* [PATCH v6 1/4] msi: Add a new MSI_FLAG_IRQ_REMAPPING flag
2016-04-04 8:19 [PATCH v6 0/4] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part 2/3: msi changes Eric Auger
@ 2016-04-04 8:19 ` Eric Auger
2016-04-04 8:19 ` [PATCH v6 2/4] irqchip/gic-v3-its: ITS advertises MSI_FLAG_IRQ_REMAPPING Eric Auger
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Eric Auger @ 2016-04-04 8:19 UTC (permalink / raw)
To: linux-arm-kernel
Let's introduce a new msi_domain_info flag value, MSI_FLAG_IRQ_REMAPPING
meant to tell the domain supports IRQ REMAPPING, also known as Interrupt
Translation Service. On Intel HW this IRQ remapping capability is
abstracted on IOMMU side while on ARM it is abstracted on MSI controller
side. This flag will be used to know whether the MSI passthrough is
safe.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
v4 -> v5:
- seperate flag introduction from first user addition (ITS)
---
include/linux/msi.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 8b425c6..08441b1 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -270,6 +270,8 @@ enum {
MSI_FLAG_MULTI_PCI_MSI = (1 << 3),
/* Support PCI MSIX interrupts */
MSI_FLAG_PCI_MSIX = (1 << 4),
+ /* Support MSI IRQ remapping service */
+ MSI_FLAG_IRQ_REMAPPING = (1 << 5),
};
int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
--
1.9.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v6 2/4] irqchip/gic-v3-its: ITS advertises MSI_FLAG_IRQ_REMAPPING
2016-04-04 8:19 [PATCH v6 0/4] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part 2/3: msi changes Eric Auger
2016-04-04 8:19 ` [PATCH v6 1/4] msi: Add a new MSI_FLAG_IRQ_REMAPPING flag Eric Auger
@ 2016-04-04 8:19 ` Eric Auger
2016-04-04 8:19 ` [PATCH v6 3/4] msi: export msi_get_domain_info Eric Auger
2016-04-04 8:19 ` [PATCH v6 4/4] msi: IOMMU map the doorbell address when needed Eric Auger
3 siblings, 0 replies; 7+ messages in thread
From: Eric Auger @ 2016-04-04 8:19 UTC (permalink / raw)
To: linux-arm-kernel
The ITS is the first ARM MSI controller advertising the new
MSI_FLAG_IRQ_REMAPPING flag. It does so because it supports
interrupt translation service. This HW support offers isolation
of MSIs, feature used when using KVM device passthrough.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
v5: new
---
drivers/irqchip/irq-gic-v3-its-pci-msi.c | 3 ++-
drivers/irqchip/irq-gic-v3-its-platform-msi.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3-its-pci-msi.c b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
index aee60ed..8223765 100644
--- a/drivers/irqchip/irq-gic-v3-its-pci-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-pci-msi.c
@@ -96,7 +96,8 @@ static struct msi_domain_ops its_pci_msi_ops = {
static struct msi_domain_info its_pci_msi_domain_info = {
.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
- MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
+ MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX |
+ MSI_FLAG_IRQ_REMAPPING),
.ops = &its_pci_msi_ops,
.chip = &its_msi_irq_chip,
};
diff --git a/drivers/irqchip/irq-gic-v3-its-platform-msi.c b/drivers/irqchip/irq-gic-v3-its-platform-msi.c
index 470b4aa..8c0d69d 100644
--- a/drivers/irqchip/irq-gic-v3-its-platform-msi.c
+++ b/drivers/irqchip/irq-gic-v3-its-platform-msi.c
@@ -63,7 +63,8 @@ static struct msi_domain_ops its_pmsi_ops = {
};
static struct msi_domain_info its_pmsi_domain_info = {
- .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_IRQ_REMAPPING),
.ops = &its_pmsi_ops,
.chip = &its_pmsi_irq_chip,
};
--
1.9.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH v6 4/4] msi: IOMMU map the doorbell address when needed
2016-04-04 8:19 [PATCH v6 0/4] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part 2/3: msi changes Eric Auger
` (2 preceding siblings ...)
