[Xen-devel] [PATCH 24/24] [HACK] xen/arm: implement xen_remap_domain_mfn_range

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

From: Ian Campbell <Ian.Campbell@xxxxxxxxxx>

Do not apply!

This is a simple, hacky implementation of xen_remap_domain_mfn_range,
using XENMAPSPACE_gmfn_foreign.

It should use same interface as hybrid x86.

Signed-off-by: Ian Campbell <Ian.Campbell@xxxxxxxxxx>
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 arch/arm/xen/enlighten.c       |   79 +++++++++++++++++++++++++++++++++++++++-
 drivers/xen/privcmd.c          |   16 +++++----
 drivers/xen/xenfs/super.c      |    7 ++++
 include/xen/interface/memory.h |   10 ++++--
 4 files changed, 101 insertions(+), 11 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 1476b0b..7092015 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -16,6 +16,10 @@
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/mm.h>
+#include <linux/ioport.h>
+
+#include <asm/pgtable.h>
 
 struct start_info _xen_start_info;
 struct start_info *xen_start_info = &_xen_start_info;
@@ -38,12 +42,85 @@ EXPORT_SYMBOL_GPL(xen_platform_pci_unplug);
 
 static __read_mostly int xen_events_irq = -1;
 
+#define FOREIGN_MAP_BUFFER 0x90000000UL
+#define FOREIGN_MAP_BUFFER_SIZE 0x10000000UL
+struct resource foreign_map_resource = {
+       .start = FOREIGN_MAP_BUFFER,
+       .end = FOREIGN_MAP_BUFFER + FOREIGN_MAP_BUFFER_SIZE,
+       .name = "Xen foreign map buffer",
+       .flags = 0,
+};
+
+static unsigned long foreign_map_buffer_pfn = FOREIGN_MAP_BUFFER >> PAGE_SHIFT;
+
+struct remap_data {
+       struct mm_struct *mm;
+       unsigned long mfn;
+       pgprot_t prot;
+};
+
+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 = pfn_pte(rmd->mfn, rmd->prot);
+
+       if (rmd->mfn < 0x90010)
+               pr_crit("%s: ptep %p addr %#lx => %#x / %#lx\n",
+                      __func__, ptep, addr, pte_val(pte), rmd->mfn);
+
+       set_pte_at(rmd->mm, addr, ptep, pte);
+
+       rmd->mfn++;
+       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)
 {
-       return -ENOSYS;
+       int i, rc = 0;
+       struct remap_data rmd = {
+               .mm = vma->vm_mm,
+               .prot = prot,
+       };
+       struct xen_add_to_physmap xatp = {
+               .domid = DOMID_SELF,
+               .space = XENMAPSPACE_gmfn_foreign,
+
+               .foreign_domid = domid,
+       };
+
+       if (foreign_map_buffer_pfn + nr > ((FOREIGN_MAP_BUFFER +
+                                       FOREIGN_MAP_BUFFER_SIZE)>>PAGE_SHIFT)) {
+               pr_crit("RAM out of foreign map buffers...\n");
+               return -EBUSY;
+       }
+
+       for (i = 0; i < nr; i++) {
+               xatp.idx = mfn + i;
+               xatp.gpfn = foreign_map_buffer_pfn + i;
+               rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
+               if (rc != 0) {
+                       pr_crit("foreign map add_to_physmap failed, err=%d\n", 
rc);
+                       goto out;
+               }
+       }
+
+       rmd.mfn = foreign_map_buffer_pfn;
+       rc = apply_to_page_range(vma->vm_mm,
+                                addr,
+                                (unsigned long)nr << PAGE_SHIFT,
+                                remap_area_mfn_pte_fn, &rmd);
+       if (rc != 0) {
+               pr_crit("apply_to_page_range failed rc=%d\n", rc);
+               goto out;
+       }
+
+       foreign_map_buffer_pfn += nr;
+out:
+       return rc;
 }
 EXPORT_SYMBOL_GPL(xen_remap_domain_mfn_range);
 
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 85226cb..3e15c22 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -20,6 +20,8 @@
 #include <linux/pagemap.h>
 #include <linux/seq_file.h>
 #include <linux/miscdevice.h>
+#include <linux/resource.h>
+#include <linux/ioport.h>
 
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
@@ -196,9 +198,6 @@ static long privcmd_ioctl_mmap(void __user *udata)
        LIST_HEAD(pagelist);
        struct mmap_mfn_state state;
 
-       if (!xen_initial_domain())
-               return -EPERM;
-
        if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
                return -EFAULT;
 
@@ -286,9 +285,6 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
        LIST_HEAD(pagelist);
        struct mmap_batch_state state;
 
-       if (!xen_initial_domain())
-               return -EPERM;
-
        if (copy_from_user(&m, udata, sizeof(m)))
                return -EFAULT;
 
@@ -365,6 +361,11 @@ static long privcmd_ioctl(struct file *file,
        return ret;
 }
 
+static void privcmd_close(struct vm_area_struct *vma)
+{
+       /* TODO: unmap VMA */
+}
+
 static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
        printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
@@ -375,7 +376,8 @@ static int privcmd_fault(struct vm_area_struct *vma, struct 
vm_fault *vmf)
 }
 
 static struct vm_operations_struct privcmd_vm_ops = {
-       .fault = privcmd_fault
+       .fault = privcmd_fault,
+       .close = privcmd_close,
 };
 
 static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
index a84b53c..edbe22f 100644
--- a/drivers/xen/xenfs/super.c
+++ b/drivers/xen/xenfs/super.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/magic.h>
+#include <linux/ioport.h>
 
 #include <xen/xen.h>
 
@@ -80,6 +81,8 @@ static const struct file_operations capabilities_file_ops = {
        .llseek = default_llseek,
 };
 
+extern struct resource foreign_map_resource;
+
 static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
 {
        static struct tree_descr xenfs_files[] = {
@@ -100,6 +103,10 @@ static int xenfs_fill_super(struct super_block *sb, void 
*data, int silent)
                                  &xsd_kva_file_ops, NULL, S_IRUSR|S_IWUSR);
                xenfs_create_file(sb, sb->s_root, "xsd_port",
                                  &xsd_port_file_ops, NULL, S_IRUSR|S_IWUSR);
+               rc = request_resource(&iomem_resource, &foreign_map_resource);
+               if (rc < 0)
+                       pr_crit("failed to register foreign map resource\n");
+               rc = 0; /* ignore */
        }
 
        return rc;
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index d8e33a9..ec68945 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -167,9 +167,13 @@ struct xen_add_to_physmap {
     uint16_t    size;
 
     /* Source mapping space. */
-#define XENMAPSPACE_shared_info 0 /* shared info page */
-#define XENMAPSPACE_grant_table 1 /* grant table page */
-    unsigned int space;
+#define XENMAPSPACE_shared_info  0 /* shared info page */
+#define XENMAPSPACE_grant_table  1 /* grant table page */
+#define XENMAPSPACE_gmfn         2 /* GMFN */
+#define XENMAPSPACE_gmfn_range   3 /* GMFN range */
+#define XENMAPSPACE_gmfn_foreign 4 /* GMFN from another guest */
+    uint16_t space;
+    domid_t foreign_domid; /* IFF gmfn_foreign */
 
     /* Index into source mapping space. */
     unsigned long idx;
-- 
1.7.2.5


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