Re: [PATCH v1 2/8] x86/xen: simplify xen_oldmem_pfn_is_ram()

quoted

How about

      return a.mem_type != HVMMEM_mmio_dm;

Ha, how could I have missed that :)

quoted

Result should be promoted to int and this has added benefit of not requiring changes in patch 4.

Can we go one step further and do

@@ -20,24 +20,11 @@ static int xen_oldmem_pfn_is_ram(unsigned long pfn)
          struct xen_hvm_get_mem_type a = {
                  .domid = DOMID_SELF,
                  .pfn = pfn,
+               .mem_type = HVMMEM_ram_rw,
          };
-       int ram;
   
-       if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
-               return -ENXIO;
-
-       switch (a.mem_type) {
-       case HVMMEM_mmio_dm:
-               ram = 0;
-               break;
-       case HVMMEM_ram_rw:
-       case HVMMEM_ram_ro:
-       default:
-               ram = 1;
-               break;
-       }
-
-       return ram;
+       HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a);
+       return a.mem_type != HVMMEM_mmio_dm;
   }
   #endif

Assuming that if HYPERVISOR_hvm_op() fails that
.mem_type is not set to HVMMEM_mmio_dm.