From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Tue, 28 Feb 2017 15:17:17 +0000 (+0000)
Subject: x86/layout: Correct Xen's idea of its own memory layout
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=c9a4a1c419;p=people%2Froyger%2Fxen.git

x86/layout: Correct Xen's idea of its own memory layout

c/s b4cd59fe "x86: reorder .data and .init when linking" had an unintended
side effect, where xen_in_range() and the tboot S3 MAC were no longer correct.

In practice, it means that Xen's .data section is excluded from consideration,
which means:
 1) Default IOMMU construction for the hardware domain could create mappings.
 2) .data isn't included in the tboot MAC checked on resume from S3.

Adjust the comments and virtual address anchors used to define the regions.

Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 66b7aba165..dab67d5491 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1685,7 +1685,7 @@ int __hwdom_init xen_in_range(unsigned long mfn)
     paddr_t start, end;
     int i;
 
-    enum { region_s3, region_text, region_bss, nr_regions };
+    enum { region_s3, region_ro, region_rw, nr_regions };
     static struct {
         paddr_t s, e;
     } xen_regions[nr_regions] __hwdom_initdata;
@@ -1696,12 +1696,12 @@ int __hwdom_init xen_in_range(unsigned long mfn)
         /* S3 resume code (and other real mode trampoline code) */
         xen_regions[region_s3].s = bootsym_phys(trampoline_start);
         xen_regions[region_s3].e = bootsym_phys(trampoline_end);
-        /* hypervisor code + data */
-        xen_regions[region_text].s =__pa(&_stext);
-        xen_regions[region_text].e = __pa(&__init_begin);
-        /* bss */
-        xen_regions[region_bss].s = __pa(&__bss_start);
-        xen_regions[region_bss].e = __pa(&__bss_end);
+        /* hypervisor .text + .rodata */
+        xen_regions[region_ro].s = __pa(&_stext);
+        xen_regions[region_ro].e = __pa(&__2M_rodata_end);
+        /* hypervisor .data + .bss */
+        xen_regions[region_rw].s = __pa(&__2M_rwdata_start);
+        xen_regions[region_rw].e = __pa(&__2M_rwdata_end);
     }
 
     start = (paddr_t)mfn << PAGE_SHIFT;
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index eac182ddcd..a0d1d0fbe5 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -11,6 +11,7 @@
 #include <asm/processor.h>
 #include <asm/e820.h>
 #include <asm/tboot.h>
+#include <asm/setup.h>
 #include <crypto/vmac.h>
 
 /* tboot=<physical address of shared page> */
@@ -369,13 +370,14 @@ void tboot_shutdown(uint32_t shutdown_type)
         g_tboot_shared->mac_regions[0].start = bootsym_phys(trampoline_start);
         g_tboot_shared->mac_regions[0].size = bootsym_phys(trampoline_end) -
                                               bootsym_phys(trampoline_start);
-        /* hypervisor code + data */
+        /* hypervisor .text + .rodata */
         g_tboot_shared->mac_regions[1].start = (uint64_t)__pa(&_stext);
-        g_tboot_shared->mac_regions[1].size = __pa(&__init_begin) -
+        g_tboot_shared->mac_regions[1].size = __pa(&__2M_rodata_end) -
                                               __pa(&_stext);
-        /* bss */
-        g_tboot_shared->mac_regions[2].start = (uint64_t)__pa(&__bss_start);
-        g_tboot_shared->mac_regions[2].size = __pa(&__bss_end) - __pa(&__bss_start);
+        /* hypervisor .data + .bss */
+        g_tboot_shared->mac_regions[2].start = (uint64_t)__pa(&__2M_rwdata_start);
+        g_tboot_shared->mac_regions[2].size = __pa(&__2M_rwdata_end) -
+                                              __pa(&__2M_rwdata_start);
 
         /*
          * MAC domains and other Xen memory