[Xen-devel] [PATCH v3 07/16] hvmloader: Grab the hvm_start_info pointer

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

---
Change in V3:
- remove cmdline parser
- load hvm_start_info pointer earlier, before calling main().
- Add struct hvm_start_info definition to hvmloader.
---
 tools/firmware/hvmloader/hvm_start_info.h | 32 +++++++++++++++++++++++++++++++
 tools/firmware/hvmloader/hvmloader.c      |  6 ++++++
 2 files changed, 38 insertions(+)
 create mode 100644 tools/firmware/hvmloader/hvm_start_info.h

diff --git a/tools/firmware/hvmloader/hvm_start_info.h 
b/tools/firmware/hvmloader/hvm_start_info.h
new file mode 100644
index 0000000..b95d60d
--- /dev/null
+++ b/tools/firmware/hvmloader/hvm_start_info.h
@@ -0,0 +1,32 @@
+#ifndef __HVM_START_INFO_H__
+#define __HVM_START_INFO_H__
+
+/* C representation of the x86/HVM start info layout.
+ *
+ * The canonical definition of this layout resides in public/xen.h, this
+ * is just a way to represent the layout described there using C types.
+ *
+ * NB: the packed attribute is not really needed, but it helps us enforce
+ * the fact this this is just a representation, and it might indeed
+ * be required in the future if there are alignment changes.
+ */
+struct hvm_start_info {
+    uint32_t magic;             /* Contains the magic value 0x336ec578       */
+                                /* ("xEn3" with the 0x80 bit of the "E" set).*/
+    uint32_t version;           /* Version of this structure.                */
+    uint32_t flags;             /* SIF_xxx flags.                            */
+    uint32_t cmdline_paddr;     /* Physical address of the command line.     */
+    uint32_t nr_modules;        /* Number of modules passed to the kernel.   */
+    uint32_t modlist_paddr;     /* Physical address of an array of           */
+                                /* hvm_modlist_entry.                        */
+    uint32_t rsdp_paddr;        /* Physical address of the RSDP ACPI data    */
+                                /* structure.                                */
+} __attribute__((packed));
+
+struct hvm_modlist_entry {
+    uint64_t paddr;             /* Physical address of the module.           */
+    uint64_t size;              /* Size of the module in bytes.              */
+    uint64_t cmdline_paddr;     /* Physical address of the command line.     */
+    uint64_t reserved;
+} __attribute__((packed));
+#endif /* __HVM_START_INFO_H__ */
diff --git a/tools/firmware/hvmloader/hvmloader.c 
b/tools/firmware/hvmloader/hvmloader.c
index 716d03c..20ec8dc 100644
--- a/tools/firmware/hvmloader/hvmloader.c
+++ b/tools/firmware/hvmloader/hvmloader.c
@@ -28,6 +28,9 @@
 #include "vnuma.h"
 #include <xen/version.h>
 #include <xen/hvm/params.h>
+#include "hvm_start_info.h"
+
+const struct hvm_start_info *hvm_start_info;
 
 asm (
     "    .text                       \n"
@@ -46,6 +49,8 @@ asm (
     "    ljmp $"STR(SEL_CODE32)",$1f \n"
     "1:  movl $stack_top,%esp        \n"
     "    movl %esp,%ebp              \n"
+    /* store HVM start info ptr */
+    "    mov  %ebx, hvm_start_info   \n"
     "    call main                   \n"
     /* Relocate real-mode trampoline to 0x0. */
     "    mov  $trampoline_start,%esi \n"
@@ -258,6 +263,7 @@ int main(void)
     memset((void *)HYPERCALL_PHYSICAL_ADDRESS, 0xc3 /* RET */, PAGE_SIZE);
 
     printf("HVM Loader\n");
+    BUG_ON(hvm_start_info->magic != XEN_HVM_START_MAGIC_VALUE);
 
     init_hypercalls();
 
-- 
Anthony PERARD


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