* [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report
@ 2017-10-26 8:00 Alexey Kardashevskiy
2017-11-06 10:54 ` Markus Armbruster
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Alexey Kardashevskiy @ 2017-10-26 8:00 UTC (permalink / raw)
To: qemu-devel; +Cc: Alexey Kardashevskiy
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
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report
2017-10-26 8:00 [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report Alexey Kardashevskiy
@ 2017-11-06 10:54 ` Markus Armbruster
2017-11-06 11:07 ` Peter Maydell
2017-11-07 0:49 ` John Snow
2 siblings, 0 replies; 4+ messages in thread
From: Markus Armbruster @ 2017-11-06 10:54 UTC (permalink / raw)
To: Alexey Kardashevskiy; +Cc: qemu-devel
Alexey Kardashevskiy <aik@ozlabs.ru> writes:
> 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;
> }
Quote include/qapi/error.h:
* Please don't error_setg(&error_fatal, ...), use error_report() and
* exit(), because that's more obvious.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report
2017-10-26 8:00 [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report Alexey Kardashevskiy
2017-11-06 10:54 ` Markus Armbruster
@ 2017-11-06 11:07 ` Peter Maydell
2017-11-07 0:49 ` John Snow
2 siblings, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2017-11-06 11:07 UTC (permalink / raw)
To: Alexey Kardashevskiy; +Cc: QEMU Developers
On 26 October 2017 at 09:00, Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
> 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>
Does it ever make sense for the user to try to create this
device on the command line? If not, maybe we should set
it to dc->user_creatable = false; ?
If it can be usefully user-created, then rather than being
a fatal error in this function the error should be passed
back up so that we can fail the 'realize' method of the device.
thanks
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report
2017-10-26 8:00 [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report Alexey Kardashevskiy
2017-11-06 10:54 ` Markus Armbruster
2017-11-06 11:07 ` Peter Maydell
@ 2017-11-07 0:49 ` John Snow
2 siblings, 0 replies; 4+ messages in thread
From: John Snow @ 2017-11-07 0:49 UTC (permalink / raw)
To: Alexey Kardashevskiy, qemu-devel; +Cc: Eric Blake, Markus Armbruster
On 10/26/2017 04:00 AM, Alexey Kardashevskiy wrote:
> 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;
> }
>
I suppose it's an improvement strictly, but really we're just naming a
runtime assertion here. We should be avoiding the assertion -- and then
how valuable is the error message?
Is this something we anticipate can never be fixed? (I.e. exclusively
the cause of asking for impossible configurations?)
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-11-07 0:49 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-10-26 8:00 [Qemu-devel] [PATCH qemu] isa-bus: Replace assert() about DMA with error report Alexey Kardashevskiy
2017-11-06 10:54 ` Markus Armbruster
2017-11-06 11:07 ` Peter Maydell
2017-11-07 0:49 ` John Snow
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