The struct intel_svm was used for keeping attached devices info for sva
domain. Since sva domain is a kind of iommu_domain, the struct
dmar_domain should centralize all info of a sva domain, including the
info of attached devices. Therefore, retire struct intel_svm to clean up
the code.
Besides, allocate sva domain in domain_alloc_sva() callback which allows
the memory management notifier lifetime to follow the lifetime of the
iommu_domain.
Co-developed-by: Tina Zhang <[email protected]>
Signed-off-by: Tina Zhang <[email protected]>
Signed-off-by: Lu Baolu <[email protected]>
---
drivers/iommu/intel/iommu.h | 26 ++++------
drivers/iommu/intel/iommu.c | 9 +---
drivers/iommu/intel/svm.c | 94 +++++++++----------------------------
3 files changed, 32 insertions(+), 97 deletions(-)
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 90611ec08a7c..0951be947ff9 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -649,8 +649,12 @@ struct dmar_domain {
/* link to parent domain siblings */
struct list_head s2_link;
};
+
+ /* SVA domain */
+ struct {
+ struct mmu_notifier notifier;
+ };
};
- struct intel_svm *svm;
struct iommu_domain domain; /* generic domain data structure for
iommu core */
@@ -1144,26 +1148,16 @@ int intel_svm_enable_prq(struct intel_iommu *iommu);
int intel_svm_finish_prq(struct intel_iommu *iommu);
void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
struct iommu_page_response *msg);
-struct iommu_domain *intel_svm_domain_alloc(void);
-void intel_svm_remove_dev_pasid(struct iommu_domain *domain);
+struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
+ struct mm_struct *mm);
void intel_drain_pasid_prq(struct device *dev, u32 pasid);
-
-struct intel_svm {
- struct mmu_notifier notifier;
- struct mm_struct *mm;
- u32 pasid;
- struct dmar_domain *domain;
-};
#else
static inline void intel_svm_check(struct intel_iommu *iommu) {}
static inline void intel_drain_pasid_prq(struct device *dev, u32 pasid) {}
-static inline struct iommu_domain *intel_svm_domain_alloc(void)
-{
- return NULL;
-}
-
-static inline void intel_svm_remove_dev_pasid(struct iommu_domain *domain)
+static inline struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
+ struct mm_struct *mm)
{
+ return ERR_PTR(-ENODEV);
}
#endif
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index d7f205cd0aac..b8a0f759a24f 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3680,8 +3680,6 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
return domain;
case IOMMU_DOMAIN_IDENTITY:
return &si_domain->domain;
- case IOMMU_DOMAIN_SVA:
- return intel_svm_domain_alloc();
default:
return NULL;
}
@@ -4388,14 +4386,8 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
WARN_ON_ONCE(!dev_pasid);
spin_unlock_irqrestore(&dmar_domain->lock, flags);
- /*
- * The SVA implementation needs to handle its own stuffs like the mm
- * notification. Before consolidating that code into iommu core, let
- * the intel sva code handle it.
