This patch handles the iommu mapping of MSI doorbells that require to
be mapped in an iommu domain. This happens on msi_domain_alloc/free_irqs
since this is called in code that can sleep (pci_enable/disable_msi):
iommu_map/unmap is not stated as atomic. On msi_domain_(de)activate and
msi_domain_set_affinity, which must be atomic, we just lookup for this
pre-allocated/mapped IOVA.
Signed-off-by: Eric Auger <eric.au...@linaro.org>
---
v7: creation
---
kernel/irq/msi.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 85 insertions(+), 9 deletions(-)
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 72bf4d6..e45907e 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -14,6 +14,8 @@
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/msi.h>
+#include <linux/dma-reserved-iommu.h>
+#include <linux/iommu.h>
/* Temparory solution for building, will be removed later */
#include <linux/pci.h>
@@ -322,6 +324,59 @@ int msi_domain_populate_irqs(struct irq_domain *domain,
struct device *dev,
}
/**
+ * msi_handle_doorbell_mapping: in case the irq data corresponds to an
+ * MSI that requires iommu mapping, traverse the irq domain hierarchy
+ * to retrieve the doorbells to handle and iommu_map/unmap them according
+ * to @map boolean.
+ *
+ * @data: irq data handle
+ * @map: mapping if true, unmapping if false
+ */
+static int msi_handle_doorbell_mappings(struct irq_data *data, bool map)
+{
+
+ for (; data; data = data->parent_data) {
+ const struct irq_chip_msi_doorbell_info *dbinfo;
+ struct iommu_domain *domain;
+ struct msi_desc *desc;
+ struct irq_chip *chip;
+ dma_addr_t iova;
+ int ret = 0, i;
+
+ chip = irq_data_get_irq_chip(data);
+ desc = irq_data_get_msi_desc(data);
+
+ domain = iommu_msi_mapping_desc_to_domain(desc);
+ if (!domain)
+ continue;
+
+ if (!chip->msi_doorbell_info)
+ continue;
+
+ dbinfo = chip->msi_doorbell_info(data);
+ if (!dbinfo)
+ return -EINVAL;
+
+ for (i = 0; i < dbinfo->nb_doorbells; i++) {
+ struct irq_chip_msi_doorbell __percpu *db;
+
+ db = per_cpu_ptr(dbinfo->percpu_doorbells, i);
+ if (map) {
+ ret = iommu_get_reserved_iova(domain,
+ db->base,
+ db->size,
+ db->prot,
+ &iova);
+ if (ret)
+ return ret;
+ } else
+ iommu_put_reserved_iova(domain, db->base);
+ }
+ }
+ return 0;
+}
+
+/**
* msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
* @domain: The domain to allocate from
* @dev: Pointer to device struct of the device for which the interrupts
@@ -352,17 +407,25 @@ int msi_domain_alloc_irqs(struct irq_domain *domain,
struct device *dev,
virq = __irq_domain_alloc_irqs(domain, virq, desc->nvec_used,
dev_to_node(dev), &arg, false);
- if (virq < 0) {
- ret = -ENOSPC;
- if (ops->handle_error)
- ret = ops->handle_error(domain, desc, ret);
- if (ops->msi_finish)
- ops->msi_finish(&arg, ret);
- return ret;
- }
+ if (virq < 0)
+ goto error;
- for (i = 0; i < desc->nvec_used; i++)
+ for (i = 0; i < desc->nvec_used; i++) {
irq_set_msi_desc_off(virq, i, desc);
+ ret = msi_handle_doorbell_mappings(
+ irq_get_irq_data(virq + i), true);
+ if (ret)
+ break;
+ }
+
+ if (ret) {
+ for (; i >= 0; i--) {
+ ret = msi_handle_doorbell_mappings(
+ irq_get_irq_data(virq + i), false);
+ irq_set_msi_desc_off(virq, i, NULL);
+ }
+ goto error;
+ }
}
if (ops->msi_finish)
@@ -377,6 +440,13 @@ int msi_domain_alloc_irqs(struct irq_domain *domain,
struct device *dev,
}
return 0;
+error:
+ ret = -ENOSPC;
+ if (ops->handle_error)
+ ret = ops->handle_error(domain, desc, ret);
+ if (ops->msi_finish)
+ ops->msi_finish(&arg, ret);
+ return ret;
}
/**
@@ -396,6 +466,12 @@ void msi_domain_free_irqs(struct irq_domain *domain,
struct device *dev)
* entry. If that's the case, don't do anything.
*/
if (desc->irq) {
+ int ret;
+
+ ret = msi_handle_doorbell_mappings(
+ irq_get_irq_data(desc->irq),
+ false);
+ WARN_ON(ret);
irq_domain_free_irqs(desc->irq, desc->nvec_used);
desc->irq = 0;
}
--
1.9.1
