Re: [Xen-devel] [PATCH] xen/physmap: Propagate error rc from xenmem_add_to_physmap_one

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 07.12.16 at 02:07, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 07/12/2016 01:00, Jiandi An wrote:
>> --- a/xen/common/memory.c
>> +++ b/xen/common/memory.c
>> @@ -762,6 +762,8 @@ static int xenmem_add_to_physmap_batch(struct domain *d,
>>          rc = xenmem_add_to_physmap_one(d, xatpb->space,
>>                                         xatpb->u,
>>                                         idx, _gfn(gpfn));
>> +        if ( rc < 0 )
>> +            goto out;
>>  
>>          if ( unlikely(__copy_to_guest_offset(xatpb->errs, 0, &rc, 1)) )
>>          {
> 
> This can't be correct.  You now skip writing rc into the errs[] array on
> a failure, which means that userspace will get an overall failure but an
> errs[] array which said that nothing went wrong.
> 
> This code addition looks like it wants to be an "else if" on the end of
> this if() in context.

Why would this go elsewhere? It's unneeded - it's a property of the
hypercall that when seeing overall success you still need to look at
errs[].

Jan


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