xen/mmu: tune pgtable alloc/release

Make sure the fastpath code is inlined.  Batch the page permission change
and the pin/unpin, and make sure that it can be batched with any
adjacent set_pte/pmd/etc operations.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

1 files changed, 44 insertions, 9 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index eb9112687cee..f987bde77c49 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1497,22 +1497,52 @@ static void __init xen_release_pmd_init(unsigned long pfn)
         make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
 }
 
+static inline void __pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+        struct multicall_space mcs;
+        struct mmuext_op *op;
+
+        mcs = __xen_mc_entry(sizeof(*op));
+        op = mcs.args;
+        op->cmd = cmd;
+        op->arg1.mfn = pfn_to_mfn(pfn);
+
+        MULTI_mmuext_op(mcs.mc, mcs.args, 1, NULL, DOMID_SELF);
+}
+
+static inline void __set_pfn_prot(unsigned long pfn, pgprot_t prot)
+{
+        struct multicall_space mcs;
+        unsigned long addr = (unsigned long)__va(pfn << PAGE_SHIFT);
+
+        mcs = __xen_mc_entry(0);
+        MULTI_update_va_mapping(mcs.mc, (unsigned long)addr,
+                                pfn_pte(pfn, prot), 0);
+}
+
 /* This needs to make sure the new pte page is pinned iff its being
    attached to a pinned pagetable. */
-static void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn, unsigned level)
+static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
+                                    unsigned level)
 {
-        struct page *page = pfn_to_page(pfn);
-        int pinned = PagePinned(virt_to_page(mm->pgd));
- 
+        bool pinned = PagePinned(virt_to_page(mm->pgd));
+
         trace_xen_mmu_alloc_ptpage(mm, pfn, level, pinned);
 
         if (pinned) {
+                struct page *page = pfn_to_page(pfn);
+
                 SetPagePinned(page);
 
                 if (!PageHighMem(page)) {
-                        make_lowmem_page_readonly(__va(PFN_PHYS((unsigned long)pfn)));
+                        xen_mc_batch();
+
+                        __set_pfn_prot(pfn, PAGE_KERNEL_RO);
+
                         if (level == PT_PTE && USE_SPLIT_PTLOCKS)
-                                pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+                                __pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
+
+                        xen_mc_issue(PARAVIRT_LAZY_MMU);
                 } else {
                         /* make sure there are no stray mappings of
                            this page */
@@ -1532,7 +1562,7 @@ static void xen_alloc_pmd(struct mm_struct *mm, unsigned long pfn)
 }
 
 /* This should never happen until we're OK to use struct page */
-static void xen_release_ptpage(unsigned long pfn, unsigned level)
+static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
 {
         struct page *page = pfn_to_page(pfn);
         bool pinned = PagePinned(page);
@@ -1541,9 +1571,14 @@ static void xen_release_ptpage(unsigned long pfn, unsigned level)
 
         if (pinned) {
                 if (!PageHighMem(page)) {
+                        xen_mc_batch();
+
                         if (level == PT_PTE && USE_SPLIT_PTLOCKS)
-                                pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
-                        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+                                __pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
+
+                        __set_pfn_prot(pfn, PAGE_KERNEL);
+
+                        xen_mc_issue(PARAVIRT_LAZY_MMU);
                 }
                 ClearPagePinned(page);
         }