xen: unify foreign GFN map/unmap for auto-xlated physmap guests

Auto-translated physmap guests (arm, arm64 and x86 PVHVM/PVH) map and
unmap foreign GFNs using the same method (updating the physmap).
Unify the two arm and x86 implementations into one commont one.

Note that on arm and arm64, the correct error code will be returned
(instead of always -EFAULT) and map/unmap failure warnings are no
longer printed.  These changes are required if the foreign domain is
paging (-ENOENT failures are expected and must be propagated up to the
caller).

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

2 files changed, 6 insertions, 194 deletions

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 263a2044c65b..5c04389fc9ef 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -53,105 +53,21 @@ EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
 
 static __read_mostly int xen_events_irq = -1;
 
-/* map fgmfn of domid to lpfn in the current domain */
-static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
-			    unsigned int domid)
-{
-	int rc;
-	struct xen_add_to_physmap_range xatp = {
-		.domid = DOMID_SELF,
-		.foreign_domid = domid,
-		.size = 1,
-		.space = XENMAPSPACE_gmfn_foreign,
-	};
-	xen_ulong_t idx = fgmfn;
-	xen_pfn_t gpfn = lpfn;
-	int err = 0;
-
-	set_xen_guest_handle(xatp.idxs, &idx);
-	set_xen_guest_handle(xatp.gpfns, &gpfn);
-	set_xen_guest_handle(xatp.errs, &err);
-
-	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
-	if (rc || err) {
-		pr_warn("Failed to map pfn to mfn rc:%d:%d pfn:%lx mfn:%lx\n",
-			rc, err, lpfn, fgmfn);
-		return 1;
-	}
-	return 0;
-}
-
-struct remap_data {
-	xen_pfn_t fgmfn; /* foreign domain's gmfn */
-	pgprot_t prot;
-	domid_t  domid;
-	struct vm_area_struct *vma;
-	int index;
-	struct page **pages;
-	struct xen_remap_mfn_info *info;
-};
-
-static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
-			void *data)
-{
-	struct remap_data *info = data;
-	struct page *page = info->pages[info->index++];
-	unsigned long pfn = page_to_pfn(page);
-	pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));
-
-	if (map_foreign_page(pfn, info->fgmfn, info->domid))
-		return -EFAULT;
-	set_pte_at(info->vma->vm_mm, addr, ptep, pte);
-
-	return 0;
-}
-
 int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
 			       unsigned long addr,
 			       xen_pfn_t mfn, int nr,
 			       pgprot_t prot, unsigned domid,
 			       struct page **pages)
 {
-	int err;
-	struct remap_data data;
-
-	/* TBD: Batching, current sole caller only does page at a time */
-	if (nr > 1)
-		return -EINVAL;
-
-	data.fgmfn = mfn;
-	data.prot = prot;
-	data.domid = domid;
-	data.vma = vma;
-	data.index = 0;
-	data.pages = pages;
-	err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,
-				  remap_pte_fn, &data);
-	return err;
+	return xen_xlate_remap_gfn_range(vma, addr, mfn, nr,
+					 prot, domid, pages);
 }
 EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
 
 int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
 			       int nr, struct page **pages)
 {
-	int i;
-
-	for (i = 0; i < nr; i++) {
-		struct xen_remove_from_physmap xrp;
-		unsigned long rc, pfn;
-
-		pfn = page_to_pfn(pages[i]);
-
-		xrp.domid = DOMID_SELF;
-		xrp.gpfn = pfn;
-		rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
-		if (rc) {
-			pr_warn("Failed to unmap pfn:%lx rc:%ld\n",
-				pfn, rc);
-			return rc;
-		}
-	}
-	return 0;
+	return xen_xlate_unmap_gfn_range(vma, nr, pages);
 }
 EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
 
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index adca9e2b6553..3d536a56ddf1 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2436,95 +2436,6 @@ void __init xen_hvm_init_mmu_ops(void)
 }
 #endif
 
