linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH 1/1] iommu/vt-d: Use device numa domain if RHSA is missing
@ 2020-08-27  5:56 Lu Baolu
  2020-08-28  2:13 ` Tian, Kevin
  0 siblings, 1 reply; 3+ messages in thread
From: Lu Baolu @ 2020-08-27  5:56 UTC (permalink / raw)
  To: Joerg Roedel
  Cc: iommu, linux-kernel, Lu Baolu, Jacob Pan, Kevin Tian, Ashok Raj

If there are multiple NUMA domains but the RHSA is missing in ACPI/DMAR
table, we could default to the device NUMA domain as fall back. This also
benefits the vIOMMU use case where only a single vIOMMU is exposed, hence
no RHSA will be present but device numa domain can be correct.

Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index e0516d64d7a3..bce158468abf 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -700,12 +700,41 @@ static int domain_update_iommu_superpage(struct dmar_domain *domain,
 	return fls(mask);
 }
 
+static int domain_update_device_node(struct dmar_domain *domain)
+{
+	struct device_domain_info *info;
+	int nid = NUMA_NO_NODE;
+
+	assert_spin_locked(&device_domain_lock);
+
+	if (list_empty(&domain->devices))
+		return NUMA_NO_NODE;
+
+	list_for_each_entry(info, &domain->devices, link) {
+		if (!info->dev)
+			continue;
+
+		nid = dev_to_node(info->dev);
+		if (nid != NUMA_NO_NODE)
+			break;
+	}
+
+	return nid;
+}
+
 /* Some capabilities may be different across iommus */
 static void domain_update_iommu_cap(struct dmar_domain *domain)
 {
 	domain_update_iommu_coherency(domain);
 	domain->iommu_snooping = domain_update_iommu_snooping(NULL);
 	domain->iommu_superpage = domain_update_iommu_superpage(domain, NULL);
+
+	/*
+	 * If RHSA is missing, we should default to the device numa domain
+	 * as fall back.
+	 */
+	if (domain->nid == NUMA_NO_NODE)
+		domain->nid = domain_update_device_node(domain);
 }
 
 struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8 bus,
@@ -5086,8 +5115,6 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
 		if (type == IOMMU_DOMAIN_DMA)
 			intel_init_iova_domain(dmar_domain);
 
-		domain_update_iommu_cap(dmar_domain);
-
 		domain = &dmar_domain->domain;
 		domain->geometry.aperture_start = 0;
 		domain->geometry.aperture_end   =
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* RE: [PATCH 1/1] iommu/vt-d: Use device numa domain if RHSA is missing
  2020-08-27  5:56 [PATCH 1/1] iommu/vt-d: Use device numa domain if RHSA is missing Lu Baolu
@ 2020-08-28  2:13 ` Tian, Kevin
  2020-08-31  1:16   ` Lu Baolu
  0 siblings, 1 reply; 3+ messages in thread
From: Tian, Kevin @ 2020-08-28  2:13 UTC (permalink / raw)
  To: Lu Baolu, Joerg Roedel
  Cc: iommu, linux-kernel, Jacob Pan, Raj, Ashok, Jean-Philippe Brucker

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Thursday, August 27, 2020 1:57 PM
> 
> If there are multiple NUMA domains but the RHSA is missing in ACPI/DMAR
> table, we could default to the device NUMA domain as fall back. This also
> benefits the vIOMMU use case where only a single vIOMMU is exposed,
> hence
> no RHSA will be present but device numa domain can be correct.

this benefits vIOMMU but not necessarily only applied to single-vIOMMU
case. The logic still holds in multiple vIOMMU cases as long as RHSA is
not provided.

> 
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Ashok Raj <ashok.raj@intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/intel/iommu.c | 31 +++++++++++++++++++++++++++++--
>  1 file changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index e0516d64d7a3..bce158468abf 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -700,12 +700,41 @@ static int
> domain_update_iommu_superpage(struct dmar_domain *domain,
>  	return fls(mask);
>  }
> 
> +static int domain_update_device_node(struct dmar_domain *domain)
> +{
> +	struct device_domain_info *info;
> +	int nid = NUMA_NO_NODE;
> +
> +	assert_spin_locked(&device_domain_lock);
> +
> +	if (list_empty(&domain->devices))
> +		return NUMA_NO_NODE;
> +
> +	list_for_each_entry(info, &domain->devices, link) {
> +		if (!info->dev)
> +			continue;
> +
> +		nid = dev_to_node(info->dev);
> +		if (nid != NUMA_NO_NODE)
> +			break;
> +	}

There could be multiple device numa nodes as devices within the
same domain may sit behind different IOMMUs. Of course there
is no perfect answer in such situation, and this patch is still an
obvious improvement on current always-on-node0 policy. But 
some comment about such implication is welcomed.

