diff mbox series

[v2,17/24] PCI: vmd: Use RESPONSE_IS_PCI_ERROR() to check read from hardware

Message ID 0da4dfe7642bf89d954c7062a40566bf28d94da1.1634306198.git.naveennaidu479@gmail.com
State Superseded
Headers show
Series Unify PCI error response checking | expand

Commit Message

Naveen Naidu Oct. 15, 2021, 2:38 p.m. UTC 
An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error.  There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

Use RESPONSE_IS_PCI_ERROR() to check the response we get when we read
data from hardware.

This helps unify PCI error response checking and make error checks
consistent and easier to find.

Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/controller/vmd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Naveen Naidu Oct. 15, 2021, 2:52 p.m. UTC | #1 
On 15/10, Naveen Naidu wrote:
> An MMIO read from a PCI device that doesn't exist or doesn't respond
> causes a PCI error.  There's no real data to return to satisfy the
> CPU read, so most hardware fabricates ~0 data.
> 
> Use RESPONSE_IS_PCI_ERROR() to check the response we get when we read
> data from hardware.
> 
> This helps unify PCI error response checking and make error checks
> consistent and easier to find.
> 
> Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
> Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
> ---
>  drivers/pci/controller/vmd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index a5987e52700e..db81bc4cfe8c 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -538,7 +538,7 @@ static int vmd_get_phys_offsets(struct vmd_dev *vmd, bool native_hint,
>  		int ret;
>  
>  		ret = pci_read_config_dword(dev, PCI_REG_VMLOCK, &vmlock);
> -		if (ret || vmlock == ~0)
> +		if (ret || RESPONSE_IS_PCI_ERROR(&vmlock))
>  			return -ENODEV;
>  
>  		if (MB2_SHADOW_EN(vmlock)) {
> -- 
> 2.25.1
> 

Jonathan, I have added your Reviewed-by tag from the first version [1] of
the patch series, since this patch did not change in the version 2. I
hope that's okay. If not, I really apologize for that and can you 
please let me know how to rectify that mistake.

[1]:
https://lore.kernel.org/linux-pci/f3aca934-7dee-b294-ad3c-264e773eddda@linux.dev/T/#u

Thanks,
Naveen
diff mbox series

Patch

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index a5987e52700e..db81bc4cfe8c 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -538,7 +538,7 @@  static int vmd_get_phys_offsets(struct vmd_dev *vmd, bool native_hint,
 		int ret;
 
 		ret = pci_read_config_dword(dev, PCI_REG_VMLOCK, &vmlock);
-		if (ret || vmlock == ~0)
+		if (ret || RESPONSE_IS_PCI_ERROR(&vmlock))
 			return -ENODEV;
 
 		if (MB2_SHADOW_EN(vmlock)) {