argc, char **argv)
         return 1;
     }
 
-    config= xlu_cfg_init(stderr, "command line");
+    config= xlu_cfg_init(stderr, "command line", ctx);
     if (!config) {
         fprintf(stderr, "Failed to allocate for configuration\n");
         return 1;
@@ -5467,7 +5467,7 @@ int main_networkdetach(int argc, char **argv)
 int main_blockattach(int argc, char **argv)
 {
     int opt;
-    uint32_t fe_domid, be_domid = 0;
+    uint32_t fe_domid;
     libxl_device_disk disk = { 0 };
     XLU_Config *config = 0;
 
@@ -5483,8 +5483,6 @@ int main_blockattach(int argc, char **argv)
     parse_disk_config_multistring
         (&config, argc-optind, (const char* const*)argv + optind, &disk);
 
-    disk.backend_domid = be_domid;
-
     if (dryrun_only) {
         char *json = libxl_device_disk_to_json(ctx, &disk);
         printf("disk: %s\n", json);
@@ -6078,7 +6076,7 @@ int main_cpupoolcreate(int argc, char **argv)
         config_len += strlen(extra_config) + 1;
     }
 
-    config = xlu_cfg_init(stderr, config_src);
+    config = xlu_cfg_init(stderr, config_src, ctx);
     if (!config) {
         fprintf(stderr, "Failed to allocate for configuration\n");
         goto out;
-- 
1.7.11.4