[PATCH 0/2] iommu/amd: Correctly Align Multiple MSI IRQs

[PATCH 0/2] iommu/amd: Correctly Align Multiple MSI IRQs

[Joerg Roedel]

Hi,

Thomas made me recently aware of the fact that the IRQ
remapping code in the AMD IOMMU driver does not enforce the
required alignment of IRQ indexes for multiple MSI IRQs.

This patch-set adds the correct alignment for these IRQs.

Regards,

	Joerg

Joerg Roedel (2):
  iommu/amd: Add align parameter to alloc_irq_index()
  iommu/amd: Enforce alignment for MSI IRQs

 drivers/iommu/amd_iommu.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

-- 
2.7.4

[PATCH 1/2] iommu/amd: Add align parameter to alloc_irq_index()

[Joerg Roedel]

From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

For multi-MSI IRQ ranges the IRQ index needs to be aligned
to the power-of-two of the requested IRQ count. Extend the
alloc_irq_index() function to allow such an allocation.

Reported-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Fixes: 2b324506341cb ('iommu/amd: Add routines to manage irq remapping tables')
Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
---
 drivers/iommu/amd_iommu.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 51f8215..2d4ee25 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3660,11 +3660,11 @@ static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic)
 	return table;
 }
 
-static int alloc_irq_index(u16 devid, int count)
+static int alloc_irq_index(u16 devid, int count, bool align)
 {
 	struct irq_remap_table *table;
+	int index, c, alignment = 1;
 	unsigned long flags;
-	int index, c;
 	struct amd_iommu *iommu = amd_iommu_rlookup_table[devid];
 
 	if (!iommu)
@@ -3674,16 +3674,22 @@ static int alloc_irq_index(u16 devid, int count)
 	if (!table)
 		return -ENODEV;
 
+	if (align)
+		alignment = roundup_pow_of_two(count);
+
 	spin_lock_irqsave(&table->lock, flags);
 
 	/* Scan table for free entries */
-	for (c = 0, index = table->min_index;
+	for (index = ALIGN(table->min_index, alignment), c = 0;
 	     index < MAX_IRQS_PER_TABLE;
-	     ++index) {
-		if (!iommu->irte_ops->is_allocated(table, index))
+	     index++) {
+		if (!iommu->irte_ops->is_allocated(table, index)) {
 			c += 1;
-		else
-			c = 0;
+		} else {
+			c     = 0;
+			index = ALIGN(index, alignment);
+			continue;
+		}
 
 		if (c == count)	{
 			for (; c != 0; --c)
@@ -4096,7 +4102,7 @@ static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
 		else
 			ret = -ENOMEM;
 	} else {
-		index = alloc_irq_index(devid, nr_irqs);
+		index = alloc_irq_index(devid, nr_irqs, false);
 	}
 	if (index < 0) {
 		pr_warn("Failed to allocate IRTE\n");
-- 
2.7.4

Re: [PATCH 1/2] iommu/amd: Add align parameter to alloc_irq_index()

[Thomas Gleixner]

On Fri, 6 Oct 2017, Joerg Roedel wrote:

> From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> 
> For multi-MSI IRQ ranges the IRQ index needs to be aligned
> to the power-of-two of the requested IRQ count. Extend the
> alloc_irq_index() function to allow such an allocation.
> 
> Reported-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
> Fixes: 2b324506341cb ('iommu/amd: Add routines to manage irq remapping tables')
> Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>

[PATCH 2/2] iommu/amd: Enforce alignment for MSI IRQs

[Joerg Roedel]

From: Joerg Roedel <jroedel@suse.de>

Make use of the new alignment capability of
alloc_irq_index() to enforce IRQ index alignment
for MSI.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Fixes: 2b324506341cb ('iommu/amd: Add routines to manage irq remapping tables')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/iommu/amd_iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 2d4ee25..cb7c531 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -4102,7 +4102,9 @@ static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
 		else
 			ret = -ENOMEM;
 	} else {
-		index = alloc_irq_index(devid, nr_irqs, false);
+		bool align = (info->type == X86_IRQ_ALLOC_TYPE_MSI);
+
+		index = alloc_irq_index(devid, nr_irqs, align);
 	}
 	if (index < 0) {
 		pr_warn("Failed to allocate IRTE\n");
-- 
2.7.4

Re: [PATCH 2/2] iommu/amd: Enforce alignment for MSI IRQs

[Thomas Gleixner]

On Fri, 6 Oct 2017, Joerg Roedel wrote:

> From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
> 
> Make use of the new alignment capability of
> alloc_irq_index() to enforce IRQ index alignment
> for MSI.
> 
> Reported-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
> Fixes: 2b324506341cb ('iommu/amd: Add routines to manage irq remapping tables')
> Signed-off-by: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>

Reviewed-by: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>