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Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one context entry

From "Sironi, Filippo" <sironi@amazon.de>
Newsgroups linux.kernel
Subject Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one context entry
Date 2017-08-31 10:50 +0200
Message-ID <uktkJ-3lv-7@gated-at.bofh.it> (permalink)
References <ujt3s-6CP-9@gated-at.bofh.it> <ukbnP-rR-3@gated-at.bofh.it>
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Hi Joerg,

> On 30. Aug 2017, at 15:31, Joerg Roedel <joro@8bytes.org> wrote:
> 
> Hi Filippo,
> 
> please change the subject to:
> 
> 	iommu/vt-d: Don't be too aggressive when clearing one context entry
> 
> to follow the convention used in the iommu-tree. Another comment below.

Will do.

> On Mon, Aug 28, 2017 at 04:16:29PM +0200, Filippo Sironi wrote:
>> static void domain_context_clear_one(struct intel_iommu *iommu, u8 bus, u8 devfn)
>> {
>> +	unsigned long flags;
>> +	struct context_entry *context;
>> +	u16 did_old;
>> +
>> 	if (!iommu)
>> 		return;
>> 
>> +	spin_lock_irqsave(&iommu->lock, flags);
>> +	context = iommu_context_addr(iommu, bus, devfn, 0);
>> +	if (!context) {
>> +		spin_unlock_irqrestore(&iommu->lock, flags);
>> +		return;
>> +	}
>> +	did_old = context_domain_id(context);
>> +	spin_unlock_irqrestore(&iommu->lock, flags);
>> 	clear_context_table(iommu, bus, devfn);
> 
> This function is the only caller of clear_context_table(), which does
> similar things (like fetching the context-entry) as you are adding
> above.
> 
> So you can either make clear_context_table() return the old domain-id
> so that you don't need to do it here, or you get rid of the function
> entirely and add the context_clear_entry() and __iommu_flush_cache()
> calls into this code-path.
> 
> Regards,
> 
> 	Joerg

I went for merging domain_context_clear_one() with context_clear_one().

Regards,
Filippo


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Thread

[PATCH] intel-iommu: Don't be too aggressive when clearing one context entry Filippo Sironi <sironi@amazon.de> - 2017-08-28 16:20 +0200
  Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry Joerg Roedel <joro@8bytes.org> - 2017-08-30 15:40 +0200
    Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry "Sironi, Filippo" <sironi@amazon.de> - 2017-08-31 10:50 +0200
  Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry Jacob Pan <jacob.jun.pan@linux.intel.com> - 2017-08-30 17:50 +0200
    Re: [PATCH] intel-iommu: Don't be too aggressive when clearing one  context entry "Sironi, Filippo" <sironi@amazon.de> - 2017-08-31 10:50 +0200
  [PATCH v2] iommu/vt-d: Don't be too aggressive when clearing one context entry Filippo Sironi <sironi@amazon.de> - 2017-08-31 11:10 +0200
    Re: [PATCH v2] iommu/vt-d: Don't be too aggressive when clearing one  context entry Joerg Roedel <joro@8bytes.org> - 2017-09-01 11:40 +0200

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