xen: deal with virtually mapped percpu data

The virtually mapped percpu space causes us two problems:

 - for hypercalls which take an mfn, we need to do a full pagetable
   walk to convert the percpu va into an mfn, and

 - when a hypercall requires a page to be mapped RO via all its aliases,
   we need to make sure its RO in both the percpu mapping and in the
   linear mapping

This primarily affects the gdt and the vcpu info structure.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Xen-devel <xen-devel@lists.xensource.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 319bd40a57c2..cb6afa4ec95c 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -276,6 +276,13 @@ void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
         p2m_top[topidx][idx] = mfn;
 }
 
+unsigned long arbitrary_virt_to_mfn(void *vaddr)
+{
+        xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
+
+        return PFN_DOWN(maddr.maddr);
+}
+
 xmaddr_t arbitrary_virt_to_machine(void *vaddr)
 {
         unsigned long address = (unsigned long)vaddr;