From: Kirti Wankhede <kwankhede@nvidia.com>
To: Yan Zhao <yan.y.zhao@intel.com>,
Alex Williamson <alex.williamson@redhat.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, 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 12:39:48 +0530 [thread overview]
Message-ID: <d8b40fed-5f54-31ac-0b7c-e2ae74a0ad19@nvidia.com> (raw)
In-Reply-To: <20200521050846.GC10369@joy-OptiPlex-7040>
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?
Thanks,
Kirti
next prev parent reply other threads:[~2020-05-21 7:10 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 [this message]
2020-05-21 7:04 ` Yan Zhao
2020-05-21 7:28 ` Kirti Wankhede
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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