[Xen-devel] [PATCH 2/5] x86/ioapic: introduce helper to fetch triggering mode of GSI

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

This helper is used in order to fetch the triggering mode of a GSI. This is
needed in order to figure out if a GSI can be bound with the shared attribute
or not (only level triggered interrupts should be shared).

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/io_apic.c        | 22 ++++++++++++++++++++++
 xen/include/asm-x86/io_apic.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/xen/arch/x86/io_apic.c b/xen/arch/x86/io_apic.c
index d18046067c..df5bc52392 100644
--- a/xen/arch/x86/io_apic.c
+++ b/xen/arch/x86/io_apic.c
@@ -2261,6 +2261,28 @@ int io_apic_set_pci_routing (int ioapic, int pin, int 
irq, int edge_level, int a
     return 0;
 }
 
+unsigned int io_apic_get_gsi_trigger(unsigned int gsi)
+{
+    struct IO_APIC_route_entry entry;
+    unsigned int ioapic, base_gsi;
+
+    ASSERT(gsi < nr_irqs_gsi);
+
+    /* For GSI type find if the GSI is level or edge triggered */
+    for ( ioapic = 0; ioapic < nr_ioapics; ioapic++ )
+    {
+        base_gsi = io_apic_gsi_base(ioapic);
+
+        if ( gsi >= base_gsi && gsi < base_gsi + nr_ioapic_entries[ioapic] )
+            break;
+    }
+    ASSERT(ioapic < nr_ioapics);
+
+    entry = ioapic_read_entry(ioapic, gsi - base_gsi, 0);
+
+    return entry.trigger;
+}
+
 static int ioapic_physbase_to_id(unsigned long physbase)
 {
     int apic;
diff --git a/xen/include/asm-x86/io_apic.h b/xen/include/asm-x86/io_apic.h
index 8029c8f400..43bcb656ee 100644
--- a/xen/include/asm-x86/io_apic.h
+++ b/xen/include/asm-x86/io_apic.h
@@ -179,6 +179,7 @@ extern int io_apic_get_unique_id (int ioapic, int apic_id);
 extern int io_apic_get_version (int ioapic);
 extern int io_apic_get_redir_entries (int ioapic);
 extern int io_apic_set_pci_routing (int ioapic, int pin, int irq, int 
edge_level, int active_high_low);
+extern unsigned int io_apic_get_gsi_trigger(unsigned int gsi);
 
 extern void init_ioapic_mappings(void);
 
-- 
2.12.1


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