diff mbox

[v9,4/8] iommu/msi-iommu: initialization

Message ID 1462362007-2753-5-git-send-email-eric.auger@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Auger May 4, 2016, 11:40 a.m. UTC 
iommu_get/put_msi_cookie allocates/frees the resource used to store
and ref count the MSI doorbell mappings. iommu_msi_set_aperture
initializes the iova domain used for MSI IOVA allocation and sets the
iommu domain's msi geometry.

The implementation relies on dma-iommu API and iova API.

New msi functions are fully implemented if CONFIG_IOMMU_MSI is set.

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

---
v9:
- remove is_aperture_set and use iommu_domain_msi_aperture_valid helper
  instead
- set iommu domain's msi geometry

v8:
- new design where msi-iommu relies on dma-iommu
- remove the iommu_domain * from the doorbell_mapping struct
- added is_aperture_set

v7:
- fix locking
- add iova_cache_get/put
- static inline functions when CONFIG_IOMMU_DMA_RESERVED is not set
- introduce struct reserved_iova_domain to encapsulate prot info &
  add prot parameter in alloc_reserved_iova_domain

v5 -> v6:
- use spin lock instead of mutex

v3 -> v4:
- formerly in "iommu/arm-smmu: implement alloc/free_reserved_iova_domain" &
  "iommu: add alloc/free_reserved_iova_domain"

v2 -> v3:
- remove iommu_alloc_reserved_iova_domain & iommu_free_reserved_iova_domain
  static implementation in case CONFIG_IOMMU_API is not set

v1 -> v2:
- moved from vfio API to IOMMU API
---
 drivers/iommu/Kconfig     |  7 ++++
 drivers/iommu/Makefile    |  1 +
 drivers/iommu/msi-iommu.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/msi-iommu.h | 65 +++++++++++++++++++++++++++++++
 4 files changed, 170 insertions(+)
 create mode 100644 drivers/iommu/msi-iommu.c
 create mode 100644 include/linux/msi-iommu.h

Comments

Alex Williamson May 9, 2016, 8:57 p.m. UTC | #1 
On Wed,  4 May 2016 11:40:03 +0000
Eric Auger <eric.auger@linaro.org> wrote:

