diff mbox

[v11,08/10] iommu/vt-d: assign new page table for dma_map

Message ID 1431337974-545-9-git-send-email-zhen-hual@hp.com (mailing list archive)
State New, archived
Headers show

Commit Message

Li, Zhen-Hua May 11, 2015, 9:52 a.m. UTC
When a device driver issues the first dma_map command for a device, we
assign a new and empty page-table, thus removing all mappings from the
old kernel for the device.

Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
---
 drivers/iommu/intel-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 8 deletions(-)

Comments

Baoquan He May 20, 2015, 11:52 p.m. UTC | #1
On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
> When a device driver issues the first dma_map command for a device, we
> assign a new and empty page-table, thus removing all mappings from the
> old kernel for the device.

Hi Zhenhua,

From your patch I got it will remove all mappings, assign a new
page-table. But I didn't got why you stress an empty page-table. Did I
miss anything?

Thanks
Baoquan

> 
> Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
> ---
>  drivers/iommu/intel-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 50 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 91545bf..3cc1027 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -396,6 +396,9 @@ static int copy_root_entry_table(struct intel_iommu *iommu);
>  
>  static int intel_iommu_load_translation_tables(struct intel_iommu *iommu);
>  
> +static void unmap_device_dma(struct dmar_domain *domain,
> +				struct device *dev,
> +				struct intel_iommu *iommu);
>  static void iommu_check_pre_te_status(struct intel_iommu *iommu);
>  static u8 g_translation_pre_enabled;
>  
> @@ -3115,6 +3118,7 @@ static struct iova *intel_alloc_iova(struct device *dev,
>  static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
>  {
>  	struct dmar_domain *domain;
> +	struct intel_iommu *iommu;
>  	int ret;
>  
>  	domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
> @@ -3124,14 +3128,30 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
>  		return NULL;
>  	}
>  
> -	/* make sure context mapping is ok */
> -	if (unlikely(!domain_context_mapped(dev))) {
> -		ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> -		if (ret) {
> -			printk(KERN_ERR "Domain context map for %s failed",
> -			       dev_name(dev));
> -			return NULL;
> -		}
> +	/* if in kdump kernel, we need to unmap the mapped dma pages,
> +	 * detach this device first.
> +	 */
> +	if (likely(domain_context_mapped(dev))) {
> +		iommu = domain_get_iommu(domain);
> +		if (iommu->pre_enabled_trans) {
> +			unmap_device_dma(domain, dev, iommu);
> +
> +			domain = get_domain_for_dev(dev,
> +				DEFAULT_DOMAIN_ADDRESS_WIDTH);
> +			if (!domain) {
> +				pr_err("Allocating domain for %s failed",
> +				       dev_name(dev));
> +				return NULL;
> +			}
> +		} else
> +			return domain;
> +	}
> +
> +	ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> +	if (ret) {
> +		pr_err("Domain context map for %s failed",
> +		       dev_name(dev));
> +		return NULL;
>  	}
>  
>  	return domain;
> @@ -5168,6 +5188,28 @@ static int intel_iommu_load_translation_tables(struct intel_iommu *iommu)
>  	return ret;
>  }
>  
> +static void unmap_device_dma(struct dmar_domain *domain,
> +				struct device *dev,
> +				struct intel_iommu *iommu)
> +{
> +	struct context_entry *ce;
> +	struct iova *iova;
> +	phys_addr_t phys_addr;
> +	dma_addr_t dev_addr;
> +	struct pci_dev *pdev;
> +
> +	pdev = to_pci_dev(dev);
> +	ce = iommu_context_addr(iommu, pdev->bus->number, pdev->devfn, 1);
> +	phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
> +	dev_addr = phys_to_dma(dev, phys_addr);
> +
> +	iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
> +	if (iova)
> +		intel_unmap(dev, dev_addr);
> +
> +	domain_remove_one_dev_info(domain, dev);
> +}
> +
>  static void iommu_check_pre_te_status(struct intel_iommu *iommu)
>  {
>  	u32 sts;
> -- 
> 2.0.0-rc0
> 
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Li, Zhen-Hua May 21, 2015, 1:27 a.m. UTC | #2
Hi Baoquan,

In the early version of this patchset, old page tables are used by new
kernel.  But as discussed, we need to make kernel use new pages when
there is a new dma request , so we need to unmap the pages which were
mapped in old kernel, and this is what this patch does.