-#ifdef CONFIG_XEN_PVH
-/*
- * Map foreign gfn (fgfn), to local pfn (lpfn). This for the user
- * space creating new guest on pvh dom0 and needing to map domU pages.
- */
-static int xlate_add_to_p2m(unsigned long lpfn, unsigned long fgfn,
-			    unsigned int domid)
-{
-	int rc, err = 0;
-	xen_pfn_t gpfn = lpfn;
-	xen_ulong_t idx = fgfn;
-
-	struct xen_add_to_physmap_range xatp = {
-		.domid = DOMID_SELF,
-		.foreign_domid = domid,
-		.size = 1,
-		.space = XENMAPSPACE_gmfn_foreign,
-	};
-	set_xen_guest_handle(xatp.idxs, &idx);
-	set_xen_guest_handle(xatp.gpfns, &gpfn);
-	set_xen_guest_handle(xatp.errs, &err);
-
-	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
-	if (rc < 0)
-		return rc;
-	return err;
-}
-
-static int xlate_remove_from_p2m(unsigned long spfn, int count)
-{
-	struct xen_remove_from_physmap xrp;
-	int i, rc;
-
-	for (i = 0; i < count; i++) {
-		xrp.domid = DOMID_SELF;
-		xrp.gpfn = spfn+i;
-		rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
-		if (rc)
-			break;
-	}
-	return rc;
-}
-
-struct xlate_remap_data {
-	unsigned long fgfn; /* foreign domain's gfn */
-	pgprot_t prot;
-	domid_t  domid;
-	int index;
-	struct page **pages;
-};
-
-static int xlate_map_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
-			    void *data)
-{
-	int rc;
-	struct xlate_remap_data *remap = data;
-	unsigned long pfn = page_to_pfn(remap->pages[remap->index++]);
-	pte_t pteval = pte_mkspecial(pfn_pte(pfn, remap->prot));
-
-	rc = xlate_add_to_p2m(pfn, remap->fgfn, remap->domid);
-	if (rc)
-		return rc;
-	native_set_pte(ptep, pteval);
-
-	return 0;
-}
-
-static int xlate_remap_gfn_range(struct vm_area_struct *vma,
-				 unsigned long addr, unsigned long mfn,
-				 int nr, pgprot_t prot, unsigned domid,
-				 struct page **pages)
-{
-	int err;
-	struct xlate_remap_data pvhdata;
-
-	BUG_ON(!pages);
-
-	pvhdata.fgfn = mfn;
-	pvhdata.prot = prot;
-	pvhdata.domid = domid;
-	pvhdata.index = 0;
-	pvhdata.pages = pages;
-	err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,
-				  xlate_map_pte_fn, &pvhdata);
-	flush_tlb_all();
-	return err;
-}
-#endif
-
 #define REMAP_BATCH_SIZE 16
 
 struct remap_data {
@@ -2564,8 +2475,8 @@ int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
 	if (xen_feature(XENFEAT_auto_translated_physmap)) {
 #ifdef CONFIG_XEN_PVH
 		/* We need to update the local page tables and the xen HAP */
-		return xlate_remap_gfn_range(vma, addr, mfn, nr, prot,
-					     domid, pages);
+		return xen_xlate_remap_gfn_range(vma, addr, mfn, nr, prot,
+						 domid, pages);
 #else
 		return -EINVAL;
 #endif
@@ -2609,22 +2520,7 @@ int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
 		return 0;
 
 #ifdef CONFIG_XEN_PVH
-	while (numpgs--) {
-		/*
-		 * The mmu has already cleaned up the process mmu
-		 * resources at this point (lookup_address will return
-		 * NULL).
-		 */
-		unsigned long pfn = page_to_pfn(pages[numpgs]);
-
-		xlate_remove_from_p2m(pfn, 1);
-	}
-	/*
-	 * We don't need to flush tlbs because as part of
-	 * xlate_remove_from_p2m, the hypervisor will do tlb flushes
-	 * after removing the p2m entries from the EPT/NPT
-	 */
-	return 0;
+	return xen_xlate_unmap_gfn_range(vma, numpgs, pages);
 #else
 	return -EINVAL;
 #endif