diff options
| author | Matthew Ogilvie <mmogilvi_qemu@miniinfo.net> | 2012-08-23 00:24:43 -0600 |
|---|---|---|
| committer | malc <av1474@comtv.ru> | 2012-08-24 07:44:39 +0400 |
| commit | f278d4947fff814dcde2ef2acad36d172ff8be35 (patch) | |
| tree | c483f5871bb83294728a3b3026206c56ad7485a9 /hw | |
| parent | 482f7bf86b43af9f6903c52726fedf82b28bf953 (diff) | |
i8259: add -no-spurious-interrupt-hack option
This patch provides a way to optionally suppress spurious interrupts,
as a workaround for systems described below:
Some old operating systems do not handle spurious interrupts well,
and qemu tends to generate them significantly more often than
real hardware.
Examples:
- Microport UNIX System V/386 v 2.1 (ca 1987)
(The main problem I'm fixing: Without this patch, it panics
sporadically when accessing the hard disk.)
- AT&T UNIX System V/386 Release 4.0 Version 2.1a (ca 1991)
See screenshot in "QEMU Official OS Support List":
http://www.claunia.com/qemu/objectManager.php?sClass=application&iId=9
(I don't have this system to test.)
- A report about OS/2 boot lockup from 2004 by Hampa Hug:
http://lists.nongnu.org/archive/html/qemu-devel/2004-09/msg00367.html
(My patch was partially inspired by his.)
Also: http://lists.nongnu.org/archive/html/qemu-devel/2005-06/msg00243.html
(I don't have this system to test.)
Signed-off-by: Matthew Ogilvie <mmogilvi_qemu@miniinfo.net>
Signed-off-by: malc <av1474@comtv.ru>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/i8259.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/hw/i8259.c b/hw/i8259.c index 65876662a1..7ecb7e1de6 100644 --- a/hw/i8259.c +++ b/hw/i8259.c @@ -26,6 +26,7 @@ #include "isa.h" #include "monitor.h" #include "qemu-timer.h" +#include "sysemu.h" #include "i8259_internal.h" /* debug PIC */ @@ -193,6 +194,20 @@ int pic_read_irq(DeviceState *d) pic_intack(slave_pic, irq2); } else { /* spurious IRQ on slave controller */ + if (no_spurious_interrupt_hack) { + /* Pretend it was delivered and acknowledged. If + * it was spurious due to slave_pic->imr, then + * as soon as the mask is cleared, the slave will + * re-trigger IRQ2 on the master. If it is spurious for + * some other reason, make sure we don't keep trying + * to half-process the same spurious interrupt over + * and over again. + */ + s->irr &= ~(1<<irq); + s->last_irr &= ~(1<<irq); + s->isr &= ~(1<<irq); + return -1; + } irq2 = 7; } intno = slave_pic->irq_base + irq2; @@ -202,6 +217,9 @@ int pic_read_irq(DeviceState *d) pic_intack(s, irq); } else { /* spurious IRQ on host controller */ + if (no_spurious_interrupt_hack) { + return -1; + } irq = 7; intno = s->irq_base + irq; } |