[Xen-devel] [PATCH XEN v6 17/32] tools/libs/foreignmemory: provide xenforeignmemory_unmap.

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

And require it be used instead of direct munmap.

This will allow e.g. Valgrind hooks to help track incorrect use of
foreign mappings.

Switch all uses of xenforeignmemory_map to use
xenforeignmemory_unmap, not that foreign mappings via the libxc compat
xc_map_foreign_* interface will not take advantage of this and will
need converting.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
v4: xenforeignmemory_unmap takes pages not bytes, adjust callers.
v6: Document error behaviour
    Use an osdep layer, although there is no current need for common
    code on _unmap there is for _map so use this indirection for
    consistency.
---
 tools/libs/foreignmemory/freebsd.c                  |  6 ++++++
 tools/libs/foreignmemory/include/xenforeignmemory.h | 11 +++++++++--
 tools/libs/foreignmemory/libxenforeignmemory.map    |  1 +
 tools/libs/foreignmemory/linux.c                    |  6 ++++++
 tools/libs/foreignmemory/minios.c                   |  6 ++++++
 tools/libs/foreignmemory/netbsd.c                   |  6 ++++++
 tools/libs/foreignmemory/solaris.c                  |  6 ++++++
 tools/libxc/xc_sr_restore.c                         |  2 +-
 tools/libxc/xc_sr_save.c                            |  2 +-
 tools/libxc/xc_vm_event.c                           |  2 +-
 10 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/tools/libs/foreignmemory/freebsd.c 
b/tools/libs/foreignmemory/freebsd.c
index 4b2815d..3c3ad09 100644
--- a/tools/libs/foreignmemory/freebsd.c
+++ b/tools/libs/foreignmemory/freebsd.c
@@ -118,6 +118,12 @@ void *osdep_xenforeignmemory_map(xenforeignmemory_handle 
*fmem,
     return addr;
 }
 
+int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
+                                 void *addr, unsigned int num)
+{
+       return munmap(addr, num << PAGE_SHIFT);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/foreignmemory/include/xenforeignmemory.h 
b/tools/libs/foreignmemory/include/xenforeignmemory.h
index 0909585..b1cae30 100644
--- a/tools/libs/foreignmemory/include/xenforeignmemory.h
+++ b/tools/libs/foreignmemory/include/xenforeignmemory.h
@@ -44,8 +44,8 @@ int xenforeignmemory_close(xenforeignmemory_handle *xmem);
 
 /*
  * Maps a range within one domain to a local address range.  Mappings
- * should be unmapped with munmap and should follow the same rules as mmap
- * regarding page alignment.
+ * must be unmapped with xenforeignmemory_unmap and should follow the
+ * same rules as mmap regarding page alignment.
  *
  * prot is as for mmap(2).
  *
@@ -57,6 +57,13 @@ int xenforeignmemory_close(xenforeignmemory_handle *xmem);
 void *xenforeignmemory_map(xenforeignmemory_handle *fmem, uint32_t dom,
                            int prot, const xen_pfn_t *arr, int *err,
                            unsigned int num);
+/*
+ * Unmap a mapping previous created with xenforeignmemory_map().
+ *
+ * Returns 0 on success on failure sets errno and returns -1.
+ */
+int xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
+                           void *addr, unsigned int num);
 
 #endif
 
diff --git a/tools/libs/foreignmemory/libxenforeignmemory.map 
b/tools/libs/foreignmemory/libxenforeignmemory.map
index 11f0d2b..df206b3 100644
--- a/tools/libs/foreignmemory/libxenforeignmemory.map
+++ b/tools/libs/foreignmemory/libxenforeignmemory.map
@@ -3,5 +3,6 @@ VERS_1.0 {
                xenforeignmemory_open;
                xenforeignmemory_close;
                xenforeignmemory_map;
+               xenforeignmemory_unmap;
        local: *; /* Do not expose anything by default */
 };
diff --git a/tools/libs/foreignmemory/linux.c b/tools/libs/foreignmemory/linux.c
index b403ca7..40ecd41 100644
--- a/tools/libs/foreignmemory/linux.c
+++ b/tools/libs/foreignmemory/linux.c
@@ -282,6 +282,12 @@ void *osdep_xenforeignmemory_map(xenforeignmemory_handle 
*fmem,
     return addr;
 }
 
