From: Avi Kivity <avi@redhat.com>
To: Alexander Graf <agraf@suse.de>
Cc: Scott Wood <scottwood@freescale.com>,
linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
kvm-ppc@vger.kernel.org, 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 19:00:24 +0300 [thread overview]
Message-ID: <4E0C9D98.5000904@redhat.com> (raw)
In-Reply-To: <4E0C94A0.3090301@suse.de>
On 06/30/2011 06:22 PM, Alexander Graf wrote:
>> Regarding that. There's another option - the ioctl code embeds the
>> structure size. So if we extend the ioctl parsing to pad up (or
>> truncate down) from the user's size to our size, and similarly in the
>> other direction, we can get away from this ugliness.
>>
>> Some years ago I posted a generic helper that did this (and also
>> kmalloc'ed and kfree'd the data itself), but it wasn't received
>> favourably. Maybe I should try again (and we can possibly use it in
>> kvm even if it is rejected for general use, though that's against our
>> principles of pushing all generic infrastructure to the wider kernel).
>
>
> That does sound interesting, but requires a lot more thought to be put
> into the actual code, as we basically need to read out the feature
> bitmap, then provide a minimum size for the chosen features and then
> decide if they fit in.
Why? just put the things you want in the structure.
old userspace -> new kernel: we auto-zero the parts userspace left out,
and zero means old behaviour, so everthing works
new userspace -> old kernel: truncate. Userspace shouldn't have used
any new features (KVM_CAP), and we can -EINVAL if the truncated section
contains a nonzero bit.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-06-30 16:00 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
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 [this message]
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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