From: Paul Mackerras <paulus@samba.org>
To: Alexander Graf <agraf@suse.de>
Cc: "Cédric Le Goater" <clg@fr.ibm.com>,
"kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
"kvm@vger.kernel.org mailing list" <kvm@vger.kernel.org>
Subject: Re: [PATCH v2 3/3] KVM: PPC: Book3S: MMIO emulation support for little endian guests
Date: Thu, 10 Oct 2013 21:16:07 +1100 [thread overview]
Message-ID: <20131010101607.GB9906@iris.ozlabs.ibm.com> (raw)
In-Reply-To: <B26163CF-F7B5-4396-A544-DC9FEF983D34@suse.de>
On Wed, Oct 09, 2013 at 10:29:53AM +0200, Alexander Graf wrote:
>
>
> Am 09.10.2013 um 07:59 schrieb Paul Mackerras <paulus@samba.org>:
>
> > On Wed, Oct 09, 2013 at 01:46:29AM +0200, Alexander Graf wrote:
> >>
> >>
> >> Am 09.10.2013 um 01:31 schrieb Paul Mackerras <paulus@samba.org>:
> >>
> >>> True, until we get to POWER8 with its split little-endian support,
> >>> where instructions and data can have different endianness...
> >>
> >> How exactly does that work?
> >
> > They added an extra MSR bit called SLE which enables the split-endian
> > mode. It's bit 5 (IBM numbering). For backwards compatibility, the
> > LE bit controls instruction endianness, and data endianness depends on
> > LE ^ SLE, that is, with SLE = 0 things work as before. With SLE=1 and
> > LE=0 you get little-endian data and big-endian instructions, and vice
> > versa with SLE=1 and LE=1.
>
> So ld32 should only honor LE and get_last_inst only looks at SLE and swaps even the vcpu cached version if it's set, no?
Not exactly; instruction endianness depends only on MSR[LE], so
get_last_inst should not look at MSR[SLE]. I would think the vcpu
cached version should be host endian always.
Paul.
next prev parent reply other threads:[~2013-10-10 10:16 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-08 14:12 [PATCH v2 0/3] KVM: PPC: Book3S: MMIO support for Little Endian guests Cédric Le Goater
2013-10-08 14:12 ` [PATCH v2 1/3] KVM: PPC: Book3S: add helper routine to load guest instructions Cédric Le Goater
2013-10-08 14:12 ` [PATCH v2 2/3] KVM: PPC: Book3S: add helper routines to detect endian Cédric Le Goater
2013-10-08 14:12 ` [PATCH v2 3/3] KVM: PPC: Book3S: MMIO emulation support for little endian guests Cédric Le Goater
2013-10-08 14:25 ` Alexander Graf
2013-10-08 15:07 ` Cedric Le Goater
2013-10-08 15:31 ` [PATCH v3 " Cédric Le Goater
2013-10-08 15:36 ` Alexander Graf
2013-10-08 16:10 ` Cedric Le Goater
2013-10-08 16:43 ` [PATCH v4 0/3] KVM: PPC: Book3S: MMIO support for Little Endian guests Cédric Le Goater
2013-10-08 16:43 ` [PATCH v4 1/3] KVM: PPC: Book3S: add helper routine to load guest instructions Cédric Le Goater
2013-10-08 16:43 ` [PATCH v4 2/3] KVM: PPC: Book3S: add helper routines to detect endian order Cédric Le Goater
2013-10-08 16:43 ` [PATCH v4 3/3] KVM: PPC: Book3S: MMIO emulation support for little endian guests Cédric Le Goater
2013-10-08 23:31 ` [PATCH v2 " Paul Mackerras
2013-10-08 23:46 ` Alexander Graf
2013-10-09 5:59 ` Paul Mackerras
2013-10-09 8:29 ` Alexander Graf
2013-10-09 8:42 ` Cedric Le Goater
2013-10-10 10:16 ` Paul Mackerras [this message]
2013-11-04 11:44 ` Alexander Graf
2013-11-05 12:28 ` Cedric Le Goater
2013-11-05 13:01 ` Alexander Graf
2013-11-05 17:22 ` [PATCH v5 0/6] KVM: PPC: Book3S: MMIO support for Little Endian guests Cédric Le Goater
2013-11-05 17:22 ` [PATCH v5 1/6] KVM: PPC: Book3S: add helper routine to load guest instructions Cédric Le Goater
2013-11-05 17:22 ` [PATCH v5 2/6] KVM: PPC: Book3S: add helper routines to detect endian Cédric Le Goater
2014-01-02 20:05 ` Alexander Graf
2014-01-08 17:22 ` Cedric Le Goater
2013-11-05 17:22 ` [PATCH v5 3/6] KVM: PPC: Book3S: MMIO emulation support for little endian guests Cédric Le Goater
2014-01-02 20:22 ` Alexander Graf
2014-01-08 17:23 ` Cedric Le Goater
2014-01-08 17:34 ` Alexander Graf
2014-01-08 17:40 ` Cedric Le Goater
2014-01-08 17:35 ` [PATCH v6] " Cédric Le Goater
2014-01-09 10:02 ` [PATCH v7] " Cédric Le Goater
2014-01-09 10:17 ` Alexander Graf
2014-01-09 10:33 ` Cedric Le Goater
2014-01-09 10:51 ` [PATCH v8] " Cédric Le Goater
2014-01-09 10:55 ` Alexander Graf
2013-11-05 17:22 ` [PATCH v5 4/6] KVM: PPC: Book3S: modify kvmppc_need_byteswap() for little endian host Cédric Le Goater
2013-11-08 14:36 ` [PATCH v5.1 " Cedric Le Goater
2014-01-02 20:28 ` Alexander Graf
2014-01-02 20:25 ` [PATCH v5 " Alexander Graf
2013-11-05 17:22 ` [PATCH v5 5/6] powerpc: add Split Little Endian bit to MSR Cédric Le Goater
2013-11-05 17:22 ` [PATCH v5 6/6] KVM: PPC: Book3S: modify byte loading when guest uses Split Little Endian Cédric Le Goater
2014-01-02 20:26 ` Alexander Graf
2013-11-06 5:55 ` [PATCH v2 3/3] KVM: PPC: Book3S: MMIO emulation support for little endian guests Paul Mackerras
2013-11-08 14:29 ` Cedric Le Goater
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