> iommu_get/put_msi_cookie allocates/frees the resource used to store
> and ref count the MSI doorbell mappings. iommu_msi_set_aperture
> initializes the iova domain used for MSI IOVA allocation and sets the
> iommu domain's msi geometry.
> 
> The implementation relies on dma-iommu API and iova API.
> 
> New msi functions are fully implemented if CONFIG_IOMMU_MSI is set.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> v9:
> - remove is_aperture_set and use iommu_domain_msi_aperture_valid helper
>   instead
> - set iommu domain's msi geometry
> 
> v8:
> - new design where msi-iommu relies on dma-iommu
> - remove the iommu_domain * from the doorbell_mapping struct
> - added is_aperture_set
> 
> v7:
> - fix locking
> - add iova_cache_get/put
> - static inline functions when CONFIG_IOMMU_DMA_RESERVED is not set
> - introduce struct reserved_iova_domain to encapsulate prot info &
>   add prot parameter in alloc_reserved_iova_domain
> 
> v5 -> v6:
> - use spin lock instead of mutex
> 
> v3 -> v4:
> - formerly in "iommu/arm-smmu: implement alloc/free_reserved_iova_domain" &
>   "iommu: add alloc/free_reserved_iova_domain"
> 
> v2 -> v3:
> - remove iommu_alloc_reserved_iova_domain & iommu_free_reserved_iova_domain
>   static implementation in case CONFIG_IOMMU_API is not set
> 
> v1 -> v2:
> - moved from vfio API to IOMMU API
> ---
>  drivers/iommu/Kconfig     |  7 ++++
>  drivers/iommu/Makefile    |  1 +
>  drivers/iommu/msi-iommu.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/msi-iommu.h | 65 +++++++++++++++++++++++++++++++
>  4 files changed, 170 insertions(+)
>  create mode 100644 drivers/iommu/msi-iommu.c
>  create mode 100644 include/linux/msi-iommu.h
> 
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index dd1dc39..0078b72 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -74,6 +74,11 @@ config IOMMU_DMA
>  	select IOMMU_IOVA
>  	select NEED_SG_DMA_LENGTH
>  
> +# IOMMU MSI mapping
> +config IOMMU_MSI
> +	bool
> +	select IOMMU_DMA
> +
>  config FSL_PAMU
>  	bool "Freescale IOMMU support"
>  	depends on PPC32
> @@ -307,6 +312,7 @@ config SPAPR_TCE_IOMMU
>  config ARM_SMMU
>  	bool "ARM Ltd. System MMU (SMMU) Support"
>  	depends on (ARM64 || ARM) && MMU
> +	select IOMMU_MSI
>  	select IOMMU_API
>  	select IOMMU_IO_PGTABLE_LPAE
>  	select ARM_DMA_USE_IOMMU if ARM
> @@ -320,6 +326,7 @@ config ARM_SMMU
>  config ARM_SMMU_V3
>  	bool "ARM Ltd. System MMU Version 3 (SMMUv3) Support"
>  	depends on ARM64 && PCI
> +	select IOMMU_MSI
>  	select IOMMU_API
>  	select IOMMU_IO_PGTABLE_LPAE
