32-on-64: Fix physaddr_bitsize computation when creating a 32b x86

compat domain.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index c3522c516ca7c9949cd69b986b9b00cf4b12430a..3483efa8670efb13da85c8dc9c9be209561b71e9 100644 (file)
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -350,8 +350,10 @@ int switch_compat(struct domain *d)
     }
 
     d->arch.physaddr_bitsize =
-        fls((1UL << 32) - HYPERVISOR_COMPAT_VIRT_START(d)) - 1
-        + (PAGE_SIZE - 2);
+        /* 2^n entries can be contained in guest's p2m mapping space */
+        fls((1UL << 32) - HYPERVISOR_COMPAT_VIRT_START(d)) - 3
+        /* 2^n pages -> 2^(n+PAGE_SHIFT) bits */
+        + PAGE_SHIFT;
 
     return 0;
 

diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index b28ca3d2357b210f6b38c51e148c7a1386ca23ac..e602b273f39b6ee0c56f481132130faf5b308cba 100644 (file)
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -356,8 +356,10 @@ int __init construct_dom0(
 #if defined(__x86_64__)
     if ( is_pv_32on64_domain(d) )
         d->arch.physaddr_bitsize =
-            fls((1UL << 32) - HYPERVISOR_COMPAT_VIRT_START(d)) - 1
-            + (PAGE_SIZE - 2);
+            /* 2^n entries can be contained in guest's p2m mapping space */
+            fls((1UL << 32) - HYPERVISOR_COMPAT_VIRT_START(d)) - 3
+            /* 2^n pages -> 2^(n+PAGE_SHIFT) bits */
+            + PAGE_SHIFT;
 #endif
 
     /*