diff mbox series

[4/7] bus/pci: avoid call to DMA mask check

Message ID 20181031172931.11894-5-alejandro.lucero@netronome.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers
Series fix DMA mask check |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation fail Compilation issues

Commit Message

Alejandro Lucero Oct. 31, 2018, 5:29 p.m. UTC 
  Calling rte_mem_check_dma_mask when memory has not been initialized
yet is wrong. This patch use rte_mem_set_dma_mask instead.

Once memory initialization is done, the dma mask set will be used
for checking memory mapped is within the specified mask.

Fixes: fe822eb8c565 ("bus/pci: use IOVA DMA mask check when setting IOVA mode")

Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
---
 drivers/bus/pci/linux/pci.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Comments

Anatoly Burakov Nov. 1, 2018, 10:12 a.m. UTC | #1 
On 31-Oct-18 5:29 PM, Alejandro Lucero wrote:
> Calling rte_mem_check_dma_mask when memory has not been initialized
> yet is wrong. This patch use rte_mem_set_dma_mask instead.
> 
> Once memory initialization is done, the dma mask set will be used
> for checking memory mapped is within the specified mask.
> 
> Fixes: fe822eb8c565 ("bus/pci: use IOVA DMA mask check when setting IOVA mode")
> 
> Signed-off-by: Alejandro Lucero <alejandro.lucero@netronome.com>
> ---
>   drivers/bus/pci/linux/pci.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
> index 0a81e063b..d87384c72 100644
> --- a/drivers/bus/pci/linux/pci.c
> +++ b/drivers/bus/pci/linux/pci.c
> @@ -590,7 +590,16 @@ pci_one_device_iommu_support_va(struct rte_pci_device *dev)
>   
>   	mgaw = ((vtd_cap_reg & VTD_CAP_MGAW_MASK) >> VTD_CAP_MGAW_SHIFT) + 1;
>   
> -	return rte_mem_check_dma_mask(mgaw) == 0 ? true : false;
> +	/*
> +	 * Assuming there is no limitation by now. We can not know at this point
> +	 * because the memory has not been initialized yet. Setting the dma mask
> +	 * will force a check once memory initialization is done. We can not do
> +	 * a fallback to IOVA PA now, but if the dma check fails, the error
> +	 * message should advice for using '--iova-mode pa' if IOVA VA is the
> +	 * current mode.
> +	 */
> +	rte_mem_set_dma_mask(mgaw);
> +	return true;

This is IMO a good solution to the circular dependency between setting 
DMA mask and memory init. At least i can't think of a better one :)

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

>   }
>   #elif defined(RTE_ARCH_PPC_64)
>   static bool
>
diff mbox series

Patch

diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
index 0a81e063b..d87384c72 100644
--- a/drivers/bus/pci/linux/pci.c
+++ b/drivers/bus/pci/linux/pci.c
@@ -590,7 +590,16 @@  pci_one_device_iommu_support_va(struct rte_pci_device *dev)
 
 	mgaw = ((vtd_cap_reg & VTD_CAP_MGAW_MASK) >> VTD_CAP_MGAW_SHIFT) + 1;
 
-	return rte_mem_check_dma_mask(mgaw) == 0 ? true : false;
+	/*
+	 * Assuming there is no limitation by now. We can not know at this point
+	 * because the memory has not been initialized yet. Setting the dma mask
+	 * will force a check once memory initialization is done. We can not do
+	 * a fallback to IOVA PA now, but if the dma check fails, the error
+	 * message should advice for using '--iova-mode pa' if IOVA VA is the
+	 * current mode.
+	 */
+	rte_mem_set_dma_mask(mgaw);
+	return true;
 }
 #elif defined(RTE_ARCH_PPC_64)
 static bool