- */
if (domain->type == IOMMU_DOMAIN_SVA) {
cache_tag_unassign_domain(dmar_domain, FLPT_DEFAULT_DID, dev, pasid);
- intel_svm_remove_dev_pasid(domain);
} else {
did = domain_id_iommu(dmar_domain, iommu);
cache_tag_unassign_domain(dmar_domain, did, dev, pasid);
@@ -4624,6 +4616,7 @@ const struct iommu_ops intel_iommu_ops = {
.hw_info = intel_iommu_hw_info,
.domain_alloc = intel_iommu_domain_alloc,
.domain_alloc_user = intel_iommu_domain_alloc_user,
+ .domain_alloc_sva = intel_svm_domain_alloc,
.probe_device = intel_iommu_probe_device,
.probe_finalize = intel_iommu_probe_finalize,
.release_device = intel_iommu_release_device,
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 0b767d16fb71..47e475f67046 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -26,23 +26,6 @@
static irqreturn_t prq_event_thread(int irq, void *d);
-static DEFINE_XARRAY_ALLOC(pasid_private_array);
-static int pasid_private_add(ioasid_t pasid, void *priv)
-{
- return xa_alloc(&pasid_private_array, &pasid, priv,
- XA_LIMIT(pasid, pasid), GFP_ATOMIC);
-}
-
-static void pasid_private_remove(ioasid_t pasid)
-{
- xa_erase(&pasid_private_array, pasid);
-}
-
-static void *pasid_private_find(ioasid_t pasid)
-{
- return xa_load(&pasid_private_array, pasid);
-}
-
int intel_svm_enable_prq(struct intel_iommu *iommu)
{
struct iopf_queue *iopfq;
@@ -156,8 +139,7 @@ static void intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
struct mm_struct *mm,
unsigned long start, unsigned long end)
{
- struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
- struct dmar_domain *domain = svm->domain;
+ struct dmar_domain *domain = container_of(mn, struct dmar_domain, notifier);
if (start == 0 && end == -1UL) {
cache_tag_flush_all(domain);
@@ -169,8 +151,7 @@ static void intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
{
- struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
- struct dmar_domain *domain = svm->domain;
+ struct dmar_domain *domain = container_of(mn, struct dmar_domain, notifier);
struct dev_pasid_info *dev_pasid;
struct device_domain_info *info;
unsigned long flags;
@@ -210,41 +191,13 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
struct intel_iommu *iommu = info->iommu;
struct mm_struct *mm = domain->mm;
struct dev_pasid_info *dev_pasid;
- struct intel_svm *svm;
unsigned long sflags;
unsigned long flags;
int ret = 0;
- svm = pasid_private_find(pasid);
- if (!svm) {
- svm = kzalloc(sizeof(*svm), GFP_KERNEL);
- if (!svm)
- return -ENOMEM;
-
- svm->pasid = pasid;
- svm->mm = mm;
-
- svm->notifier.ops = &intel_mmuops;
- svm->domain = to_dmar_domain(domain);
- ret = mmu_notifier_register(&svm->notifier, mm);
- if (ret) {
- kfree(svm);
- return ret;
- }
-
- ret = pasid_private_add(svm->pasid, svm);
- if (ret) {
- mmu_notifier_unregister(&svm->notifier, mm);
- kfree(svm);
- return ret;
- }
- }
-
- dmar_domain->svm = svm;
-
dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
if (!dev_pasid)
- goto free_svm;
+ return -ENOMEM;
dev_pasid->dev = dev;
dev_pasid->pasid = pasid;
@@ -272,30 +225,10 @@ static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
FLPT_DEFAULT_DID, dev, pasid);
free_dev_pasid:
kfree(dev_pasid);
-free_svm:
- if (list_empty(&dmar_domain->dev_pasids)) {
- mmu_notifier_unregister(&svm->notifier, mm);
- pasid_private_remove(pasid);
- kfree(svm);
- }
return ret;
}
-void intel_svm_remove_dev_pasid(struct iommu_domain *domain)
-{
- struct dmar_domain *dmar_domain = to_dmar_domain(domain);
- struct intel_svm *svm = dmar_domain->svm;
- struct mm_struct *mm = domain->mm;
-
- if (list_empty(&dmar_domain->dev_pasids)) {
- if (svm->notifier.ops)
- mmu_notifier_unregister(&svm->notifier, mm);
- pasid_private_remove(svm->pasid);
- kfree(svm);
- }
-}
-
/* Page request queue descriptor */
struct page_req_dsc {
union {
@@ -663,7 +596,12 @@ void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
static void intel_svm_domain_free(struct iommu_domain *domain)
