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[Qemu-devel] [PATCH v2 7/8] pc: port 92 reset requires a low->high trans
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH v2 7/8] pc: port 92 reset requires a low->high transition |
Date: |
Fri, 2 May 2014 16:33:21 +0200 |
The PIIX datasheet says that "before another INIT pulse can be
generated via [port 92h], [bit 0] must be written back to a
zero.
This bug is masked right now because a full reset will clear the
value of port 92h. But once we implement soft reset correctly,
the next attempt to enable the A20 line by setting bit 1 (and
leaving the others untouched) will cause another reset.
Reviewed-by: Anthony Liguori <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
hw/i386/pc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 14f0d91..a59e958 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -471,11 +471,12 @@ static void port92_write(void *opaque, hwaddr addr,
uint64_t val,
unsigned size)
{
Port92State *s = opaque;
+ int oldval = s->outport;
DPRINTF("port92: write 0x%02x\n", val);
s->outport = val;
qemu_set_irq(*s->a20_out, (val >> 1) & 1);
- if (val & 1) {
+ if ((val & 1) && !(oldval & 1)) {
qemu_system_reset_request();
}
}
--
1.8.3.1
- [Qemu-devel] [PATCH v2 1/8] kvm: reset state from the CPU's reset method, (continued)
- [Qemu-devel] [PATCH v2 1/8] kvm: reset state from the CPU's reset method, Paolo Bonzini, 2014/05/02
- [Qemu-devel] [PATCH v2 3/8] target-i386: fix set of registers zeroed on reset, Paolo Bonzini, 2014/05/02
- [Qemu-devel] [PATCH v2 4/8] target-i386: preserve FPU and MSR state on INIT, Paolo Bonzini, 2014/05/02
- [Qemu-devel] [PATCH v2 5/8] apic: do not accept SIPI on the bootstrap processor, Paolo Bonzini, 2014/05/02
- [Qemu-devel] [PATCH v2 2/8] kvm: forward INIT signals coming from the chipset, Paolo Bonzini, 2014/05/02
- [Qemu-devel] [PATCH v2 7/8] pc: port 92 reset requires a low->high transition,
Paolo Bonzini <=
- [Qemu-devel] [PATCH v2 6/8] cpu: make CPU_INTERRUPT_RESET available on all targets, Paolo Bonzini, 2014/05/02
- Re: [Qemu-devel] [PATCH v2 6/8] cpu: make CPU_INTERRUPT_RESET available on all targets, Peter Maydell, 2014/05/23