linux-kernel - Re: [PATCH 1/1] iommu/vt-d: Fix incorrect cache invalidation for mm notification

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Message-ID: <c67754fc-9fff-43b4-82ce-078e71134815@linux.intel.com>
Date:   Mon, 20 Nov 2023 12:17:28 +0800
From:   Baolu Lu <baolu.lu@...ux.intel.com>
To:     "Tian, Kevin" <kevin.tian@...el.com>,
        Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Jason Gunthorpe <jgg@...pe.ca>
Cc:     baolu.lu@...ux.intel.com,
        "iommu@...ts.linux.dev" <iommu@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "Huang, Ying" <ying.huang@...el.com>,
        Alistair Popple <apopple@...dia.com>,
        "Luo, Yuzhang" <yuzhang.luo@...el.com>,
        "Zhu, Tony" <tony.zhu@...el.com>
Subject: Re: [PATCH 1/1] iommu/vt-d: Fix incorrect cache invalidation for mm
 notification

On 11/20/23 11:45 AM, Tian, Kevin wrote:
>> From: Lu Baolu<baolu.lu@...ux.intel.com>
>> Sent: Friday, November 17, 2023 5:10 PM
>>
>> Commit 6bbd42e2df8f ("mmu_notifiers: call invalidate_range() when
>> invalidating TLBs") moved the secondary TLB invalidations into the TLB
>> invalidation functions to ensure that all secondary TLB invalidations
>> happen at the same time as the CPU invalidation and added a flush-all
>> type of secondary TLB invalidation for the batched mode, where a range
>> of [0, -1UL) is used to indicates that the range extends to the end of
>> the address space.
>>
>> However, using an end address of -1UL caused an overflow in the Intel
>> IOMMU driver, where the end address was rounded up to the next page.
>> As a result, both the IOTLB and device ATC were not invalidated correctly.
>>
>> Add a flush all helper function and call it when the invalidation range
>> is from 0 to -1UL, ensuring that the entire caches are invalidated
>> correctly.
>>
>> Fixes: 6bbd42e2df8f ("mmu_notifiers: call invalidate_range() when
>> invalidating TLBs")
>> Cc:stable@...r.kernel.org
>> Cc: Huang Ying<ying.huang@...el.com>
>> Cc: Alistair Popple<apopple@...dia.com>
>> Tested-by: Luo Yuzhang<yuzhang.luo@...el.com>  # QAT
>> Tested-by: Tony Zhu<tony.zhu@...el.com>  # DSA
>> Signed-off-by: Lu Baolu<baolu.lu@...ux.intel.com>
>> ---
>>   drivers/iommu/intel/svm.c | 26 ++++++++++++++++++++++++++
>>   1 file changed, 26 insertions(+)
>>
>> diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
>> index 50a481c895b8..588385050a07 100644
>> --- a/drivers/iommu/intel/svm.c
>> +++ b/drivers/iommu/intel/svm.c
>> @@ -216,6 +216,27 @@ static void intel_flush_svm_range(struct intel_svm
>> *svm, unsigned long address,
>>   	rcu_read_unlock();
>>   }
>>
>> +static void intel_flush_svm_all(struct intel_svm *svm)
>> +{
>> +	struct device_domain_info *info;
>> +	struct intel_svm_dev *sdev;
>> +
>> +	rcu_read_lock();
>> +	list_for_each_entry_rcu(sdev, &svm->devs, list) {
>> +		info = dev_iommu_priv_get(sdev->dev);
>> +
>> +		qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, 0, -1UL,
>> 1);
> Why setting 'ih' to skip invalidating page structure caches?

It should be set to '0'. Good catch! Thank you!

Best regards,
baolu