{
- kfree(to_dmar_domain(domain));
+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+
+ if (dmar_domain->notifier.ops)
+ mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
+
+ kfree(dmar_domain);
}
static const struct iommu_domain_ops intel_svm_domain_ops = {
@@ -671,13 +609,16 @@ static const struct iommu_domain_ops intel_svm_domain_ops = {
.free = intel_svm_domain_free
};
-struct iommu_domain *intel_svm_domain_alloc(void)
+struct iommu_domain *intel_svm_domain_alloc(struct device *dev,
+ struct mm_struct *mm)
{
struct dmar_domain *domain;
+ int ret;
domain = kzalloc(sizeof(*domain), GFP_KERNEL);
if (!domain)
- return NULL;
+ return ERR_PTR(-ENOMEM);
+
domain->domain.ops = &intel_svm_domain_ops;
domain->use_first_level = true;
INIT_LIST_HEAD(&domain->dev_pasids);
@@ -685,5 +626,12 @@ struct iommu_domain *intel_svm_domain_alloc(void)
spin_lock_init(&domain->cache_lock);
spin_lock_init(&domain->lock);
+ domain->notifier.ops = &intel_mmuops;
+ ret = mmu_notifier_register(&domain->notifier, mm);
+ if (ret) {
+ kfree(domain);
+ return ERR_PTR(ret);
+ }
+
return &domain->domain;
}
--
2.34.1
On Wed, Apr 10, 2024 at 10:08:44AM +0800, Lu Baolu wrote:
> The struct intel_svm was used for keeping attached devices info for sva
> domain. Since sva domain is a kind of iommu_domain, the struct
> dmar_domain should centralize all info of a sva domain, including the
> info of attached devices. Therefore, retire struct intel_svm to clean up
> the code.
>
> Besides, allocate sva domain in domain_alloc_sva() callback which allows
> the memory management notifier lifetime to follow the lifetime of the
> iommu_domain.
>
> Co-developed-by: Tina Zhang <[email protected]>
> Signed-off-by: Tina Zhang <[email protected]>
> Signed-off-by: Lu Baolu <[email protected]>
> ---
> drivers/iommu/intel/iommu.h | 26 ++++------
> drivers/iommu/intel/iommu.c | 9 +---
> drivers/iommu/intel/svm.c | 94 +++++++++----------------------------
> 3 files changed, 32 insertions(+), 97 deletions(-)
Happy to see the pasid xarray in the driver go away.
> @@ -4388,14 +4386,8 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
> WARN_ON_ONCE(!dev_pasid);
> spin_unlock_irqrestore(&dmar_domain->lock, flags);
>
> - /*
> - * The SVA implementation needs to handle its own stuffs like the mm
> - * notification. Before consolidating that code into iommu core, let
> - * the intel sva code handle it.
> - */
> if (domain->type == IOMMU_DOMAIN_SVA) {
> cache_tag_unassign_domain(dmar_domain, FLPT_DEFAULT_DID, dev, pasid);
> - intel_svm_remove_dev_pasid(domain);
> } else {
> did = domain_id_iommu(dmar_domain, iommu);
> cache_tag_unassign_domain(dmar_domain, did, dev, pasid);
It seems very strange that SVA has a different DID scheme, why is
this? PASID and SVA should not be different at this layer.
> @@ -663,7 +596,12 @@ void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
>
> static void intel_svm_domain_free(struct iommu_domain *domain)
> {
> - kfree(to_dmar_domain(domain));
> + struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> +
> + if (dmar_domain->notifier.ops)
> + mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
This should really use mmu_notifier_put() and a delayed kfree, see my
part 2 ARM series for how that should look.
Otherwise I think it looks fine
Jason
> From: Baolu Lu <[email protected]>
> Sent: Thursday, April 11, 2024 3:56 PM
>
> On 2024/4/10 23:49, Jason Gunthorpe wrote:
> > On Wed, Apr 10, 2024 at 10:08:44AM +0800, Lu Baolu wrote:
> >> @@ -4388,14 +4386,8 @@ static void
> intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
> >> WARN_ON_ONCE(!dev_pasid);
> >> spin_unlock_irqrestore(&dmar_domain->lock, flags);
> >>
> >> - /*
> >> - * The SVA implementation needs to handle its own stuffs like the
> mm
> >> - * notification. Before consolidating that code into iommu core, let
> >> - * the intel sva code handle it.