>  	select GENERIC_MSI_IRQ_DOMAIN
> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> index c6edb31..a381e66 100644
> --- a/drivers/iommu/Makefile
> +++ b/drivers/iommu/Makefile
> @@ -2,6 +2,7 @@ obj-$(CONFIG_IOMMU_API) += iommu.o
>  obj-$(CONFIG_IOMMU_API) += iommu-traces.o
>  obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o
>  obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o
> +obj-$(CONFIG_IOMMU_MSI) += msi-iommu.o
>  obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o
>  obj-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o
>  obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o
> diff --git a/drivers/iommu/msi-iommu.c b/drivers/iommu/msi-iommu.c
> new file mode 100644
> index 0000000..4292957
> --- /dev/null
> +++ b/drivers/iommu/msi-iommu.c
> @@ -0,0 +1,97 @@
> +/*
> + * Reserved IOVA Management
> + *
> + * Copyright (c) 2015 Linaro Ltd.
> + *              www.linaro.org
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/iommu.h>
> +#include <linux/dma-iommu.h>
> +#include <linux/msi-iommu.h>
> +#include <linux/spinlock.h>
> +#include <linux/iova.h>
> +
> +struct doorbell_mapping {
> +	struct kref		kref;
> +	struct list_head	next;
> +	phys_addr_t		addr;
> +	dma_addr_t		iova;
> +	size_t			size;
> +};
> +
> +struct doorbell_mapping_info {
> +	struct list_head list; /* list of doorbell mapping entries */
> +	spinlock_t lock;
> +};
> +
> +int iommu_get_msi_cookie(struct iommu_domain *domain)
> +{
> +	struct doorbell_mapping_info *dmi;
> +	int ret;
> +
> +	if (domain->msi_cookie || domain->iova_cookie)
> +		return -EINVAL;
> +
> +	ret = iommu_get_dma_cookie(domain);
> +	if (ret)
> +		return ret;
> +
> +	dmi = kzalloc(sizeof(*dmi), GFP_KERNEL);
> +
> +	INIT_LIST_HEAD(&dmi->list);
> +	spin_lock_init(&dmi->lock);
> +	iova_cache_get();
> +
> +	domain->msi_cookie = dmi;
> +
> +	return dmi ? 0 : -ENOMEM;
> +}
> +EXPORT_SYMBOL(iommu_get_msi_cookie);
> +
> +void iommu_put_msi_cookie(struct iommu_domain *domain)
> +{
> +	struct doorbell_mapping_info *dmi = domain->msi_cookie;
> +
> +	if (!dmi)
> +		return;
> +
> +	domain->msi_cookie = NULL;
> +
> +	WARN_ON(!list_empty(&dmi->list));
> +
> +	kfree(dmi);
> +	iommu_put_dma_cookie(domain);
> +	iova_cache_put();
> +}
> +EXPORT_SYMBOL(iommu_put_msi_cookie);
> +
> +int iommu_msi_set_aperture(struct iommu_domain *domain,
> +			   dma_addr_t start, dma_addr_t end)
> +{
> +	struct doorbell_mapping_info *dmi = domain->msi_cookie;
> +	int ret;
> +
> +	if (!dmi || iommu_domain_msi_aperture_valid(domain))
> +		return -ENODEV;


