[Qemu-devel] [PATCH 1/2] qemu kvm: Set up gsi bitmap correctly

[Jason Baron]

The current 'kvm_init_irq_routing()' doesn't set up the gsi bitmap
correctly, and as a consequence pins max_gsi to 32 when it really
should be 1024. I ran into this limitation while testing pci
passthrough, where I consistently would get -ENOSPACE return from
kvm_get_irq_route_gsi() in assigned_dev_update_msix_mmio().

Signed-off-by: Jason Baron <address@hidden>
---
 kvm-all.c  |    4 ++--
 qemu-kvm.c |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kvm-all.c b/kvm-all.c
index ab88c7c..7d602af 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -873,9 +873,9 @@ static void kvm_init_irq_routing(KVMState *s)
         unsigned int gsi_bits, i;
 
         /* Round up so we can search ints using ffs */
-        gsi_bits = (gsi_count + 31) / 32;
+        gsi_bits = ALIGN(gsi_count, 32);
         s->used_gsi_bitmap = g_malloc0(gsi_bits / 8);
-        s->max_gsi = gsi_bits;
+        s->max_gsi = gsi_count;
 
         /* Mark any over-allocated bits as already in use */
         for (i = gsi_count; i < gsi_bits; i++) {
diff --git a/qemu-kvm.c b/qemu-kvm.c
index 2047ebb..b17cae0 100644
--- a/qemu-kvm.c
+++ b/qemu-kvm.c
@@ -249,7 +249,7 @@ int kvm_get_irq_route_gsi(void)
     uint32_t *buf = s->used_gsi_bitmap;
 
     /* Return the lowest unused GSI in the bitmap */
-    for (i = 0; i < s->max_gsi / 32; i++) {
+    for (i = 0; i < (ALIGN(s->max_gsi, 32) / 32); i++) {
         bit = ffs(~buf[i]);
         if (!bit) {
             continue;
-- 
1.7.1