[Qemu-devel] [PATCH] PPC: openpic_kvm: Only map first occurence in address space

[Qemu-devel] [PATCH] PPC: openpic_kvm: Only map first occurence in address space

[Alexander Graf]

The in-kernel OpenPIC emulation only supports a single map. However, we
map the OpenPIC at 2 locations: The CPU visible one and the PCI visible
one. For KVM acceleration, we only care about the first one.

To make sure that we only map that first mapping and not the PCI map that
happens dynamically later during bootup, ignore maps that happen when
we are already considering ourselves mapped.

Credits due are to Bogdan and Mihai for debugging this.

Reported-by: Bogdan Purcareata <bogdan.purcareata@freescale.com>
Reported-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 hw/intc/openpic_kvm.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/hw/intc/openpic_kvm.c b/hw/intc/openpic_kvm.c
index e3bce04..3e2cd18 100644
--- a/hw/intc/openpic_kvm.c
+++ b/hw/intc/openpic_kvm.c
@@ -45,6 +45,7 @@ typedef struct KVMOpenPICState {
     MemoryListener mem_listener;
     uint32_t fd;
     uint32_t model;
+    hwaddr mapped;
 } KVMOpenPICState;
 
 static void kvm_openpic_set_irq(void *opaque, int n_IRQ, int level)
@@ -128,7 +129,16 @@ static void kvm_openpic_region_add(MemoryListener *listener,
         return;
     }
 
+    if (opp->mapped) {
+        /*
+         * We can only map the MPIC once. Since we are already mapped,
+         * the best we can do is ignore new maps.
+         */
+        return;
+    }
+
     reg_base = section->offset_within_address_space;
+    opp->mapped = reg_base;
 
     attr.group = KVM_DEV_MPIC_GRP_MISC;
     attr.attr = KVM_DEV_MPIC_BASE_ADDR;
@@ -155,6 +165,15 @@ static void kvm_openpic_region_del(MemoryListener *listener,
         return;
     }
 
+    if (section->offset_within_address_space != opp->mapped) {
+        /*
+         * We can only map the MPIC once. This mapping was a secondary
+         * one that we couldn't fulfill. Ignore it.
+         */
+        return;
+    }
+    opp->mapped = 0;
+
     attr.group = KVM_DEV_MPIC_GRP_MISC;
     attr.attr = KVM_DEV_MPIC_BASE_ADDR;
     attr.addr = (uint64_t)(unsigned long)&reg_base;
-- 
1.8.1.4