[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <a03d3bf6-0610-427c-bf2a-5f6c410e220e@linux.intel.com>
Date: Wed, 8 May 2024 18:05:06 +0800
From: Baolu Lu <baolu.lu@...ux.intel.com>
To: Jason Gunthorpe <jgg@...pe.ca>
Cc: baolu.lu@...ux.intel.com, Kevin Tian <kevin.tian@...el.com>,
Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Jean-Philippe Brucker <jean-philippe@...aro.org>,
Nicolin Chen <nicolinc@...dia.com>, Yi Liu <yi.l.liu@...el.com>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>,
Joel Granados <j.granados@...sung.com>, iommu@...ts.linux.dev,
virtualization@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 5/9] iommufd: Add iommufd fault object
On 2024/5/8 8:11, Jason Gunthorpe wrote:
> On Tue, Apr 30, 2024 at 10:57:06PM +0800, Lu Baolu wrote:
>> diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h
>> index ae65e0b85d69..1a0450a83bd0 100644
>> --- a/drivers/iommu/iommu-priv.h
>> +++ b/drivers/iommu/iommu-priv.h
>> @@ -36,6 +36,10 @@ struct iommu_attach_handle {
>> struct device *dev;
>> refcount_t users;
>> };
>> + /* attach data for IOMMUFD */
>> + struct {
>> + void *idev;
>> + };
> We can use a proper type here, just forward declare it.
>
> But this sequence in the other patch:
>
> + ret = iommu_attach_group(hwpt->domain, idev->igroup->group);
> + if (ret) {
> + iommufd_fault_iopf_disable(idev);
> + return ret;
> + }
> +
> + handle = iommu_attach_handle_get(idev->igroup->group, IOMMU_NO_PASID, 0);
> + handle->idev = idev;
>
> Is why I was imagining the caller would allocate, because now we have
> the issue that a fault capable domain was installed into the IOMMU
> before it's handle could be fully setup, so we have a race where a
> fault could come in right between those things. Then what happens?
> I suppose we can retry the fault and by the time it comes back the
> race should resolve. A bit ugly I suppose.
You are right. It makes more sense if the attached data is allocated and
managed by the caller. I will go in this direction and update my series.
I will also consider other review comments you have given in other
places.
Best regards,
baolu
Powered by blists - more mailing lists