xen/privcmd: Further s/MFN/GFN/ clean-up

The privcmd code is mixing the usage of GFN and MFN within the same
functions which make the code difficult to understand when you only work
with auto-translated guests.

The privcmd driver is only dealing with GFN so replace all the mention
of MFN into GFN.

The ioctl structure used to map foreign change has been left unchanged
given that the userspace is using it. Nonetheless, add a comment to
explain the expected value within the "mfn" field.

Signed-off-by: Julien Grall <[e-mail]>
Reviewed-by: David Vrabel <[e-mail]>
Signed-off-by: David Vrabel <[e-mail]>

arch/arm/xen/enlighten.c

···
 
 static __initdata struct device_node *xen_node;
 
-int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
+int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
 			       unsigned long addr,
-			       xen_pfn_t *mfn, int nr,
+			       xen_pfn_t *gfn, int nr,
 			       int *err_ptr, pgprot_t prot,
 			       unsigned domid,
 			       struct page **pages)
 {
-	return xen_xlate_remap_gfn_array(vma, addr, mfn, nr, err_ptr,
+	return xen_xlate_remap_gfn_array(vma, addr, gfn, nr, err_ptr,
 					 prot, domid, pages);
 }
-EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_array);
+EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);
 
 /* Not used by XENFEAT_auto_translated guests. */
-int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+int xen_remap_domain_gfn_range(struct vm_area_struct *vma,
                               unsigned long addr,
-                              xen_pfn_t mfn, int nr,
+                              xen_pfn_t gfn, int nr,
                               pgprot_t prot, unsigned domid,
                               struct page **pages)
 {
 	return -ENOSYS;
 }
-EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
+EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_range);
 
-int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
+int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 			       int nr, struct page **pages)
 {
 	return xen_xlate_unmap_gfn_range(vma, nr, pages);
 }
-EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
+EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
 
 static void xen_percpu_init(void)
 {

arch/x86/xen/mmu.c

···
 	return 0;
 }
 
-static int do_remap_mfn(struct vm_area_struct *vma,
+static int do_remap_gfn(struct vm_area_struct *vma,
 			unsigned long addr,
-			xen_pfn_t *mfn, int nr,
+			xen_pfn_t *gfn, int nr,
 			int *err_ptr, pgprot_t prot,
 			unsigned domid,
 			struct page **pages)
···
 	if (xen_feature(XENFEAT_auto_translated_physmap)) {
 #ifdef CONFIG_XEN_PVH
 		/* We need to update the local page tables and the xen HAP */
-		return xen_xlate_remap_gfn_array(vma, addr, mfn, nr, err_ptr,
+		return xen_xlate_remap_gfn_array(vma, addr, gfn, nr, err_ptr,
 						 prot, domid, pages);
 #else
 		return -EINVAL;
 #endif
         }
 
-	rmd.mfn = mfn;
+	rmd.mfn = gfn;
 	rmd.prot = prot;
 	/* We use the err_ptr to indicate if there we are doing a contigious
 	 * mapping or a discontigious mapping. */
···
 						    batch_left, &done, domid);
 
 			/*
-			 * @err_ptr may be the same buffer as @mfn, so
-			 * only clear it after each chunk of @mfn is
+			 * @err_ptr may be the same buffer as @gfn, so
+			 * only clear it after each chunk of @gfn is
 			 * used.
 			 */
 			if (err_ptr) {
···
 	return err < 0 ? err : mapped;
 }
 
-int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+int xen_remap_domain_gfn_range(struct vm_area_struct *vma,
 			       unsigned long addr,
-			       xen_pfn_t mfn, int nr,
+			       xen_pfn_t gfn, int nr,
 			       pgprot_t prot, unsigned domid,
 			       struct page **pages)
 {
-	return do_remap_mfn(vma, addr, &mfn, nr, NULL, prot, domid, pages);
+	return do_remap_gfn(vma, addr, &gfn, nr, NULL, prot, domid, pages);
 }
-EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
+EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_range);
 
-int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
+int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
 			       unsigned long addr,
-			       xen_pfn_t *mfn, int nr,
+			       xen_pfn_t *gfn, int nr,
 			       int *err_ptr, pgprot_t prot,
 			       unsigned domid, struct page **pages)
 {
···
 	 * cause of "wrong memory was mapped in".
 	 */
 	BUG_ON(err_ptr == NULL);
-	return do_remap_mfn(vma, addr, mfn, nr, err_ptr, prot, domid, pages);
+	return do_remap_gfn(vma, addr, gfn, nr, err_ptr, prot, domid, pages);
 }
-EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_array);
+EXPORT_SYMBOL_GPL(xen_remap_domain_gfn_array);
 
