Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
On Sat, Jan 16, 2021 at 04:47:40PM +0800, Lu Baolu wrote:
> Hi Leon,
>
> On 2021/1/16 16:39, Leon Romanovsky wrote:
> > On Sat, Jan 16, 2021 at 09:20:16AM +0800, Lu Baolu wrote:
> > > Hi,
> > >
> > > On 2021/1/15 14:31, Leon Romanovsky wrote:
> > > > On Fri, Jan 15, 2021 at 07:49:47AM +0800, Lu Baolu wrote:
> > > > > Hi Leon,
> > > > >
> > > > > On 1/14/21 9:26 PM, Leon Romanovsky wrote:
> > > > > > On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
> > > > > > > Some vendor IOMMU drivers are able to declare that it is running
> > > > > > > in a VM
> > > > > > > context. This is very valuable for the features that only want to
> > > > > > > be
> > > > > > > supported on bare metal. Add a capability bit so that it could be
> > > > > > > used.
> > > > > >
> > > > > > And how is it used? Who and how will set it?
> > > > >
> > > > > Use the existing iommu_capable(). I should add more descriptions about
> > > > > who and how to use it.
> > > >
> > > > I want to see the code that sets this capability.
> > >
> > > Currently we have Intel VT-d and the virt-iommu setting this capability.
> > >
> > > static bool intel_iommu_capable(enum iommu_cap cap)
> > > {
> > > if (cap == IOMMU_CAP_CACHE_COHERENCY)
> > > return domain_update_iommu_snooping(NULL) == 1;
> > > if (cap == IOMMU_CAP_INTR_REMAP)
> > > return irq_remapping_enabled == 1;
> > > + if (cap == IOMMU_CAP_VIOMMU)
> > > + return caching_mode_enabled();
> > >
> > > return false;
> > > }
> > >
> > > And,
> > >
> > > +static bool viommu_capable(enum iommu_cap cap)
> > > +{
> > > + if (cap == IOMMU_CAP_VIOMMU)
> > > + return true;
> > > +
> > > + return false;
> > > +}
> >
> > These two functions are reading this cap and not setting.
> > Where can I see code that does "cap = IOMMU_CAP_VIOMMU" and not "=="?
>
> The iommu_capable() is a generic IOMMU interface to query IOMMU
> capabilities. It takes @bus and @cap as input, and calls the callback
> of vendor iommu. If the vendor iommu driver supports the specific
> capability, it returns true. Otherwise, it returns false.
>
> bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
> {
> if (!bus->iommu_ops || !bus->iommu_ops->capable)
> return false;
>
> return bus->iommu_ops->capable(cap);
> }
> EXPORT_SYMBOL_GPL(iommu_capable);
>
> In the vendor iommu's callback, it checks the capability and returns a
> value according to its capability, just as showed above.
Ohh, sorry.
I missed "iommu_capable(dev->bus, IOMMU_CAP_VIOMMU)" from second patch.
Thanks
>
> Best regards,
> baolu
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Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
Hi Leon,
On 2021/1/16 16:39, Leon Romanovsky wrote:
On Sat, Jan 16, 2021 at 09:20:16AM +0800, Lu Baolu wrote:
Hi,
On 2021/1/15 14:31, Leon Romanovsky wrote:
On Fri, Jan 15, 2021 at 07:49:47AM +0800, Lu Baolu wrote:
Hi Leon,
On 1/14/21 9:26 PM, Leon Romanovsky wrote:
On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
Some vendor IOMMU drivers are able to declare that it is running in a VM
context. This is very valuable for the features that only want to be
supported on bare metal. Add a capability bit so that it could be used.
And how is it used? Who and how will set it?
Use the existing iommu_capable(). I should add more descriptions about
who and how to use it.
I want to see the code that sets this capability.
Currently we have Intel VT-d and the virt-iommu setting this capability.
static bool intel_iommu_capable(enum iommu_cap cap)
{
if (cap == IOMMU_CAP_CACHE_COHERENCY)
return domain_update_iommu_snooping(NULL) == 1;
if (cap == IOMMU_CAP_INTR_REMAP)
return irq_remapping_enabled == 1;
+ if (cap == IOMMU_CAP_VIOMMU)
+ return caching_mode_enabled();
return false;
}
And,
+static bool viommu_capable(enum iommu_cap cap)
+{
+ if (cap == IOMMU_CAP_VIOMMU)
+ return true;
+
+ return false;
+}
These two functions are reading this cap and not setting.
