[PATCH] x86/irq: do not insert IRQ_MSI_EMU in emuirq mappings

[Xenia Ragiadakou <xenia.ragiadakou@xxxxxxx>]

Do not use emuirq mappings for MSIs injected by emulated devices.
This kind of pirq shares the same emuirq value and is not remapped.

Fixes: 88fccdd11ca0 ('xen: event channel remapping for emulated MSIs')
Signed-off-by: Xenia Ragiadakou <xenia.ragiadakou@xxxxxxx>
---

Question: is there any strong reason why Linux HVM guests still use pirqs?

 xen/arch/x86/irq.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index f42ad539dc..cdc8dc5a55 100644
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -2684,7 +2684,7 @@ int map_domain_emuirq_pirq(struct domain *d, int pirq, 
int emuirq)
     }
 
     old_emuirq = domain_pirq_to_emuirq(d, pirq);
-    if ( emuirq != IRQ_PT )
+    if ( (emuirq != IRQ_PT) && (emuirq != IRQ_MSI_EMU) )
         old_pirq = domain_emuirq_to_pirq(d, emuirq);
 
     if ( (old_emuirq != IRQ_UNBOUND && (old_emuirq != emuirq) ) ||
@@ -2699,8 +2699,8 @@ int map_domain_emuirq_pirq(struct domain *d, int pirq, 
int emuirq)
     if ( !info )
         return -ENOMEM;
 
-    /* do not store emuirq mappings for pt devices */
-    if ( emuirq != IRQ_PT )
+    /* do not store emuirq mappings for pt devices and emulated MSIs */
+    if ( (emuirq != IRQ_PT) && (emuirq != IRQ_MSI_EMU) )
     {
         int err = radix_tree_insert(&d->arch.hvm.emuirq_pirq, emuirq,
                                     radix_tree_int_to_ptr(pirq));
@@ -2753,7 +2753,7 @@ int unmap_domain_pirq_emuirq(struct domain *d, int pirq)
         info->arch.hvm.emuirq = IRQ_UNBOUND;
         pirq_cleanup_check(info, d);
     }
-    if ( emuirq != IRQ_PT )
+    if ( (emuirq != IRQ_PT) && (emuirq != IRQ_MSI_EMU) )
         radix_tree_delete(&d->arch.hvm.emuirq_pirq, emuirq);
 
  done:
-- 
2.34.1