From: Kirti Wankhede <kwankhede@nvidia.com>
To: Yan Zhao <yan.y.zhao@intel.com>
Cc: <Zhengxiao.zx@Alibaba-inc.com>, <kevin.tian@intel.com>,
<yi.l.liu@intel.com>, <cjia@nvidia.com>, <kvm@vger.kernel.org>,
<eskultet@redhat.com>, <ziye.yang@intel.com>,
<qemu-devel@nongnu.org>, <cohuck@redhat.com>,
<shuangtai.tst@alibaba-inc.com>, <dgilbert@redhat.com>,
<zhi.a.wang@intel.com>, <mlevitsk@redhat.com>,
<pasic@linux.ibm.com>, <aik@ozlabs.ru>,
Alex Williamson <alex.williamson@redhat.com>, <eauger@redhat.com>,
<felipe@nutanix.com>, <jonathan.davies@nutanix.com>,
<changpeng.liu@intel.com>, <Ken.Xue@amd.com>
Subject: Re: [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices
Date: Thu, 21 May 2020 12:58:49 +0530 [thread overview]
Message-ID: <5abfe792-bbec-eee5-a74a-ed7d6a49653e@nvidia.com> (raw)
In-Reply-To: <20200521070403.GD10369@joy-OptiPlex-7040>
On 5/21/2020 12:34 PM, Yan Zhao wrote:
> On Thu, May 21, 2020 at 12:39:48PM +0530, Kirti Wankhede wrote:
>>
>>
>> On 5/21/2020 10:38 AM, Yan Zhao wrote:
>>> On Wed, May 20, 2020 at 10:46:12AM -0600, Alex Williamson wrote:
>>>> On Wed, 20 May 2020 19:10:07 +0530
>>>> Kirti Wankhede <kwankhede@nvidia.com> wrote:
>>>>
>>>>> On 5/20/2020 8:25 AM, Yan Zhao wrote:
>>>>>> On Tue, May 19, 2020 at 10:58:04AM -0600, Alex Williamson wrote:
>>>>>>> Hi folks,
>>>>>>>
>>>>>>> My impression is that we're getting pretty close to a workable
>>>>>>> implementation here with v22 plus respins of patches 5, 6, and 8. We
>>>>>>> also have a matching QEMU series and a proposal for a new i40e
>>>>>>> consumer, as well as I assume GVT-g updates happening internally at
>>>>>>> Intel. I expect all of the latter needs further review and discussion,
>>>>>>> but we should be at the point where we can validate these proposed
>>>>>>> kernel interfaces. Therefore I'd like to make a call for reviews so
>>>>>>> that we can get this wrapped up for the v5.8 merge window. I know
>>>>>>> Connie has some outstanding documentation comments and I'd like to make
>>>>>>> sure everyone has an opportunity to check that their comments have been
>>>>>>> addressed and we don't discover any new blocking issues. Please send
>>>>>>> your Acked-by/Reviewed-by/Tested-by tags if you're satisfied with this
>>>>>>> interface and implementation. Thanks!
>>>>>> hi Alex and Kirti,
>>>>>> after porting to qemu v22 and kernel v22, it is found out that
>>>>>> it can not even pass basic live migration test with error like
>>>>>>
>>>>>> "Failed to get dirty bitmap for iova: 0xca000 size: 0x3000 err: 22"
>>>>>
>>>>> Thanks for testing Yan.
>>>>> I think last moment change in below cause this failure
>>>>>
>>>>> https://lore.kernel.org/kvm/1589871178-8282-1-git-send-email-kwankhede@nvidia.com/
>>>>>
>>>>> > if (dma->iova > iova + size)
>>>>> > break;
>>>>>
>>>>> Surprisingly with my basic testing with 2G sys mem QEMU didn't raise
>>>>> abort on g_free, but I do hit this with large sys mem.
>>>>> With above change, that function iterated through next vfio_dma as well.
>>>>> Check should be as below:
>>>>>
>>>>> - if (dma->iova > iova + size)
>>>>> + if (dma->iova > iova + size -1)
>>>>
>>>>
>>>> Or just:
>>>>
>>>> if (dma->iova >= iova + size)
>>>>
>>>> Thanks,
>>>> Alex
>>>>
>>>>
>>>>> break;
>>>>>
>>>>> Another fix is in QEMU.
>>>>> https://lists.gnu.org/archive/html/qemu-devel/2020-05/msg04751.html
>>>>>
>>>>> > > + range->bitmap.size = ROUND_UP(pages, 64) / 8;
>>>>> >
>>>>> > ROUND_UP(npages/8, sizeof(u64))?
