tools: Modify single-domid callers of xc_domain_getinfolist()

xc_domain_getinfolist() internally relies on a sysctl that performs
a linear search for the domids. Many callers of xc_domain_getinfolist()
who require information about a precise domid are much better off calling
xc_domain_getinfo_single() instead, that will use the getdomaininfo domctl
instead and ensure the returned domid matches the requested one. The domtctl
will find the domid faster too, because that uses hashed lists.

Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>

tools/libs/light/libxl_dom.c

@@ -32,9 +32,9 @@ libxl_domain_type libxl__domain_type(libxl__gc *gc, uint32_t domid)
     xc_domaininfo_t info;
     int ret;
 
-    ret = xc_domain_getinfolist(ctx->xch, domid, 1, &info);
-    if (ret != 1 || info.domain != domid) {
-        LOG(ERROR, "unable to get domain type for domid=%"PRIu32, domid);
+    ret = xc_domain_getinfo_single(ctx->xch, domid, &info);
+    if (ret < 0) {
+        LOGED(ERROR, domid, "unable to get dominfo");
         return LIBXL_DOMAIN_TYPE_INVALID;
     }
     if (info.flags & XEN_DOMINF_hvm_guest) {
@@ -70,15 +70,10 @@ int libxl__domain_cpupool(libxl__gc *gc, uint32_t domid)
     xc_domaininfo_t info;
     int ret;
 
-    ret = xc_domain_getinfolist(CTX->xch, domid, 1, &info);
-    if (ret != 1)
+    ret = xc_domain_getinfo_single(CTX->xch, domid, &info);
+    if (ret < 0)
     {
-        LOGE(ERROR, "getinfolist failed %d", ret);
-        return ERROR_FAIL;
-    }
-    if (info.domain != domid)
-    {
-        LOGE(ERROR, "got info for dom%d, wanted dom%d\n", info.domain, domid);
+        LOGED(ERROR, domid, "get domaininfo failed");
         return ERROR_FAIL;
     }
     return info.cpupool;

tools/libs/light/libxl_dom_suspend.c

@@ -332,13 +332,8 @@ static void suspend_common_wait_guest_check(libxl__egc *egc,
     /* Convenience aliases */
     const uint32_t domid = dsps->domid;
 
-    ret = xc_domain_getinfolist(CTX->xch, domid, 1, &info);
+    ret = xc_domain_getinfo_single(CTX->xch, domid, &info);
     if (ret < 0) {
-        LOGED(ERROR, domid, "unable to check for status of guest");
-        goto err;
-    }
-
-    if (!(ret == 1 && info.domain == domid)) {
         LOGED(ERROR, domid, "guest we were suspending has been destroyed");
         goto err;
     }

tools/libs/light/libxl_domain.c

@@ -349,15 +349,11 @@ int libxl_domain_info(libxl_ctx *ctx, libxl_dominfo *info_r,
     int ret;
     GC_INIT(ctx);
 
-    ret = xc_domain_getinfolist(ctx->xch, domid, 1, &xcinfo);
-    if (ret<0) {
-        LOGED(ERROR, domid, "Getting domain info list");
+    ret = xc_domain_getinfo_single(ctx->xch, domid, &xcinfo);
+    if (ret < 0) {
+        LOGED(ERROR, domid, "Getting domain info");
         GC_FREE;
-        return ERROR_FAIL;
-    }
-    if (ret==0 || xcinfo.domain != domid) {
-        GC_FREE;
-        return ERROR_DOMAIN_NOTFOUND;
+        return errno == ESRCH ? ERROR_DOMAIN_NOTFOUND : ERROR_FAIL;
     }
 
     if (info_r)
@@ -1657,14 +1653,16 @@ int libxl__resolve_domid(libxl__gc *gc, const char *name, uint32_t *domid)
 libxl_vcpuinfo *libxl_list_vcpu(libxl_ctx *ctx, uint32_t domid,
                                        int *nr_vcpus_out, int *nr_cpus_out)
 {
+    int r;
     GC_INIT(ctx);
     libxl_vcpuinfo *ptr, *ret;
     xc_domaininfo_t domaininfo;
     xc_vcpuinfo_t vcpuinfo;
     unsigned int nr_vcpus;
 