nit, the next patch splits to use different errnos for each issue,
which seems preferable.


> +
> +	ret = iommu_dma_init_domain(domain, start, end - start + 1);
> +
> +	if (!ret) {
> +		domain->msi_geometry.aperture_start = start;
> +		domain->msi_geometry.aperture_end = end;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_msi_set_aperture);
> +
> diff --git a/include/linux/msi-iommu.h b/include/linux/msi-iommu.h
> new file mode 100644
> index 0000000..392aa6f
> --- /dev/null
> +++ b/include/linux/msi-iommu.h
> @@ -0,0 +1,65 @@
> +/*
> + * Copyright (c) 2015 Linaro Ltd.
> + *              www.linaro.org
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +#ifndef __MSI_IOMMU_H
> +#define __MSI_IOMMU_H
> +
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +
> +struct iommu_domain;
> +
> +#ifdef CONFIG_IOMMU_MSI
> +
> +/**
> + * iommu_get_msi_cookie - Acquire MSI mapping resources for a domain
> + * @domain: IOMMU domain to prepare for MSI mapping
> + *
> + * IOMMU drivers which require MSI mapping should normally call this
> + * from their domain_alloc callback when domain->type ==
> + * IOMMU_DOMAIN_UNMANAGED.
> + */
> +int iommu_get_msi_cookie(struct iommu_domain *domain);
> +
> +/**
> + * iommu_put_msi_cookie - Release a domain's MSI mapping resources
> + * @domain: IOMMU domain previously prepared by iommu_get_msi_cookie()
> + *
> + * IOMMU drivers requesting MSI mapping should normally call this from
> + * their domain_free callback.
> + */
> +void iommu_put_msi_cookie(struct iommu_domain *domain);
> +
> +/**
> + * iommu_msi_set_aperture: allocate the msi iova domain
> + * according to the specified start/end IOVAs
> + *
> + * @domain: iommu domain handle
> + * @start: MSI iova start address
> + * @end: MSI iova end address
> + */
> +int iommu_msi_set_aperture(struct iommu_domain *domain,
> +			   dma_addr_t start, dma_addr_t end);
> +
> +#else
> +
> +static inline int
> +iommu_msi_set_aperture(struct iommu_domain *domain,
> +		       dma_addr_t start, dma_addr_t end)
> +{
> +	return -ENOENT;
> +}
> +
> +#endif	/* CONFIG_IOMMU_MSI */
> +#endif	/* __MSI_IOMMU_H */
Eric Auger May 10, 2016, 2:43 p.m. UTC | #2 
Hi Alex,
On 05/09/2016 10:57 PM, Alex Williamson wrote:
> On Wed,  4 May 2016 11:40:03 +0000
> Eric Auger <eric.auger@linaro.org> wrote:
> 
>> iommu_get/put_msi_cookie allocates/frees the resource used to store
>> and ref count the MSI doorbell mappings. iommu_msi_set_aperture
>> initializes the iova domain used for MSI IOVA allocation and sets the
>> iommu domain's msi geometry.
>>
>> The implementation relies on dma-iommu API and iova API.
>>
>> New msi functions are fully implemented if CONFIG_IOMMU_MSI is set.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>> v9:
>> - remove is_aperture_set and use iommu_domain_msi_aperture_valid helper
>>   instead
>> - set iommu domain's msi geometry
>>
>> v8:
>> - new design where msi-iommu relies on dma-iommu
>> - remove the iommu_domain * from the doorbell_mapping struct
>> - added is_aperture_set
>>
>> v7:
>> - fix locking
>> - add iova_cache_get/put
>> - static inline functions when CONFIG_IOMMU_DMA_RESERVED is not set
>> - introduce struct reserved_iova_domain to encapsulate prot info &
>>   add prot parameter in alloc_reserved_iova_domain
>>
>> v5 -> v6:
>> - use spin lock instead of mutex
>>
>> v3 -> v4:
>> - formerly in "iommu/arm-smmu: implement alloc/free_reserved_iova_domain" &
>>   "iommu: add alloc/free_reserved_iova_domain"
>>
>> v2 -> v3:
>> - remove iommu_alloc_reserved_iova_domain & iommu_free_reserved_iova_domain
>>   static implementation in case CONFIG_IOMMU_API is not set
>>
>> v1 -> v2:
>> - moved from vfio API to IOMMU API
>> ---
>>  drivers/iommu/Kconfig     |  7 ++++
>>  drivers/iommu/Makefile    |  1 +
>>  drivers/iommu/msi-iommu.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/msi-iommu.h | 65 +++++++++++++++++++++++++++++++