Thanks
Zhenhua

On 05/21/2015 07:52 AM, Baoquan He wrote:
> On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
>> When a device driver issues the first dma_map command for a device, we
>> assign a new and empty page-table, thus removing all mappings from the
>> old kernel for the device.
>
> Hi Zhenhua,
>
>  From your patch I got it will remove all mappings, assign a new
> page-table. But I didn't got why you stress an empty page-table. Did I
> miss anything?
>
> Thanks
> Baoquan
>
>>
>> Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
>> ---
>>   drivers/iommu/intel-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++-------
>>   1 file changed, 50 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
>> index 91545bf..3cc1027 100644
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -396,6 +396,9 @@ static int copy_root_entry_table(struct intel_iommu *iommu);
>>
>>   static int intel_iommu_load_translation_tables(struct intel_iommu *iommu);
>>
>> +static void unmap_device_dma(struct dmar_domain *domain,
>> +				struct device *dev,
>> +				struct intel_iommu *iommu);
>>   static void iommu_check_pre_te_status(struct intel_iommu *iommu);
>>   static u8 g_translation_pre_enabled;
>>
>> @@ -3115,6 +3118,7 @@ static struct iova *intel_alloc_iova(struct device *dev,
>>   static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
>>   {
>>   	struct dmar_domain *domain;
>> +	struct intel_iommu *iommu;
>>   	int ret;
>>
>>   	domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
>> @@ -3124,14 +3128,30 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
>>   		return NULL;
>>   	}
>>
>> -	/* make sure context mapping is ok */
>> -	if (unlikely(!domain_context_mapped(dev))) {
>> -		ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
>> -		if (ret) {
>> -			printk(KERN_ERR "Domain context map for %s failed",
>> -			       dev_name(dev));
>> -			return NULL;
>> -		}
>> +	/* if in kdump kernel, we need to unmap the mapped dma pages,
>> +	 * detach this device first.
>> +	 */
>> +	if (likely(domain_context_mapped(dev))) {
>> +		iommu = domain_get_iommu(domain);
>> +		if (iommu->pre_enabled_trans) {
>> +			unmap_device_dma(domain, dev, iommu);
>> +
>> +			domain = get_domain_for_dev(dev,
>> +				DEFAULT_DOMAIN_ADDRESS_WIDTH);
>> +			if (!domain) {
>> +				pr_err("Allocating domain for %s failed",
>> +				       dev_name(dev));
>> +				return NULL;
>> +			}
>> +		} else
>> +			return domain;
>> +	}
>> +
>> +	ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
>> +	if (ret) {
>> +		pr_err("Domain context map for %s failed",
>> +		       dev_name(dev));
>> +		return NULL;
>>   	}
>>
>>   	return domain;
>> @@ -5168,6 +5188,28 @@ static int intel_iommu_load_translation_tables(struct intel_iommu *iommu)
>>   	return ret;
>>   }
>>
>> +static void unmap_device_dma(struct dmar_domain *domain,
>> +				struct device *dev,
>> +				struct intel_iommu *iommu)
>> +{
>> +	struct context_entry *ce;
>> +	struct iova *iova;
>> +	phys_addr_t phys_addr;
>> +	dma_addr_t dev_addr;
>> +	struct pci_dev *pdev;
>> +
>> +	pdev = to_pci_dev(dev);
>> +	ce = iommu_context_addr(iommu, pdev->bus->number, pdev->devfn, 1);
>> +	phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
>> +	dev_addr = phys_to_dma(dev, phys_addr);
>> +
>> +	iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
>> +	if (iova)
>> +		intel_unmap(dev, dev_addr);
>> +
>> +	domain_remove_one_dev_info(domain, dev);
>> +}
>> +
>>   static void iommu_check_pre_te_status(struct intel_iommu *iommu)
>>   {
>>   	u32 sts;
>> --
>> 2.0.0-rc0
>>

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Baoquan He May 21, 2015, 6:54 a.m. UTC | #3
On 05/21/15 at 09:27am, Li, ZhenHua wrote:
> Hi Baoquan,
> 
> In the early version of this patchset, old page tables are used by new
> kernel.  But as discussed, we need to make kernel use new pages when
> there is a new dma request , so we need to unmap the pages which were
> mapped in old kernel, and this is what this patch does.

