Re: [v7][RFC][PATCH 01/13] introduce XENMEM_reserved_device_memory_map

["Chen, Tiejun" <tiejun.chen@intel.com>]

On 2014/10/28 18:36, Jan Beulich wrote:
>>>> On 28.10.14 at 03:35, <tiejun.chen@intel.com> wrote:
>> On 2014/10/27 21:35, Julien Grall wrote:
>>> Hi,
>>>
>>> On 10/24/2014 08:34 AM, Tiejun Chen wrote:
>>>> diff --git a/xen/common/memory.c b/xen/common/memory.c
>>>> index cc36e39..51a32a8 100644
>>>> --- a/xen/common/memory.c
>>>> +++ b/xen/common/memory.c
>>>> @@ -692,6 +692,32 @@ out:
>>>>        return rc;
>>>>    }
>>>>
>>>> +struct get_reserved_device_memory {
>>>> +    struct xen_mem_reserved_device_memory_map map;
>>>> +    unsigned int used_entries;
>>>> +};
>>>> +
>>>> +static int get_reserved_device_memory(xen_pfn_t start,
>>>> +                                      xen_ulong_t nr, void *ctxt)
>>>
>>> This function is only used when HAS_PASSTHROUGH is defined. You have to
>>> protected by an #ifdef HAS_PASSTHROUGH.
>>>
>>
>> I guess you mean we need to do this,
>>
>> diff --git a/xen/common/memory.c b/xen/common/memory.c
>> index 1449c10..2177c56 100644
>> --- a/xen/common/memory.c
>> +++ b/xen/common/memory.c
>> @@ -692,6 +692,7 @@ out:
>>        return rc;
>>    }
>>
>> +#ifdef HAS_PASSTHROUGH
>>    struct get_reserved_device_memory {
>>        struct xen_reserved_device_memory_map map;
>>        unsigned int used_entries;
>> @@ -717,6 +718,7 @@ static int get_reserved_device_memory(xen_pfn_t start,
>>
>>        return 0;
>>    }
>> +#endif
>>
>>    long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>>    {
>>
>> Jan,
>>
>> With this above change, is the following working for you?
>
> I already fixed this in my version (which I view to be the canonical
> one).
>

Are you point that attached patch? Are you sure? Here I pick some code 
fragments from your latest patch,

--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -692,6 +692,32 @@ out:
      return rc;
  }

+struct get_reserved_device_memory {
+    struct xen_reserved_device_memory_map map;
+    unsigned int used_entries;
+};
+
+static int get_reserved_device_memory(xen_pfn_t start,
+                                      xen_ulong_t nr, void *ctxt)
+{
+    struct get_reserved_device_memory *grdm = ctxt;
+
+    if ( grdm->used_entries < grdm->map.nr_entries )
+    {
+        struct xen_reserved_device_memory rdm = {
+            .start_pfn = start, .nr_pages = nr
+        };
+
+        if ( __copy_to_guest_offset(grdm->map.buffer, grdm->used_entries,
+                                    &rdm, 1) )
+            return -EFAULT;
+    }
+
+    ++grdm->used_entries;
+
+    return 0;
+}
+
  long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
  {
      struct domain *d;
@@ -1101,6 +1127,29 @@ long do_memory_op(unsigned long cmd, XEN
          break;
      }

+#ifdef HAS_PASSTHROUGH
+    case XENMEM_reserved_device_memory_map:
+    {
+        struct get_reserved_device_memory grdm;
+
+        if ( copy_from_guest(&grdm.map, arg, 1) ||
+             !guest_handle_okay(grdm.map.buffer, grdm.map.nr_entries) )
+            return -EFAULT;
+
+        grdm.used_entries = 0;
+        rc = iommu_get_reserved_device_memory(get_reserved_device_memory,
+                                              &grdm);
+
+        if ( !rc && grdm.map.nr_entries < grdm.used_entries )
+            rc = -ENOBUFS;
+        grdm.map.nr_entries = grdm.used_entries;
+        if ( __copy_to_guest(arg, &grdm.map, 1) )
+            rc = -EFAULT;
+
+        break;
+    }
+#endif
+
      default:
          rc = arch_memory_op(cmd, arg);
          break;
--- a/xen/drivers/passthrough/iommu.c

Thanks
Tiejun

> Jan
>
>