xen: add support for PAT
Convert Linux PAT entries into Xen ones when constructing ptes. Linux
doesn't use _PAGE_PAT for ptes, so the only difference in the first 4
entries is that Linux uses _PAGE_PWT for WC, whereas Xen (and default)
use it for WT.
xen_pte_val does the inverse conversion.
We hard-code assumptions about Linux's current PAT layout, but a
warning on the wrmsr to MSR_IA32_CR_PAT should point out any problems.
If necessary we could go to a more general table-based conversion between
Linux and Xen PAT entries.
hugetlbfs poses a problem at the moment, the x86 architecture uses the
same flag for _PAGE_PAT and _PAGE_PSE, which changes meaning depending
on which pagetable level we're using. At the moment this should be OK
so long as nobody tries to do a pte_val on a hugetlbfs pte.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index d505e98..6404474 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -32,6 +32,8 @@
void xen_reserve_top(void);
extern unsigned long xen_max_p2m_pfn;
+void xen_set_pat(u64);
+
char * __init xen_memory_setup(void);
void __init xen_arch_setup(void);
void __init xen_init_IRQ(void);