> >> - */
> >> if (domain->type == IOMMU_DOMAIN_SVA) {
> >> cache_tag_unassign_domain(dmar_domain,
> FLPT_DEFAULT_DID, dev, pasid);
> >> - intel_svm_remove_dev_pasid(domain);
> >> } else {
> >> did = domain_id_iommu(dmar_domain, iommu);
> >> cache_tag_unassign_domain(dmar_domain, did, dev, pasid);
> >
> > It seems very strange that SVA has a different DID scheme, why is
> > this? PASID and SVA should not be different at this layer.
>
> The VT-d spec recommends that all SVA domains share a single domain ID.
> The PASID is unique to each SVA domain, hence the cache tags are unique.
> Currently, the Intel IOMMU driver assigns different domain IDs for all
> domains except the SVA type.
>
> Sharing a domain ID is not specific to SVA. In general, for devices
> under a single IOMMU, domains with unique PASIDs can share the same
> domain ID.
>
> In the long term (also on my task list), we will extend the cache tag
> code to support sharing domain IDs and remove the domain type check from
> the main code. This will also benefit the nesting case, where user
> domains nested on the same parent could share a domain ID.
>
at least above might be changed to a unified call with the helper
accepting an iommu parameter and then finding proper did
internally based on domain type, e.g.
cache_tag_unassign_domain(domain, iommu, dev, pasid)
{
if (domain->type == IOMMU_DOMAIN_SVA)
did = FLPT_DEFAULT_DID;
else
did = domain_id_iommu(domain, iommu);
...
}
On 2024/4/10 23:49, Jason Gunthorpe wrote:
> On Wed, Apr 10, 2024 at 10:08:44AM +0800, Lu Baolu wrote:
>> The struct intel_svm was used for keeping attached devices info for sva
>> domain. Since sva domain is a kind of iommu_domain, the struct
>> dmar_domain should centralize all info of a sva domain, including the
>> info of attached devices. Therefore, retire struct intel_svm to clean up
>> the code.
>>
>> Besides, allocate sva domain in domain_alloc_sva() callback which allows
>> the memory management notifier lifetime to follow the lifetime of the
>> iommu_domain.
>>
>> Co-developed-by: Tina Zhang <[email protected]>
>> Signed-off-by: Tina Zhang <[email protected]>
>> Signed-off-by: Lu Baolu <[email protected]>
>> ---
>> drivers/iommu/intel/iommu.h | 26 ++++------
>> drivers/iommu/intel/iommu.c | 9 +---
>> drivers/iommu/intel/svm.c | 94 +++++++++----------------------------
>> 3 files changed, 32 insertions(+), 97 deletions(-)
>
> Happy to see the pasid xarray in the driver go away.
Yeah, it was really ugly.
>
>> @@ -4388,14 +4386,8 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
>> WARN_ON_ONCE(!dev_pasid);
>> spin_unlock_irqrestore(&dmar_domain->lock, flags);
>>
>> - /*
>> - * The SVA implementation needs to handle its own stuffs like the mm
>> - * notification. Before consolidating that code into iommu core, let
>> - * the intel sva code handle it.
>> - */
>> if (domain->type == IOMMU_DOMAIN_SVA) {
>> cache_tag_unassign_domain(dmar_domain, FLPT_DEFAULT_DID, dev, pasid);
>> - intel_svm_remove_dev_pasid(domain);
>> } else {
>> did = domain_id_iommu(dmar_domain, iommu);
>> cache_tag_unassign_domain(dmar_domain, did, dev, pasid);
>
> It seems very strange that SVA has a different DID scheme, why is
> this? PASID and SVA should not be different at this layer.
The VT-d spec recommends that all SVA domains share a single domain ID.
The PASID is unique to each SVA domain, hence the cache tags are unique.
Currently, the Intel IOMMU driver assigns different domain IDs for all
domains except the SVA type.
Sharing a domain ID is not specific to SVA. In general, for devices
under a single IOMMU, domains with unique PASIDs can share the same
domain ID.
In the long term (also on my task list), we will extend the cache tag
code to support sharing domain IDs and remove the domain type check from
the main code. This will also benefit the nesting case, where user
domains nested on the same parent could share a domain ID.
