From: Thomas Huth <thuth@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Richard Henderson <richard.henderson@linaro.org>
Cc: qemu-s390x <qemu-s390x@nongnu.org>,
Eric Farman <farman@linux.ibm.com>,
Cornelia Huck <cohuck@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: getting the console output for s390 cdrom-test?
Date: Fri, 12 Feb 2021 15:10:40 +0100 [thread overview]
Message-ID: <64011f66-3911-131a-700c-cac504b4e0cc@redhat.com> (raw)
In-Reply-To: <CAFEAcA99R8Fc1+S2SS31KAA8tsGx-BSgP5FaH37fYeE4gJa0Sw@mail.gmail.com>
On 12/02/2021 13.05, Peter Maydell wrote:
> On Fri, 12 Feb 2021 at 11:45, Thomas Huth <thuth@redhat.com> wrote:
>> I guess Cornelia simply meant a:
>>
>> asm volatile("nop":::"memory");
>
> That will force the compiler not to reorder, but it doesn't
> seem to me that it would really force the memory accesses to
> appear to the other host CPU thread that's running the device
> emulation. So either it's insufficient in the s390 memory model,
> or our s390 emulation isn't being sufficiently rigorous about
> implementing the memory model...
AFAIK s390x has a very strict memory ordering model... so maybe this is a
problem with emulating a strict CPU on a less strict host CPU, indeed? ...
CC:-ing Christian and Richard, maybe they have some additional ideas here...
Thomas
prev parent reply other threads:[~2021-02-12 14:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 20:32 getting the console output for s390 cdrom-test? Peter Maydell
2021-02-04 16:08 ` Thomas Huth
2021-02-08 10:27 ` Peter Maydell
2021-02-08 11:34 ` Thomas Huth
2021-02-08 12:08 ` Peter Maydell
2021-02-09 14:58 ` Peter Maydell
2021-02-09 17:10 ` Cornelia Huck
2021-02-09 17:17 ` Peter Maydell
2021-02-09 17:24 ` Cornelia Huck
2021-02-09 18:25 ` Peter Maydell
2021-02-12 11:44 ` Thomas Huth
2021-02-12 12:05 ` Peter Maydell
2021-02-12 14:10 ` Thomas Huth [this message]
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