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From: Anthony Liguori <anthony@codemonkey.ws>
To: Peter Maydell <peter.maydell@linaro.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Liu Ping Fan" <pingfank@linux.vnet.ibm.com>,
	"Alexander Graf" <agraf@suse.de>,
	"qemu-devel Developers" <qemu-devel@nongnu.org>,
	"qemu-ppc@nongnu.org list:PowerPC" <qemu-ppc@nongnu.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Jan Kiszka" <jan.kiszka@web.de>,
	"Andreas Färber" <afaerber@suse.de>,
	"Hervé Poussineau" <hpoussin@reactos.org>
Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH v3 11/14] ioport: Switch dispatching to memory core layer
Date: Mon, 15 Jul 2013 09:01:13 -0500	[thread overview]
Message-ID: <87sizfudli.fsf@codemonkey.ws> (raw)
In-Reply-To: <CAFEAcA9qGE4pgM_DBJ2w0d16Jef8W6GkUbOTQvCFm3c-EZCYnA@mail.gmail.com>

Peter Maydell <peter.maydell@linaro.org> writes:

> On 12 July 2013 23:50, Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
>> Our experience is that it actually works fine for almost everything
>> except virtio :-) ie mostly TARGET_WORDS_BIGENDIAN is irrelevant (and
>> should be).
>
> I agree that TARGET_WORDS_BIGENDIAN *should* go away, but
> it exists currently. Do you actually implement a CPU which
> does dynamic endianness flipping?

TCG already supports bi-endianness for PPC.  Grep for 'le_mode' in
target-ppc/translate.c to see how the TCG instruction stream is affected
by it.

On PPC, le_mode only really affects load/stores and instruction
decoding.  Any shared data structures between the CPU and OS remain big
endian.

So TARGET_WORDS_BIGENDIAN is still accurate even when le_mode=1.  It's
not the semantic equivalent of changing TARGET_WORDS.

Regards,

Anthony Liguori

> Is it at all efficient
> in the config which is the opposite of whatever
> TARGET_WORDS_BIGENDIAN says?
>
> thanks
> -- PMM

  parent reply	other threads:[~2013-07-15 14:01 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-22  6:06 [Qemu-devel] [PATCH v3 00/14] Refactor portio dispatching Jan Kiszka
2013-06-22  6:06 ` [Qemu-devel] [PATCH v3 01/14] adlib: replace register_ioport* Jan Kiszka
2013-06-22  6:06 ` [Qemu-devel] [PATCH v3 02/14] applesmc: " Jan Kiszka
2013-06-22  6:06 ` [Qemu-devel] [PATCH v3 03/14] wdt_ib700: " Jan Kiszka
2013-06-22  6:06 ` [Qemu-devel] [PATCH v3 04/14] i82374: " Jan Kiszka
2013-06-22  6:06 ` [Qemu-devel] [PATCH v3 05/14] prep: " Jan Kiszka
2013-06-22  6:06 ` [Qemu-devel] [PATCH v3 06/14] vt82c686: " Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 07/14] Privatize register_ioport_read/write Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 08/14] isa: implement isa_is_ioport_assigned via memory_region_find Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 09/14] vmware-vga: Accept unaligned I/O accesses Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 10/14] xen: Mark fixed platform I/O as unaligned Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 11/14] ioport: Switch dispatching to memory core layer Jan Kiszka
2013-06-23 20:50   ` Hervé Poussineau
2013-06-24  6:07     ` Jan Kiszka
2013-07-11 12:29       ` Alexander Graf
2013-07-11 12:34         ` Alexander Graf
2013-07-11 12:46           ` Andreas Färber
2013-07-11 12:48             ` Alexander Graf
2013-07-11 13:28               ` Alexander Graf
2013-07-11 13:35                 ` Alexander Graf
2013-07-11 22:30                 ` [Qemu-devel] [Qemu-ppc] " Benjamin Herrenschmidt
2013-07-11 22:32                 ` Benjamin Herrenschmidt
2013-07-12  3:18                   ` Alexander Graf
2013-07-12 11:35                     ` Benjamin Herrenschmidt
2013-07-12 17:04                       ` Hervé Poussineau
2013-07-12 19:06                         ` Anthony Liguori
2013-07-12 22:59                           ` Benjamin Herrenschmidt
2013-07-12 22:39                         ` Benjamin Herrenschmidt
2013-07-12 17:49                       ` Anthony Liguori
2013-07-12 18:26                         ` Peter Maydell
2013-07-12 22:50                           ` Benjamin Herrenschmidt
2013-07-12 23:10                             ` Peter Maydell
2013-07-12 23:49                               ` Benjamin Herrenschmidt
2013-07-15 14:01                               ` Anthony Liguori [this message]
2013-07-15 14:10                                 ` Peter Maydell
2013-07-15 14:16                                 ` Benjamin Herrenschmidt
2013-07-12 22:44                         ` Benjamin Herrenschmidt
2013-07-13 14:38             ` [Qemu-devel] " Paolo Bonzini
2013-07-13 15:22               ` Anthony Liguori
2013-07-13 18:11                 ` Hervé Poussineau
2013-07-14  6:15                 ` Paolo Bonzini
2013-07-14 13:05                   ` Anthony Liguori
2013-07-14 14:58                     ` Peter Maydell
2013-07-14 15:18                       ` Anthony Liguori
2013-07-14 16:50                         ` Peter Maydell
2013-07-16  7:18                         ` Jan Kiszka
2013-07-16  7:33                           ` Paolo Bonzini
2013-07-16 16:59                             ` Hervé Poussineau
2013-07-16 17:12                               ` Paolo Bonzini
2013-07-12 12:56           ` Anthony Liguori
2013-07-12 14:30             ` Alexander Graf
2013-07-19 11:09         ` [Qemu-devel] BUG: " Alexey Kardashevskiy
2013-07-19 12:49           ` Paolo Bonzini
2013-07-19 15:48             ` Alexey Kardashevskiy
2013-07-20  0:55               ` Alexey Kardashevskiy
2013-07-20  1:11                 ` Alexey Kardashevskiy
2013-07-20 10:11                   ` Paolo Bonzini
2013-07-20 20:53                     ` Edgar E. Iglesias
2013-07-21 15:13                     ` Hervé Poussineau
2013-07-22 10:25                       ` Paolo Bonzini
2013-06-24  8:45     ` [Qemu-devel] [PATCH v4 " Jan Kiszka
2013-07-12 19:36     ` [Qemu-devel] [PATCH v3 " Anthony Liguori
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 12/14] ioport: Remove unused old dispatching services Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 13/14] vmport: Disentangle read handler type from portio Jan Kiszka
2013-06-22  6:07 ` [Qemu-devel] [PATCH v3 14/14] ioport: Move portio types to ioport.h Jan Kiszka
2013-06-23 20:45 ` [Qemu-devel] [PATCH v3 00/14] Refactor portio dispatching Hervé Poussineau

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