OK, just a new page table allocated in init_domain(), right? I thought a
specific empty page-table is allocated for these new domains in kdump
kernel.

> 
> Thanks
> Zhenhua
> 
> On 05/21/2015 07:52 AM, Baoquan He wrote:
> >On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
> >>When a device driver issues the first dma_map command for a device, we
> >>assign a new and empty page-table, thus removing all mappings from the
> >>old kernel for the device.
> >
> >Hi Zhenhua,
> >
> > From your patch I got it will remove all mappings, assign a new
> >page-table. But I didn't got why you stress an empty page-table. Did I
> >miss anything?
> >
> >Thanks
> >Baoquan
> >
> >>
> >>Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
> >>---
> >>  drivers/iommu/intel-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++-------
> >>  1 file changed, 50 insertions(+), 8 deletions(-)
> >>
> >>diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> >>index 91545bf..3cc1027 100644
> >>--- a/drivers/iommu/intel-iommu.c
> >>+++ b/drivers/iommu/intel-iommu.c
> >>@@ -396,6 +396,9 @@ static int copy_root_entry_table(struct intel_iommu *iommu);
> >>
> >>  static int intel_iommu_load_translation_tables(struct intel_iommu *iommu);
> >>
> >>+static void unmap_device_dma(struct dmar_domain *domain,
> >>+				struct device *dev,
> >>+				struct intel_iommu *iommu);
> >>  static void iommu_check_pre_te_status(struct intel_iommu *iommu);
> >>  static u8 g_translation_pre_enabled;
> >>
> >>@@ -3115,6 +3118,7 @@ static struct iova *intel_alloc_iova(struct device *dev,
> >>  static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
> >>  {
> >>  	struct dmar_domain *domain;
> >>+	struct intel_iommu *iommu;
> >>  	int ret;
> >>
> >>  	domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
> >>@@ -3124,14 +3128,30 @@ static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
> >>  		return NULL;
> >>  	}
> >>
> >>-	/* make sure context mapping is ok */
> >>-	if (unlikely(!domain_context_mapped(dev))) {
> >>-		ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> >>-		if (ret) {
> >>-			printk(KERN_ERR "Domain context map for %s failed",
> >>-			       dev_name(dev));
> >>-			return NULL;
> >>-		}
> >>+	/* if in kdump kernel, we need to unmap the mapped dma pages,
> >>+	 * detach this device first.
> >>+	 */
> >>+	if (likely(domain_context_mapped(dev))) {
> >>+		iommu = domain_get_iommu(domain);
> >>+		if (iommu->pre_enabled_trans) {
> >>+			unmap_device_dma(domain, dev, iommu);
> >>+
> >>+			domain = get_domain_for_dev(dev,
> >>+				DEFAULT_DOMAIN_ADDRESS_WIDTH);
> >>+			if (!domain) {
> >>+				pr_err("Allocating domain for %s failed",
> >>+				       dev_name(dev));
> >>+				return NULL;
> >>+			}
> >>+		} else
> >>+			return domain;
> >>+	}
> >>+
> >>+	ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
> >>+	if (ret) {
> >>+		pr_err("Domain context map for %s failed",
> >>+		       dev_name(dev));
> >>+		return NULL;
> >>  	}
> >>
> >>  	return domain;
> >>@@ -5168,6 +5188,28 @@ static int intel_iommu_load_translation_tables(struct intel_iommu *iommu)
> >>  	return ret;
> >>  }
> >>
> >>+static void unmap_device_dma(struct dmar_domain *domain,
> >>+				struct device *dev,
> >>+				struct intel_iommu *iommu)
> >>+{
> >>+	struct context_entry *ce;
> >>+	struct iova *iova;
> >>+	phys_addr_t phys_addr;
> >>+	dma_addr_t dev_addr;
> >>+	struct pci_dev *pdev;
> >>+
> >>+	pdev = to_pci_dev(dev);
> >>+	ce = iommu_context_addr(iommu, pdev->bus->number, pdev->devfn, 1);
> >>+	phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
> >>+	dev_addr = phys_to_dma(dev, phys_addr);
> >>+
> >>+	iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
> >>+	if (iova)
> >>+		intel_unmap(dev, dev_addr);
> >>+
> >>+	domain_remove_one_dev_info(domain, dev);
> >>+}
> >>+
> >>  static void iommu_check_pre_te_status(struct intel_iommu *iommu)
> >>  {
> >>  	u32 sts;
> >>--
> >>2.0.0-rc0
> >>
> 
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Li, Zhen-Hua May 21, 2015, 8:40 a.m. UTC | #4
Hi Baoquan,
During driver being loaded and initialized, when there is a new dma
request, the function
                __get_valid_domain_for_dev
is called, and then new page is mapped.