>>>>> >
>>>>>
>>>>> If npages < 8, npages/8 is 0 and ROUND_UP(0, 8) returns 0.
>>>>>
>>>>> Changing it as below
>>>>>
>>>>> - range->bitmap.size = ROUND_UP(pages / 8, sizeof(uint64_t));
>>>>> + range->bitmap.size = ROUND_UP(pages, sizeof(__u64) *
>>>>> BITS_PER_BYTE) /
>>>>> + BITS_PER_BYTE;
>>>>>
>>>>> I'm updating patches with these fixes and Cornelia's suggestion soon.
>>>>>
>>>>> Due to short of time I may not be able to address all the concerns
>>>>> raised on previous versions of QEMU, I'm trying make QEMU side code
>>>>> available for testing for others with latest kernel changes. Don't
>>>>> worry, I will revisit comments on QEMU patches. Right now first priority
>>>>> is to test kernel UAPI and prepare kernel patches for 5.8
>>>>>
>>>>
>>> hi Kirti
>>> by updating kernel/qemu to v23, still met below two types of errors.
>>> just basic migration test.
>>> (the guest VM size is 2G for all reported bugs).
>>>
>>> "Failed to get dirty bitmap for iova: 0xfe011000 size: 0x3fb0 err: 22"
>>>
>>
>> size doesn't look correct here, below check should be failing.
>> range.size & (iommu_pgsize - 1)
>>
>>> or
>>>
>>> "qemu-system-x86_64-lm: vfio_load_state: Error allocating buffer
>>> qemu-system-x86_64-lm: error while loading state section id 49(vfio)
>>> qemu-system-x86_64-lm: load of migration failed: Cannot allocate memory"
>>>
>>>
>>
>> Above error is from:
>> buf = g_try_malloc0(data_size);
>> if (!buf) {
>> error_report("%s: Error allocating buffer ", __func__);
>> return -ENOMEM;
>> }
>>
>> Seems you are running out of memory?
>>
> no. my host memory is about 60G.
> just migrate with command "migrate -d xxx" without speed limit.
> FYI.
>
Probably you will have to figure out why g_try_malloc0() is failing.
what is data_size when it fails?
Thanks,
Kirti
next prev parent reply other threads:[~2020-05-21 7:29 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-18 5:56 [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 1/8] vfio: UAPI for migration interface for device state Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 2/8] vfio iommu: Remove atomicity of ref_count of pinned pages Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 3/8] vfio iommu: Cache pgsize_bitmap in struct vfio_iommu Kirti Wankhede
2020-05-20 10:08 ` Cornelia Huck
2020-05-20 14:46 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 4/8] vfio iommu: Add ioctl definition for dirty pages tracking Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 5/8] vfio iommu: Implementation of ioctl " Kirti Wankhede
2020-05-18 21:53 ` Alex Williamson
2020-05-19 7:11 ` Kirti Wankhede
2020-05-19 6:52 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 6/8] vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap Kirti Wankhede
2020-05-19 6:54 ` Kirti Wankhede
2020-05-20 10:27 ` Cornelia Huck
2020-05-20 15:16 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 7/8] vfio iommu: Add migration capability to report supported features Kirti Wankhede
2020-05-20 10:42 ` Cornelia Huck
2020-05-20 15:23 ` Kirti Wankhede
2020-05-18 5:56 ` [PATCH Kernel v22 8/8] vfio: Selective dirty page tracking if IOMMU backed device pins pages Kirti Wankhede
2020-05-19 6:54 ` Kirti Wankhede
2020-05-19 16:58 ` [PATCH Kernel v22 0/8] Add UAPIs to support migration for VFIO devices Alex Williamson
2020-05-20 2:55 ` Yan Zhao
2020-05-20 13:40 ` Kirti Wankhede
2020-05-20 16:46 ` Alex Williamson
2020-05-21 5:08 ` Yan Zhao
2020-05-21 7:09 ` Kirti Wankhede
2020-05-21 7:04 ` Yan Zhao
2020-05-21 7:28 ` Kirti Wankhede [this message]
2020-05-21 7:32 ` Kirti Wankhede
2020-05-25 6:59 ` Yan Zhao
2020-05-25 13:20 ` Kirti Wankhede
2020-05-26 20:19 ` Alex Williamson
2020-05-27 6:23 ` Yan Zhao
2020-05-27 8:48 ` Dr. David Alan Gilbert
2020-05-28 8:01 ` Yan Zhao
2020-05-28 22:53 ` Alex Williamson
2020-05-29 11:12 ` Dr. David Alan Gilbert
2020-05-28 22:59 ` Alex Williamson
2020-05-29 4:15 ` Yan Zhao
2020-05-29 17:57 ` Kirti Wankhede
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