[Xen-devel] [PATCH, v4] linux-2.6.18: add privileged/unprivileged kernel feature indication

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

This is the kernel side change accompanying the earlier sent Xen side
patch titled identically.

(This depends on the public headers to be synced over after the
respective hypervisor side change.)

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/arch/i386/kernel/head-xen.S
+++ b/arch/i386/kernel/head-xen.S
@@ -12,6 +12,7 @@
 #include <asm/dwarf2.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/elfnote.h>
+#include <xen/interface/features.h>
 
 /*
  * References to members of the new_cpu_data structure.
@@ -142,6 +143,18 @@ ENTRY(cpu_gdt_table)
        .quad 0x0000000000000000        /* 0xf0 - unused */
        .quad 0x0000000000000000        /* 0xf8 - GDT entry 31: double-fault 
TSS */
 
+#ifdef CONFIG_XEN_UNPRIVILEGED_GUEST
+# define XEN_DOM0_CAP          0
+# define XEN_DOM0_CAP_STR      ""
+#else
+# define XEN_DOM0_CAP          (1 << XENFEAT_dom0)
+# if CONFIG_XEN_COMPAT < 0x040200
+#  define XEN_DOM0_CAP_STR     ""
+# else
+#  define XEN_DOM0_CAP_STR     "|dom0"
+# endif
+#endif
+
 #if CONFIG_XEN_COMPAT <= 0x030002
 /*
  * __xen_guest information
@@ -195,7 +208,18 @@ ENTRY(cpu_gdt_table)
        ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .long,  startup_32)
        ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .long,  hypercall_page)
        ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW,   .long,  HYPERVISOR_VIRT_START)
-       ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz, 
"writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_pgdir_above_4gb|supervisor_mode_kernel")
+       ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii, "writable_page_tables";
+                                                .ascii  
"|writable_descriptor_tables";
+                                                .ascii  
"|auto_translated_physmap";
+                                                .ascii  "|pae_pgdir_above_4gb";
+                                                .ascii  
"|supervisor_mode_kernel";
+                                                .asciz  XEN_DOM0_CAP_STR)
+       ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long, XEN_DOM0_CAP |
+                                          (1 << XENFEAT_writable_page_tables) |
+                                          (1 << 
XENFEAT_writable_descriptor_tables) |
+                                          (1 << 
XENFEAT_auto_translated_physmap) |
+                                          (1 << XENFEAT_pae_pgdir_above_4gb) |
+                                          (1 << 
XENFEAT_supervisor_mode_kernel))
 #ifdef CONFIG_X86_PAE
        ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz, "yes")
        ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,   .quad,  
_PAGE_PRESENT,_PAGE_PRESENT)
--- a/arch/x86_64/kernel/head-xen.S
+++ b/arch/x86_64/kernel/head-xen.S
@@ -24,6 +24,7 @@
 #include <asm/cache.h>
 #include <asm/dwarf2.h>
 #include <xen/interface/elfnote.h>
+#include <xen/interface/features.h>
 
        .section .bootstrap.text, "ax", @progbits
        .code64
@@ -160,6 +161,18 @@ gdt_end:
 ENTRY(empty_zero_page)
        .skip PAGE_SIZE
 
+#ifdef CONFIG_XEN_UNPRIVILEGED_GUEST
+# define XEN_DOM0_CAP          0
+# define XEN_DOM0_CAP_STR      ""
+#else
+# define XEN_DOM0_CAP          (1 << XENFEAT_dom0)
+# if CONFIG_XEN_COMPAT < 0x040200
+#  define XEN_DOM0_CAP_STR     ""
+# else
+#  define XEN_DOM0_CAP_STR     "|dom0"
+# endif
+#endif
+
 #if CONFIG_XEN_COMPAT <= 0x030002
 /*
  * __xen_guest information
@@ -206,6 +219,15 @@ ENTRY(empty_zero_page)
        ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .quad,  startup_64)
        ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .quad,  hypercall_page)
        ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,   .quad,  
_PAGE_PRESENT,_PAGE_PRESENT)
-       ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz, 
"writable_page_tables|writable_descriptor_tables|auto_translated_physmap|supervisor_mode_kernel")
+       ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii, "writable_page_tables";
+                                                .ascii  
"|writable_descriptor_tables";
+                                                .ascii  
"|auto_translated_physmap";
+                                                .ascii  
"|supervisor_mode_kernel";
+                                                .asciz  XEN_DOM0_CAP_STR)
+       ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long, XEN_DOM0_CAP |
+                                          (1 << XENFEAT_writable_page_tables) |
+                                          (1 << 
XENFEAT_writable_descriptor_tables) |
+                                          (1 << 
XENFEAT_auto_translated_physmap) |
+                                          (1 << 
XENFEAT_supervisor_mode_kernel))
        ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz, "generic")
        ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long,  1)

Attachment: xen-dom0-cap.patch
Description: Text document

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