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From: Paolo Bonzini <pbonzini@redhat.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Alexander Graf <agraf@suse.de>, Gleb Natapov <gleb@redhat.com>,
	Jens Freimann <jfrei@linux.vnet.ibm.com>,
	KVM list <kvm@vger.kernel.org>,
	"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: RFC: KVM _CREATE_DEVICE considered harmful?
Date: Wed, 16 Oct 2013 16:59:14 +0200	[thread overview]
Message-ID: <525EA9C2.90805@redhat.com> (raw)
In-Reply-To: <525EA150.3060107@de.ibm.com>

Il 16/10/2013 16:23, Christian Borntraeger ha scritto:
> That would work, but it would change the ioctl number of KVM_*_DEVICE_ADDR,
> due to the changed size of struct kvm_device_attr. We would then need compat
>  handlers in the kernel.

Actually I did that on purpose :) but perhaps you're right that the
complication would be too high.

> If we could encode it in the existing interface the impact would be smaller.
> e.g. 
> 
> #define ATTR_ATTR_MASK 0xffffffffULL
> #define ATTR_LEN_MASK 0xffffffff00000000ULL
> 
> 
>     switch (attr->attr) {
> ---> 
>     switch (attr->attr & ATTR_ATTR_MASK) {
> 
> Then we could keep the device model abstraction.

That makes sense too.

Paolo

WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
	Jens Freimann <jfrei@linux.vnet.ibm.com>,
	Alexander Graf <agraf@suse.de>, Gleb Natapov <gleb@redhat.com>,
	KVM list <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] RFC: KVM _CREATE_DEVICE considered harmful?
Date: Wed, 16 Oct 2013 16:59:14 +0200	[thread overview]
Message-ID: <525EA9C2.90805@redhat.com> (raw)
In-Reply-To: <525EA150.3060107@de.ibm.com>

Il 16/10/2013 16:23, Christian Borntraeger ha scritto:
> That would work, but it would change the ioctl number of KVM_*_DEVICE_ADDR,
> due to the changed size of struct kvm_device_attr. We would then need compat
>  handlers in the kernel.

Actually I did that on purpose :) but perhaps you're right that the
complication would be too high.

> If we could encode it in the existing interface the impact would be smaller.
> e.g. 
> 
> #define ATTR_ATTR_MASK 0xffffffffULL
> #define ATTR_LEN_MASK 0xffffffff00000000ULL
> 
> 
>     switch (attr->attr) {
> ---> 
>     switch (attr->attr & ATTR_ATTR_MASK) {
> 
> Then we could keep the device model abstraction.

That makes sense too.

Paolo

  reply	other threads:[~2013-10-16 14:59 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-16 12:59 RFC: KVM _CREATE_DEVICE considered harmful? Christian Borntraeger
2013-10-16 12:59 ` [Qemu-devel] " Christian Borntraeger
2013-10-16 13:06 ` Paolo Bonzini
2013-10-16 13:06   ` [Qemu-devel] " Paolo Bonzini
2013-10-16 14:23   ` Christian Borntraeger
2013-10-16 14:23     ` [Qemu-devel] " Christian Borntraeger
2013-10-16 14:59     ` Paolo Bonzini [this message]
2013-10-16 14:59       ` Paolo Bonzini
2013-10-16 15:44 ` Gleb Natapov
2013-10-16 15:44   ` [Qemu-devel] " Gleb Natapov
2013-10-16 19:47   ` Christian Borntraeger
2013-10-16 19:47     ` [Qemu-devel] " Christian Borntraeger

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