Patchwork PCI/VFIO: use pcie_flags_reg instead of access PCI-E Capabilities Register

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Submitter Yijing Wang
Date March 27, 2013, 9:05 a.m.
Message ID <1364375140-6388-1-git-send-email-wangyijing@huawei.com>
Download mbox | patch
Permalink /patch/231614/
State Not Applicable
Headers show

Comments

Yijing Wang - March 27, 2013, 9:05 a.m.
Currently, we use pcie_flags_reg to cache PCI-E Capabilities Register,
because PCI-E Capabilities Register bits are almost read-only. This patch
use pcie_flags_reg instead of another access PCI-E Capabilities Register.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
 drivers/vfio/pci/vfio_pci_config.c |    6 +-----
 1 files changed, 1 insertions(+), 5 deletions(-)
Alex Williamson - April 1, 2013, 3:16 p.m.
On Wed, 2013-03-27 at 17:05 +0800, Yijing Wang wrote:
> Currently, we use pcie_flags_reg to cache PCI-E Capabilities Register,
> because PCI-E Capabilities Register bits are almost read-only. This patch
> use pcie_flags_reg instead of another access PCI-E Capabilities Register.
> 
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> ---
>  drivers/vfio/pci/vfio_pci_config.c |    6 +-----
>  1 files changed, 1 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> index aeb00fc..afc6ca4 100644
> --- a/drivers/vfio/pci/vfio_pci_config.c
> +++ b/drivers/vfio/pci/vfio_pci_config.c
> @@ -1017,13 +1017,9 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
>  		return byte;
>  	case PCI_CAP_ID_EXP:
>  		/* length based on version */
> -		ret = pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &word);
> -		if (ret)
> -			return pcibios_err_to_errno(ret);
> -
>  		vdev->extended_caps = true;
>  
> -		if ((word & PCI_EXP_FLAGS_VERS) == 1)
> +		if ((pdev->pcie_flags_reg & PCI_EXP_FLAGS_VERS) == 1)

It looks like we should be using pcie_caps_reg(pdev) here instead of
directly accessing pcie_flags_reg.  Thanks,

Alex

>  			return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1;
>  		else
>  			return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2;



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Yijing Wang - April 2, 2013, 1:47 a.m.
>> @@ -1017,13 +1017,9 @@ static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
>>  		return byte;
>>  	case PCI_CAP_ID_EXP:
>>  		/* length based on version */
>> -		ret = pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &word);
>> -		if (ret)
>> -			return pcibios_err_to_errno(ret);
>> -
>>  		vdev->extended_caps = true;
>>  
>> -		if ((word & PCI_EXP_FLAGS_VERS) == 1)
>> +		if ((pdev->pcie_flags_reg & PCI_EXP_FLAGS_VERS) == 1)
> 
> It looks like we should be using pcie_caps_reg(pdev) here instead of
> directly accessing pcie_flags_reg.  Thanks,

That's right, I forget Myron Stowe introduced the PCIe Cap accessor function  pcie_caps_reg().
I will resend the updated patch.

Thanks!
Yijing

> 
> Alex
> 
>>  			return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1;
>>  		else
>>  			return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2;
> 
> 
> 
> 
> .
>

Patch

diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
index aeb00fc..afc6ca4 100644
--- a/drivers/vfio/pci/vfio_pci_config.c
+++ b/drivers/vfio/pci/vfio_pci_config.c
@@ -1017,13 +1017,9 @@  static int vfio_cap_len(struct vfio_pci_device *vdev, u8 cap, u8 pos)
 		return byte;
 	case PCI_CAP_ID_EXP:
 		/* length based on version */
-		ret = pci_read_config_word(pdev, pos + PCI_EXP_FLAGS, &word);
-		if (ret)
-			return pcibios_err_to_errno(ret);
-
 		vdev->extended_caps = true;
 
-		if ((word & PCI_EXP_FLAGS_VERS) == 1)
+		if ((pdev->pcie_flags_reg & PCI_EXP_FLAGS_VERS) == 1)
 			return PCI_CAP_EXP_ENDPOINT_SIZEOF_V1;
 		else
 			return PCI_CAP_EXP_ENDPOINT_SIZEOF_V2;