>>  4 files changed, 170 insertions(+)
>>  create mode 100644 drivers/iommu/msi-iommu.c
>>  create mode 100644 include/linux/msi-iommu.h
>>
>> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
>> index dd1dc39..0078b72 100644
>> --- a/drivers/iommu/Kconfig
>> +++ b/drivers/iommu/Kconfig
>> @@ -74,6 +74,11 @@ config IOMMU_DMA
>>  	select IOMMU_IOVA
>>  	select NEED_SG_DMA_LENGTH
>>  
>> +# IOMMU MSI mapping
>> +config IOMMU_MSI
>> +	bool
>> +	select IOMMU_DMA
>> +
>>  config FSL_PAMU
>>  	bool "Freescale IOMMU support"
>>  	depends on PPC32
>> @@ -307,6 +312,7 @@ config SPAPR_TCE_IOMMU
>>  config ARM_SMMU
>>  	bool "ARM Ltd. System MMU (SMMU) Support"
>>  	depends on (ARM64 || ARM) && MMU
>> +	select IOMMU_MSI
>>  	select IOMMU_API
>>  	select IOMMU_IO_PGTABLE_LPAE
>>  	select ARM_DMA_USE_IOMMU if ARM
>> @@ -320,6 +326,7 @@ config ARM_SMMU
>>  config ARM_SMMU_V3
>>  	bool "ARM Ltd. System MMU Version 3 (SMMUv3) Support"
>>  	depends on ARM64 && PCI
>> +	select IOMMU_MSI
>>  	select IOMMU_API
>>  	select IOMMU_IO_PGTABLE_LPAE
>>  	select GENERIC_MSI_IRQ_DOMAIN
>> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
>> index c6edb31..a381e66 100644
>> --- a/drivers/iommu/Makefile
>> +++ b/drivers/iommu/Makefile
>> @@ -2,6 +2,7 @@ obj-$(CONFIG_IOMMU_API) += iommu.o
>>  obj-$(CONFIG_IOMMU_API) += iommu-traces.o
>>  obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o
>>  obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o
>> +obj-$(CONFIG_IOMMU_MSI) += msi-iommu.o
>>  obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o
>>  obj-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o
>>  obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o
>> diff --git a/drivers/iommu/msi-iommu.c b/drivers/iommu/msi-iommu.c
>> new file mode 100644
>> index 0000000..4292957
>> --- /dev/null
>> +++ b/drivers/iommu/msi-iommu.c
>> @@ -0,0 +1,97 @@
>> +/*
>> + * Reserved IOVA Management
>> + *
>> + * Copyright (c) 2015 Linaro Ltd.
>> + *              www.linaro.org
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + */
>> +
>> +#include <linux/iommu.h>
>> +#include <linux/dma-iommu.h>
>> +#include <linux/msi-iommu.h>
>> +#include <linux/spinlock.h>
>> +#include <linux/iova.h>
>> +
>> +struct doorbell_mapping {
>> +	struct kref		kref;
>> +	struct list_head	next;
>> +	phys_addr_t		addr;
>> +	dma_addr_t		iova;
>> +	size_t			size;
>> +};
>> +
>> +struct doorbell_mapping_info {
>> +	struct list_head list; /* list of doorbell mapping entries */
>> +	spinlock_t lock;
>> +};
>> +
>> +int iommu_get_msi_cookie(struct iommu_domain *domain)
>> +{
>> +	struct doorbell_mapping_info *dmi;
>> +	int ret;
>> +
>> +	if (domain->msi_cookie || domain->iova_cookie)
>> +		return -EINVAL;
>> +
>> +	ret = iommu_get_dma_cookie(domain);
>> +	if (ret)
>> +		return ret;
>> +
>> +	dmi = kzalloc(sizeof(*dmi), GFP_KERNEL);
>> +
>> +	INIT_LIST_HEAD(&dmi->list);
>> +	spin_lock_init(&dmi->lock);
>> +	iova_cache_get();
>> +
>> +	domain->msi_cookie = dmi;
>> +
>> +	return dmi ? 0 : -ENOMEM;
>> +}
>> +EXPORT_SYMBOL(iommu_get_msi_cookie);
>> +
>> +void iommu_put_msi_cookie(struct iommu_domain *domain)
>> +{
>> +	struct doorbell_mapping_info *dmi = domain->msi_cookie;
>> +
>> +	if (!dmi)
>> +		return;
>> +
>> +	domain->msi_cookie = NULL;
>> +
>> +	WARN_ON(!list_empty(&dmi->list));
>> +
>> +	kfree(dmi);
>> +	iommu_put_dma_cookie(domain);
>> +	iova_cache_put();
>> +}
>> +EXPORT_SYMBOL(iommu_put_msi_cookie);
>> +
>> +int iommu_msi_set_aperture(struct iommu_domain *domain,
>> +			   dma_addr_t start, dma_addr_t end)
>> +{
>> +	struct doorbell_mapping_info *dmi = domain->msi_cookie;
>> +	int ret;
>> +
>> +	if (!dmi || iommu_domain_msi_aperture_valid(domain))
>> +		return -ENODEV;
> 
> 
> nit, the next patch splits to use different errnos for each issue,
> which seems preferable.

