[Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Running "qemu-system-ppc64 -machine prep -device i82374" creates an ISA
bus with two i82374 DMA controllers - one is implicit from ppc_prep_init(),
the other one is from "-device i82374". QEMU asserts but it is not
immediately clear why.

This adds an error message to explain the failure.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---


Better phase suggestions are welcome. Thanks!


---
 hw/isa/isa-bus.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hw/isa/isa-bus.c b/hw/isa/isa-bus.c
index 348e0eab9d..553707b18d 100644
--- a/hw/isa/isa-bus.c
+++ b/hw/isa/isa-bus.c
@@ -107,7 +107,10 @@ void isa_connect_gpio_out(ISADevice *isadev, int gpioirq, int isairq)
 void isa_bus_dma(ISABus *bus, IsaDma *dma8, IsaDma *dma16)
 {
     assert(bus && dma8 && dma16);
-    assert(!bus->dma[0] && !bus->dma[1]);
+    if (bus->dma[0] || bus->dma[1]) {
+        error_setg(&error_fatal,
+                   "DMA is already set to ISA bus, duplicated DMA controller?");
+    }
     bus->dma[0] = dma8;
     bus->dma[1] = dma16;
 }
-- 
2.11.0