x86-64: properly handle alias mappings beyond _end

Changeset 19632:b0966b6f5180 wasn't really complete: The Xen image
mapping doesn't end at _end, but a full 16Mb gets mapped during boot
(and never got unmapped so far), hence all of this space was subject
to alias mappings when it comes to cache attribute changes. Unmap all
full large pages between _end and the 16Mb boundary, and include all
other pages beyond _end when checking for aliases.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index a3ca63f54937ce3f1b496e8cffe80de981889705..7e4473c822d92de752b0b35106f2470ce2f36920 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -805,7 +805,7 @@ static int update_xen_mappings(unsigned long mfn, unsigned long cacheattr)
     int err = 0;
 #ifdef __x86_64__
     bool_t alias = mfn >= PFN_DOWN(xen_phys_start) &&
-         mfn < PFN_UP(xen_phys_start + (unsigned long)_end - XEN_VIRT_START);
+         mfn < PFN_UP(xen_phys_start + xen_virt_end - XEN_VIRT_START);
     unsigned long xen_va =
         XEN_VIRT_START + ((mfn - PFN_DOWN(xen_phys_start)) << PAGE_SHIFT);
 

diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index a7d132a250e33bb25c291c67dc28cf997e3dac96..c2a2aaab564226a2285180781c220fd72389024b 100644 (file)
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -94,6 +94,8 @@ unsigned long __read_mostly xen_phys_start;
 /* Limits of Xen heap, used to initialise the allocator. */
 unsigned long __initdata xenheap_initial_phys_start;
 unsigned long __read_mostly xenheap_phys_end;
+#else
+unsigned long __read_mostly xen_virt_end;
 #endif
 
 DEFINE_PER_CPU(struct tss_struct, init_tss);
@@ -1094,6 +1096,9 @@ void __init __start_xen(unsigned long mbi_p)
     map_pages_to_xen((unsigned long)__va(kexec_crash_area.start),
                      kexec_crash_area.start >> PAGE_SHIFT,
                      PFN_UP(kexec_crash_area.size), PAGE_HYPERVISOR);
+    xen_virt_end = ((unsigned long)_end + (1UL << L2_PAGETABLE_SHIFT) - 1) &
+                   ~((1UL << L2_PAGETABLE_SHIFT) - 1);
+    destroy_xen_mappings(xen_virt_end, XEN_VIRT_START + BOOTSTRAP_MAP_BASE);
 #endif
 
     memguard_init();

diff --git a/xen/include/asm-x86/x86_64/page.h b/xen/include/asm-x86/x86_64/page.h
index fc006f44566451ceed137eb01b5a7ff784ebf9e5..82397c4d60faafed0f211315fc6a04f47f7572f4 100644 (file)
--- a/xen/include/asm-x86/x86_64/page.h
+++ b/xen/include/asm-x86/x86_64/page.h
@@ -35,6 +35,8 @@
 #include <xen/config.h>
 #include <asm/types.h>
 
+extern unsigned long xen_virt_end;
+
 extern unsigned long max_pdx;
 extern unsigned long pfn_pdx_bottom_mask, ma_va_bottom_mask;
 extern unsigned int pfn_pdx_hole_shift;