+int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
+                                 void *addr, unsigned int num)
+{
+    return munmap(addr, (unsigned long)num << PAGE_SHIFT);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/foreignmemory/minios.c 
b/tools/libs/foreignmemory/minios.c
index a542e3d..5fcb861 100644
--- a/tools/libs/foreignmemory/minios.c
+++ b/tools/libs/foreignmemory/minios.c
@@ -51,6 +51,12 @@ void *osdep_xenforeignmemory_map(xenforeignmemory_handle 
*fmem,
     return map_frames_ex(arr, num, 1, 0, 1, dom, err, pt_prot);
 }
 
+int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
+                                 void *addr, unsigned int num)
+{
+       return munmap(addr, num << PAGE_SHIFT);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/foreignmemory/netbsd.c 
b/tools/libs/foreignmemory/netbsd.c
index 704a096..740c26f 100644
--- a/tools/libs/foreignmemory/netbsd.c
+++ b/tools/libs/foreignmemory/netbsd.c
@@ -94,6 +94,12 @@ void *osdep_map_foreign_batch(xenforeignmem_handle *fmem, 
uint32_t dom,
 
 }
 
+int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
+                                 void *addr, unsigned int num)
+{
+       return munmap(addr, num*XC_PAGE_SIZE);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/foreignmemory/solaris.c 
b/tools/libs/foreignmemory/solaris.c
index f4dd634..966fccb 100644
--- a/tools/libs/foreignmemory/solaris.c
+++ b/tools/libs/foreignmemory/solaris.c
@@ -91,3 +91,9 @@ void *osdep_map_foreign_batch(xenforeignmem_handle *fmem, 
uint32_t dom,
     }
     return addr;
 }
+
+int osdep_xenforeignmemory_unmap(xenforeignmemory_handle *fmem,
+                                 void *addr, unsigned int num)
+{
+       return munmap(addr, num*XC_PAGE_SIZE);
+}
diff --git a/tools/libxc/xc_sr_restore.c b/tools/libxc/xc_sr_restore.c
index 8e9e9c7..a334efd 100644
--- a/tools/libxc/xc_sr_restore.c
+++ b/tools/libxc/xc_sr_restore.c
@@ -378,7 +378,7 @@ static int process_page_data(struct xc_sr_context *ctx, 
unsigned count,
 
  err:
     if ( mapping )
-        munmap(mapping, nr_pages * PAGE_SIZE);
+        xenforeignmemory_unmap(xch->fmem, mapping, nr_pages);
 
     free(map_errs);
     free(mfns);
diff --git a/tools/libxc/xc_sr_save.c b/tools/libxc/xc_sr_save.c
index ccefa89..0851905 100644
--- a/tools/libxc/xc_sr_save.c
+++ b/tools/libxc/xc_sr_save.c
@@ -263,7 +263,7 @@ static int write_batch(struct xc_sr_context *ctx)
  err:
     free(rec_pfns);
     if ( guest_mapping )
-        munmap(guest_mapping, nr_pages_mapped * PAGE_SIZE);
+        xenforeignmemory_unmap(xch->fmem, guest_mapping, nr_pages_mapped);
     for ( i = 0; local_pages && i < nr_pfns; ++i )
         free(local_pages[i]);
     free(iov);
diff --git a/tools/libxc/xc_vm_event.c b/tools/libxc/xc_vm_event.c
index d2d99e4..57abce0 100644
--- a/tools/libxc/xc_vm_event.c
+++ b/tools/libxc/xc_vm_event.c
@@ -148,7 +148,7 @@ void *xc_vm_event_enable(xc_interface *xch, domid_t 
domain_id, int param,
         }
 
         if ( ring_page )
-            munmap(ring_page, XC_PAGE_SIZE);
+            xenforeignmemory_unmap(xch->fmem, ring_page, 1);
         ring_page = NULL;
 
         errno = saved_errno;
-- 
2.1.4


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