xen: avoid hypercalls when updating unpinned pud/pmd

[karo-tx-linux.git] / arch / x86 / xen / mmu.c

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 17f374eb1faa4abbe077c24beb98de92651fe818..4fa0934db9252f04484750b563d5cf9886b874f4 100644 (file)
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -223,7 +223,14 @@ void make_lowmem_page_readwrite(void *vaddr)
 }
 
 
-void xen_set_pmd(pmd_t *ptr, pmd_t val)
+static bool page_pinned(void *ptr)
+{
+       struct page *page = virt_to_page(ptr);
+
+       return PagePinned(page);
+}
+
+void xen_set_pmd_hyper(pmd_t *ptr, pmd_t val)
 {
        struct multicall_space mcs;
        struct mmu_update *u;
@@ -241,6 +248,18 @@ void xen_set_pmd(pmd_t *ptr, pmd_t val)
        preempt_enable();
 }
 
+void xen_set_pmd(pmd_t *ptr, pmd_t val)
+{
+       /* If page is not pinned, we can just update the entry
+          directly */
+       if (!page_pinned(ptr)) {
+               *ptr = val;
+               return;
+       }
+
+       xen_set_pmd_hyper(ptr, val);
+}
+
 /*
  * Associate a virtual page frame with a given physical page frame
  * and protection flags for that frame.
@@ -348,7 +367,7 @@ pmdval_t xen_pmd_val(pmd_t pmd)
        return ret;
 }
 
-void xen_set_pud(pud_t *ptr, pud_t val)
+void xen_set_pud_hyper(pud_t *ptr, pud_t val)
 {
        struct multicall_space mcs;
        struct mmu_update *u;
@@ -366,6 +385,18 @@ void xen_set_pud(pud_t *ptr, pud_t val)
        preempt_enable();
 }
 
+void xen_set_pud(pud_t *ptr, pud_t val)
+{
+       /* If page is not pinned, we can just update the entry
+          directly */
+       if (!page_pinned(ptr)) {
+               *ptr = val;
+               return;
+       }
+
+       xen_set_pud_hyper(ptr, val);
+}
+
 void xen_set_pte(pte_t *ptep, pte_t pte)
 {
        ptep->pte_high = pte.pte_high;
@@ -387,7 +418,7 @@ void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
 
 void xen_pmd_clear(pmd_t *pmdp)
 {
-       xen_set_pmd(pmdp, __pmd(0));
+       set_pmd(pmdp, __pmd(0));
 }
 
 pmd_t xen_make_pmd(pmdval_t pmd)
@@ -758,7 +789,7 @@ void xen_exit_mmap(struct mm_struct *mm)
        spin_lock(&mm->page_table_lock);
 
        /* pgd may not be pinned in the error exit path of execve */
-       if (PagePinned(virt_to_page(mm->pgd)))
+       if (page_pinned(mm->pgd))
                xen_pgd_unpin(mm->pgd);
 
        spin_unlock(&mm->page_table_lock);