Re: [PATCH 2/2] vfio/common: Add trace point when a MMIO RAM section less than PAGE_SIZE

[Kunkun Jiang]

Hi Alex,

On 2021/9/9 4:45, Alex Williamson wrote:

On Fri, 3 Sep 2021 17:36:11 +0800
Kunkun Jiang  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

(0x30-0x). 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 
---
  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()));

.

Re: [PATCH 2/2] vfio/common: Add trace point when a MMIO RAM section less than PAGE_SIZE

[Alex Williamson]

On Fri, 3 Sep 2021 17:36:11 +0800
Kunkun Jiang  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/

> (0x30-0x). 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 
> ---
>  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()));

[PATCH 2/2] vfio/common: Add trace point when a MMIO RAM section less than PAGE_SIZE

[Kunkun Jiang]

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
(0x30-0x). 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 
---
 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