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Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support
From: |
Jike Song |
Subject: |
Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu |
Date: |
Mon, 16 May 2016 14:57:40 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux i686 on x86_64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 |
On 05/13/2016 11:50 PM, Neo Jia wrote:
> On Fri, May 13, 2016 at 05:23:44PM +0800, Jike Song wrote:
>> On 05/13/2016 04:31 PM, Neo Jia wrote:
>>> On Fri, May 13, 2016 at 07:45:14AM +0000, Tian, Kevin wrote:
>>>>
>>>> We use page tracking framework, which is newly added to KVM recently,
>>>> to mark RAM pages as read-only so write accesses are intercepted to
>>>> device model.
>>>
>>> Yes, I am aware of that patchset from Guangrong. So far the interface are
>>> all
>>> requiring struct *kvm, copied from https://lkml.org/lkml/2015/11/30/644
>>>
>>> - kvm_page_track_add_page(): add the page to the tracking pool after
>>> that later specified access on that page will be tracked
>>>
>>> - kvm_page_track_remove_page(): remove the page from the tracking pool,
>>> the specified access on the page is not tracked after the last user is
>>> gone
>>>
>>> void kvm_page_track_add_page(struct kvm *kvm, gfn_t gfn,
>>> enum kvm_page_track_mode mode);
>>> void kvm_page_track_remove_page(struct kvm *kvm, gfn_t gfn,
>>> enum kvm_page_track_mode mode);
>>>
>>> Really curious how you are going to have access to the struct kvm *kvm, or
>>> you
>>> are relying on the userfaultfd to track the write faults only as part of the
>>> QEMU userfault thread?
>>>
>>
>> Hi Neo,
>>
>> For the vGPU used as a device for KVM guest, there will be interfaces
>> wrapped or implemented in KVM layer, as a rival thing diverted from
>> the interfaces for Xen. That is where the KVM related code supposed to be.
>
> Hi Jike,
>
> Is this discussed anywhere on the mailing list already? Sorry if I have missed
> such conversation.
>
Hi Neo,
Not exactly, but we can discuss it if necessary :)
Intel vGPU device-model, which is a part of i915 driver, has to be able to
emulate vGPU for *both* XenGT and KVMGT guests. That means there must be
a ridge somewhere, directing to Xen-specific and KVM-specific logic accordingly.
--
Thanks,
Jike
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, (continued)
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu,
Jike Song <=
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/13
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Tian, Kevin, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Alex Williamson, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Neo Jia, 2016/05/12
- Re: [Qemu-devel] [RFC PATCH v3 3/3] VFIO Type1 IOMMU change: to support with iommu and without iommu, Jike Song, 2016/05/13