[PATCH 1/3] iommu: Add MMIO mapping type

[PATCH 1/3] iommu: Add MMIO mapping type

[Robin Murphy]

On some platforms, MMIO regions might need slightly different treatment
compared to mapping regular memory; add the notion of MMIO mappings to
the IOMMU API's memory type flags, so that callers can let the IOMMU
drivers know to do the right thing.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

Hi all,

Since this is a prerequisite for both MSI remapping and slave DMA
handling to function properly, and the latter still needs some design
work to reach a consensus[1], I thought it worth reposting this
separately from Niklas' series. I've also split it up now that there's
short-descriptor format to cover as well.

Robin.

[1]:http://lists.linuxfoundation.org/pipermail/iommu/2016-March/016059.html

 include/linux/iommu.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a5c539f..34b6432 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -30,6 +30,7 @@
 #define IOMMU_WRITE	(1 << 1)
 #define IOMMU_CACHE	(1 << 2) /* DMA cache coherency */
 #define IOMMU_NOEXEC	(1 << 3)
+#define IOMMU_MMIO	(1 << 4) /* e.g. things like MSI doorbells */
 
 struct iommu_ops;
 struct iommu_group;
-- 
2.7.3.dirty

[PATCH 2/3] iommu/io-pgtable-arm: Support IOMMU_MMIO flag

[Robin Murphy]

Teach the LPAE format to create Device mappings when asked.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/io-pgtable-arm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index f433b51..a1ed1b7 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -355,7 +355,10 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 		if (!(prot & IOMMU_WRITE) && (prot & IOMMU_READ))
 			pte |= ARM_LPAE_PTE_AP_RDONLY;
 
-		if (prot & IOMMU_CACHE)
+		if (prot & IOMMU_MMIO)
+			pte |= (ARM_LPAE_MAIR_ATTR_IDX_DEV
+				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
+		else if (prot & IOMMU_CACHE)
 			pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE
 				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
 	} else {
@@ -364,7 +367,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 			pte |= ARM_LPAE_PTE_HAP_READ;
 		if (prot & IOMMU_WRITE)
 			pte |= ARM_LPAE_PTE_HAP_WRITE;
-		if (prot & IOMMU_CACHE)
+		if (prot & IOMMU_MMIO)
+			pte |= ARM_LPAE_PTE_MEMATTR_DEV;
+		else if (prot & IOMMU_CACHE)
 			pte |= ARM_LPAE_PTE_MEMATTR_OIWB;
 		else
 			pte |= ARM_LPAE_PTE_MEMATTR_NC;
-- 
2.7.3.dirty

[PATCH 2/3] iommu/io-pgtable-arm: Support IOMMU_MMIO flag

[Eric Auger]

Hi Robin,
On 04/05/2016 01:39 PM, Robin Murphy wrote:
> Teach the LPAE format to create Device mappings when asked.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
don't know if it helps in any way but I tested that with my KVM PCIe/MSI
passthrough series for mapping the GICv2m doorbell.

Tested-by: Eric Auger <eric.auger@linaro.org>

Best Regards

Eric

> ---
>  drivers/iommu/io-pgtable-arm.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
> index f433b51..a1ed1b7 100644
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -355,7 +355,10 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
>  		if (!(prot & IOMMU_WRITE) && (prot & IOMMU_READ))
>  			pte |= ARM_LPAE_PTE_AP_RDONLY;
>  
> -		if (prot & IOMMU_CACHE)
> +		if (prot & IOMMU_MMIO)
> +			pte |= (ARM_LPAE_MAIR_ATTR_IDX_DEV
> +				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
> +		else if (prot & IOMMU_CACHE)
>  			pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE
>  				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
>  	} else {
> @@ -364,7 +367,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
>  			pte |= ARM_LPAE_PTE_HAP_READ;
>  		if (prot & IOMMU_WRITE)
>  			pte |= ARM_LPAE_PTE_HAP_WRITE;
> -		if (prot & IOMMU_CACHE)
> +		if (prot & IOMMU_MMIO)
> +			pte |= ARM_LPAE_PTE_MEMATTR_DEV;
> +		else if (prot & IOMMU_CACHE)
>  			pte |= ARM_LPAE_PTE_MEMATTR_OIWB;
>  		else
>  			pte |= ARM_LPAE_PTE_MEMATTR_NC;
> 

[PATCH 3/3] iommu/io-pgtable-arm-v7s: Support IOMMU_MMIO flag

[Robin Murphy]

Teach the short-descriptor format to create Device mappings when asked.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/io-pgtable-arm-v7s.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
index 9488e3c..de5865e 100644
--- a/drivers/iommu/io-pgtable-arm-v7s.c
+++ b/drivers/iommu/io-pgtable-arm-v7s.c
@@ -258,9 +258,10 @@ static arm_v7s_iopte arm_v7s_prot_to_pte(int prot, int lvl,
 					 struct io_pgtable_cfg *cfg)
 {
 	bool ap = !(cfg->quirks & IO_PGTABLE_QUIRK_NO_PERMS);
-	arm_v7s_iopte pte = ARM_V7S_ATTR_NG | ARM_V7S_ATTR_S |
-			    ARM_V7S_ATTR_TEX(1);
+	arm_v7s_iopte pte = ARM_V7S_ATTR_NG | ARM_V7S_ATTR_S;
 
+	if (!(prot & IOMMU_MMIO))
+		pte |= ARM_V7S_ATTR_TEX(1);
 	if (ap) {
 		pte |= ARM_V7S_PTE_AF | ARM_V7S_PTE_AP_UNPRIV;
 		if (!(prot & IOMMU_WRITE))
@@ -270,7 +271,9 @@ static arm_v7s_iopte arm_v7s_prot_to_pte(int prot, int lvl,
 
 	if ((prot & IOMMU_NOEXEC) && ap)
 		pte |= ARM_V7S_ATTR_XN(lvl);
-	if (prot & IOMMU_CACHE)
+	if (prot & IOMMU_MMIO)
+		pte |= ARM_V7S_ATTR_B;
+	else if (prot & IOMMU_CACHE)
 		pte |= ARM_V7S_ATTR_B | ARM_V7S_ATTR_C;
 
 	return pte;
@@ -279,10 +282,13 @@ static arm_v7s_iopte arm_v7s_prot_to_pte(int prot, int lvl,
 static int arm_v7s_pte_to_prot(arm_v7s_iopte pte, int lvl)
 {
 	int prot = IOMMU_READ;
+	arm_v7s_iopte attr = pte >> ARM_V7S_ATTR_SHIFT(lvl);
 
-	if (pte & (ARM_V7S_PTE_AP_RDONLY << ARM_V7S_ATTR_SHIFT(lvl)))
+	if (attr & ARM_V7S_PTE_AP_RDONLY)
 		prot |= IOMMU_WRITE;
-	if (pte & ARM_V7S_ATTR_C)
+	if ((attr & (ARM_V7S_TEX_MASK << ARM_V7S_TEX_SHIFT)) == 0)
+		prot |= IOMMU_MMIO;
+	else if (pte & ARM_V7S_ATTR_C)
 		prot |= IOMMU_CACHE;
 
 	return prot;
-- 
2.7.3.dirty

[PATCH 1/3] iommu: Add MMIO mapping type

[Joerg Roedel]

On Tue, Apr 05, 2016 at 12:39:30PM +0100, Robin Murphy wrote:
> On some platforms, MMIO regions might need slightly different treatment
> compared to mapping regular memory; add the notion of MMIO mappings to
> the IOMMU API's memory type flags, so that callers can let the IOMMU
> drivers know to do the right thing.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

Applied the series, thanks.