On 9/29/21 5:03 AM, David Hildenbrand wrote:
> On 29.09.21 10:45, David Hildenbrand wrote:
>>>
>> 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;
I was actually thinking of asking you to add another patch with pr_warn_once() here (and print error code as well). This call failing is indication of something going quite wrong and it would be good to know about this.
>> }
>> #endif
>>
>>
>> Assuming that if HYPERVISOR_hvm_op() fails that
>> .mem_type is not set to HVMMEM_mmio_dm.
I don't think we can assume that argument described as OUT in the ABI will not be clobbered in case of error
>>
>
> Okay we can't, due to "__must_check" ...
so this is a good thing ;-)
-boris
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