xen/privcmd: move remap_domain_mfn_range() to core xen code and export.

This allows xenfs to be built as a module, previously it required flush_tlb_all
and arbitrary_virt_to_machine to be exported.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

3 files changed, 79 insertions, 73 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 1ceb0f2fa0af..f08ea045620f 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2265,6 +2265,72 @@ void __init xen_hvm_init_mmu_ops(void)
 }
 #endif
 
+#define REMAP_BATCH_SIZE 16
+
+struct remap_data {
+        unsigned long mfn;
+        pgprot_t prot;
+        struct mmu_update *mmu_update;
+};
+
+static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
+                                 unsigned long addr, void *data)
+{
+        struct remap_data *rmd = data;
+        pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
+
+        rmd->mmu_update->ptr = arbitrary_virt_to_machine(ptep).maddr;
+        rmd->mmu_update->val = pte_val_ma(pte);
+        rmd->mmu_update++;
+
+        return 0;
+}
+
+int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+                               unsigned long addr,
+                               unsigned long mfn, int nr,
+                               pgprot_t prot, unsigned domid)
+{
+        struct remap_data rmd;
+        struct mmu_update mmu_update[REMAP_BATCH_SIZE];
+        int batch;
+        unsigned long range;
+        int err = 0;
+
+        prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
+
+        vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
+
+        rmd.mfn = mfn;
+        rmd.prot = prot;
+
+        while (nr) {
+                batch = min(REMAP_BATCH_SIZE, nr);
+                range = (unsigned long)batch << PAGE_SHIFT;
+
+                rmd.mmu_update = mmu_update;
+                err = apply_to_page_range(vma->vm_mm, addr, range,
+                                          remap_area_mfn_pte_fn, &rmd);
+                if (err)
+                        goto out;
+
+                err = -EFAULT;
+                if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0)
+                        goto out;
+
+                nr -= batch;
+                addr += range;
+        }
+
+        err = 0;
+out:
+
+        flush_tlb_all();
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
+
 #ifdef CONFIG_XEN_DEBUG_FS
 
 static struct dentry *d_mmu_debug;
diff --git a/drivers/xen/xenfs/privcmd.c b/drivers/xen/xenfs/privcmd.c
index 438223ae0fc3..f80be7f6eb95 100644
--- a/drivers/xen/xenfs/privcmd.c
+++ b/drivers/xen/xenfs/privcmd.c
@@ -31,76 +31,12 @@
 #include <xen/interface/xen.h>
 #include <xen/features.h>
 #include <xen/page.h>
-
-#define REMAP_BATCH_SIZE 16
+#include <xen/xen-ops.h>
 
 #ifndef HAVE_ARCH_PRIVCMD_MMAP
 static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma);
 #endif
 
-struct remap_data {
-        unsigned long mfn;
-        pgprot_t prot;
-        struct mmu_update *mmu_update;
-};
-
-static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
-                                 unsigned long addr, void *data)
-{
-        struct remap_data *rmd = data;
-        pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
-
-        rmd->mmu_update->ptr = arbitrary_virt_to_machine(ptep).maddr;
-        rmd->mmu_update->val = pte_val_ma(pte);
-        rmd->mmu_update++;
-
-        return 0;
-}
-
-static int remap_domain_mfn_range(struct vm_area_struct *vma,
-                                  unsigned long addr,
-                                  unsigned long mfn, int nr,
-                                  pgprot_t prot, unsigned domid)
-{
-        struct remap_data rmd;
-        struct mmu_update mmu_update[REMAP_BATCH_SIZE];
-        int batch;
-        unsigned long range;
-        int err = 0;
-
-        prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
-
-        vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
-
-        rmd.mfn = mfn;
-        rmd.prot = prot;
-
-        while (nr) {
-                batch = min(REMAP_BATCH_SIZE, nr);
-                range = (unsigned long)batch << PAGE_SHIFT;
-
-                rmd.mmu_update = mmu_update;
-                err = apply_to_page_range(vma->vm_mm, addr, range,
-                                          remap_area_mfn_pte_fn, &rmd);
-                if (err)
-                        goto out;
-
-                err = -EFAULT;
-                if (HYPERVISOR_mmu_update(mmu_update, batch, NULL, domid) < 0)
-                        goto out;
-
-                nr -= batch;
-                addr += range;
-        }
-
-        err = 0;
-out:
-
-        flush_tlb_all();
-
-        return err;
-}
-
 static long privcmd_ioctl_hypercall(void __user *udata)
 {
         struct privcmd_hypercall hypercall;
@@ -233,11 +169,11 @@ static int mmap_mfn_range(void *data, void *state)
             ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
                 return -EINVAL;
 
-        rc = remap_domain_mfn_range(vma,
-                                    msg->va & PAGE_MASK,
-                                    msg->mfn, msg->npages,
-                                    vma->vm_page_prot,
-                                    st->domain);
+        rc = xen_remap_domain_mfn_range(vma,
+                                        msg->va & PAGE_MASK,
+                                        msg->mfn, msg->npages,
+                                        vma->vm_page_prot,
+                                        st->domain);
         if (rc < 0)
                 return rc;
 
@@ -315,9 +251,8 @@ static int mmap_batch_fn(void *data, void *state)
         xen_pfn_t *mfnp = data;
         struct mmap_batch_state *st = state;
 
-        if (remap_domain_mfn_range(st->vma, st->va & PAGE_MASK,
-                                   *mfnp, 1,
-                                   st->vma->vm_page_prot, st->domain) < 0) {
+        if (xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
+                                       st->vma->vm_page_prot, st->domain) < 0) {
                 *mfnp |= 0xf0000000U;
                 st->err++;
         }
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 351f4051f6d8..98b92154a264 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -23,4 +23,9 @@ int xen_create_contiguous_region(unsigned long vstart, unsigned int order,
 
 void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order);
 
+int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+                               unsigned long addr,
+                               unsigned long mfn, int nr,
+                               pgprot_t prot, unsigned domid);
+
 #endif /* INCLUDE_XEN_OPS_H */