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From: Richard Henderson <rth@twiddle.net>
To: Alexander Graf <agraf@suse.de>
Cc: kbastian@mail.uni-paderborn.de, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] s390x: Implement SAM{24,31,64}
Date: Wed, 05 Nov 2014 07:53:57 +0100	[thread overview]
Message-ID: <5459C985.9070902@twiddle.net> (raw)
In-Reply-To: <1415132365-16759-1-git-send-email-agraf@suse.de>

On 11/04/2014 09:19 PM, Alexander Graf wrote:
> The SAM instructions simply change 2 bits in PSW.MASK to advertise
> the current memory mode. While we can't fully guarantee that 31 bit
> mode (or even remotely 24 bit mode) actually work correctly, we don't
> check whether lpswe modifies these bits, so we shouldn't keep the
> guest from executing SAM instructions either.
> 
> This patch implements all SAM instrutions with their actual PSW changing
> semantics, making more recent Linux kernels boot properly which do issue
> a SAM31 call during early boot.
> 
> Signed-off-by: Alexander Graf <agraf@suse.de>

Ho hum.  Reminds me that I should revive my tgt-s390 branch that
got bogged down last year on facilities management.

I think this is technically missing a SPECIFICATION exception if
the PC is out of range for the new mode.  But otherwise...

Reviewed-by: Richard Henderson <rth@twiddle.net>


r~

      parent reply	other threads:[~2014-11-05  6:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-04 20:19 [Qemu-devel] [PATCH] s390x: Implement SAM{24,31,64} Alexander Graf
2014-11-04 22:02 ` Bastian Koppelmann
2014-11-04 21:32   ` Alexander Graf
2014-11-04 23:09 ` Bastian Koppelmann
2014-11-05  6:53 ` Richard Henderson [this message]

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