[Xen-devel] [PATCH v4 13/17] libxc: arm: allow passing a device tree blob to the guest

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Placement of the blob in guest RAM is simplistic but will do for now.

This operation is only supported on ARM.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
---
v4: Return EINVAL on non-ARM platforms (which do not support device-tree)
    Slightly less rubbish DTB placement which isn't perfect but at least now
    doesn't fail with <128MB of RAM.
---
 tools/libxc/xc_dom.h      |    8 +++++++
 tools/libxc/xc_dom_arm.c  |   22 ++++++++++++++++++-
 tools/libxc/xc_dom_core.c |   53 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/tools/libxc/xc_dom.h b/tools/libxc/xc_dom.h
index ed49aa7..bf56436 100644
--- a/tools/libxc/xc_dom.h
+++ b/tools/libxc/xc_dom.h
@@ -54,9 +54,12 @@ struct xc_dom_image {
     size_t kernel_size;
     void *ramdisk_blob;
     size_t ramdisk_size;
+    void *devicetree_blob;
+    size_t devicetree_size;
 
     size_t max_kernel_size;
     size_t max_ramdisk_size;
+    size_t max_devicetree_size;
 
     /* arguments and parameters */
     char *cmdline;
@@ -217,6 +220,8 @@ int xc_dom_kernel_max_size(struct xc_dom_image *dom, size_t 
sz);
 int xc_dom_ramdisk_check_size(struct xc_dom_image *dom, size_t sz);
 int xc_dom_ramdisk_max_size(struct xc_dom_image *dom, size_t sz);
 
+int xc_dom_devicetree_max_size(struct xc_dom_image *dom, size_t sz);
+
 size_t xc_dom_check_gzip(xc_interface *xch,
                      void *blob, size_t ziplen);
 int xc_dom_do_gunzip(xc_interface *xch,
@@ -229,6 +234,9 @@ int xc_dom_kernel_mem(struct xc_dom_image *dom, const void 
*mem,
                       size_t memsize);
 int xc_dom_ramdisk_mem(struct xc_dom_image *dom, const void *mem,
                        size_t memsize);
+int xc_dom_devicetree_file(struct xc_dom_image *dom, const char *filename);
+int xc_dom_devicetree_mem(struct xc_dom_image *dom, const void *mem,
+                          size_t memsize);
 
 int xc_dom_parse_image(struct xc_dom_image *dom);
 struct xc_dom_arch *xc_dom_find_arch_hooks(xc_interface *xch, char 
*guest_type);
diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c
index 9f3fdd3..4c59177 100644
--- a/tools/libxc/xc_dom_arm.c
+++ b/tools/libxc/xc_dom_arm.c
@@ -124,7 +124,8 @@ static int vcpu_arm(struct xc_dom_image *dom, void *ptr)
      * using CONFIG_ARM_APPENDED_DTB. Ensure that r2 does not look
      * like a valid pointer to a set of ATAGS or a DTB.
      */
-    ctxt->user_regs.r2_usr = 0xffffffff;
+    ctxt->user_regs.r2_usr = dom->devicetree_blob ?
+        dom->devicetree_seg.vstart : 0xffffffff;
 
     ctxt->sctlr = SCTLR_GUEST_INIT;
 
@@ -191,6 +192,25 @@ int arch_setup_meminit(struct xc_dom_image *dom)
             0, 0, &dom->p2m_host[i]);
     }
 
+    if ( dom->devicetree_blob )
+    {
+        const uint64_t rambase = dom->rambase_pfn << XC_PAGE_SHIFT;
+        const uint64_t ramend = rambase + ( dom->total_pages << XC_PAGE_SHIFT 
);
+        const uint64_t dtbsize = ( dom->devicetree_size + 3 ) & ~0x3;
+
+        /* Place at 128MB if there is sufficient RAM */
+        if (ramend >= rambase + 128*1024*1024 + dtbsize )
+            dom->devicetree_seg.vstart = rambase + 128*1024*1024;
+        else /* otherwise at top of RAM */
+            dom->devicetree_seg.vstart = ramend - dtbsize;
+
+        dom->devicetree_seg.vend =
+            dom->devicetree_seg.vstart + dom->devicetree_size;
+        DOMPRINTF("%s: devicetree: 0x%" PRIx64 " -> 0x%" PRIx64 "",
+                  __FUNCTION__,
+                  dom->devicetree_seg.vstart, dom->devicetree_seg.vend);
+    }
+
     return 0;
 }
 
diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c
index 6aa0176..4bd37cc 100644
--- a/tools/libxc/xc_dom_core.c
+++ b/tools/libxc/xc_dom_core.c
@@ -671,6 +671,7 @@ struct xc_dom_image *xc_dom_allocate(xc_interface *xch,
 
     dom->max_kernel_size = XC_DOM_DECOMPRESS_MAX;
     dom->max_ramdisk_size = XC_DOM_DECOMPRESS_MAX;
+    dom->max_devicetree_size = XC_DOM_DECOMPRESS_MAX;
 
     if ( cmdline )
         dom->cmdline = xc_dom_strdup(dom, cmdline);
@@ -706,6 +707,13 @@ int xc_dom_ramdisk_max_size(struct xc_dom_image *dom, 
size_t sz)
     return 0;
 }
 
+int xc_dom_devicetree_max_size(struct xc_dom_image *dom, size_t sz)
+{
+    DOMPRINTF("%s: devicetree_max_size=%zx", __FUNCTION__, sz);
+    dom->max_devicetree_size = sz;
+    return 0;
+}
+
 int xc_dom_kernel_file(struct xc_dom_image *dom, const char *filename)
 {
     DOMPRINTF("%s: filename=\"%s\"", __FUNCTION__, filename);
@@ -729,6 +737,23 @@ int xc_dom_ramdisk_file(struct xc_dom_image *dom, const 
char *filename)
     return 0;
 }
 
+int xc_dom_devicetree_file(struct xc_dom_image *dom, const char *filename)
+{
+#if defined (__arm__) || defined(__aarch64__)
+    DOMPRINTF("%s: filename=\"%s\"", __FUNCTION__, filename);
+    dom->devicetree_blob =
+        xc_dom_malloc_filemap(dom, filename, &dom->devicetree_size,
+                              dom->max_devicetree_size);
+
+    if ( dom->devicetree_blob == NULL )
+        return -1;
+    return 0;
+#else
+    errno = -EINVAL;
+    return -1;
+#endif
+}
+
 int xc_dom_kernel_mem(struct xc_dom_image *dom, const void *mem, size_t 
memsize)
 {
     DOMPRINTF_CALLED(dom->xch);
@@ -747,6 +772,15 @@ int xc_dom_ramdisk_mem(struct xc_dom_image *dom, const 
void *mem,
     return 0;
 }
 
+int xc_dom_devicetree_mem(struct xc_dom_image *dom, const void *mem,
+                          size_t memsize)
+{
+    DOMPRINTF_CALLED(dom->xch);
+    dom->devicetree_blob = (void *)mem;
+    dom->devicetree_size = memsize;
+    return 0;
+}
+
 int xc_dom_parse_image(struct xc_dom_image *dom)
 {
     int i;
@@ -916,6 +950,25 @@ int xc_dom_build_image(struct xc_dom_image *dom)
             memcpy(ramdiskmap, dom->ramdisk_blob, dom->ramdisk_size);
     }
 
+    /* load devicetree */
+    if ( dom->devicetree_blob )
+    {
+        void *devicetreemap;
+
+        if ( xc_dom_alloc_segment(dom, &dom->devicetree_seg, "devicetree",
+                                  dom->devicetree_seg.vstart,
+                                  dom->devicetree_size) != 0 )
+            goto err;
+        devicetreemap = xc_dom_seg_to_ptr(dom, &dom->devicetree_seg);
+        if ( devicetreemap == NULL )
+        {
+            DOMPRINTF("%s: xc_dom_seg_to_ptr(dom, &dom->devicetree_seg) => 
NULL",
+                      __FUNCTION__);
+            goto err;
+        }
+        memcpy(devicetreemap, dom->devicetree_blob, dom->devicetree_size);
+    }
+
     /* allocate other pages */
     if ( dom->arch_hooks->alloc_magic_pages(dom) != 0 )
         goto err;
-- 
1.7.10.4


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