Re: [PATCH 12/12] xen/cpupool: make per-cpupool sched-gran hypfs node writable

[Jürgen Groß]

On 29.10.20 15:58, Jan Beulich wrote:

On 26.10.2020 10:13, Juergen Gross wrote:

@@ -1088,13 +1098,58 @@ static int cpupool_gran_read(const struct hypfs_entry 
*entry,
      return copy_to_guest(uaddr, name, strlen(name) + 1) ? -EFAULT : 0;
  }

+static int cpupool_gran_write(struct hypfs_entry_leaf *leaf,

+                              XEN_GUEST_HANDLE_PARAM(void) uaddr,
+                              unsigned int ulen)
+{
+    const struct hypfs_dyndir_id *data;
+    struct cpupool *cpupool;
+    enum sched_gran gran;
+    unsigned int sched_gran;
+    char name[SCHED_GRAN_NAME_LEN];
+    int ret = 0;
+
+    if ( ulen > SCHED_GRAN_NAME_LEN )
+        return -ENOSPC;
+
+    if ( copy_from_guest(name, uaddr, ulen) )
+        return -EFAULT;
+
+    sched_gran = sched_gran_get(name, &gran) ? 0
+                                             : cpupool_check_granularity(gran);
+    if ( memchr(name, 0, ulen) != (name + ulen - 1) || sched_gran == 0 )
+        return -EINVAL;

I guess the memchr() check wants to happen before the call to
sched_gran_get()?

Yes.


Juergen