Where can I see code that does "cap = IOMMU_CAP_VIOMMU" and not "=="?
The iommu_capable() is a generic IOMMU interface to query IOMMU
capabilities. It takes @bus and @cap as input, and calls the callback
of vendor iommu. If the vendor iommu driver supports the specific
capability, it returns true. Otherwise, it returns false.
bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
{
if (!bus->iommu_ops || !bus->iommu_ops->capable)
return false;
return bus->iommu_ops->capable(cap);
}
EXPORT_SYMBOL_GPL(iommu_capable);
In the vendor iommu's callback, it checks the capability and returns a
value according to its capability, just as showed above.
Best regards,
baolu
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Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
On Sat, Jan 16, 2021 at 09:20:16AM +0800, Lu Baolu wrote:
> Hi,
>
> On 2021/1/15 14:31, Leon Romanovsky wrote:
> > On Fri, Jan 15, 2021 at 07:49:47AM +0800, Lu Baolu wrote:
> > > Hi Leon,
> > >
> > > On 1/14/21 9:26 PM, Leon Romanovsky wrote:
> > > > On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
> > > > > Some vendor IOMMU drivers are able to declare that it is running in a
> > > > > VM
> > > > > context. This is very valuable for the features that only want to be
> > > > > supported on bare metal. Add a capability bit so that it could be
> > > > > used.
> > > >
> > > > And how is it used? Who and how will set it?
> > >
> > > Use the existing iommu_capable(). I should add more descriptions about
> > > who and how to use it.
> >
> > I want to see the code that sets this capability.
>
> Currently we have Intel VT-d and the virt-iommu setting this capability.
>
> static bool intel_iommu_capable(enum iommu_cap cap)
> {
> if (cap == IOMMU_CAP_CACHE_COHERENCY)
> return domain_update_iommu_snooping(NULL) == 1;
> if (cap == IOMMU_CAP_INTR_REMAP)
> return irq_remapping_enabled == 1;
> + if (cap == IOMMU_CAP_VIOMMU)
> + return caching_mode_enabled();
>
> return false;
> }
>
> And,
>
> +static bool viommu_capable(enum iommu_cap cap)
> +{
> + if (cap == IOMMU_CAP_VIOMMU)
> + return true;
> +
> + return false;
> +}
These two functions are reading this cap and not setting.
Where can I see code that does "cap = IOMMU_CAP_VIOMMU" and not "=="?
>
> Best regards,
> baolu
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Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
Hi,
On 2021/1/15 14:31, Leon Romanovsky wrote:
On Fri, Jan 15, 2021 at 07:49:47AM +0800, Lu Baolu wrote:
Hi Leon,
On 1/14/21 9:26 PM, Leon Romanovsky wrote:
On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
Some vendor IOMMU drivers are able to declare that it is running in a VM
context. This is very valuable for the features that only want to be
supported on bare metal. Add a capability bit so that it could be used.
And how is it used? Who and how will set it?
Use the existing iommu_capable(). I should add more descriptions about
who and how to use it.
I want to see the code that sets this capability.
Currently we have Intel VT-d and the virt-iommu setting this capability.
static bool intel_iommu_capable(enum iommu_cap cap)
{
if (cap == IOMMU_CAP_CACHE_COHERENCY)
return domain_update_iommu_snooping(NULL) == 1;
if (cap == IOMMU_CAP_INTR_REMAP)
return irq_remapping_enabled == 1;
+ if (cap == IOMMU_CAP_VIOMMU)
+ return caching_mode_enabled();
return false;
}
And,
+static bool viommu_capable(enum iommu_cap cap)
+{
+ if (cap == IOMMU_CAP_VIOMMU)
+ return true;
+
+ return false;
+}
Best regards,
baolu
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Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
On Fri, Jan 15, 2021 at 07:49:47AM +0800, Lu Baolu wrote: > Hi Leon, > > On 1/14/21 9:26 PM, Leon Romanovsky wrote: > > On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote: > > > Some vendor IOMMU drivers are able to declare that it is running in a VM > > > context. This is very valuable for the features that only want to be > > > supported on bare metal. Add a capability bit so that it could be used. > > > > And how is it used? Who and how will set it? > > Use the existing iommu_capable(). I should add more descriptions about > who and how to use it. I want to see the code that sets this capability. Thanks ___ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
On 2021/1/14 上午9:30, Lu Baolu wrote:
Some vendor IOMMU drivers are able to declare that it is running in a VM
context. This is very valuable for the features that only want to be
supported on bare metal. Add a capability bit so that it could be used.
