Re: [PATCH v2] iommu/arm: Add module parameter to set msi iova address

2020-09-22 Thread Vennila Megavannan

Sure, that's a great suggestion, I'll rework on the patch and post again.

Vennila

On 9/21/2020 1:45 PM, Will Deacon wrote:

On Mon, Sep 14, 2020 at 11:13:07AM -0700, Vennila Megavannan wrote:

From: Srinath Mannam 

Add provision to change default value of MSI IOVA base to platform's
suitable IOVA using module parameter. The present hardcoded MSI IOVA base
may not be the accessible IOVA ranges of platform.

If any platform has the limitaion to access default MSI IOVA, then it can
be changed using "arm-smmu.msi_iova_base=0xa000" command line argument.

Signed-off-by: Srinath Mannam 
Co-developed-by: Vennila Megavannan 
Signed-off-by: Vennila Megavannan 
---
  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 5 -
  drivers/iommu/arm/arm-smmu/arm-smmu.c   | 5 -
  2 files changed, 8 insertions(+), 2 deletions(-)

This feels pretty fragile. Wouldn't it be better to realise that there's
a region conflict with iommu_dma_get_resv_regions() and move the MSI window
accordingly at runtime?

Will

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[PATCH v2] iommu/arm: Add module parameter to set msi iova address

2020-09-14 Thread Vennila Megavannan
From: Srinath Mannam 

Add provision to change default value of MSI IOVA base to platform's
suitable IOVA using module parameter. The present hardcoded MSI IOVA base
may not be the accessible IOVA ranges of platform.

If any platform has the limitaion to access default MSI IOVA, then it can
be changed using "arm-smmu.msi_iova_base=0xa000" command line argument.

Signed-off-by: Srinath Mannam 
Co-developed-by: Vennila Megavannan 
Signed-off-by: Vennila Megavannan 
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 5 -
 drivers/iommu/arm/arm-smmu/arm-smmu.c   | 5 -
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c 
b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index c192544e874b..dfef0df66c19 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -417,6 +417,9 @@ static bool disable_bypass = 1;
 module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_bypass,
"Disable bypass streams such that incoming transactions from devices 
that are not attached to an iommu domain will report an abort back to the 
device and will not be allowed to pass through the SMMU.");
+static unsigned long msi_iova_base = MSI_IOVA_BASE;
+module_param(msi_iova_base, ulong, S_IRUGO);
+MODULE_PARM_DESC(msi_iova_base, "set MSI IOVA base address if default 
(0x800) does not work for your platform.");
 
 enum pri_resp {
PRI_RESP_DENY = 0,
@@ -3102,7 +3105,7 @@ static void arm_smmu_get_resv_regions(struct device *dev,
struct iommu_resv_region *region;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
 
-   region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
+   region = iommu_alloc_resv_region(msi_iova_base, MSI_IOVA_LENGTH,
 prot, IOMMU_RESV_SW_MSI);
if (!region)
return;
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c 
b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 09c42af9f31e..9d46a2628dd5 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -64,6 +64,9 @@ static bool disable_bypass =
 module_param(disable_bypass, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_bypass,
"Disable bypass streams such that incoming transactions from devices 
that are not attached to an iommu domain will report an abort back to the 
device and will not be allowed to pass through the SMMU.");
+static unsigned long msi_iova_base = MSI_IOVA_BASE;
+module_param(msi_iova_base, ulong, S_IRUGO);
+MODULE_PARM_DESC(msi_iova_base, "set MSI IOVA base address if default 
(0x800) does not work for your platform.");
 
 struct arm_smmu_s2cr {
struct iommu_group  *group;
@@ -1603,7 +1606,7 @@ static void arm_smmu_get_resv_regions(struct device *dev,
struct iommu_resv_region *region;
int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
 
-   region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
+   region = iommu_alloc_resv_region(msi_iova_base, MSI_IOVA_LENGTH,
 prot, IOMMU_RESV_SW_MSI);
if (!region)
return;
-- 
2.17.1

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