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[Qemu-devel] [PATCH v2 07/18] s390x/tcg: tolerate wrong wakeups due to f
From: |
David Hildenbrand |
Subject: |
[Qemu-devel] [PATCH v2 07/18] s390x/tcg: tolerate wrong wakeups due to floating interrupts |
Date: |
Wed, 17 Jan 2018 18:40:36 +0100 |
This is a prparation for floating interrupt support and only applies to
MTTCG, single threaded TCG works just fine. If a floating interrupt wakes
up a VCPU and the CPU thinks it can run (clearing cs->halted), at
the point where the interrupt would be delivered, already another VCPU
might have picked up the interrupt, resulting in a wakeup without an
interrupt (executing wrong code).
It is wrong to let the VCPU continue to execute (the WAIT PSW). Instead,
we have to put the VCPU back to sleep.
Signed-off-by: David Hildenbrand <address@hidden>
---
target/s390x/excp_helper.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
index a18842ccbd..eeffb49f63 100644
--- a/target/s390x/excp_helper.c
+++ b/target/s390x/excp_helper.c
@@ -503,6 +503,11 @@ bool s390_cpu_exec_interrupt(CPUState *cs, int
interrupt_request)
s390_cpu_do_interrupt(cs);
return true;
}
+ if (env->psw.mask & PSW_MASK_WAIT) {
+ /* Woken up because of a floating interrupt but it has already
+ * been delivered. Go back to sleep. */
+ cpu_interrupt(CPU(cpu), CPU_INTERRUPT_HALT);
+ }
}
return false;
}
--
2.14.3
- [Qemu-devel] [PATCH v2 00/18] s390x: flic rework, tcg flic support and STSI, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 01/18] s390x/tcg: deliver multiple interrupts in a row, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 02/18] s390x/flic: simplify flic initialization, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 03/18] s390x/tcg: simplify lookup of flic, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 04/18] s390x/tcg: simplify machine check handling, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 05/18] s390x/flic: factor out injection of floating interrupts, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 06/18] s390x/flic: no need to call s390_io_interrupt() from flic, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 07/18] s390x/tcg: tolerate wrong wakeups due to floating interrupts,
David Hildenbrand <=
- [Qemu-devel] [PATCH v2 09/18] s390x/tcg: implement TEST PENDING INTERRUPTION, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 10/18] s390x/flic: implement qemu_s390_clear_io_flic(), David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 08/18] s390x/flic: make floating interrupts on TCG actually floating, David Hildenbrand, 2018/01/17
- [Qemu-devel] [PATCH v2 12/18] s390x: fix size + content of STSI blocks, David Hildenbrand, 2018/01/17