[Xen-devel] [PATCH v7 25/32] elfnotes: intorduce a new PHYS_ENTRY elfnote

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

This new elfnote contains the 32bit entry point into the kernel. Xen will
use this entry point in order to launch the guest kernel in 32bit protected
mode with paging disabled.

Signed-off-by: Roger Pau Monnà <roger.pau@xxxxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
Changes since v6:
 - Reword a comment.

Changes since v4:
 - Add Andrew Cooper Reviewed-by and Wei Liu Acked-by.
---
 tools/xcutils/readnotes.c          |  3 +++
 xen/common/libelf/libelf-dominfo.c |  4 ++++
 xen/include/public/elfnote.h       | 12 +++++++++++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/tools/xcutils/readnotes.c b/tools/xcutils/readnotes.c
index 5fa445e..e682dd1 100644
--- a/tools/xcutils/readnotes.c
+++ b/tools/xcutils/readnotes.c
@@ -159,6 +159,9 @@ static unsigned print_notes(struct elf_binary *elf, 
ELF_HANDLE_DECL(elf_note) st
                case XEN_ELFNOTE_L1_MFN_VALID:
                        print_l1_mfn_valid_note("L1_MFN_VALID", elf , note);
                        break;
+               case XEN_ELFNOTE_PHYS32_ENTRY:
+                       print_numeric_note("PHYS32_ENTRY", elf , note);
+                       break;
                default:
                        printf("unknown note type %#x\n",
                               (unsigned)elf_uval(elf, note, type));
diff --git a/xen/common/libelf/libelf-dominfo.c 
b/xen/common/libelf/libelf-dominfo.c
index 3de1c23..dacd4ba 100644
--- a/xen/common/libelf/libelf-dominfo.c
+++ b/xen/common/libelf/libelf-dominfo.c
@@ -119,6 +119,7 @@ elf_errorstatus elf_xen_parse_note(struct elf_binary *elf,
         [XEN_ELFNOTE_BSD_SYMTAB] = { "BSD_SYMTAB", 1},
         [XEN_ELFNOTE_SUSPEND_CANCEL] = { "SUSPEND_CANCEL", 0 },
         [XEN_ELFNOTE_MOD_START_PFN] = { "MOD_START_PFN", 0 },
+        [XEN_ELFNOTE_PHYS32_ENTRY] = { "PHYS32_ENTRY", 0 },
     };
 /* *INDENT-ON* */
 
@@ -212,6 +213,9 @@ elf_errorstatus elf_xen_parse_note(struct elf_binary *elf,
                 elf, note, sizeof(*parms->f_supported), i);
         break;
 
+    case XEN_ELFNOTE_PHYS32_ENTRY:
+        parms->phys_entry = val;
+        break;
     }
     return 0;
 }
diff --git a/xen/include/public/elfnote.h b/xen/include/public/elfnote.h
index 3824a94..353985f 100644
--- a/xen/include/public/elfnote.h
+++ b/xen/include/public/elfnote.h
@@ -200,9 +200,19 @@
 #define XEN_ELFNOTE_SUPPORTED_FEATURES 17
 
 /*
+ * Physical entry point into the kernel.
+ *
+ * 32bit entry point into the kernel. When requested to launch the
+ * guest kernel in a HVM container, Xen will use this entry point to
+ * launch the guest in 32bit protected mode with paging disabled.
+ * Ignored otherwise.
+ */
+#define XEN_ELFNOTE_PHYS32_ENTRY 18
+
+/*
  * The number of the highest elfnote defined.
  */
-#define XEN_ELFNOTE_MAX XEN_ELFNOTE_SUPPORTED_FEATURES
+#define XEN_ELFNOTE_MAX XEN_ELFNOTE_PHYS32_ENTRY
 
 /*
  * System information exported through crash notes.
-- 
1.9.5 (Apple Git-50.3)


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