From: Alexander Graf <agraf@suse.de>
To: Christian Borntraeger <borntraeger@de.ibm.com>,
Jens Freimann <jfrei@linux.vnet.ibm.com>,
Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/5] s390x/gdb: don't touch the cc if tcg is not enabled
Date: Wed, 03 Sep 2014 11:27:10 +0200 [thread overview]
Message-ID: <5406DEEE.6080705@suse.de> (raw)
In-Reply-To: <54056CAA.2000201@de.ibm.com>
On 02.09.14 09:07, Christian Borntraeger wrote:
> On 02/09/14 00:39, Alexander Graf wrote:
>>
>>
>> On 29.08.14 15:52, Jens Freimann wrote:
>>> From: David Hildenbrand <dahi@linux.vnet.ibm.com>
>>>
>>> When reading/writing the psw mask, the condition code may only be touched if
>>> running on tcg.
>>
>> Why? Shouldn't we be able to set CC from gdb as well?
>>
>
> You can. What this patch does (and the patch description is a bit vague here) is to not modify the PSW it gets from KVM when passing it to gdb:
> The qemu core gets the PSW from KVM. Without this patch, we use cc_op to calculate the current CC of the PSW (No idea of TCG, I guess its evaluated lazy - at least this is how valgrind works). This is wrong for the KVM case, as cc_op does not contain any useful data for the KVM case. With this patch we simply pass the psw from KVM to gdb and back.
>
> The symptom was that the cc was always shown as zero.
Ah, I see. I agree with the patch, but the patch description does not
actually describe what the patch does. Please rework it.
I also wouldn't mind if instead of hard coding this logic in the
gdbstub, we'd extract it as helper functions to read and write the
PSW.MASK in cpu.h.
Alex
next prev parent reply other threads:[~2014-09-03 9:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-29 13:52 [Qemu-devel] [PATCH 0/5] s390x/gdb: various fixes Jens Freimann
2014-08-29 13:52 ` [Qemu-devel] [PATCH 1/5] s390x/gdb: don't touch the cc if tcg is not enabled Jens Freimann
2014-09-01 22:39 ` Alexander Graf
2014-09-02 7:07 ` Christian Borntraeger
2014-09-03 9:27 ` Alexander Graf [this message]
2014-09-05 7:29 ` Christian Borntraeger
2014-08-29 13:52 ` [Qemu-devel] [PATCH 2/5] s390x/gdb: add the feature xml files for s390x Jens Freimann
2014-08-29 13:52 ` [Qemu-devel] [PATCH 3/5] s390x/gdb: generate target.xml and handle fp/ac as coprocessors Jens Freimann
2014-08-29 13:52 ` [Qemu-devel] [PATCH 4/5] s390x/gdb: coding style fixes Jens Freimann
2014-08-29 13:52 ` [Qemu-devel] [PATCH 5/5] gdb: provide the name of the architecture in the target.xml Jens Freimann
2014-09-01 10:19 ` Peter Maydell
2014-09-01 10:25 ` Andreas Färber
2014-09-01 10:31 ` Christian Borntraeger
2014-09-01 10:32 ` Peter Maydell
2014-09-03 9:37 ` David Hildenbrand
2014-09-03 9:45 ` Edgar E. Iglesias
2014-09-03 9:59 ` David Hildenbrand
2014-09-03 10:00 ` Edgar E. Iglesias
2014-09-01 10:06 ` [Qemu-devel] [PATCH 0/5] s390x/gdb: various fixes Christian Borntraeger
2014-09-01 22:43 ` Alexander Graf
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