 
 /* Returns: 0 success */
-int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
+int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 			       int numpgs, struct page **pages)
 {
 	if (!pages || !xen_feature(XENFEAT_auto_translated_physmap))
···
 	return -EINVAL;
 #endif
 }
-EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
+EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);

drivers/xen/privcmd.c

···
 	return ret;
 }
 
-struct mmap_mfn_state {
+struct mmap_gfn_state {
 	unsigned long va;
 	struct vm_area_struct *vma;
 	domid_t domain;
 };
 
-static int mmap_mfn_range(void *data, void *state)
+static int mmap_gfn_range(void *data, void *state)
 {
 	struct privcmd_mmap_entry *msg = data;
-	struct mmap_mfn_state *st = state;
+	struct mmap_gfn_state *st = state;
 	struct vm_area_struct *vma = st->vma;
 	int rc;
 
···
 	    ((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
 		return -EINVAL;
 
-	rc = xen_remap_domain_mfn_range(vma,
+	rc = xen_remap_domain_gfn_range(vma,
 					msg->va & PAGE_MASK,
 					msg->mfn, msg->npages,
 					vma->vm_page_prot,
···
 	struct vm_area_struct *vma;
 	int rc;
 	LIST_HEAD(pagelist);
-	struct mmap_mfn_state state;
+	struct mmap_gfn_state state;
 
 	/* We only support privcmd_ioctl_mmap_batch for auto translated. */
 	if (xen_feature(XENFEAT_auto_translated_physmap))
···
 
 	rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
 			    &pagelist,
-			    mmap_mfn_range, &state);
+			    mmap_gfn_range, &state);
 
 
 out_up:
···
 	int global_error;
 	int version;
 
-	/* User-space mfn array to store errors in the second pass for V1. */
-	xen_pfn_t __user *user_mfn;
+	/* User-space gfn array to store errors in the second pass for V1. */
+	xen_pfn_t __user *user_gfn;
 	/* User-space int array to store errors in the second pass for V2. */
 	int __user *user_err;
 };
 
-/* auto translated dom0 note: if domU being created is PV, then mfn is
- * mfn(addr on bus). If it's auto xlated, then mfn is pfn (input to HAP).
+/* auto translated dom0 note: if domU being created is PV, then gfn is
+ * mfn(addr on bus). If it's auto xlated, then gfn is pfn (input to HAP).
  */
 static int mmap_batch_fn(void *data, int nr, void *state)
 {
-	xen_pfn_t *mfnp = data;
+	xen_pfn_t *gfnp = data;
 	struct mmap_batch_state *st = state;
 	struct vm_area_struct *vma = st->vma;
 	struct page **pages = vma->vm_private_data;
···
 		cur_pages = &pages[st->index];
 
 	BUG_ON(nr < 0);
-	ret = xen_remap_domain_mfn_array(st->vma, st->va & PAGE_MASK, mfnp, nr,
-					 (int *)mfnp, st->vma->vm_page_prot,
+	ret = xen_remap_domain_gfn_array(st->vma, st->va & PAGE_MASK, gfnp, nr,
+					 (int *)gfnp, st->vma->vm_page_prot,
 					 st->domain, cur_pages);
 
 	/* Adjust the global_error? */
···
 
 	if (st->version == 1) {
 		if (err) {
-			xen_pfn_t mfn;
+			xen_pfn_t gfn;
 
-			ret = get_user(mfn, st->user_mfn);
+			ret = get_user(gfn, st->user_gfn);
 			if (ret < 0)
 				return ret;
 			/*
 			 * V1 encodes the error codes in the 32bit top
-			 * nibble of the mfn (with its known
+			 * nibble of the gfn (with its known
 			 * limitations vis-a-vis 64 bit callers).
 			 */
-			mfn |= (err == -ENOENT) ?
+			gfn |= (err == -ENOENT) ?
 				PRIVCMD_MMAPBATCH_PAGED_ERROR :
 				PRIVCMD_MMAPBATCH_MFN_ERROR;
-			return __put_user(mfn, st->user_mfn++);
+			return __put_user(gfn, st->user_gfn++);
 		} else
-			st->user_mfn++;
+			st->user_gfn++;
 	} else { /* st->version == 2 */
 		if (err)
 			return __put_user(err, st->user_err++);
···
 	return 0;
 }
 
