x86: Support loading Linux bzImage v2.08 and up.

The latest -mm kernel (2.6.25-rc3-mm1) contains v2.08 of the Linux
bzImage format which embeds an ELF file in place of the raw payload
allowing it to be extracted and used by the Xen domain builder.

It is expected that this functionality will be put forward for 2.6.26.

Signed-off-by : Ian Campbell <ijc@hellion.org.uk>

diff --git a/tools/libxc/Makefile b/tools/libxc/Makefile
index b73bbfe55b6b97c55550ab9d35dfa4270c7630b3..82c58f9ebfd370a0c9b6e0811304f562ca00c2e1 100644 (file)
--- a/tools/libxc/Makefile
+++ b/tools/libxc/Makefile
@@ -46,10 +46,11 @@ GUEST_SRCS-y += libelf-tools.c libelf-loader.c
 GUEST_SRCS-y += libelf-dominfo.c libelf-relocate.c
 
 # new domain builder
-GUEST_SRCS-y += xc_dom_core.c xc_dom_boot.c
-GUEST_SRCS-y += xc_dom_elfloader.c
-GUEST_SRCS-y += xc_dom_binloader.c
-GUEST_SRCS-y += xc_dom_compat_linux.c
+GUEST_SRCS-y                 += xc_dom_core.c xc_dom_boot.c
+GUEST_SRCS-y                 += xc_dom_elfloader.c
+GUEST_SRCS-$(CONFIG_X86)     += xc_dom_bzimageloader.c
+GUEST_SRCS-y                 += xc_dom_binloader.c
+GUEST_SRCS-y                 += xc_dom_compat_linux.c
 
 GUEST_SRCS-$(CONFIG_X86)     += xc_dom_x86.c
 GUEST_SRCS-$(CONFIG_IA64)    += xc_dom_ia64.c