>
>> @@ -663,7 +596,12 @@ void intel_svm_page_response(struct device *dev, struct iopf_fault *evt,
>>
>> static void intel_svm_domain_free(struct iommu_domain *domain)
>> {
>> - kfree(to_dmar_domain(domain));
>> + struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>> +
>> + if (dmar_domain->notifier.ops)
>> + mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
>
> This should really use mmu_notifier_put() and a delayed kfree, see my
> part 2 ARM series for how that should look.
Learning from
https://lore.kernel.org/linux-iommu/[email protected]/
I will make it like below
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 47e475f67046..41374979eecc 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -178,9 +178,15 @@ static void intel_mm_release(struct mmu_notifier
*mn, struct mm_struct *mm)
}
+static void intel_mm_free_notifier(struct mmu_notifier *mn)
+{
+ kfree(container_of(mn, struct dmar_domain, notifier));
+}
+
static const struct mmu_notifier_ops intel_mmuops = {
.release = intel_mm_release,
.arch_invalidate_secondary_tlbs =
intel_arch_invalidate_secondary_tlbs,
+ .free_notifier = intel_mm_free_notifier,
};
static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
@@ -598,10 +604,8 @@ static void intel_svm_domain_free(struct
iommu_domain *domain)
{
struct dmar_domain *dmar_domain = to_dmar_domain(domain);
- if (dmar_domain->notifier.ops)
- mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
-
- kfree(dmar_domain);
+ /* dmar_domain free is defered to the mmu free_notifier callback. */
+ mmu_notifier_put(&dmar_domain->notifier);
}
static const struct iommu_domain_ops intel_svm_domain_ops = {
>
> Otherwise I think it looks fine
Thank you for review.
Best regards,
baolu
On Thu, Apr 11, 2024 at 03:55:50PM +0800, Baolu Lu wrote:
> > > @@ -4388,14 +4386,8 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
> > > WARN_ON_ONCE(!dev_pasid);
> > > spin_unlock_irqrestore(&dmar_domain->lock, flags);
> > > - /*
> > > - * The SVA implementation needs to handle its own stuffs like the mm
> > > - * notification. Before consolidating that code into iommu core, let
> > > - * the intel sva code handle it.
> > > - */
> > > if (domain->type == IOMMU_DOMAIN_SVA) {
> > > cache_tag_unassign_domain(dmar_domain, FLPT_DEFAULT_DID, dev, pasid);
> > > - intel_svm_remove_dev_pasid(domain);
> > > } else {
> > > did = domain_id_iommu(dmar_domain, iommu);
> > > cache_tag_unassign_domain(dmar_domain, did, dev, pasid);
> >
> > It seems very strange that SVA has a different DID scheme, why is
> > this? PASID and SVA should not be different at this layer.
>
> The VT-d spec recommends that all SVA domains share a single domain ID.
> The PASID is unique to each SVA domain, hence the cache tags are unique.
> Currently, the Intel IOMMU driver assigns different domain IDs for all
> domains except the SVA type.
>
> Sharing a domain ID is not specific to SVA. In general, for devices
> under a single IOMMU, domains with unique PASIDs can share the same
> domain ID.
>
> In the long term (also on my task list), we will extend the cache tag
> code to support sharing domain IDs and remove the domain type check from
> the main code. This will also benefit the nesting case, where user
> domains nested on the same parent could share a domain ID.
Okay, that makes sense
> +static void intel_mm_free_notifier(struct mmu_notifier *mn)
> +{
> + kfree(container_of(mn, struct dmar_domain, notifier));
> +}
> +
> static const struct mmu_notifier_ops intel_mmuops = {
> .release = intel_mm_release,
> .arch_invalidate_secondary_tlbs =
> intel_arch_invalidate_secondary_tlbs,
> + .free_notifier = intel_mm_free_notifier,
> };
>
> static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
> @@ -598,10 +604,8 @@ static void intel_svm_domain_free(struct iommu_domain
> *domain)
> {
> struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>
> - if (dmar_domain->notifier.ops)
> - mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
> -
> - kfree(dmar_domain);
> + /* dmar_domain free is defered to the mmu free_notifier callback. */
> + mmu_notifier_put(&dmar_domain->notifier);
> }
Yeah, that is better.