-/* Allocate pfns that are then mapped with gmfns from foreign domid. Update
+/* Allocate pfns that are then mapped with gfns from foreign domid. Update
  * the vma with the page info to use later.
  * Returns: 0 if success, otherwise -errno
  */
···
 
 	if (state.global_error) {
 		/* Write back errors in second pass. */
-		state.user_mfn = (xen_pfn_t *)m.arr;
+		state.user_gfn = (xen_pfn_t *)m.arr;
 		state.user_err = m.err;
 		ret = traverse_pages_block(m.num, sizeof(xen_pfn_t),
 					   &pagelist, mmap_return_errors, &state);
···
 	if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
 		return;
 
-	rc = xen_unmap_domain_mfn_range(vma, numpgs, pages);
+	rc = xen_unmap_domain_gfn_range(vma, numpgs, pages);
 	if (rc == 0)
 		free_xenballooned_pages(numpgs, pages);
 	else

drivers/xen/xlate_mmu.c

···
 #include <xen/interface/xen.h>
 #include <xen/interface/memory.h>
 
-/* map fgmfn of domid to lpfn in the current domain */
-static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
+/* map fgfn of domid to lpfn in the current domain */
+static int map_foreign_page(unsigned long lpfn, unsigned long fgfn,
 			    unsigned int domid)
 {
 	int rc;
···
 		.size = 1,
 		.space = XENMAPSPACE_gmfn_foreign,
 	};
-	xen_ulong_t idx = fgmfn;
+	xen_ulong_t idx = fgfn;
 	xen_pfn_t gpfn = lpfn;
 	int err = 0;
 
···
 }
 
 struct remap_data {
-	xen_pfn_t *fgmfn; /* foreign domain's gmfn */
+	xen_pfn_t *fgfn; /* foreign domain's gfn */
 	pgprot_t prot;
 	domid_t  domid;
 	struct vm_area_struct *vma;
 	int index;
 	struct page **pages;
-	struct xen_remap_mfn_info *info;
+	struct xen_remap_gfn_info *info;
 	int *err_ptr;
 	int mapped;
 };
···
 	pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));
 	int rc;
 
-	rc = map_foreign_page(pfn, *info->fgmfn, info->domid);
+	rc = map_foreign_page(pfn, *info->fgfn, info->domid);
 	*info->err_ptr++ = rc;
 	if (!rc) {
 		set_pte_at(info->vma->vm_mm, addr, ptep, pte);
 		info->mapped++;
 	}
-	info->fgmfn++;
+	info->fgfn++;
 
 	return 0;
 }
 
 int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
 			      unsigned long addr,
-			      xen_pfn_t *mfn, int nr,
+			      xen_pfn_t *gfn, int nr,
 			      int *err_ptr, pgprot_t prot,
 			      unsigned domid,
 			      struct page **pages)
···
 	   x86 PVOPS */
 	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
 
-	data.fgmfn = mfn;
+	data.fgfn = gfn;
 	data.prot  = prot;
 	data.domid = domid;
 	data.vma   = vma;

include/uapi/xen/privcmd.h

···
 
 struct privcmd_mmap_entry {
 	__u64 va;
+	/*
+	 * This should be a GFN. It's not possible to change the name because
+	 * it's exposed to the user-space.
+	 */
 	__u64 mfn;
 	__u64 npages;
 };

include/xen/xen-ops.h

···
 struct vm_area_struct;
 
 /*
- * xen_remap_domain_mfn_array() - map an array of foreign frames
+ * xen_remap_domain_gfn_array() - map an array of foreign frames
  * @vma:     VMA to map the pages into
  * @addr:    Address at which to map the pages
  * @gfn:     Array of GFNs to map
···
  * Returns the number of successfully mapped frames, or a -ve error
  * code.
  */
-int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
+int xen_remap_domain_gfn_array(struct vm_area_struct *vma,
 			       unsigned long addr,
 			       xen_pfn_t *gfn, int nr,
 			       int *err_ptr, pgprot_t prot,
 			       unsigned domid,
 			       struct page **pages);
 
-/* xen_remap_domain_mfn_range() - map a range of foreign frames
+/* xen_remap_domain_gfn_range() - map a range of foreign frames
  * @vma:     VMA to map the pages into
  * @addr:    Address at which to map the pages
  * @gfn:     First GFN to map.
···
  * Returns the number of successfully mapped frames, or a -ve error
  * code.
  */
-int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
+int xen_remap_domain_gfn_range(struct vm_area_struct *vma,
 			       unsigned long addr,
 			       xen_pfn_t gfn, int nr,
 			       pgprot_t prot, unsigned domid,
 			       struct page **pages);
-int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
+int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 			       int numpgs, struct page **pages);
 int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
 			      unsigned long addr,