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-rw-r--r--arch/x86/xen/mmu.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index d4d52f5a1cf..aba77b2b7d1 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -246,11 +246,21 @@ xmaddr_t arbitrary_virt_to_machine(void *vaddr)
{
unsigned long address = (unsigned long)vaddr;
unsigned int level;
- pte_t *pte = lookup_address(address, &level);
- unsigned offset = address & ~PAGE_MASK;
+ pte_t *pte;
+ unsigned offset;
- BUG_ON(pte == NULL);
+ /*
+ * if the PFN is in the linear mapped vaddr range, we can just use
+ * the (quick) virt_to_machine() p2m lookup
+ */
+ if (virt_addr_valid(vaddr))
+ return virt_to_machine(vaddr);
+ /* otherwise we have to do a (slower) full page-table walk */
+
+ pte = lookup_address(address, &level);
+ BUG_ON(pte == NULL);
+ offset = address & ~PAGE_MASK;
return XMADDR(((phys_addr_t)pte_mfn(*pte) << PAGE_SHIFT) + offset);
}
@@ -410,7 +420,7 @@ void xen_ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
xen_mc_batch();
- u.ptr = virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
+ u.ptr = arbitrary_virt_to_machine(ptep).maddr | MMU_PT_UPDATE_PRESERVE_AD;
u.val = pte_val_ma(pte);
xen_extend_mmu_update(&u);