Signed-off-by: Lu Baolu
---
drivers/iommu/intel/iommu.c | 20
drivers/iommu/virtio-iommu.c | 9 +
include/linux/iommu.h| 1 +
3 files changed, 30 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cb205a04fe4c..8eb022d0e8aa 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void)
return ret;
}
+static inline bool caching_mode_enabled(void)
+{
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ bool ret = false;
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ if (cap_caching_mode(iommu->cap)) {
+ ret = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
static bool intel_iommu_capable(enum iommu_cap cap)
{
if (cap == IOMMU_CAP_CACHE_COHERENCY)
return domain_update_iommu_snooping(NULL) == 1;
if (cap == IOMMU_CAP_INTR_REMAP)
return irq_remapping_enabled == 1;
+ if (cap == IOMMU_CAP_VIOMMU)
+ return caching_mode_enabled();
This part I don't understand. Does it mean Intel IOMMU can't be used in
VM without caching mode?
Thanks
return false;
}
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 2bfdd5734844..719793e103db 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct
of_phandle_args *args)
return iommu_fwspec_add_ids(dev, args->args, 1);
}
+static bool viommu_capable(enum iommu_cap cap)
+{
+ if (cap == IOMMU_CAP_VIOMMU)
+ return true;
+
+ return false;
+}
+
static struct iommu_ops viommu_ops = {
+ .capable= viommu_capable,
.domain_alloc = viommu_domain_alloc,
.domain_free= viommu_domain_free,
.attach_dev = viommu_attach_dev,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index b95a6f8db6ff..1d24be667a03 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -94,6 +94,7 @@ enum iommu_cap {
transactions */
IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
+ IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */
};
/*
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Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
Hi Leon,
On 1/14/21 9:26 PM, Leon Romanovsky wrote:
On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
Some vendor IOMMU drivers are able to declare that it is running in a VM
context. This is very valuable for the features that only want to be
supported on bare metal. Add a capability bit so that it could be used.
And how is it used? Who and how will set it?
Use the existing iommu_capable(). I should add more descriptions about
who and how to use it.
Signed-off-by: Lu Baolu
---
drivers/iommu/intel/iommu.c | 20
drivers/iommu/virtio-iommu.c | 9 +
include/linux/iommu.h| 1 +
3 files changed, 30 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cb205a04fe4c..8eb022d0e8aa 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void)
return ret;
}
+static inline bool caching_mode_enabled(void)
+{
Kernel coding style is not in favour of inline functions in *.c files.
Yes, agreed.
Best regards,
baolu
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ bool ret = false;
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ if (cap_caching_mode(iommu->cap)) {
+ ret = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
static bool intel_iommu_capable(enum iommu_cap cap)
{
if (cap == IOMMU_CAP_CACHE_COHERENCY)
return domain_update_iommu_snooping(NULL) == 1;
if (cap == IOMMU_CAP_INTR_REMAP)
return irq_remapping_enabled == 1;
+ if (cap == IOMMU_CAP_VIOMMU)
+ return caching_mode_enabled();
return false;
}
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 2bfdd5734844..719793e103db 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct
of_phandle_args *args)
return iommu_fwspec_add_ids(dev, args->args, 1);
}
+static bool viommu_capable(enum iommu_cap cap)
+{
+ if (cap == IOMMU_CAP_VIOMMU)
+ return true;
+
+ return false;
+}
+
static struct iommu_ops viommu_ops = {
+ .capable= viommu_capable,
.domain_alloc = viommu_domain_alloc,
.domain_free= viommu_domain_free,
.attach_dev = viommu_attach_dev,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index b95a6f8db6ff..1d24be667a03 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -94,6 +94,7 @@ enum iommu_cap {
transactions */
IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
+ IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */
};
/*
--
2.25.1
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Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
On Thu, Jan 14, 2021 at 09:30:02AM +0800, Lu Baolu wrote:
> Some vendor IOMMU drivers are able to declare that it is running in a VM
> context. This is very valuable for the features that only want to be
> supported on bare metal. Add a capability bit so that it could be used.
