[2/8] xen: restrict: use xentoolcore_restrict_all

Commit Message

Ian Jackson Oct. 9, 2017, 4:01 p.m. UTC

And insist that it works.

Drop individual use of xendevicemodel_restrict and
xenforeignmemory_restrict.  These are not actually effective in this
version of qemu, because qemu has a large number of fds open onto
various Xen control devices.

The restriction arrangements are still not right, because the
restriction needs to be done very late - after qemu has opened all of
its control fds.

xentoolcore_restrict_all and xentoolcore.h are available in Xen 4.10
and later, only.  Provide a compatibility stub.  And drop the
compatibility stubs for the old functions.

Signed-off-by: Ian Jackson <[e-mail]>
---
v2: Modify the compatibility code, too.
    Bump this patch ahead of "defer call to xen_restrict until running"
    Retain call to xentoolcore_restrict_all

Signed-off-by: Ian Jackson <[e-mail]>
---
 include/hw/xen/xen_common.h | 46 +++++++++++----------------------------------
 1 file changed, 11 insertions(+), 35 deletions(-)

Comments

Anthony PERARD Oct. 10, 2017, 11:26 a.m. UTC | #1

On Mon, Oct 09, 2017 at 05:01:36PM +0100, Ian Jackson wrote:
> And insist that it works.
> 
> Drop individual use of xendevicemodel_restrict and
> xenforeignmemory_restrict.  These are not actually effective in this
> version of qemu, because qemu has a large number of fds open onto
> various Xen control devices.
> 
> The restriction arrangements are still not right, because the
> restriction needs to be done very late - after qemu has opened all of
> its control fds.
> 
> xentoolcore_restrict_all and xentoolcore.h are available in Xen 4.10
> and later, only.  Provide a compatibility stub.  And drop the
> compatibility stubs for the old functions.
> 
> Signed-off-by: Ian Jackson <[e-mail]>

Reviewed-by: Anthony PERARD <[e-mail]>

Patch

diff --git a/include/hw/xen/xen_common.h b/include/hw/xen/xen_common.h
index 86c7f26..3f44a63 100644
--- a/include/hw/xen/xen_common.h
+++ b/include/hw/xen/xen_common.h
@@ -91,6 +91,16 @@  static inline void *xenforeignmemory_map2(xenforeignmemory_handle *h,
     return xenforeignmemory_map(h, dom, prot, pages, arr, err);
 }
 
+static inline int xentoolcore_restrict_all(domid_t domid)
+{
+    errno = ENOTTY;
+    return -1;
+}
+
+#else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 41000 */
+
+#include <xentoolcore.h>
+
 #endif
 
 #if CONFIG_XEN_CTRL_INTERFACE_VERSION < 40900
@@ -218,20 +228,6 @@  static inline int xendevicemodel_set_mem_type(
     return xc_hvm_set_mem_type(dmod, domid, mem_type, first_pfn, nr);
 }
 
-static inline int xendevicemodel_restrict(
-    xendevicemodel_handle *dmod, domid_t domid)
-{
-    errno = ENOTTY;
-    return -1;
-}
-
-static inline int xenforeignmemory_restrict(
-    xenforeignmemory_handle *fmem, domid_t domid)
-{
-    errno = ENOTTY;
-    return -1;
-}
-
 #else /* CONFIG_XEN_CTRL_INTERFACE_VERSION >= 40900 */
 
 #undef XC_WANT_COMPAT_DEVICEMODEL_API
@@ -290,28 +286,8 @@  static inline int xen_modified_memory(domid_t domid, uint64_t first_pfn,
 static inline int xen_restrict(domid_t domid)
 {
     int rc;
-
-    /* Attempt to restrict devicemodel operations */
-    rc = xendevicemodel_restrict(xen_dmod, domid);
+    rc = xentoolcore_restrict_all(domid);
     trace_xen_domid_restrict(rc ? errno : 0);
-
-    if (rc < 0) {
-        /*
-         * If errno is ENOTTY then restriction is not implemented so
-         * there's no point in trying to restrict other types of
-         * operation, but it should not be treated as a failure.
-         */
-        if (errno == ENOTTY) {
-            return 0;
-        }
-
-        return rc;
-    }
-
-    /* Restrict foreignmemory operations */
-    rc = xenforeignmemory_restrict(xen_fmem, domid);
-    trace_xen_domid_restrict(rc ? errno : 0);
-
     return rc;
 }