2016-04-04 8:19 ` [PATCH v6 3/4] msi: export msi_get_domain_info Eric Auger
@ 2016-04-04 8:19 ` Eric Auger
2016-04-04 9:22 ` kbuild test robot
3 siblings, 1 reply; 7+ messages in thread
From: Eric Auger @ 2016-04-04 8:19 UTC (permalink / raw)
To: linux-arm-kernel
In case the msi is emitted by a device attached to an iommu domain
and this iommu domain requires MSI mapping, the msi address (aka
doorbell) must be mapped in the IOMMU. Else MSI write transaction
will cause a fault.
We handle the iommu mapping/unmapping anytime the msi address is
updated.
In case the mapping fails we just WARN_ON.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
v6:
- check the domain type to detect bypass situation (rebase on
new default domain modality)
- fix the msi_domain_set_affinity sequence:
unmap the address once the PCI device has been given the new address
- use new proto for iommu_put_reserved_iova. New function names
v5:
- use macros to increase the readability
- add comments
- fix a typo that caused a compilation error if CONFIG_IOMMU_API
is not set
---
include/linux/msi.h | 15 +++++++
kernel/irq/msi.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 138 insertions(+)
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 08441b1..1dc41db 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -10,6 +10,21 @@ struct msi_msg {
u32 data; /* 16 bits of msi message data */
};
+/* Helpers to convert the msi message address to a an iova/physical address */
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+#define msg_to_dma_addr(msg) \
+ (((dma_addr_t)((msg)->address_hi) << 32) | (msg)->address_lo)
+#else
+#define msg_to_dma_addr(msg) ((msg)->address_lo)
+#endif
+
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+#define msg_to_phys_addr(msg) \
+ (((phys_addr_t)((msg)->address_hi) << 32) | (msg)->address_lo)
+#else
+#define msg_to_phys_addr(msg) ((msg)->address_lo)
+#endif
+
extern int pci_msi_ignore_mask;
/* Helper functions */
struct irq_data;
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 9b0ba4a..7440653 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -17,6 +17,8 @@
/* Temparory solution for building, will be removed later */
#include <linux/pci.h>
+#include <linux/iommu.h>
+#include <linux/dma-reserved-iommu.h>
struct msi_desc *alloc_msi_entry(struct device *dev)
{
@@ -56,6 +58,94 @@ static inline void irq_chip_write_msi_msg(struct irq_data *data,
}
/**
+ * msi_map_doorbell: make sure an IOMMU mapping exists on domain @d
+ * for the message physical address (aka. doorbell)
+ *
+ * Either allocate an IOVA and create a mapping or simply increment
+ * a reference count on the existing IOMMU mapping
+ * @d: iommu domain handle the mapping belongs to
+ * @msg: msi message handle
+ */
+static int msi_map_doorbell(struct iommu_domain *d, struct msi_msg *msg)
+{
+#ifdef CONFIG_IOMMU_DMA_RESERVED
+ phys_addr_t addr;
+ dma_addr_t iova;
+ int ret;
+
+ addr = msg_to_phys_addr(msg);
+ ret = iommu_get_reserved_iova(d, addr, sizeof(addr), IOMMU_WRITE, &iova);
+ if (!ret) {
+ msg->address_lo = lower_32_bits(iova);
+ msg->address_hi = upper_32_bits(iova);
+ }
+ return ret;
+#else
+ return -ENODEV;
+#endif
+}
+
+/**
+ * msi_unmap_doorbell: decrements the reference count on an existing
