diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2022-05-05 11:18:42 +0100 |
|---|---|---|
| committer | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2022-06-11 11:36:14 +0200 |
| commit | 0c285e01280d9bccda36717bad369082356cf8f4 (patch) | |
| tree | 5b0844921d2e40f74add79d1efbbb401f745af36 /hw/mips | |
| parent | 8e0e23445acdf1cfbe7714f685c4a7404b3fa467 (diff) | |
hw/block/fdc-sysbus: Always mark sysbus floppy controllers as not having DMA
The sysbus floppy controllers (devices sysbus-fdc and sun-fdtwo)
don't support DMA. The core floppy controller code expects this to
be indicated by setting FDCtrl::dma_chann to -1. This used to be
done in the device instance_init functions sysbus_fdc_initfn() and
sun4m_fdc_initfn(), but in commit 1430759ec3e we refactored this code
and accidentally lost the setting of dma_chann.
For sysbus-fdc this has no ill effects because we were redundantly
also setting dma_chann in fdctrl_init_sysbus(), but for sun-fdtwo
this means that guests which try to enable DMA on the floppy
controller will cause QEMU to crash because FDCtrl::dma is NULL.
Set dma_chann to -1 in the common instance init, and remove the
redundant code in fdctrl_init_sysbus() that is also setting it.
There is a six-year-old FIXME comment in the jazz board code to the
effect that in theory it should support doing DMA via a custom DMA
controller. If anybody ever chooses to fix that they can do it by
adding support for setting both FDCtrl::dma_chann and FDCtrl::dma.
(A QOM link property 'dma-controller' on the sysbus device which can
be set to an instance of IsaDmaClass is probably the way to go.)
Fixes: 1430759ec3 ("hw/block/fdc: Extract SysBus floppy controllers to fdc-sysbus.c")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/958
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220505101842.2757905-1-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Diffstat (limited to 'hw/mips')
| -rw-r--r-- | hw/mips/jazz.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/mips/jazz.c b/hw/mips/jazz.c index 6598d7dddd..96dc6ab32d 100644 --- a/hw/mips/jazz.c +++ b/hw/mips/jazz.c @@ -353,7 +353,7 @@ static void mips_jazz_init(MachineState *machine, fds[n] = drive_get(IF_FLOPPY, 0, n); } /* FIXME: we should enable DMA with a custom IsaDma device */ - fdctrl_init_sysbus(qdev_get_gpio_in(rc4030, 1), -1, 0x80003000, fds); + fdctrl_init_sysbus(qdev_get_gpio_in(rc4030, 1), 0x80003000, fds); /* Real time clock */ mc146818_rtc_init(isa_bus, 1980, NULL); |