From: Michael Walle <michael@walle.cc>
To: Blue Swirl <blauwirbel@gmail.com>
Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>,
Richard Henderson <rth@twiddle.net>,
qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>
Subject: Re: [Qemu-devel] [PATCH 02/17] lm32: translation routines
Date: Fri, 11 Feb 2011 23:23:05 +0100 [thread overview]
Message-ID: <201102112323.06089.michael@walle.cc> (raw)
In-Reply-To: <AANLkTikp7gAhFthZjvZzvbFWGZg+_zyHQFLVwGQj+6kx@mail.gmail.com>
Hi,
Regarding all the comments on raising an exception. The real hardware does
only support a few basic exception (like div by zero or interrupts and system
calls). There is no checking if an instruction is supported or not. If an
illegal opcode (like divu if the hardware divider is not enabled) is decoded,
the behaviour is undefined.
Additionally, there are no privileged instructions, no distinction between
kernel and userspace, no memory protection, the LM32 CPU targets to be a
lightweight and relative fast softcore for FPGAs. There are many ways to kill
the VM from 'userspace' (in real hardware and in my qemu port :) )
I treat QEMU as a tool to help developers writing software for this platform,
rather than really running software inside a VM.
That said, IMHO the best handling of unknown opcodes would be to kill the VM.
--
Michael
next prev parent reply other threads:[~2011-02-11 22:23 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-10 23:11 [Qemu-devel] [PATCH 00/17 v2] LatticeMico32 target Michael Walle
2011-02-10 23:11 ` [Qemu-devel] [PATCH 01/17] LatticeMico32 target support Michael Walle
2011-02-10 23:11 ` [Qemu-devel] [PATCH 02/17] lm32: translation routines Michael Walle
2011-02-11 21:42 ` Blue Swirl
2011-02-11 22:23 ` Michael Walle [this message]
2011-02-12 6:49 ` Blue Swirl
2011-02-17 22:51 ` Michael Walle
2011-03-11 5:57 ` Alexander Graf
2011-03-16 23:08 ` Michael Walle
2011-03-16 23:48 ` Alexander Graf
2011-02-12 13:18 ` Michael Walle
2011-02-10 23:11 ` [Qemu-devel] [PATCH 03/17] lm32: translation code helper Michael Walle
2011-02-10 23:11 ` [Qemu-devel] [PATCH 04/17] lm32: machine state loading/saving Michael Walle
2011-02-10 23:11 ` [Qemu-devel] [PATCH 05/17] lm32: gdbstub support Michael Walle
2011-02-10 23:11 ` [Qemu-devel] [PATCH 06/17] lm32: interrupt controller model Michael Walle
2011-02-11 21:49 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 07/17] lm32: juart model Michael Walle
2011-02-11 21:09 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 08/17] lm32: pic and juart helper functions Michael Walle
2011-02-11 20:57 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 09/17] lm32: timer model Michael Walle
2011-02-11 21:22 ` Blue Swirl
2011-02-11 22:29 ` Michael Walle
2011-02-12 6:56 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 10/17] lm32: uart model Michael Walle
2011-02-11 21:16 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 11/17] lm32: system control model Michael Walle
2011-02-11 21:03 ` Blue Swirl
2011-02-11 22:35 ` Michael Walle
2011-02-12 7:54 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 12/17] lm32: support for creating device tree Michael Walle
2011-02-11 20:52 ` Blue Swirl
2011-02-11 22:40 ` Michael Walle
2011-02-12 7:56 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 13/17] lm32: EVR32 and uclinux BSP Michael Walle
2011-02-11 20:47 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 14/17] lm32: todo and documentation Michael Walle
2011-02-11 20:41 ` Blue Swirl
2011-02-11 22:45 ` Michael Walle
2011-02-12 8:00 ` Blue Swirl
2011-02-10 23:12 ` [Qemu-devel] [PATCH 15/17] lm32: opcode testsuite Michael Walle
2011-02-10 23:12 ` [Qemu-devel] [PATCH 16/17] Add lm32 target to configure Michael Walle
2011-02-10 23:12 ` [Qemu-devel] [PATCH 17/17] MAINTAINERS: add LatticeMico32 maintainer Michael Walle
2011-02-11 9:48 ` [Qemu-devel] Re: [PATCH 00/17 v2] LatticeMico32 target Edgar E. Iglesias
-- strict thread matches above, loose matches on Subject: below --
2011-02-17 22:45 [Qemu-devel] [PATCH 00/17 v3] " Michael Walle
2011-02-17 22:45 ` [Qemu-devel] [PATCH 02/17] lm32: translation routines Michael Walle
2011-01-31 0:30 [Qemu-devel] [PATCH 00/17] LatticeMico32 target Michael Walle
2011-01-31 0:30 ` [Qemu-devel] [PATCH 02/17] lm32: translation routines Michael Walle
2011-02-08 17:32 ` Richard Henderson
2011-02-08 20:00 ` Edgar E. Iglesias
2011-02-08 21:32 ` Michael Walle
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