From: Avi Kivity <avi@redhat.com>
To: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: kvm-ppc@vger.kernel.org, linuxppc-dev@ozlabs.org,
Paul Mackerras <paulus@samba.org>, Alexander Graf <agraf@suse.de>,
kvm@vger.kernel.org
Subject: Re: [RFC PATCH 17/17] KVM: PPC: Add an ioctl for userspace to select which platform to emulate
Date: Thu, 30 Jun 2011 11:34:53 +0300 [thread overview]
Message-ID: <4E0C352D.60008@redhat.com> (raw)
In-Reply-To: <20110629115857.GB17551@zod.rchland.ibm.com>
On 06/29/2011 02:58 PM, Josh Boyer wrote:
> >> This makes me wonder if a similar thing might eventually be usable for
> >> running an i686 or x32 guest on an x86_64 KVM host. I have no idea if
> >> that is even theoretically possible, but if it is it might be better to
> >> rename the ioctl to be architecture agnostic.
> >
> >On x86 this is not required unless we want to "virtualize" pre-CPUID CPUs. Everything as of Pentium has a full bitmap of feature capabilities that KVM gets from user space, including information such as "Can we do 64-bit mode?".
>
> Ah. Thank you for the explanation.
To clarify a bit further, running an i686 guest on an x86_64 host is not
only theoretically possible, but is done regularly. First, x86_64 is
backwards compatible with i686 (so you can install a 32-bit OS on 64-bit
hardware), and second, you can impersonate 32-bit guest hardware on a
64-bit host.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-06-30 8:35 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-29 10:15 [PATCH 0/17] Hypervisor-mode KVM on POWER7 and PPC970 Paul Mackerras
2011-06-29 10:16 ` [PATCH 01/17] KVM: PPC: Fix machine checks on 32-bit Book3S Paul Mackerras
2011-07-01 10:08 ` Alexander Graf
2011-06-29 10:17 ` [PATCH 02/17] KVM: PPC: Move fields between struct kvm_vcpu_arch and kvmppc_vcpu_book3s Paul Mackerras
2011-06-29 10:17 ` [PATCH 03/17] KVM: PPC: Split out code from book3s.c into book3s_pr.c Paul Mackerras
2011-06-29 10:18 ` [PATCH 04/17] powerpc, KVM: Rework KVM checks in first-level interrupt handlers Paul Mackerras
2011-06-29 10:18 ` [PATCH 05/17] KVM: PPC: Deliver program interrupts right away instead of queueing them Paul Mackerras
2011-07-01 11:47 ` Alexander Graf
2011-06-29 10:19 ` [PATCH 06/17] KVM: PPC: Pass init/destroy vm and prepare/commit memory region ops down Paul Mackerras
2011-06-29 10:19 ` [PATCH 07/17] KVM: PPC: Move guest enter/exit down into subarch-specific code Paul Mackerras
2011-06-29 10:20 ` [PATCH 08/17] powerpc: Set up LPCR for running guest partitions Paul Mackerras
2011-06-29 10:20 ` [PATCH 09/17] KVM: PPC: Split host-state fields out of kvmppc_book3s_shadow_vcpu Paul Mackerras
2011-06-29 10:21 ` [PATCH 10/17] KVM: PPC: Add support for Book3S processors in hypervisor mode Paul Mackerras
2011-07-01 18:37 ` Dave Hansen
2011-07-01 19:12 ` Alexander Graf
2011-07-04 11:51 ` Paul Mackerras
2011-06-29 10:22 ` [PATCH 11/17] KVM: PPC: Handle some PAPR hcalls in the kernel Paul Mackerras
2011-06-29 10:22 ` [PATCH 12/17] KVM: PPC: Accelerate H_PUT_TCE by implementing it in real mode Paul Mackerras
2011-06-29 10:23 ` [PATCH 13/17] KVM: PPC: Allow book3s_hv guests to use SMT processor modes Paul Mackerras
2012-04-16 9:45 ` Alexander Graf
2012-04-16 12:13 ` Paul Mackerras
2012-04-16 13:01 ` Alexander Graf
2011-06-29 10:25 ` [PATCH 14/17] KVM: PPC: Allocate RMAs (Real Mode Areas) at boot for use by guests Paul Mackerras
2011-06-29 10:26 ` [PATCH 15/17] powerpc, KVM: Split HVMODE_206 cpu feature bit into separate HV and architecture bits Paul Mackerras
2011-06-29 10:40 ` [PATCH 16/17] KVM: PPC: book3s_hv: Add support for PPC970-family processors Paul Mackerras
2011-06-29 10:41 ` [RFC PATCH 17/17] KVM: PPC: Add an ioctl for userspace to select which platform to emulate Paul Mackerras
2011-06-29 11:53 ` Josh Boyer
2011-06-29 11:56 ` Alexander Graf
2011-06-29 11:58 ` Josh Boyer
2011-06-30 8:34 ` Avi Kivity [this message]
2011-06-30 15:04 ` Alexander Graf
2011-06-30 15:16 ` Avi Kivity
2011-06-30 15:22 ` Alexander Graf
2011-06-30 16:00 ` Avi Kivity
2011-06-30 16:33 ` Alexander Graf
2011-07-03 8:15 ` Avi Kivity
2011-07-03 8:34 ` Alexander Graf
2011-07-03 8:56 ` Avi Kivity
2011-07-03 9:00 ` Alexander Graf
2011-07-03 9:05 ` Avi Kivity
2011-07-03 9:09 ` Alexander Graf
2011-07-03 9:12 ` Avi Kivity
2011-07-04 10:59 ` Alexander Graf
2011-07-04 11:22 ` Avi Kivity
2011-07-04 11:36 ` Alexander Graf
2011-07-04 11:37 ` Avi Kivity
2011-07-04 11:41 ` Alexander Graf
2011-06-30 23:13 ` Benjamin Herrenschmidt
2011-07-01 10:09 ` Paul Mackerras
2011-07-01 10:23 ` Alexander Graf
2011-07-01 18:24 ` [PATCH 0/17] Hypervisor-mode KVM on POWER7 and PPC970 Alexander Graf
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