Please check this:
struct dma_map_ops intel_dma_ops = {
         .alloc = intel_alloc_coherent,
         .free = intel_free_coherent,
         .map_sg = intel_map_sg,
         .unmap_sg = intel_unmap_sg,
         .map_page = intel_map_page,
         .unmap_page = intel_unmap_page,
         .mapping_error = intel_mapping_error,
};

You can also add dump_stack() in __get_valid_domain_for_dev to debug.

Thanks
Zhenhua

On 05/21/2015 02:54 PM, Baoquan He wrote:
> On 05/21/15 at 09:27am, Li, ZhenHua wrote:
>> Hi Baoquan,
>>
>> In the early version of this patchset, old page tables are used by new
>> kernel.  But as discussed, we need to make kernel use new pages when
>> there is a new dma request , so we need to unmap the pages which were
>> mapped in old kernel, and this is what this patch does.
>
> OK, just a new page table allocated in init_domain(), right? I thought a
> specific empty page-table is allocated for these new domains in kdump
> kernel.
>
>>
>> Thanks
>> Zhenhua
>>
>> On 05/21/2015 07:52 AM, Baoquan He wrote:
>>> On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
>>>> When a device driver issues the first dma_map command for a device, we
>>>> assign a new and empty page-table, thus removing all mappings from the
>>>> old kernel for the device.
>>>
>>> Hi Zhenhua,
>>>
>>>  From your patch I got it will remove all mappings, assign a new
>>> page-table. But I didn't got why you stress an empty page-table. Did I
>>> miss anything?
>>>
>>> Thanks
>>> Baoquan
>>>
>>>>
>>>> Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
>>>> --
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Baoquan He May 21, 2015, 10:11 a.m. UTC | #5
On 05/21/15 at 04:40pm, Li, ZhenHua wrote:
> Hi Baoquan,
> During driver being loaded and initialized, when there is a new dma
> request, the function
>                __get_valid_domain_for_dev
> is called, and then new page is mapped.
> 
> Please check this:
> struct dma_map_ops intel_dma_ops = {
>         .alloc = intel_alloc_coherent,
>         .free = intel_free_coherent,
>         .map_sg = intel_map_sg,
>         .unmap_sg = intel_unmap_sg,
>         .map_page = intel_map_page,
>         .unmap_page = intel_unmap_page,
>         .mapping_error = intel_mapping_error,
> };
> 
> You can also add dump_stack() in __get_valid_domain_for_dev to debug.

Yeah, I saw that. At the beginning I am just wondering why you say a new
page-table, and also mention it's a empty page-table. I think here that
new page-table is an empty page-table when you said them.

No confusion any more. Thanks for explanation.