+ * doorbell IOMMU mapping
+ *
+ * @d: iommu domain the mapping is attached to
+ * @msg: msi message containing the doorbell IOVA to unbind
+ */
+static void msi_unmap_doorbell(struct iommu_domain *d, struct msi_msg *msg)
+{
+#ifdef CONFIG_IOMMU_DMA_RESERVED
+ dma_addr_t iova;
+
+ iova = msg_to_dma_addr(msg);
+ iommu_put_reserved_iova(d, iova);
+#endif
+}
+
+#ifdef CONFIG_IOMMU_API
+/**
+ * irq_data_to_msi_mapping_domain: checks if an irq corresponds to
+ * an MSI whose write address must be mapped in an IOMMU domain
+ *
+ * determine whether the irq corresponds to an MSI emitted by a device,
+ * upstream to an IOMMU, and if this IOMMU requires a binding of the
+ * MSI address
+ *
+ * @irq_data: irq data handle
+ */
+static struct iommu_domain *
+irq_data_to_msi_mapping_domain(struct irq_data *irq_data)
+{
+ struct iommu_domain *d;
+ struct msi_desc *desc;
+ struct device *dev;
+ int ret;
+
+ desc = irq_data_get_msi_desc(irq_data);
+ if (!desc)
+ return NULL;
+
+ dev = msi_desc_to_dev(desc);
+
+ d = iommu_get_domain_for_dev(dev);
+ if (!d || (d->type == IOMMU_DOMAIN_DMA))
+ return NULL;
+
+ ret = iommu_domain_get_attr(d, DOMAIN_ATTR_MSI_MAPPING, NULL);
+ if (!ret)
+ return d;
+ else
+ return NULL;
+}
+#else
+static inline struct iommu_domain *
+irq_data_to_msi_mapping_domain(struct irq_data *irq_data)
+{
+ return NULL;
+}
+#endif /* CONFIG_IOMMU_API */
+
+/**
* msi_domain_set_affinity - Generic affinity setter function for MSI domains
* @irq_data: The irq data associated to the interrupt
* @mask: The affinity mask to set
@@ -73,8 +163,27 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
ret = parent->chip->irq_set_affinity(parent, mask, force);
if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
+ bool doorbell_change = false;
+ struct iommu_domain *d;
+ struct msi_msg old_msg;
+
+ d = irq_data_to_msi_mapping_domain(irq_data);
+ if (unlikely(d)) {
+ get_cached_msi_msg(irq_data->irq, &old_msg);
+ doorbell_change =
+ (old_msg.address_lo != msg.address_lo) ||
+ (old_msg.address_hi != msg.address_hi);
+ }
+
BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
+
+ if (unlikely(doorbell_change))
+ WARN_ON(msi_map_doorbell(d, &msg));
+
irq_chip_write_msi_msg(irq_data, &msg);
+
+ if (unlikely(doorbell_change))
+ msi_unmap_doorbell(d, &old_msg);
}
return ret;
@@ -83,19 +192,33 @@ int msi_domain_set_affinity(struct irq_data *irq_data,
static void msi_domain_activate(struct irq_domain *domain,
struct irq_data *irq_data)
{
+ struct iommu_domain *d;
struct msi_msg msg;
+ d = irq_data_to_msi_mapping_domain(irq_data);
+
BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
+ if (unlikely(d))
+ WARN_ON(msi_map_doorbell(d, &msg));
irq_chip_write_msi_msg(irq_data, &msg);
}
static void msi_domain_deactivate(struct irq_domain *domain,
struct irq_data *irq_data)
{
+ struct iommu_domain *d;
+ struct msi_msg old_msg;
struct msi_msg msg;
+ d = irq_data_to_msi_mapping_domain(irq_data);
+ if (unlikely(d))
+ get_cached_msi_msg(irq_data->irq, &old_msg);
+
memset(&msg, 0, sizeof(msg));
irq_chip_write_msi_msg(irq_data, &msg);
+
+ if (unlikely(d))
+ msi_unmap_doorbell(d, &old_msg);
}
static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
--
1.9.1
^ permalink raw reply related [flat|nested] 7+ messages in thread