xen_alloc_ptpage: cast PFN_PHYS() argument to unsigned long

Currently paravirt_ops alloc_p*() uses u32 for the pfn args. We should
change that later, but while the pfn parameter is still u32, we need to
cast the PFN_PHYS() argument at xen_alloc_ptpage() to unsigned long,
otherwise it will lose bits on the shift.

I think PFN_PHYS() should behave better when fed with smaller integers,
but a cast to unsigned long won't be enough for all cases on 32-bit PAE,
and a cast to u64 would be overkill for most users of PFN_PHYS().

We could have two different flavors of PFN_PHYS: one for low pages
only (unsigned long) and another that works for any page (u64)),
but while we don't have it, we will need the cast to unsigned long on
xen_alloc_ptpage().

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 04ec69e4d02ef1b35f7f68294bf0efde527b8060..53afa14eb3145c86e157f614f5a85f3cb0fc6091 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -822,7 +822,7 @@ static void xen_alloc_ptpage(struct mm_struct *mm, u32 pfn, unsigned level)
                SetPagePinned(page);
 
                if (!PageHighMem(page)) {
-                       make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+                       make_lowmem_page_readonly(__va(PFN_PHYS((unsigned long)pfn)));
                        if (level == PT_PTE)
                                pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
                } else