> 
> Thanks
> Zhenhua
> 
> On 05/21/2015 02:54 PM, Baoquan He wrote:
> >On 05/21/15 at 09:27am, Li, ZhenHua wrote:
> >>Hi Baoquan,
> >>
> >>In the early version of this patchset, old page tables are used by new
> >>kernel.  But as discussed, we need to make kernel use new pages when
> >>there is a new dma request , so we need to unmap the pages which were
> >>mapped in old kernel, and this is what this patch does.
> >
> >OK, just a new page table allocated in init_domain(), right? I thought a
> >specific empty page-table is allocated for these new domains in kdump
> >kernel.
> >
> >>
> >>Thanks
> >>Zhenhua
> >>
> >>On 05/21/2015 07:52 AM, Baoquan He wrote:
> >>>On 05/11/15 at 05:52pm, Li, Zhen-Hua wrote:
> >>>>When a device driver issues the first dma_map command for a device, we
> >>>>assign a new and empty page-table, thus removing all mappings from the
> >>>>old kernel for the device.
> >>>
> >>>Hi Zhenhua,
> >>>
> >>> From your patch I got it will remove all mappings, assign a new
> >>>page-table. But I didn't got why you stress an empty page-table. Did I
> >>>miss anything?
> >>>
> >>>Thanks
> >>>Baoquan
> >>>
> >>>>
> >>>>Signed-off-by: Li, Zhen-Hua <zhen-hual@hp.com>
> >>>>--
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diff mbox

Patch

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 91545bf..3cc1027 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -396,6 +396,9 @@  static int copy_root_entry_table(struct intel_iommu *iommu);
 
 static int intel_iommu_load_translation_tables(struct intel_iommu *iommu);
 
+static void unmap_device_dma(struct dmar_domain *domain,
+				struct device *dev,
+				struct intel_iommu *iommu);
 static void iommu_check_pre_te_status(struct intel_iommu *iommu);
 static u8 g_translation_pre_enabled;
 
@@ -3115,6 +3118,7 @@  static struct iova *intel_alloc_iova(struct device *dev,
 static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
 {
 	struct dmar_domain *domain;
+	struct intel_iommu *iommu;
 	int ret;
 
 	domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
@@ -3124,14 +3128,30 @@  static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
 		return NULL;
 	}
 
-	/* make sure context mapping is ok */
-	if (unlikely(!domain_context_mapped(dev))) {
-		ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
-		if (ret) {
-			printk(KERN_ERR "Domain context map for %s failed",
-			       dev_name(dev));
-			return NULL;
-		}
+	/* if in kdump kernel, we need to unmap the mapped dma pages,
+	 * detach this device first.
+	 */
+	if (likely(domain_context_mapped(dev))) {
+		iommu = domain_get_iommu(domain);
+		if (iommu->pre_enabled_trans) {
+			unmap_device_dma(domain, dev, iommu);
+
+			domain = get_domain_for_dev(dev,
+				DEFAULT_DOMAIN_ADDRESS_WIDTH);
+			if (!domain) {
+				pr_err("Allocating domain for %s failed",
+				       dev_name(dev));
+				return NULL;
+			}
+		} else
+			return domain;
+	}
+
+	ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
+	if (ret) {
+		pr_err("Domain context map for %s failed",
+		       dev_name(dev));
+		return NULL;
 	}
 
 	return domain;
@@ -5168,6 +5188,28 @@  static int intel_iommu_load_translation_tables(struct intel_iommu *iommu)
 	return ret;
 }
 
+static void unmap_device_dma(struct dmar_domain *domain,
+				struct device *dev,
+				struct intel_iommu *iommu)
+{
+	struct context_entry *ce;
+	struct iova *iova;
+	phys_addr_t phys_addr;
+	dma_addr_t dev_addr;
+	struct pci_dev *pdev;
+
+	pdev = to_pci_dev(dev);
+	ce = iommu_context_addr(iommu, pdev->bus->number, pdev->devfn, 1);
+	phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
+	dev_addr = phys_to_dma(dev, phys_addr);
+
+	iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
+	if (iova)
+		intel_unmap(dev, dev_addr);
+
+	domain_remove_one_dev_info(domain, dev);
+}
+
 static void iommu_check_pre_te_status(struct intel_iommu *iommu)
 {
 	u32 sts;