[PATCH v4 04/13] x86/hyperlaunch: initial support for hyperlaunch device tree

[Alejandro Vallejo <agarciav@xxxxxxx>]

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

Add the ability to detect both a formal hyperlaunch device tree or a dom0less
device tree. If the hyperlaunch device tree is found, then count the number of
domain entries, reporting an error if more than one is found.

Signed-off-by: Daniel P. Smith <dpsmith@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Andryuk <jason.andryuk@xxxxxxx>
Signed-off-by: Alejandro Vallejo <agarciav@xxxxxxx>
---
v4:
  * Panic if we're booting on hyperlaunch, but walking the DTB fails.
  * Remove inconsequential "else" clause in fdt.c
  * Remove stub, as it's not required due to DCE
  * Use min() rather than open-code it
---
 xen/arch/x86/include/asm/bootinfo.h |  1 +
 xen/common/domain-builder/core.c    | 11 +++++
 xen/common/domain-builder/fdt.c     | 63 +++++++++++++++++++++++++++++
 xen/common/domain-builder/fdt.h     |  1 +
 4 files changed, 76 insertions(+)

diff --git a/xen/arch/x86/include/asm/bootinfo.h 
b/xen/arch/x86/include/asm/bootinfo.h
index 82c2650fcf..1e3d582e45 100644
--- a/xen/arch/x86/include/asm/bootinfo.h
+++ b/xen/arch/x86/include/asm/bootinfo.h
@@ -84,6 +84,7 @@ struct boot_info {
     bool hyperlaunch_enabled;
 
     unsigned int nr_modules;
+    unsigned int nr_domains;
     struct boot_module mods[MAX_NR_BOOTMODS + 1];
     struct boot_domain domains[MAX_NR_BOOTDOMS];
 };
diff --git a/xen/common/domain-builder/core.c b/xen/common/domain-builder/core.c
index a5b21fc179..3b062e85ec 100644
--- a/xen/common/domain-builder/core.c
+++ b/xen/common/domain-builder/core.c
@@ -43,6 +43,17 @@ void __init builder_init(struct boot_info *bi)
             break;
         }
     }
+
+    if ( bi->hyperlaunch_enabled )
+    {
+        int ret;
+
+        printk(XENLOG_INFO "Hyperlaunch configuration:\n");
+        if ( (ret = walk_hyperlaunch_fdt(bi)) < 0 )
+            panic("Walk of device tree failed (%d)\n", ret);
+
+        printk(XENLOG_INFO "  number of domains: %u\n", bi->nr_domains);
+    }
 }
 
 /*
diff --git a/xen/common/domain-builder/fdt.c b/xen/common/domain-builder/fdt.c
index aaf8c1cc16..b5ff8220da 100644
--- a/xen/common/domain-builder/fdt.c
+++ b/xen/common/domain-builder/fdt.c
@@ -13,6 +13,36 @@
 
 #include "fdt.h"
 
+static int __init find_hyperlaunch_node(const void *fdt)
+{
+    int hv_node = fdt_path_offset(fdt, "/chosen/hypervisor");
+
+    if ( hv_node >= 0 )
+    {
+        /* Anything other than zero indicates no match */
+        if ( fdt_node_check_compatible(fdt, hv_node, "hypervisor,xen") )
+            return -ENODATA;
+
+        return hv_node;
+    }
+    else
+    {
+        /* Look for dom0less config */
+        int node, chosen_node = fdt_path_offset(fdt, "/chosen");
+
+        if ( chosen_node < 0 )
+            return -ENOENT;
+
+        fdt_for_each_subnode(node, fdt, chosen_node)
+        {
+            if ( !fdt_node_check_compatible(fdt, node, "xen,domain") )
+                return chosen_node;
+        }
+    }
+
+    return -ENODATA;
+}
+
 int __init has_hyperlaunch_fdt(const struct boot_info *bi)
 {
     int ret = 0;
@@ -20,7 +50,40 @@ int __init has_hyperlaunch_fdt(const struct boot_info *bi)
 
     if ( !fdt || fdt_check_header(fdt) < 0 )
         ret = -EINVAL;
+    else
+        ret = find_hyperlaunch_node(fdt);
+
+    bootstrap_unmap();
+
+    return min(0, ret);
+}
+
+int __init walk_hyperlaunch_fdt(struct boot_info *bi)
+{
+    int ret = 0, hv_node, node;
+    const void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
+
+    if ( unlikely(!fdt) )
+        return -EINVAL;
+
+    hv_node = find_hyperlaunch_node(fdt);
+    if ( hv_node < 0 )
+    {
+        ret = hv_node;
+        goto err_out;
+    }
+
+    fdt_for_each_subnode(node, fdt, hv_node)
+    {
+        if ( !fdt_node_check_compatible(fdt, node, "xen,domain") )
+            bi->nr_domains++;
+    }
+
+    /* Until multi-domain construction is added, throw an error */
+    if ( bi->nr_domains != 1 )
+        printk(XENLOG_ERR "hyperlaunch only supports dom0 construction\n");
 
+ err_out:
     bootstrap_unmap();
 
     return ret;
diff --git a/xen/common/domain-builder/fdt.h b/xen/common/domain-builder/fdt.h
index 97a45a6ec4..955aead497 100644
--- a/xen/common/domain-builder/fdt.h
+++ b/xen/common/domain-builder/fdt.h
@@ -8,5 +8,6 @@ struct boot_info;
 #define HYPERLAUNCH_MODULE_IDX 0
 
 int has_hyperlaunch_fdt(const struct boot_info *bi);
+int walk_hyperlaunch_fdt(struct boot_info *bi);
 
 #endif /* __XEN_DOMAIN_BUILDER_FDT_H__ */
-- 
2.43.0