diff --git a/tools/libxc/xc_dom_bzimageloader.c b/tools/libxc/xc_dom_bzimageloader.c
new file mode 100644 (file)
index 0000000..628cd7d
--- /dev/null
+++ b/tools/libxc/xc_dom_bzimageloader.c
@@ -0,0 +1,159 @@
+/*
+ * Xen domain builder -- bzImage bits
+ *
+ * Parse and load bzImage kernel images.
+ *
+ * This relies on version 2.08 of the boot protocol, which contains an
+ * ELF file embedded in the bzImage.  The loader extracts this ELF
+ * image and passes it off to the standard ELF loader.
+ *
+ * This code is licenced under the GPL.
+ * written 2006 by Gerd Hoffmann <kraxel@suse.de>.
+ * written 2007 by Jeremy Fitzhardinge <jeremy@xensource.com>
+ * written 2008 by Ian Campbell <ijc@hellion.org.uk>
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <inttypes.h>
+
+#include "xg_private.h"
+#include "xc_dom.h"
+
+struct setup_header {
+       uint8_t         _pad0[0x1f1];           /* skip uninteresting stuff */
+       uint8_t         setup_sects;
+       uint16_t        root_flags;
+       uint32_t        syssize;
+       uint16_t        ram_size;
+       uint16_t        vid_mode;
+       uint16_t        root_dev;
+       uint16_t        boot_flag;
+       uint16_t        jump;
+       uint32_t        header;
+#define HDR_MAGIC              "HdrS"
+#define HDR_MAGIC_SZ   4
+       uint16_t        version;
+#define VERSION(h,l)   (((h)<<8) | (l))
+       uint32_t        realmode_swtch;
+       uint16_t        start_sys;
+       uint16_t        kernel_version;
+       uint8_t         type_of_loader;
+       uint8_t         loadflags;
+       uint16_t        setup_move_size;
+       uint32_t        code32_start;
+       uint32_t        ramdisk_image;
+       uint32_t        ramdisk_size;
+       uint32_t        bootsect_kludge;
+       uint16_t        heap_end_ptr;
+       uint16_t        _pad1;
+       uint32_t        cmd_line_ptr;
+       uint32_t        initrd_addr_max;
+       uint32_t        kernel_alignment;
+       uint8_t         relocatable_kernel;
+       uint8_t         _pad2[3];
+       uint32_t        cmdline_size;
+       uint32_t        hardware_subarch;
+       uint64_t        hardware_subarch_data;
+       uint32_t        payload_offset;
+       uint32_t        payload_length;
+} __attribute__((packed));
+
+extern struct xc_dom_loader elf_loader;
+
+static unsigned int payload_offset(struct setup_header *hdr)
+{
+    unsigned int off;
+
+    off = (hdr->setup_sects + 1) * 512;
+    off += hdr->payload_offset;
+    return off;
+}
+
+static int check_bzimage_kernel(struct xc_dom_image *dom, int verbose)
+{
+    struct setup_header *hdr;
+
+    if ( dom->kernel_blob == NULL )
+    {
+        if ( verbose )
+            xc_dom_panic(XC_INTERNAL_ERROR, "%s: no kernel image loaded\n",
+                         __FUNCTION__);
+        return -EINVAL;
+    }
+    if ( dom->kernel_size < sizeof(struct setup_header) )
+    {
+        if ( verbose )
+            xc_dom_panic(XC_INTERNAL_ERROR, "%s: kernel image too small\n",
+                         __FUNCTION__);
+        return -EINVAL;
+    }
+
+    hdr = dom->kernel_blob;
+
+    if ( memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) != 0 )
+    {
+        if ( verbose )
+            xc_dom_panic(XC_INVALID_KERNEL, "%s: kernel is not a bzImage\n",
+                         __FUNCTION__);
+        return -EINVAL;
+    }
+
+    if ( hdr->version < VERSION(2,8) )
+    {
+        if ( verbose )
+            xc_dom_panic(XC_INVALID_KERNEL, "%s: boot protocol too old (%04x)\n",
+                         __FUNCTION__, hdr->version);
+        return -EINVAL;
+    }
+
+    dom->kernel_blob = dom->kernel_blob + payload_offset(hdr);
+    dom->kernel_size = hdr->payload_length;
+
+    if ( xc_dom_try_gunzip(dom, &dom->kernel_blob, &dom->kernel_size) == -1 )
+    {
+        if ( verbose )
+            xc_dom_panic(XC_INVALID_KERNEL, "%s: unable to decompress kernel\n",
+                         __FUNCTION__);
+        return -EINVAL;
+    }
+
+    return elf_loader.probe(dom);
+}
+
+static int xc_dom_probe_bzimage_kernel(struct xc_dom_image *dom)
+{
+    return check_bzimage_kernel(dom, 0);
+}
+
+static int xc_dom_parse_bzimage_kernel(struct xc_dom_image *dom)
+{
+    return elf_loader.parser(dom);
+}
+
+static int xc_dom_load_bzimage_kernel(struct xc_dom_image *dom)
+{
+    return elf_loader.loader(dom);
+}
+
+static struct xc_dom_loader bzimage_loader = {
+    .name = "Linux bzImage",
+    .probe = xc_dom_probe_bzimage_kernel,
+    .parser = xc_dom_parse_bzimage_kernel,
+    .loader = xc_dom_load_bzimage_kernel,
+};
+
+static void __init register_loader(void)
+{
+    xc_dom_register_loader(&bzimage_loader);
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */

diff --git a/tools/libxc/xc_dom_elfloader.c b/tools/libxc/xc_dom_elfloader.c
index c34c24d08a360515a9cf0018cada44e091f48cde..ec9af72548ecd0d214b85a973ded0b6e1359b41f 100644 (file)
--- a/tools/libxc/xc_dom_elfloader.c
+++ b/tools/libxc/xc_dom_elfloader.c
@@ -281,7 +281,7 @@ static int xc_dom_load_elf_kernel(struct xc_dom_image *dom)
 
 /* ------------------------------------------------------------------------ */
 
-static struct xc_dom_loader elf_loader = {
+struct xc_dom_loader elf_loader = {
     .name = "ELF-generic",
     .probe = xc_dom_probe_elf_kernel,
     .parser = xc_dom_parse_elf_kernel,