-    if (xc_domain_getinfolist(ctx->xch, domid, 1, &domaininfo) != 1) {
-        LOGED(ERROR, domid, "Getting infolist");
+    r = xc_domain_getinfo_single(ctx->xch, domid, &domaininfo);
+    if (r < 0) {
+        LOGED(ERROR, domid, "Getting dominfo");
         GC_FREE;
         return NULL;
     }

tools/libs/light/libxl_mem.c

@@ -323,8 +323,8 @@ retry_transaction:
     libxl__xs_printf(gc, t, GCSPRINTF("%s/memory/target", dompath),
                      "%"PRIu64, new_target_memkb);
 
-    r = xc_domain_getinfolist(ctx->xch, domid, 1, &info);
-    if (r != 1 || info.domain != domid) {
+    r = xc_domain_getinfo_single(ctx->xch, domid, &info);
+    if (r < 0) {
         abort_transaction = 1;
         rc = ERROR_FAIL;
         goto out;

tools/libs/light/libxl_sched.c

@@ -219,13 +219,11 @@ static int sched_credit_domain_set(libxl__gc *gc, uint32_t domid,
     xc_domaininfo_t domaininfo;
     int rc;
 
-    rc = xc_domain_getinfolist(CTX->xch, domid, 1, &domaininfo);
+    rc = xc_domain_getinfo_single(CTX->xch, domid, &domaininfo);
     if (rc < 0) {
-        LOGED(ERROR, domid, "Getting domain info list");
-        return ERROR_FAIL;
+        LOGED(ERROR, domid, "Getting domain info");
+        return errno == ESRCH ? ERROR_INVAL : ERROR_FAIL;
     }
-    if (rc != 1 || domaininfo.domain != domid)
-        return ERROR_INVAL;
 
     rc = xc_sched_credit_domain_get(CTX->xch, domid, &sdom);
     if (rc != 0) {
@@ -426,13 +424,11 @@ static int sched_credit2_domain_set(libxl__gc *gc, uint32_t domid,
     xc_domaininfo_t info;
     int rc;
 
-    rc = xc_domain_getinfolist(CTX->xch, domid, 1, &info);
+    rc = xc_domain_getinfo_single(CTX->xch, domid, &info);
     if (rc < 0) {
         LOGED(ERROR, domid, "Getting domain info");
-        return ERROR_FAIL;
+        return errno == ESRCH ? ERROR_INVAL : ERROR_FAIL;
     }
-    if (rc != 1 || info.domain != domid)
-        return ERROR_INVAL;
 
     rc = xc_sched_credit2_domain_get(CTX->xch, domid, &sdom);
     if (rc != 0) {

tools/ocaml/libs/xc/xenctrl_stubs.c

@@ -497,10 +497,8 @@ CAMLprim value stub_xc_domain_getinfo(value xch_val, value domid)
 	xc_domaininfo_t info;
 	int ret;
 
-	ret = xc_domain_getinfolist(xch, Int_val(domid), 1, &info);
-	if (ret != 1)
-		failwith_xc(xch);
-	if (info.domain != Int_val(domid))
+	ret = xc_domain_getinfo_single(xch, Int_val(domid), &info);
+	if (ret < 0)
 		failwith_xc(xch);
 
 	result = alloc_domaininfo(&info);

tools/xenpaging/xenpaging.c

@@ -169,8 +169,8 @@ static int xenpaging_get_tot_pages(struct xenpaging *paging)
     xc_domaininfo_t domain_info;
     int rc;
 
-    rc = xc_domain_getinfolist(xch, paging->vm_event.domain_id, 1, &domain_info);
-    if ( rc != 1 )
+    rc = xc_domain_getinfo_single(xch, paging->vm_event.domain_id, &domain_info);
+    if ( rc < 0 )
     {
         PERROR("Error getting domain info");
         return -1;
@@ -424,9 +424,9 @@ static struct xenpaging *xenpaging_init(int argc, char *argv[])
     /* Get max_pages from guest if not provided via cmdline */
     if ( !paging->max_pages )
     {
-        rc = xc_domain_getinfolist(xch, paging->vm_event.domain_id, 1,
-                                   &domain_info);
-        if ( rc != 1 )
+        rc = xc_domain_getinfo_single(xch, paging->vm_event.domain_id,
+                                      &domain_info);
+        if ( rc < 0 )
         {
             PERROR("Error getting domain info");
             goto err;