xen: arm: implement remap interfaces needed for privcmd mappings.

We use XENMEM_add_to_physmap_range which is the preferred interface
for foreign mappings.

Acked-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

3 files changed, 99 insertions, 3 deletions

diff --git a/arch/arm/include/asm/xen/interface.h b/arch/arm/include/asm/xen/interface.h
index 5000397134b4..1151188bcd83 100644
--- a/arch/arm/include/asm/xen/interface.h
+++ b/arch/arm/include/asm/xen/interface.h
@@ -49,6 +49,7 @@ DEFINE_GUEST_HANDLE(void);
 DEFINE_GUEST_HANDLE(uint64_t);
 DEFINE_GUEST_HANDLE(uint32_t);
 DEFINE_GUEST_HANDLE(xen_pfn_t);
+DEFINE_GUEST_HANDLE(xen_ulong_t);
 
 /* Maximum number of virtual CPUs in multi-processor guests. */
 #define MAX_VIRT_CPUS 1
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index ba5cc134a7d3..f28fc1ac8760 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 +46,106 @@ 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;
+
+        set_xen_guest_handle(xatp.idxs, &idx);
+        set_xen_guest_handle(xatp.gpfns, &gpfn);
+
+        rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &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 {
+        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 = 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)
+                               xen_pfn_t mfn, int nr,
+                               pgprot_t prot, unsigned domid,
+                               struct page **pages)
 {
-        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.index = 0;
+        data.pages = pages;
+        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);
 
+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;
+}
+EXPORT_SYMBOL_GPL(xen_unmap_domain_mfn_range);
+
 /*
  * see Documentation/devicetree/bindings/arm/xen.txt for the
  * documentation of the Xen Device Tree format.
diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
index 54d52ff1304a..fd9cb7695b5f 100644
--- a/arch/x86/include/asm/xen/interface.h
+++ b/arch/x86/include/asm/xen/interface.h
@@ -63,6 +63,7 @@ DEFINE_GUEST_HANDLE(void);
 DEFINE_GUEST_HANDLE(uint64_t);
 DEFINE_GUEST_HANDLE(uint32_t);
 DEFINE_GUEST_HANDLE(xen_pfn_t);
+DEFINE_GUEST_HANDLE(xen_ulong_t);
 #endif
 
 #ifndef HYPERVISOR_VIRT_START