[PATCH v3 09/16] x86/hyperlaunch: locate dom0 kernel with hyperlaunch

[Alejandro Vallejo <agarciav@xxxxxxx>]

From: "Daniel P. Smith" <dpsmith@xxxxxxxxxxxxxxxxxxxx>

Look for a subnode of type `multiboot,kernel` within a domain node. If
found, locate it using the multiboot module helper to generically ensure
it lives in the module list. If the bootargs property is present and
there was not an MB1 string, then use the command line from the device
tree definition.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
Signed-off-by: Alejandro Vallejo <agarciav@xxxxxxx>
---
v3:
    * Add const to fdt
    * Remove idx == NULL checks
    * Add BUILD_BUG_ON for MAX_NR_BOOTMODS fitting in a uint32_t
    * Remove trailing ) from printks
    * Return ENODATA for missing kernel
    * Re-work "max domains" warning and print limit
    * fdt_cell_as_u32/directly return values
    * Remove "pairs" looping from fdt_get_reg_prop() and only grab 1.
    * Use addr_cells and size_cells
---
 xen/arch/x86/domain-builder/core.c | 11 ++++++
 xen/arch/x86/domain-builder/fdt.c  | 57 ++++++++++++++++++++++++++++++
 xen/arch/x86/setup.c               |  5 ---
 3 files changed, 68 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/domain-builder/core.c 
b/xen/arch/x86/domain-builder/core.c
index c50eff34fb..eda7fa7a8f 100644
--- a/xen/arch/x86/domain-builder/core.c
+++ b/xen/arch/x86/domain-builder/core.c
@@ -59,6 +59,17 @@ void __init builder_init(struct boot_info *bi)
 
         printk(XENLOG_INFO "  Number of domains: %d\n", bi->nr_domains);
     }
+    else
+    {
+        unsigned int i;
+
+        /* Find first unknown boot module to use as Dom0 kernel */
+        printk("Falling back to using first boot module as dom0\n");
+        i = first_boot_module_index(bi, BOOTMOD_UNKNOWN);
+        bi->mods[i].type = BOOTMOD_KERNEL;
+        bi->domains[0].kernel = &bi->mods[i];
+        bi->nr_domains = 1;
+    }
 }
 
 /*
diff --git a/xen/arch/x86/domain-builder/fdt.c 
b/xen/arch/x86/domain-builder/fdt.c
index 9ebc8fd0e4..a037c8b6cb 100644
--- a/xen/arch/x86/domain-builder/fdt.c
+++ b/xen/arch/x86/domain-builder/fdt.c
@@ -155,6 +155,52 @@ int __init fdt_read_multiboot_module(const void *fdt, int 
node,
     return idx;
 }
 
+static int __init process_domain_node(
+    struct boot_info *bi, const void *fdt, int dom_node)
+{
+    int node;
+    struct boot_domain *bd = &bi->domains[bi->nr_domains];
+    const char *name = fdt_get_name(fdt, dom_node, NULL) ?: "unknown";
+    int address_cells = fdt_address_cells(fdt, dom_node);
+    int size_cells = fdt_size_cells(fdt, dom_node);
+
+    fdt_for_each_subnode(node, fdt, dom_node)
+    {
+        if ( fdt_node_check_compatible(fdt, node, "multiboot,kernel") == 0 )
+        {
+            int idx;
+
+            if ( bd->kernel )
+            {
+                printk(XENLOG_ERR "Duplicate kernel module for domain %s\n",
+                       name);
+                continue;
+            }
+
+            idx = fdt_read_multiboot_module(fdt, node, address_cells,
+                                            size_cells, bi);
+            if ( idx < 0 )
+            {
+                printk("  failed processing kernel module for domain %s\n",
+                       name);
+                return idx;
+            }
+
+            printk("  kernel: boot module %d\n", idx);
+            bi->mods[idx].type = BOOTMOD_KERNEL;
+            bd->kernel = &bi->mods[idx];
+        }
+    }
+
+    if ( !bd->kernel )
+    {
+        printk(XENLOG_ERR "ERR: no kernel assigned to domain\n");
+        return -ENODATA;
+    }
+
+    return 0;
+}
+
 static int __init find_hyperlaunch_node(const void *fdt)
 {
     int hv_node = fdt_path_offset(fdt, "/chosen/hypervisor");
@@ -217,9 +263,20 @@ int __init walk_hyperlaunch_fdt(struct boot_info *bi)
 
     fdt_for_each_subnode(node, fdt, hv_node)
     {
+        if ( bi->nr_domains >= MAX_NR_BOOTDOMS )
+        {
+            printk(XENLOG_WARNING
+                   "WARN: only creating first %u domains\n", MAX_NR_BOOTDOMS);
+            break;
+        }
+
         ret = fdt_node_check_compatible(fdt, node, "xen,domain");
         if ( ret == 0 )
+        {
+            if ( (ret = process_domain_node(bi, fdt, node)) < 0 )
+                break;
             bi->nr_domains++;
+        }
     }
 
     /* Until multi-domain construction is added, throw an error */
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index e5d78bcb48..00e8c8a2a3 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1284,11 +1284,6 @@ void asmlinkage __init noreturn __start_xen(void)
 
     builder_init(bi);
 
-    /* Find first unknown boot module to use as Dom0 kernel */
-    i = first_boot_module_index(bi, BOOTMOD_UNKNOWN);
-    bi->mods[i].type = BOOTMOD_KERNEL;
-    bi->domains[0].kernel = &bi->mods[i];
-
     if ( pvh_boot )
     {
         /* pvh_init() already filled in e820_raw */
-- 
2.43.0