ARM: GICv3: enable LPIs on the host

Now that the host part of the ITS code is in place, we can enable the
LPIs on each redistributor to get the show rolling.
At this point there would be no LPIs mapped, as guests don't know about
the ITS yet.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index a559e5e260e13a8c5a3ad59b82cdb08ab22843e0..eda34105762051d55d5065f1e900a098df819153 100644 (file)
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -620,6 +620,21 @@ static int gicv3_enable_redist(void)
     return 0;
 }
 
+/* Enable LPIs on this redistributor (only useful when the host has an ITS). */
+static bool gicv3_enable_lpis(void)
+{
+    uint32_t val;
+
+    val = readl_relaxed(GICD_RDIST_BASE + GICR_TYPER);
+    if ( !(val & GICR_TYPER_PLPIS) )
+        return false;
+
+    val = readl_relaxed(GICD_RDIST_BASE + GICR_CTLR);
+    writel_relaxed(val | GICR_CTLR_ENABLE_LPIS, GICD_RDIST_BASE + GICR_CTLR);
+
+    return true;
+}
+
 static int __init gicv3_populate_rdist(void)
 {
     int i;
@@ -731,11 +746,14 @@ static int gicv3_cpu_init(void)
     if ( gicv3_enable_redist() )
         return -ENODEV;
 
+    /* If the host has any ITSes, enable LPIs now. */
     if ( gicv3_its_host_has_its() )
     {
         ret = gicv3_its_setup_collection(smp_processor_id());
         if ( ret )
             return ret;
+        if ( !gicv3_enable_lpis() )
+            return -EBUSY;
     }
 
     /* Set priority on PPI and SGI interrupts */