sure

Eric
> 
> 
>> +
>> +	ret = iommu_dma_init_domain(domain, start, end - start + 1);
>> +
>> +	if (!ret) {
>> +		domain->msi_geometry.aperture_start = start;
>> +		domain->msi_geometry.aperture_end = end;
>> +	}
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_msi_set_aperture);
>> +
>> diff --git a/include/linux/msi-iommu.h b/include/linux/msi-iommu.h
>> new file mode 100644
>> index 0000000..392aa6f
>> --- /dev/null
>> +++ b/include/linux/msi-iommu.h
>> @@ -0,0 +1,65 @@
>> +/*
>> + * Copyright (c) 2015 Linaro Ltd.
>> + *              www.linaro.org
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + */
>> +#ifndef __MSI_IOMMU_H
>> +#define __MSI_IOMMU_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/kernel.h>
>> +
>> +struct iommu_domain;
>> +
>> +#ifdef CONFIG_IOMMU_MSI
>> +
>> +/**
>> + * iommu_get_msi_cookie - Acquire MSI mapping resources for a domain
>> + * @domain: IOMMU domain to prepare for MSI mapping
>> + *
>> + * IOMMU drivers which require MSI mapping should normally call this
>> + * from their domain_alloc callback when domain->type ==
>> + * IOMMU_DOMAIN_UNMANAGED.
>> + */
>> +int iommu_get_msi_cookie(struct iommu_domain *domain);
>> +
>> +/**
>> + * iommu_put_msi_cookie - Release a domain's MSI mapping resources
>> + * @domain: IOMMU domain previously prepared by iommu_get_msi_cookie()
>> + *
>> + * IOMMU drivers requesting MSI mapping should normally call this from
>> + * their domain_free callback.
>> + */
>> +void iommu_put_msi_cookie(struct iommu_domain *domain);
>> +
>> +/**
>> + * iommu_msi_set_aperture: allocate the msi iova domain
>> + * according to the specified start/end IOVAs
>> + *
>> + * @domain: iommu domain handle
>> + * @start: MSI iova start address
>> + * @end: MSI iova end address
>> + */
>> +int iommu_msi_set_aperture(struct iommu_domain *domain,
>> +			   dma_addr_t start, dma_addr_t end);
>> +
>> +#else
>> +
>> +static inline int
>> +iommu_msi_set_aperture(struct iommu_domain *domain,
>> +		       dma_addr_t start, dma_addr_t end)
>> +{
>> +	return -ENOENT;
>> +}
>> +
>> +#endif	/* CONFIG_IOMMU_MSI */
>> +#endif	/* __MSI_IOMMU_H */
>
diff mbox

Patch

diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index dd1dc39..0078b72 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -74,6 +74,11 @@  config IOMMU_DMA
 	select IOMMU_IOVA
 	select NEED_SG_DMA_LENGTH
 
