From: Jan Kiszka <jan.kiszka@siemens.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Christoffer Dall <c.dall@virtualopensystems.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, Alexander Graf <agraf@suse.de>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
kvm-ppc <kvm-ppc@vger.kernel.org>
Subject: Re: [kvmarm] [RFC PATCH 0/3] KVM: ARM: Get rid of hardcoded VGIC addresses
Date: Tue, 23 Oct 2012 13:00:14 +0200 [thread overview]
Message-ID: <508678BE.4040508@siemens.com> (raw)
In-Reply-To: <CAFEAcA_TukUrkg_M5M_6vuLgY=VCnFekCcatHs=mTySxuQ0Fow@mail.gmail.com>
On 2012-10-23 12:52, Peter Maydell wrote:
> On 23 October 2012 11:48, Jan Kiszka <jan.kiszka@siemens.com> wrote:
>> The current irqchip API is like this:
>>
>> KVM_CREATE_IRQCHIP (without any parameters)
>> ...
>> KVM_CREATE_VCPU
>> KVM_SET_IRQCHIP (or the other way around)
>> ...
>> KVM_RUN
>>
>> The arguments you cannot pass via KVM_CREATE_IRQCHIP - which is more
>> like a "Hey, there will be an IRQ chip!" - could be passed via
>> KVM_SET_IRQCHIP (it has 512 bytes space). Provided there are sane
>> configuration defaults, at least after KVM_CREATE_VCPU, KVM_SET_IRQCHIP
>> becomes optional. Then you don't need the a check on KVM_RUN.
>
> KVM_SET_IRQCHIP is the state load ioctl, right (companion to
> KVM_GET_IRQCHIP)? It seems like a bit of an abuse to use that
> for configuration rather than for migration/sync of state
> with userspace...
Depends on how reconfigurable your chip is. x86 also sends the mapping
down this way, which happens to be guest configurable but is practically
static.
>
> (For ARM we will just use the ONE_REG ABI for irqchip state
> save/load anyway, so KVM_SET_IRQCHIP isn't relevant.)
The less problems you should have using the SET interface to perform
one-time configuration.
BTW, I guess we will regret that one-reg ABI one day and have to
introduce a multi-reg version again for hot-standby, i.e. continuous
state migration. I know we also do this for c86 MSRs - that interface
has the same limitation.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2012-10-23 11:00 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-14 0:04 [RFC PATCH 0/3] KVM: ARM: Get rid of hardcoded VGIC addresses Christoffer Dall
2012-10-14 0:04 ` [RFC PATCH 1/3] KVM: ARM: Introduce KVM_INIT_IRQCHIP ioctl Christoffer Dall
2012-10-17 20:21 ` Peter Maydell
2012-10-17 20:23 ` Christoffer Dall
2012-10-17 20:31 ` Peter Maydell
2012-10-17 20:39 ` Christoffer Dall
2012-10-18 12:20 ` Avi Kivity
2012-10-19 18:42 ` Christoffer Dall
2012-10-14 0:04 ` [RFC PATCH 2/3] KVM: ARM: Introduce KVM_SET_DEVICE_ADDRESS ioctl Christoffer Dall
2012-10-17 20:29 ` Peter Maydell
2012-10-19 18:46 ` Christoffer Dall
2012-10-19 20:24 ` Peter Maydell
2012-10-19 20:27 ` Christoffer Dall
2012-10-19 20:33 ` Christoffer Dall
2012-10-14 0:04 ` [RFC PATCH 3/3] KVM: ARM: Split KVM_CREATE_IRQCHIP and KVM_INIT_IRQCHIP Christoffer Dall
2012-10-18 11:15 ` Peter Maydell
2012-10-17 20:38 ` [kvmarm] [RFC PATCH 0/3] KVM: ARM: Get rid of hardcoded VGIC addresses Alexander Graf
2012-10-17 20:39 ` Christoffer Dall
2012-10-17 21:19 ` Benjamin Herrenschmidt
2012-10-17 22:10 ` Paul Mackerras
2012-10-17 23:58 ` Benjamin Herrenschmidt
2012-10-18 13:48 ` Christoffer Dall
2012-10-18 13:49 ` Alexander Graf
2012-10-18 15:25 ` Avi Kivity
2012-10-23 10:48 ` Jan Kiszka
2012-10-23 10:52 ` Peter Maydell
2012-10-23 11:00 ` Jan Kiszka [this message]
2012-10-23 11:04 ` Peter Maydell
2012-10-23 11:08 ` Jan Kiszka
2012-10-24 0:50 ` Paul Mackerras
2012-10-25 11:57 ` Jan Kiszka
2012-10-25 16:14 ` Paolo Bonzini
2012-10-25 16:32 ` Jan Kiszka
2012-10-25 18:27 ` Paolo Bonzini
2012-10-25 19:40 ` Benjamin Herrenschmidt
2012-10-26 9:58 ` Paolo Bonzini
2012-10-26 10:09 ` Peter Maydell
2012-10-26 10:15 ` Paolo Bonzini
2012-10-26 10:22 ` Jan Kiszka
2012-10-26 10:44 ` Benjamin Herrenschmidt
2012-10-26 11:00 ` Jan Kiszka
2012-10-26 11:09 ` Benjamin Herrenschmidt
2012-10-26 11:57 ` Paolo Bonzini
2012-10-26 12:08 ` Peter Maydell
2012-10-26 12:41 ` Jan Kiszka
2012-10-26 20:21 ` Benjamin Herrenschmidt
2012-10-26 11:17 ` Peter Maydell
2012-10-26 11:39 ` Benjamin Herrenschmidt
2012-10-26 12:39 ` Jan Kiszka
2012-10-26 20:45 ` Benjamin Herrenschmidt
2012-10-26 22:03 ` Benjamin Herrenschmidt
2012-10-27 8:06 ` Jan Kiszka
2012-10-27 10:01 ` Peter Maydell
2012-10-28 22:19 ` Benjamin Herrenschmidt
2012-10-26 10:37 ` Benjamin Herrenschmidt
2012-10-26 10:40 ` Paolo Bonzini
2012-10-26 10:47 ` Benjamin Herrenschmidt
2012-10-26 11:47 ` Paolo Bonzini
2012-10-25 19:39 ` Benjamin Herrenschmidt
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