And how is it used? Who and how will set it?
>
> Signed-off-by: Lu Baolu
> ---
> drivers/iommu/intel/iommu.c | 20
> drivers/iommu/virtio-iommu.c | 9 +
> include/linux/iommu.h| 1 +
> 3 files changed, 30 insertions(+)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index cb205a04fe4c..8eb022d0e8aa 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void)
> return ret;
> }
>
> +static inline bool caching_mode_enabled(void)
> +{
Kernel coding style is not in favour of inline functions in *.c files.
> + struct dmar_drhd_unit *drhd;
> + struct intel_iommu *iommu;
> + bool ret = false;
> +
> + rcu_read_lock();
> + for_each_active_iommu(iommu, drhd) {
> + if (cap_caching_mode(iommu->cap)) {
> + ret = true;
> + break;
> + }
> + }
> + rcu_read_unlock();
> +
> + return ret;
> +}
> +
> static bool intel_iommu_capable(enum iommu_cap cap)
> {
> if (cap == IOMMU_CAP_CACHE_COHERENCY)
> return domain_update_iommu_snooping(NULL) == 1;
> if (cap == IOMMU_CAP_INTR_REMAP)
> return irq_remapping_enabled == 1;
> + if (cap == IOMMU_CAP_VIOMMU)
> + return caching_mode_enabled();
>
> return false;
> }
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 2bfdd5734844..719793e103db 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct
> of_phandle_args *args)
> return iommu_fwspec_add_ids(dev, args->args, 1);
> }
>
> +static bool viommu_capable(enum iommu_cap cap)
> +{
> + if (cap == IOMMU_CAP_VIOMMU)
> + return true;
> +
> + return false;
> +}
> +
> static struct iommu_ops viommu_ops = {
> + .capable= viommu_capable,
> .domain_alloc = viommu_domain_alloc,
> .domain_free= viommu_domain_free,
> .attach_dev = viommu_attach_dev,
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index b95a6f8db6ff..1d24be667a03 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -94,6 +94,7 @@ enum iommu_cap {
> transactions */
> IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
> IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
> + IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */
> };
>
> /*
> --
> 2.25.1
>
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[RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
Some vendor IOMMU drivers are able to declare that it is running in a VM
context. This is very valuable for the features that only want to be
supported on bare metal. Add a capability bit so that it could be used.
Signed-off-by: Lu Baolu
---
drivers/iommu/intel/iommu.c | 20
drivers/iommu/virtio-iommu.c | 9 +
include/linux/iommu.h| 1 +
3 files changed, 30 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cb205a04fe4c..8eb022d0e8aa 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void)
return ret;
}
+static inline bool caching_mode_enabled(void)
+{
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ bool ret = false;
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ if (cap_caching_mode(iommu->cap)) {
+ ret = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+
+ return ret;
+}
+
static bool intel_iommu_capable(enum iommu_cap cap)
{
if (cap == IOMMU_CAP_CACHE_COHERENCY)
return domain_update_iommu_snooping(NULL) == 1;
if (cap == IOMMU_CAP_INTR_REMAP)
return irq_remapping_enabled == 1;
+ if (cap == IOMMU_CAP_VIOMMU)
+ return caching_mode_enabled();
return false;
}
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 2bfdd5734844..719793e103db 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct
of_phandle_args *args)
return iommu_fwspec_add_ids(dev, args->args, 1);
}
+static bool viommu_capable(enum iommu_cap cap)
+{
+ if (cap == IOMMU_CAP_VIOMMU)
+ return true;
+
+ return false;
+}
+
static struct iommu_ops viommu_ops = {
+ .capable= viommu_capable,
.domain_alloc = viommu_domain_alloc,
.domain_free= viommu_domain_free,
.attach_dev = viommu_attach_dev,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index b95a6f8db6ff..1d24be667a03 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -94,6 +94,7 @@ enum iommu_cap {
transactions */
IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
+ IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */
};
/*
--
2.25.1
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