[Xen-devel] [PATCH v2 1/5] xen/arm: copy dtb fragment to guest dtb

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Read the dtb fragment corresponding to a passthrough device from memory
at the location referred to by the "multiboot,dtb" compatible node.

Copy the fragment to the guest dtb.

Add a dtb_bootmodule field to struct kernel_info to find the dtb
fragment for a guest.

Some of the code below is taken from tools/libxl/libxl_arm.c. Note that
it is OK to take LGPL 2.1 code and including it into a GPLv2 code base.
The result is GPLv2 code.

Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>

----
Changes in v2:
- add a note about the code coming from libxl in the commit message
- copy /aliases
- code style
---
 xen/arch/arm/domain_build.c  | 88 ++++++++++++++++++++++++++++++++++++++++++++
 xen/include/asm-arm/kernel.h |  2 +-
 2 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index b0ec3f0..2e04902 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -14,6 +14,7 @@
 #include <xen/guest_access.h>
 #include <xen/iocap.h>
 #include <xen/acpi.h>
+#include <xen/vmap.h>
 #include <xen/warning.h>
 #include <acpi/actables.h>
 #include <asm/device.h>
@@ -1669,6 +1670,61 @@ static int __init make_vpl011_uart_node(const struct 
domain *d, void *fdt)
 }
 #endif
 
+static int __init copy_properties(void *fdt, void *pfdt, int nodeoff)
+{
+    int propoff, nameoff, r;
+    const struct fdt_property *prop;
+
+    for ( propoff = fdt_first_property_offset(pfdt, nodeoff);
+          propoff >= 0;
+          propoff = fdt_next_property_offset(pfdt, propoff) )
+    {
+
+        if ( !(prop = fdt_get_property_by_offset(pfdt, propoff, NULL)) )
+            return -FDT_ERR_INTERNAL;
+
+        nameoff = fdt32_to_cpu(prop->nameoff);
+        r = fdt_property(fdt, fdt_string(pfdt, nameoff),
+                         prop->data, fdt32_to_cpu(prop->len));
+        if ( r )
+            return r;
+    }
+
+    /* FDT_ERR_NOTFOUND => There is no more properties for this node */
+    return ( propoff != -FDT_ERR_NOTFOUND ) ? propoff : 0;
+}
+
+static int __init copy_node(void *fdt, void *pfdt, int nodeoff, int depth)
+{
+    int r;
+
+    r = fdt_begin_node(fdt, fdt_get_name(pfdt, nodeoff, NULL));
+    if ( r )
+        return r;
+
+    r = copy_properties(fdt, pfdt, nodeoff);
+    if ( r )
+        return r;
+
+    for ( nodeoff = fdt_first_subnode(pfdt, nodeoff);
+          nodeoff >= 0;
+          nodeoff = fdt_next_subnode(pfdt, nodeoff) )
+    {
+        r = copy_node(fdt, pfdt, nodeoff, depth + 1);
+        if ( r )
+            return r;
+    }
+
+    if ( nodeoff != -FDT_ERR_NOTFOUND )
+        return nodeoff;
+
+    r = fdt_end_node(fdt);
+    if ( r )
+        return r;
+
+    return 0;
+}
+
 /*
  * The max size for DT is 2MB. However, the generated DT is small, 4KB
  * are enough for now, but we might have to increase it in the future.
@@ -1740,6 +1796,38 @@ static int __init prepare_dtb_domU(struct domain *d, 
struct kernel_info *kinfo)
             goto err;
     }
 
+    if ( kinfo->dtb_bootmodule ) {
+        int nodeoff, res;
+        void *pfdt;
+
+        pfdt = ioremap_cache(kinfo->dtb_bootmodule->start,
+                             kinfo->dtb_bootmodule->size);
+        if ( pfdt == NULL )
+            return -EFAULT;
+
+        if ( fdt_magic(pfdt) != FDT_MAGIC )
+            return -EINVAL;
+
+        nodeoff = fdt_path_offset(pfdt, "/passthrough");
+        if (nodeoff < 0)
+            return nodeoff;
+
+        res = copy_node(kinfo->fdt, pfdt, nodeoff, 0);
+        if ( res )
+            return res;
+
+        nodeoff = fdt_path_offset(pfdt, "/aliases");
+        if ( nodeoff >= 0 )
+        {
+            res = copy_node(kinfo->fdt, pfdt, nodeoff, 0);
+            if ( res )
+                return res;
+        }
+
+
+        iounmap(pfdt);
+    }
+
     ret = fdt_end_node(kinfo->fdt);
     if ( ret < 0 )
         goto err;
diff --git a/xen/include/asm-arm/kernel.h b/xen/include/asm-arm/kernel.h
index 33f3e72..720dec4 100644
--- a/xen/include/asm-arm/kernel.h
+++ b/xen/include/asm-arm/kernel.h
@@ -28,7 +28,7 @@ struct kernel_info {
     paddr_t gnttab_size;
 
     /* boot blob load addresses */
-    const struct bootmodule *kernel_bootmodule, *initrd_bootmodule;
+    const struct bootmodule *kernel_bootmodule, *initrd_bootmodule, 
*dtb_bootmodule;
     const char* cmdline;
     paddr_t dtb_paddr;
     paddr_t initrd_paddr;
-- 
1.9.1


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