shadow: Remove warnings about writes to read-only BIOS area. These

attempts can be legitimate.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

xen/arch/x86/mm/shadow/multi.c

@@ -3228,16 +3228,9 @@ static int sh_page_fault(struct vcpu *v,
         goto mmio;
     }
 
-    /* Log attempts to write to read-only memory */
+    /* Ignore attempts to write to read-only memory. */
     if ( (p2mt == p2m_ram_ro) && (ft == ft_demand_write) )
-    {
-        static unsigned long lastpage = 0;
-        if ( xchg(&lastpage, va & PAGE_MASK) != (va & PAGE_MASK) )
-            gdprintk(XENLOG_DEBUG, "guest attempted write to read-only memory"
-                     " page. va page=%#lx, mfn=%#lx\n",
-                     va & PAGE_MASK, mfn_x(gmfn));
         goto emulate_readonly; /* skip over the instruction */
-    }
 
     /* In HVM guests, we force CR0.WP always to be set, so that the
      * pagetables are always write-protected.  If the guest thinks