[Xen-changelog] [xen staging] AMD/IOMMU: allow enabling with IRQ not yet set up

[patchbot@xxxxxxx]

commit 5f569f1ac50eff9dc95ac2e4a617de657d254b52
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jul 31 13:19:27 2019 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jul 31 13:19:27 2019 +0200

    AMD/IOMMU: allow enabling with IRQ not yet set up
    
    Early enabling (to enter x2APIC mode) requires deferring of the IRQ
    setup. Code to actually do that setup in the x2APIC case will get added
    subsequently.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Brian Woods <brian.woods@xxxxxxx>
---
 xen/drivers/passthrough/amd/iommu_init.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu_init.c 
b/xen/drivers/passthrough/amd/iommu_init.c
index bc7e4270c7..02c27ab0f1 100644
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -813,7 +813,6 @@ static void amd_iommu_erratum_746_workaround(struct 
amd_iommu *iommu)
 static void enable_iommu(struct amd_iommu *iommu)
 {
     unsigned long flags;
-    struct irq_desc *desc;
 
     spin_lock_irqsave(&iommu->lock, flags);
 
@@ -833,19 +832,27 @@ static void enable_iommu(struct amd_iommu *iommu)
     if ( iommu->features.flds.ppr_sup )
         register_iommu_ppr_log_in_mmio_space(iommu);
 
-    desc = irq_to_desc(iommu->msi.irq);
-    spin_lock(&desc->lock);
-    set_msi_affinity(desc, NULL);
-    spin_unlock(&desc->lock);
+    if ( iommu->msi.irq > 0 )
+    {
+        struct irq_desc *desc = irq_to_desc(iommu->msi.irq);
+
+        spin_lock(&desc->lock);
+        set_msi_affinity(desc, NULL);
+        spin_unlock(&desc->lock);
+    }
 
     amd_iommu_msi_enable(iommu, IOMMU_CONTROL_ENABLED);
 
     set_iommu_ht_flags(iommu);
     set_iommu_command_buffer_control(iommu, IOMMU_CONTROL_ENABLED);
-    set_iommu_event_log_control(iommu, IOMMU_CONTROL_ENABLED);
 
-    if ( iommu->features.flds.ppr_sup )
-        set_iommu_ppr_log_control(iommu, IOMMU_CONTROL_ENABLED);
+    if ( iommu->msi.irq > 0 )
+    {
+        set_iommu_event_log_control(iommu, IOMMU_CONTROL_ENABLED);
+
+        if ( iommu->features.flds.ppr_sup )
+            set_iommu_ppr_log_control(iommu, IOMMU_CONTROL_ENABLED);
+    }
 
     if ( iommu->features.flds.gt_sup )
         set_iommu_guest_translation_control(iommu, IOMMU_CONTROL_ENABLED);
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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