[Xen-devel] [PATCH 11/14] arm: implement remap interfaces needed for privcmd mappings.

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 arch/arm/xen/enlighten.c |   94 +++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 92 insertions(+), 2 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index ba5cc13..9956af5 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -9,6 +9,7 @@
 #include <xen/platform_pci.h>
 #include <xen/xenbus.h>
 #include <xen/page.h>
+#include <xen/xen-ops.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
 #include <linux/interrupt.h>
@@ -18,6 +19,8 @@
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
 
+#include <linux/mm.h>
+
 struct start_info _xen_start_info;
 struct start_info *xen_start_info = &_xen_start_info;
 EXPORT_SYMBOL_GPL(xen_start_info);
@@ -43,15 +46,102 @@ 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 xatp = {
+               .domid = DOMID_SELF,
+               .u.foreign_domid = domid,
+               .space = XENMAPSPACE_gmfn_foreign,
+               .idx = fgmfn,
+               .gpfn = lpfn,
+       };
+
+       rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
+       if (rc) {
+               pr_warn("Failed to map pfn to mfn rc:%d pfn:%lx mfn:%lx\n",
+                       rc, lpfn, fgmfn);
+               return 1;
+       }
+       return 0;
+}
+
+struct remap_data {
+       unsigned long fgmfn; /* foreign domain's gmfn */
+       pgprot_t prot;
+       domid_t  domid;
+       struct vm_area_struct *vma;
+       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 xen_remap_mfn_info *savp = info->info;
+       struct page *page = savp->pi_paga[savp->pi_next_todo++];
+       unsigned long pfn = page_to_pfn(page);
+       pte_t pte = 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,
                               unsigned long mfn, int nr,
-                              pgprot_t prot, unsigned domid)
+                              pgprot_t prot, unsigned domid,
+                              struct xen_remap_mfn_info *info)
 {
-       return -ENOSYS;
+       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.info = info;
+       err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,
+                                 remap_pte_fn, &data);
+       return err;
 }
 EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
 
+/* Returns: Number of pages unmapped */
+int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
+                              struct xen_remap_mfn_info *info)
+{
+       int count = 0;
+
+       while (info->pi_next_todo--) {
+               struct xen_remove_from_physmap xrp;
+               unsigned long rc, pfn;
+
+               pfn = page_to_pfn(info->pi_paga[info->pi_next_todo]);
+
+               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 count;
+               }
+               count++;
+       }
+       return count;
+}
+EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
+
 /*
  * see Documentation/devicetree/bindings/arm/xen.txt for the
  * documentation of the Xen Device Tree format.
-- 
1.7.2.5


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