> +
> +	return nid;
> +}
> +
>  /* Some capabilities may be different across iommus */
>  static void domain_update_iommu_cap(struct dmar_domain *domain)
>  {
>  	domain_update_iommu_coherency(domain);
>  	domain->iommu_snooping =
> domain_update_iommu_snooping(NULL);
>  	domain->iommu_superpage =
> domain_update_iommu_superpage(domain, NULL);
> +
> +	/*
> +	 * If RHSA is missing, we should default to the device numa domain
> +	 * as fall back.
> +	 */
> +	if (domain->nid == NUMA_NO_NODE)
> +		domain->nid = domain_update_device_node(domain);
>  }
> 
>  struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8
> bus,
> @@ -5086,8 +5115,6 @@ static struct iommu_domain
> *intel_iommu_domain_alloc(unsigned type)
>  		if (type == IOMMU_DOMAIN_DMA)
>  			intel_init_iova_domain(dmar_domain);
> 
> -		domain_update_iommu_cap(dmar_domain);
> -

Is it intended or by mistake? If the former, looks it is a separate fix...

>  		domain = &dmar_domain->domain;
>  		domain->geometry.aperture_start = 0;
>  		domain->geometry.aperture_end   =
> --
> 2.17.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH 1/1] iommu/vt-d: Use device numa domain if RHSA is missing
  2020-08-28  2:13 ` Tian, Kevin
@ 2020-08-31  1:16   ` Lu Baolu
  0 siblings, 0 replies; 3+ messages in thread
From: Lu Baolu @ 2020-08-31  1:16 UTC (permalink / raw)
  To: Tian, Kevin, Joerg Roedel
  Cc: baolu.lu, iommu, linux-kernel, Jacob Pan, Raj, Ashok,
	Jean-Philippe Brucker

Hi Kevin,

Thanks a lot for looking at my patch.

On 8/28/20 10:13 AM, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Thursday, August 27, 2020 1:57 PM
>>
>> If there are multiple NUMA domains but the RHSA is missing in ACPI/DMAR
>> table, we could default to the device NUMA domain as fall back. This also
>> benefits the vIOMMU use case where only a single vIOMMU is exposed,
>> hence
>> no RHSA will be present but device numa domain can be correct.
> 
> this benefits vIOMMU but not necessarily only applied to single-vIOMMU
> case. The logic still holds in multiple vIOMMU cases as long as RHSA is
> not provided.

Yes. Will refine the description.

> 
>>
>> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
>> Cc: Kevin Tian <kevin.tian@intel.com>
>> Cc: Ashok Raj <ashok.raj@intel.com>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> ---
>>   drivers/iommu/intel/iommu.c | 31 +++++++++++++++++++++++++++++--
>>   1 file changed, 29 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
>> index e0516d64d7a3..bce158468abf 100644
>> --- a/drivers/iommu/intel/iommu.c
>> +++ b/drivers/iommu/intel/iommu.c
>> @@ -700,12 +700,41 @@ static int
>> domain_update_iommu_superpage(struct dmar_domain *domain,
>>   	return fls(mask);
>>   }
>>
>> +static int domain_update_device_node(struct dmar_domain *domain)
>> +{
>> +	struct device_domain_info *info;
>> +	int nid = NUMA_NO_NODE;
>> +
>> +	assert_spin_locked(&device_domain_lock);
>> +
>> +	if (list_empty(&domain->devices))
>> +		return NUMA_NO_NODE;
>> +
>> +	list_for_each_entry(info, &domain->devices, link) {
>> +		if (!info->dev)
>> +			continue;
>> +
>> +		nid = dev_to_node(info->dev);
>> +		if (nid != NUMA_NO_NODE)
>> +			break;
>> +	}
> 
> There could be multiple device numa nodes as devices within the
> same domain may sit behind different IOMMUs. Of course there
> is no perfect answer in such situation, and this patch is still an
> obvious improvement on current always-on-node0 policy. But
> some comment about such implication is welcomed.

I will add some comments here. Without more knowledge, currently we
choose to use the first hit.

> 
>> +
>> +	return nid;
>> +}
>> +
>>   /* Some capabilities may be different across iommus */
>>   static void domain_update_iommu_cap(struct dmar_domain *domain)
>>   {
>>   	domain_update_iommu_coherency(domain);
>>   	domain->iommu_snooping =
>> domain_update_iommu_snooping(NULL);
>>   	domain->iommu_superpage =
>> domain_update_iommu_superpage(domain, NULL);
>> +
>> +	/*
>> +	 * If RHSA is missing, we should default to the device numa domain
>> +	 * as fall back.
>> +	 */
>> +	if (domain->nid == NUMA_NO_NODE)
>> +		domain->nid = domain_update_device_node(domain);
>>   }
>>
>>   struct context_entry *iommu_context_addr(struct intel_iommu *iommu, u8
>> bus,
>> @@ -5086,8 +5115,6 @@ static struct iommu_domain
>> *intel_iommu_domain_alloc(unsigned type)
>>   		if (type == IOMMU_DOMAIN_DMA)
>>   			intel_init_iova_domain(dmar_domain);
>>
>> -		domain_update_iommu_cap(dmar_domain);
>> -
> 
> Is it intended or by mistake? If the former, looks it is a separate fix...

It's a cleanup. When a domain is newly created, this function is
actually a no-op.

> 
>>   		domain = &dmar_domain->domain;
>>   		domain->geometry.aperture_start = 0;
>>   		domain->geometry.aperture_end   =
>> --
>> 2.17.1
> 

Best regards,
baolu

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2020-08-31  1:21 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-27  5:56 [PATCH 1/1] iommu/vt-d: Use device numa domain if RHSA is missing Lu Baolu
2020-08-28  2:13 ` Tian, Kevin
2020-08-31  1:16   ` Lu Baolu

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).