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

David Hildenbrand david at redhat.com
Wed Sep 29 01:45:44 PDT 2021


> 
> How about
> 
>      return a.mem_type != HVMMEM_mmio_dm;
> 

Ha, how could I have missed that :)

> 
> 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.

-- 
Thanks,

David / dhildenb




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