Re: [RFC PATCH v5 1/5] iommu: Add capabilities to a group

David Gibson
2017-08-09T07:00:07Z

[-- Attachment #1: Type: text/plain, Size: 4138 bytes --]

On Mon, Aug 07, 2017 at 05:25:44PM +1000, Alexey Kardashevskiy wrote:
> This introduces capabilities to IOMMU groups. The first defined
> capability is IOMMU_GROUP_CAP_ISOLATE_MSIX which tells the IOMMU
> group users that a particular IOMMU group is capable of MSIX message
> filtering; this is useful when deciding whether or not to allow mapping
> of MSIX table to the userspace. Various architectures will enable it
> when they decide that it is safe to do so.
>
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

This seems like a reasonable concept that's probably useful for
something, whether or not it's the best approach for the problem at
hand.

> ---
> include/linux/iommu.h | 20 ++++++++++++++++++++
> drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++
> 2 files changed, 48 insertions(+)
>
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 2cb54adc4a33..6b6f3c2f4904 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -155,6 +155,9 @@ struct iommu_resv_region {
> enum iommu_resv_type type;
> };
>
> +/* IOMMU group capabilities */
> +#define IOMMU_GROUP_CAP_ISOLATE_MSIX (1U)
> +
> #ifdef CONFIG_IOMMU_API
>
> /**
> @@ -312,6 +315,11 @@ extern void *iommu_group_get_iommudata(struct iommu_group *group);
> extern void iommu_group_set_iommudata(struct iommu_group *group,
> void *iommu_data,
> void (*release)(void *iommu_data));
> +extern void iommu_group_set_caps(struct iommu_group *group,
> + unsigned long clearcaps,
> + unsigned long setcaps);
> +extern bool iommu_group_is_capable(struct iommu_group *group,
> + unsigned long cap);
> extern int iommu_group_set_name(struct iommu_group *group, const char *name);
> extern int iommu_group_add_device(struct iommu_group *group,
> struct device *dev);
> @@ -513,6 +521,18 @@ static inline void iommu_group_set_iommudata(struct iommu_group *group,
> {
> }
>
> +static inline void iommu_group_set_caps(struct iommu_group *group,
> + unsigned long clearcaps,
> + unsigned long setcaps)
> +{
> +}
> +
> +static inline bool iommu_group_is_capable(struct iommu_group *group,
> + unsigned long cap)
> +{
> + return false;
> +}
> +
> static inline int iommu_group_set_name(struct iommu_group *group,
> const char *name)
> {
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 3f6ea160afed..6b2c34fe2c3d 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -52,6 +52,7 @@ struct iommu_group {
> void (*iommu_data_release)(void *iommu_data);
> char *name;
> int id;
> + unsigned long caps;
> struct iommu_domain *default_domain;
> struct iommu_domain *domain;
> };
> @@ -447,6 +448,33 @@ void iommu_group_set_iommudata(struct iommu_group *group, void *iommu_data,
> EXPORT_SYMBOL_GPL(iommu_group_set_iommudata);
>
> /**
> + * iommu_group_set_caps - Change the group capabilities
> + * @group: the group
> + * @clearcaps: capabilities mask to remove
> + * @setcaps: capabilities mask to add
> + *
> + * IOMMU groups can be capable of various features which device drivers
> + * may read and adjust the behavior.
> + */
> +void iommu_group_set_caps(struct iommu_group *group,
> + unsigned long clearcaps, unsigned long setcaps)
> +{
> + group->caps &= ~clearcaps;
> + group->caps |= setcaps;
> +}
> +EXPORT_SYMBOL_GPL(iommu_group_set_caps);
> +
> +/**
> + * iommu_group_is_capable - Returns if a group capability is present
> + * @group: the group
> + */
> +bool iommu_group_is_capable(struct iommu_group *group, unsigned long cap)
> +{
> + return !!(group->caps & cap);
> +}
> +EXPORT_SYMBOL_GPL(iommu_group_is_capable);
> +
> +/**
> * iommu_group_set_name - set name for a group
> * @group: the group
> * @name: name

--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]