The MSI-X structures of some devices and other non-MSI-X structures
are in the same BAR. They may share one host page, especially in the
case of large page granularity, suck as 64K.

For example, MSIX-Table size of 82599 NIC is 0x30 and the offset in
Bar 3(size 64KB) is 0x0. If host page size is 64KB.
vfio_listenerregion_add() will be called to map the remaining range
(0x30-0xffff). And it will return early at
'int128_ge((int128_make64(iova), llend))' and hasn't any message.
Let's add a trace point to informed users like 5c08600547c did.

Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
---
 hw/vfio/common.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 8728d4d5c2..2fc6213c0f 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -892,6 +892,13 @@ static void vfio_listener_region_add(MemoryListener *listener,
     llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask));
 
     if (int128_ge(int128_make64(iova), llend)) {
+        if (memory_region_is_ram_device(section->mr)) {
+            trace_vfio_listener_region_add_no_dma_map(
+                memory_region_name(section->mr),
+                section->offset_within_address_space,
+                int128_getlo(section->size),
+                qemu_real_host_page_size);
+        }
         return;
     }
     end = int128_get64(int128_sub(llend, int128_one()));
-- 
2.23.0

On Fri, 3 Sep 2021 17:36:11 +0800
Kunkun Jiang <jiangkunkun@huawei.com> wrote:

> The MSI-X structures of some devices and other non-MSI-X structures
> are in the same BAR. They may share one host page, especially in the
> case of large page granularity, suck as 64K.

s/suck/such/

> For example, MSIX-Table size of 82599 NIC is 0x30 and the offset in
> Bar 3(size 64KB) is 0x0. If host page size is 64KB.
> vfio_listenerregion_add() will be called to map the remaining range

s/vfio_listenerregion_add/vfio_listener_region_add/

> (0x30-0xffff). And it will return early at
> 'int128_ge((int128_make64(iova), llend))' and hasn't any message.
> Let's add a trace point to informed users like 5c08600547c did.

Please use the following syntax for referencing previous commits
(12-char sha1 is standard):

  commit 5c08600547c0 ("vfio: Use a trace point when a RAM section
  cannot be DMA mapped")

Thanks,
Alex

> Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
> ---
>  hw/vfio/common.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 8728d4d5c2..2fc6213c0f 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -892,6 +892,13 @@ static void vfio_listener_region_add(MemoryListener *listener,
>      llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask));
>  
>      if (int128_ge(int128_make64(iova), llend)) {
> +        if (memory_region_is_ram_device(section->mr)) {
> +            trace_vfio_listener_region_add_no_dma_map(
> +                memory_region_name(section->mr),
> +                section->offset_within_address_space,
> +                int128_getlo(section->size),
> +                qemu_real_host_page_size);
> +        }
>          return;
>      }
>      end = int128_get64(int128_sub(llend, int128_one()));

Hi Alex,

On 2021/9/9 4:45, Alex Williamson wrote:
> On Fri, 3 Sep 2021 17:36:11 +0800
> Kunkun Jiang <jiangkunkun@huawei.com> wrote:
>
>> The MSI-X structures of some devices and other non-MSI-X structures
>> are in the same BAR. They may share one host page, especially in the
>> case of large page granularity, suck as 64K.
> s/suck/such/
ok
>> For example, MSIX-Table size of 82599 NIC is 0x30 and the offset in
>> Bar 3(size 64KB) is 0x0. If host page size is 64KB.
>> vfio_listenerregion_add() will be called to map the remaining range
> s/vfio_listenerregion_add/vfio_listener_region_add/
ok
>> (0x30-0xffff). And it will return early at
>> 'int128_ge((int128_make64(iova), llend))' and hasn't any message.
>> Let's add a trace point to informed users like 5c08600547c did.
> Please use the following syntax for referencing previous commits
> (12-char sha1 is standard):
>
>    commit 5c08600547c0 ("vfio: Use a trace point when a RAM section
>    cannot be DMA mapped")
Thank you for your reply. I will correct it in V2.

Thanks,
Kunkun Jiang
> Thanks,
> Alex
>
>> Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
>> ---
>>   hw/vfio/common.c | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 8728d4d5c2..2fc6213c0f 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -892,6 +892,13 @@ static void vfio_listener_region_add(MemoryListener *listener,
>>       llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask));
>>   
>>       if (int128_ge(int128_make64(iova), llend)) {
>> +        if (memory_region_is_ram_device(section->mr)) {
>> +            trace_vfio_listener_region_add_no_dma_map(
>> +                memory_region_name(section->mr),
>> +                section->offset_within_address_space,
>> +                int128_getlo(section->size),
>> +                qemu_real_host_page_size);
>> +        }
>>           return;
>>       }
>>       end = int128_get64(int128_sub(llend, int128_one()));
> .