Also you need to have mmu notifier call on module unload when using
this scheme.
Jason
On 2024/4/11 21:07, Jason Gunthorpe wrote:
>> +static void intel_mm_free_notifier(struct mmu_notifier *mn)
>> +{
>> + kfree(container_of(mn, struct dmar_domain, notifier));
>> +}
>> +
>> static const struct mmu_notifier_ops intel_mmuops = {
>> .release = intel_mm_release,
>> .arch_invalidate_secondary_tlbs =
>> intel_arch_invalidate_secondary_tlbs,
>> + .free_notifier = intel_mm_free_notifier,
>> };
>>
>> static int intel_svm_set_dev_pasid(struct iommu_domain *domain,
>> @@ -598,10 +604,8 @@ static void intel_svm_domain_free(struct iommu_domain
>> *domain)
>> {
>> struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>>
>> - if (dmar_domain->notifier.ops)
>> - mmu_notifier_unregister(&dmar_domain->notifier, domain->mm);
>> -
>> - kfree(dmar_domain);
>> + /* dmar_domain free is defered to the mmu free_notifier callback. */
>> + mmu_notifier_put(&dmar_domain->notifier);
>> }
> Yeah, that is better.
>
> Also you need to have mmu notifier call on module unload when using
> this scheme.
The Intel IOMMU driver doesn't support being a module. It's always
built-in.
Best regards,
baolu
On 2024/4/11 16:32, Tian, Kevin wrote:
>> From: Baolu Lu<[email protected]>
>> Sent: Thursday, April 11, 2024 3:56 PM
>>
>> On 2024/4/10 23:49, Jason Gunthorpe wrote:
>>> On Wed, Apr 10, 2024 at 10:08:44AM +0800, Lu Baolu wrote:
>>>> @@ -4388,14 +4386,8 @@ static void
>> intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
>>>> WARN_ON_ONCE(!dev_pasid);
>>>> spin_unlock_irqrestore(&dmar_domain->lock, flags);
>>>>
>>>> - /*
>>>> - * The SVA implementation needs to handle its own stuffs like the
>> mm
>>>> - * notification. Before consolidating that code into iommu core, let
>>>> - * the intel sva code handle it.
>>>> - */
>>>> if (domain->type == IOMMU_DOMAIN_SVA) {
>>>> cache_tag_unassign_domain(dmar_domain,
>> FLPT_DEFAULT_DID, dev, pasid);
>>>> - intel_svm_remove_dev_pasid(domain);
>>>> } else {
>>>> did = domain_id_iommu(dmar_domain, iommu);
>>>> cache_tag_unassign_domain(dmar_domain, did, dev, pasid);
>>> It seems very strange that SVA has a different DID scheme, why is
>>> this? PASID and SVA should not be different at this layer.
>> The VT-d spec recommends that all SVA domains share a single domain ID.
>> The PASID is unique to each SVA domain, hence the cache tags are unique.
>> Currently, the Intel IOMMU driver assigns different domain IDs for all
>> domains except the SVA type.
>>
>> Sharing a domain ID is not specific to SVA. In general, for devices
>> under a single IOMMU, domains with unique PASIDs can share the same
>> domain ID.
>>
>> In the long term (also on my task list), we will extend the cache tag
>> code to support sharing domain IDs and remove the domain type check from
>> the main code. This will also benefit the nesting case, where user
>> domains nested on the same parent could share a domain ID.
>>
> at least above might be changed to a unified call with the helper
> accepting an iommu parameter and then finding proper did
> internally based on domain type, e.g.
>
> cache_tag_unassign_domain(domain, iommu, dev, pasid)
> {
> if (domain->type == IOMMU_DOMAIN_SVA)
> did = FLPT_DEFAULT_DID;
> else
> did = domain_id_iommu(domain, iommu);
>
> ...
> }
Yeah, your code is more graceful.
Best regards,
baolu