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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Raj Ashok <ashok.raj@intel.com>,
	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
	LKML <linux-kernel@vger.kernel.org>,
	iommu@lists.linux-foundation.org,
	Andriy Shevchenko <andriy.shevchenko@linux.intel.com>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v4 20/22] iommu/vt-d: Add bind guest PASID support
Date: Fri, 5 Jul 2019 10:21:27 +0800
Message-ID: <840a6943-87ab-938f-5f8d-3a2c21e08549@linux.intel.com> (raw)
In-Reply-To: <20190627132244.351c7426@jacob-builder>

Hi Jacob,

On 6/28/19 4:22 AM, Jacob Pan wrote:
>>> +		}
>>> +		refcount_set(&svm->refs, 0);
>>> +		ioasid_set_data(data->hpasid, svm);
>>> +		INIT_LIST_HEAD_RCU(&svm->devs);
>>> +		INIT_LIST_HEAD(&svm->list);
>>> +
>>> +		mmput(svm->mm);
>>> +	}
>>> +	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
>>> +	if (!sdev) {
>>> +		ret = -ENOMEM;
>>> +		goto out;
>> I think you need to clean up svm if its device list is empty here, as
>> you said above:
>>
> No, we come here only if the device list is not empty and the new
> device to bind is different than any existing device in the list. If we
> cannot allocate memory for the new device, should not free the existing
> SVM, right?
> 

I'm sorry, but the code doesn't show this. We come here even an svm data
structure was newly created with an empty device list. I post the code
below to ensure that we are reading a same piece of code.

         mutex_lock(&pasid_mutex);
         svm = ioasid_find(NULL, data->hpasid, NULL);
         if (IS_ERR(svm)) {
                 ret = PTR_ERR(svm);
                 goto out;
         }
         if (svm) {
                 /*
                  * If we found svm for the PASID, there must be at
                  * least one device bond, otherwise svm should be freed.
                  */
                 BUG_ON(list_empty(&svm->devs));

                 for_each_svm_dev() {
                         /* In case of multiple sub-devices of the same 
pdev assigned, we should
                          * allow multiple bind calls with the same 
PASID and pdev.
                          */
                         sdev->users++;
                         goto out;
                 }
         } else {
                 /* We come here when PASID has never been bond to a 
device. */
                 svm = kzalloc(sizeof(*svm), GFP_KERNEL);
                 if (!svm) {
                         ret = -ENOMEM;
                         goto out;
                 }
                 /* REVISIT: upper layer/VFIO can track host process 
that bind the PASID.
                  * ioasid_set = mm might be sufficient for vfio to 
check pasid VMM
                  * ownership.
                  */
                 svm->mm = get_task_mm(current);
                 svm->pasid = data->hpasid;
                 if (data->flags & IOMMU_SVA_GPASID_VAL) {
                         svm->gpasid = data->gpasid;
                         svm->flags &= SVM_FLAG_GUEST_PASID;
                 }
                 refcount_set(&svm->refs, 0);
                 ioasid_set_data(data->hpasid, svm);
                 INIT_LIST_HEAD_RCU(&svm->devs);
                 INIT_LIST_HEAD(&svm->list);

                 mmput(svm->mm);
         }
         sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
         if (!sdev) {
                 ret = -ENOMEM;
                 goto out;
         }
         sdev->dev = dev;
         sdev->users = 1;

Best regards,
Baolu
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  reply index

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-09 13:44 [PATCH v4 00/22] Shared virtual address IOMMU and VT-d support Jacob Pan
2019-06-09 13:44 ` [PATCH v4 01/22] driver core: Add per device iommu param Jacob Pan
2019-06-09 13:44 ` [PATCH v4 02/22] iommu: Introduce device fault data Jacob Pan
2019-06-18 15:42   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 03/22] iommu: Introduce device fault report API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 04/22] iommu: Add recoverable fault reporting Jacob Pan
2019-06-18 15:44   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 05/22] iommu: Add a timeout parameter for PRQ response Jacob Pan
2019-06-09 13:44 ` [PATCH v4 06/22] trace/iommu: Add sva trace events Jacob Pan
2019-06-09 13:44 ` [PATCH v4 07/22] iommu: Use device fault trace event Jacob Pan
2019-06-09 13:44 ` [PATCH v4 08/22] iommu: Introduce attach/detach_pasid_table API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-24 15:06     ` Auger Eric
2019-06-24 15:23       ` Jean-Philippe Brucker
2019-06-09 13:44 ` [PATCH v4 09/22] iommu: Introduce cache_invalidate API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 10/22] iommu: Fix compile error without IOMMU_API Jacob Pan
2019-06-18 14:10   ` Jonathan Cameron
2019-06-24 22:28     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 11/22] iommu: Introduce guest PASID bind function Jacob Pan
2019-06-18 15:36   ` Jean-Philippe Brucker
2019-06-24 22:24     ` Jacob Pan
2019-07-16 16:44   ` Auger Eric
2019-08-05 21:02     ` Jacob Pan
2019-08-05 23:13     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 12/22] iommu: Add I/O ASID allocator Jacob Pan
2019-06-18 16:50   ` Jonathan Cameron
2019-06-25 18:55     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 13/22] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2019-07-16  9:29   ` Auger Eric
2019-08-13 16:57     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 14/22] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2019-07-16  9:30   ` Auger Eric
2019-08-05 20:02     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 15/22] iommu/vt-d: Replace Intel specific PASID allocator with IOASID Jacob Pan
2019-06-18 15:57   ` Jonathan Cameron
2019-06-24 21:36     ` Jacob Pan
2019-06-27  1:53   ` Lu Baolu
2019-06-27 15:40     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 16/22] iommu/vt-d: Move domain helper to header Jacob Pan
2019-07-16  9:33   ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 17/22] iommu/vt-d: Avoid duplicated code for PASID setup Jacob Pan
2019-06-18 16:03   ` Jonathan Cameron
2019-06-24 23:44     ` Jacob Pan
2019-07-16  9:52   ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 18/22] iommu/vt-d: Add nested translation helper function Jacob Pan
2019-06-09 13:44 ` [PATCH v4 19/22] iommu/vt-d: Clean up for SVM device list Jacob Pan
2019-06-18 16:42   ` Jonathan Cameron
2019-06-24 23:59     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 20/22] iommu/vt-d: Add bind guest PASID support Jacob Pan
2019-06-18 16:44   ` Jonathan Cameron
2019-06-24 22:41     ` Jacob Pan
2019-06-27  2:50   ` Lu Baolu
2019-06-27 20:22     ` Jacob Pan
2019-07-05  2:21       ` Lu Baolu [this message]
2019-08-14 17:20         ` Jacob Pan
2019-07-16 16:45   ` Auger Eric
2019-07-16 17:04     ` Raj, Ashok
2019-07-18  7:47       ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 21/22] iommu/vt-d: Support flushing more translation cache types Jacob Pan
2019-07-18  8:35   ` Auger Eric
2019-08-14 20:17     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 22/22] iommu/vt-d: Add svm/sva invalidate function Jacob Pan

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