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genirq/msi: Add a new field in msi_desc to store an IOMMU cookie 

When an MSI doorbell is located downstream of an IOMMU, it is required
to swizzle the physical address with an appropriately-mapped IOVA for any
device attached to one of our DMA ops domain.

At the moment, the allocation of the mapping may be done when composing
the message. However, the composing may be done in non-preemtible
context while the allocation requires to be called from preemptible
context.

A follow-up change will split the current logic in two functions
requiring to keep an IOMMU cookie per MSI.

A new field is introduced in msi_desc to store an IOMMU cookie. As the
cookie may not be required in some configuration, the field is protected
under a new config CONFIG_IRQ_MSI_IOMMU.

A pair of helpers has also been introduced to access the field.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
hifive-unleashed-5.2
Julien Grall 2019-05-01 14:58:18 +01:00 committed by Marc Zyngier
parent 009669e748
commit aaebdf8d68
2 changed files with 29 additions and 0 deletions
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26
include/linux/msi.h
View File

@ -86,6 +86,9 @@ struct msi_desc {
struct device *dev;
struct msi_msg msg;
struct irq_affinity_desc *affinity;
#ifdef CONFIG_IRQ_MSI_IOMMU
const void *iommu_cookie;
#endif
union {
/* PCI MSI/X specific data */
@ -129,6 +132,29 @@ struct msi_desc {
#define for_each_msi_entry_safe(desc, tmp, dev) \
list_for_each_entry_safe((desc), (tmp), dev_to_msi_list((dev)), list)
#ifdef CONFIG_IRQ_MSI_IOMMU
static inline const void *msi_desc_get_iommu_cookie(struct msi_desc *desc)
{
return desc->iommu_cookie;
}
static inline void msi_desc_set_iommu_cookie(struct msi_desc *desc,
const void *iommu_cookie)
{
desc->iommu_cookie = iommu_cookie;
}
#else
static inline const void *msi_desc_get_iommu_cookie(struct msi_desc *desc)
{
return NULL;
}
static inline void msi_desc_set_iommu_cookie(struct msi_desc *desc,
const void *iommu_cookie)
{
}
#endif
#ifdef CONFIG_PCI_MSI
#define first_pci_msi_entry(pdev) first_msi_entry(&(pdev)->dev)
#define for_each_pci_msi_entry(desc, pdev) \

3
kernel/irq/Kconfig
View File

@ -91,6 +91,9 @@ config GENERIC_MSI_IRQ_DOMAIN
select IRQ_DOMAIN_HIERARCHY
select GENERIC_MSI_IRQ
config IRQ_MSI_IOMMU
bool
config HANDLE_DOMAIN_IRQ
bool