+# IOMMU MSI mapping
+config IOMMU_MSI
+	bool
+	select IOMMU_DMA
+
 config FSL_PAMU
 	bool "Freescale IOMMU support"
 	depends on PPC32
@@ -307,6 +312,7 @@  config SPAPR_TCE_IOMMU
 config ARM_SMMU
 	bool "ARM Ltd. System MMU (SMMU) Support"
 	depends on (ARM64 || ARM) && MMU
+	select IOMMU_MSI
 	select IOMMU_API
 	select IOMMU_IO_PGTABLE_LPAE
 	select ARM_DMA_USE_IOMMU if ARM
@@ -320,6 +326,7 @@  config ARM_SMMU
 config ARM_SMMU_V3
 	bool "ARM Ltd. System MMU Version 3 (SMMUv3) Support"
 	depends on ARM64 && PCI
+	select IOMMU_MSI
 	select IOMMU_API
 	select IOMMU_IO_PGTABLE_LPAE
 	select GENERIC_MSI_IRQ_DOMAIN
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index c6edb31..a381e66 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -2,6 +2,7 @@  obj-$(CONFIG_IOMMU_API) += iommu.o
 obj-$(CONFIG_IOMMU_API) += iommu-traces.o
 obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o
 obj-$(CONFIG_IOMMU_DMA) += dma-iommu.o
+obj-$(CONFIG_IOMMU_MSI) += msi-iommu.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE) += io-pgtable.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) += io-pgtable-arm-v7s.o
 obj-$(CONFIG_IOMMU_IO_PGTABLE_LPAE) += io-pgtable-arm.o
diff --git a/drivers/iommu/msi-iommu.c b/drivers/iommu/msi-iommu.c
new file mode 100644
index 0000000..4292957
--- /dev/null
+++ b/drivers/iommu/msi-iommu.c
@@ -0,0 +1,97 @@ 
+/*
+ * Reserved IOVA Management
+ *
+ * Copyright (c) 2015 Linaro Ltd.
+ *              www.linaro.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/iommu.h>
+#include <linux/dma-iommu.h>
+#include <linux/msi-iommu.h>
+#include <linux/spinlock.h>
+#include <linux/iova.h>
+
+struct doorbell_mapping {
+	struct kref		kref;
+	struct list_head	next;
+	phys_addr_t		addr;
+	dma_addr_t		iova;
+	size_t			size;
+};
+
+struct doorbell_mapping_info {
+	struct list_head list; /* list of doorbell mapping entries */
+	spinlock_t lock;
+};
+
+int iommu_get_msi_cookie(struct iommu_domain *domain)
+{
+	struct doorbell_mapping_info *dmi;
+	int ret;
+
+	if (domain->msi_cookie || domain->iova_cookie)
+		return -EINVAL;
+
+	ret = iommu_get_dma_cookie(domain);
+	if (ret)
+		return ret;
+
+	dmi = kzalloc(sizeof(*dmi), GFP_KERNEL);
+
+	INIT_LIST_HEAD(&dmi->list);
+	spin_lock_init(&dmi->lock);
+	iova_cache_get();
+
+	domain->msi_cookie = dmi;
+
+	return dmi ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL(iommu_get_msi_cookie);
+
+void iommu_put_msi_cookie(struct iommu_domain *domain)
+{
+	struct doorbell_mapping_info *dmi = domain->msi_cookie;
+
+	if (!dmi)
+		return;
+
+	domain->msi_cookie = NULL;
+
+	WARN_ON(!list_empty(&dmi->list));
+
+	kfree(dmi);
+	iommu_put_dma_cookie(domain);
+	iova_cache_put();
+}
+EXPORT_SYMBOL(iommu_put_msi_cookie);
+
+int iommu_msi_set_aperture(struct iommu_domain *domain,
+			   dma_addr_t start, dma_addr_t end)
+{
+	struct doorbell_mapping_info *dmi = domain->msi_cookie;
+	int ret;
+
+	if (!dmi || iommu_domain_msi_aperture_valid(domain))
+		return -ENODEV;
+
+	ret = iommu_dma_init_domain(domain, start, end - start + 1);
+
+	if (!ret) {
+		domain->msi_geometry.aperture_start = start;
+		domain->msi_geometry.aperture_end = end;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_msi_set_aperture);
+
diff --git a/include/linux/msi-iommu.h b/include/linux/msi-iommu.h
new file mode 100644
index 0000000..392aa6f
--- /dev/null
+++ b/include/linux/msi-iommu.h
@@ -0,0 +1,65 @@ 
+/*
+ * Copyright (c) 2015 Linaro Ltd.
+ *              www.linaro.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#ifndef __MSI_IOMMU_H
+#define __MSI_IOMMU_H
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+
+struct iommu_domain;
+
+#ifdef CONFIG_IOMMU_MSI
+
+/**
+ * iommu_get_msi_cookie - Acquire MSI mapping resources for a domain
+ * @domain: IOMMU domain to prepare for MSI mapping
+ *
+ * IOMMU drivers which require MSI mapping should normally call this
+ * from their domain_alloc callback when domain->type ==
+ * IOMMU_DOMAIN_UNMANAGED.
+ */
+int iommu_get_msi_cookie(struct iommu_domain *domain);
+
+/**
+ * iommu_put_msi_cookie - Release a domain's MSI mapping resources
+ * @domain: IOMMU domain previously prepared by iommu_get_msi_cookie()
+ *
+ * IOMMU drivers requesting MSI mapping should normally call this from
+ * their domain_free callback.
+ */
+void iommu_put_msi_cookie(struct iommu_domain *domain);
+
+/**
+ * iommu_msi_set_aperture: allocate the msi iova domain
+ * according to the specified start/end IOVAs
+ *
+ * @domain: iommu domain handle
+ * @start: MSI iova start address
+ * @end: MSI iova end address
+ */
+int iommu_msi_set_aperture(struct iommu_domain *domain,
+			   dma_addr_t start, dma_addr_t end);
+
+#else
+
+static inline int
+iommu_msi_set_aperture(struct iommu_domain *domain,
+		       dma_addr_t start, dma_addr_t end)
+{
+	return -ENOENT;
+}
+
+#endif	/* CONFIG_IOMMU_MSI */
+#endif	/* __MSI_IOMMU_H */