[v8 7/9] iommu, x86: Setup Posted-Interrupts capability for Intel iommu

[Feng Wu]

Set Posted-Interrupts capability for Intel iommu when IR is enabled,
clear it when IR is disabled.

Signed-off-by: Feng Wu <feng...@intel.com>
---
 drivers/iommu/intel_irq_remapping.c | 30 ++++++++++++++++++++++++++++++
 drivers/iommu/irq_remapping.c       |  2 ++
 drivers/iommu/irq_remapping.h       |  3 +++
 3 files changed, 35 insertions(+)

diff --git a/drivers/iommu/intel_irq_remapping.c 
b/drivers/iommu/intel_irq_remapping.c
index d230edc..c21a2a9 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -581,6 +581,26 @@ error:
        return -ENODEV;
 }
 
+/*
+ * Set Posted-Interrupts capability.
+ */
+static inline void set_irq_posting_cap(void)
+{
+       struct dmar_drhd_unit *drhd;
+       struct intel_iommu *iommu;
+
+       if (!disable_irq_post) {
+               intel_irq_remap_ops.capability |= 1 << IRQ_POSTING_CAP;
+
+               for_each_iommu(iommu, drhd)
+                       if (!cap_pi_support(iommu->cap)) {
+                               intel_irq_remap_ops.capability &=
+                                               ~(1 << IRQ_POSTING_CAP);
+                               break;
+                       }
+       }
+}
+
 static int __init intel_enable_irq_remapping(void)
 {
        struct dmar_drhd_unit *drhd;
@@ -656,6 +676,8 @@ static int __init intel_enable_irq_remapping(void)
 
        irq_remapping_enabled = 1;
 
+       set_irq_posting_cap();
+
        pr_info("Enabled IRQ remapping in %s mode\n", eim ? "x2apic" : "xapic");
 
        return eim ? IRQ_REMAP_X2APIC_MODE : IRQ_REMAP_XAPIC_MODE;
@@ -856,6 +878,12 @@ static void disable_irq_remapping(void)
 
                iommu_disable_irq_remapping(iommu);
        }
+
+       /*
+        * Clear Posted-Interrupts capability.
+        */
+       if (!disable_irq_post)
+               intel_irq_remap_ops.capability &= ~(1 << IRQ_POSTING_CAP);
 }
 
 static int reenable_irq_remapping(int eim)
@@ -883,6 +911,8 @@ static int reenable_irq_remapping(int eim)
        if (!setup)
                goto error;
 
+       set_irq_posting_cap();
+
        return 0;
 
 error:
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index fc78b0d..ed605a9 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -22,6 +22,8 @@ int irq_remap_broken;
 int disable_sourceid_checking;
 int no_x2apic_optout;
 
+int disable_irq_post = 1;
+
 static int disable_irq_remap;
 static struct irq_remap_ops *remap_ops;
 
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index b6ca30d..039c7af 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -34,6 +34,8 @@ extern int disable_sourceid_checking;
 extern int no_x2apic_optout;
 extern int irq_remapping_enabled;
 
+extern int disable_irq_post;
+
 struct irq_remap_ops {
        /* The supported capabilities */
        int capability;
@@ -69,6 +71,7 @@ extern void ir_ack_apic_edge(struct irq_data *data);
 
 #define irq_remapping_enabled 0
 #define irq_remap_broken      0
+#define disable_irq_post      1
 
 #endif /* CONFIG_IRQ_REMAP */
 
-- 
2.1.0

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