diff mbox

[v7,6/8] irqchip/gicv2m: implement msi_doorbell_info callback

Message ID 1461085990-2547-7-git-send-email-eric.auger@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Auger April 19, 2016, 5:13 p.m. UTC
This patch implements the msi_doorbell_info callback in the
gicv2m driver.

The driver now is able to return its doorbell characteristics
(base, size, prot). A single doorbell is exposed.

This will allow the msi layer to iommu_map this doorbell when
requested.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---

v7: creation
---
 drivers/irqchip/irq-gic-v2m.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

Comments

Marc Zyngier April 20, 2016, 9:27 a.m. UTC | #1
On 19/04/16 18:13, Eric Auger wrote:
> This patch implements the msi_doorbell_info callback in the
> gicv2m driver.
> 
> The driver now is able to return its doorbell characteristics
> (base, size, prot). A single doorbell is exposed.
> 
> This will allow the msi layer to iommu_map this doorbell when
> requested.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> 
> v7: creation
> ---
>  drivers/irqchip/irq-gic-v2m.c | 32 +++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
> index 28f047c..54690b9 100644
> --- a/drivers/irqchip/irq-gic-v2m.c
> +++ b/drivers/irqchip/irq-gic-v2m.c
> @@ -24,6 +24,8 @@
>  #include <linux/of_pci.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
> +#include <linux/percpu.h>
> +#include <linux/iommu.h>
>  
>  /*
>  * MSI_TYPER:
> @@ -64,6 +66,7 @@ struct v2m_data {
>  	u32 nr_spis;		/* The number of SPIs for MSIs */
>  	unsigned long *bm;	/* MSI vector bitmap */
>  	u32 flags;		/* v2m flags for specific implementation */
> +	struct irq_chip_msi_doorbell_info doorbell_info;
>  };
>  
>  static void gicv2m_mask_msi_irq(struct irq_data *d)
> @@ -105,6 +108,16 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
>  		msg->data -= v2m->spi_start;
>  }
>  
> +static const struct irq_chip_msi_doorbell_info *
> +gicv2m_msi_doorbell_info(struct irq_data *data)
> +{
> +	struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
> +
> +	if (!v2m)
> +		return NULL;

How can this ever be NULL? I think you can drop that test.

> +	return (const struct irq_chip_msi_doorbell_info *)(&v2m->doorbell_info);

Please don't do that. Use "const" in the functions that are using
irq_chip_msi_doorbell_info, but do not make this "const" here.

> +}
> +
>  static struct irq_chip gicv2m_irq_chip = {
>  	.name			= "GICv2m",
>  	.irq_mask		= irq_chip_mask_parent,
> @@ -112,6 +125,7 @@ static struct irq_chip gicv2m_irq_chip = {
>  	.irq_eoi		= irq_chip_eoi_parent,
>  	.irq_set_affinity	= irq_chip_set_affinity_parent,
>  	.irq_compose_msi_msg	= gicv2m_compose_msi_msg,
> +	.msi_doorbell_info	= gicv2m_msi_doorbell_info,
>  };
>  
>  static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
> @@ -247,6 +261,7 @@ static void gicv2m_teardown(void)
>  
>  	list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
>  		list_del(&v2m->entry);
> +		free_percpu(v2m->doorbell_info.percpu_doorbells);
>  		kfree(v2m->bm);
>  		iounmap(v2m->base);
>  		of_node_put(to_of_node(v2m->fwnode));
> @@ -299,6 +314,7 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>  {
>  	int ret;
>  	struct v2m_data *v2m;
> +	struct irq_chip_msi_doorbell __percpu *doorbell;
>  
>  	v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
>  	if (!v2m) {
> @@ -311,11 +327,23 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>  
>  	memcpy(&v2m->res, res, sizeof(struct resource));
>  
> +	v2m->doorbell_info.percpu_doorbells =
> +		alloc_percpu(struct irq_chip_msi_doorbell);
> +	if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
> +		ret = -ENOMEM;
> +		goto err_free_v2m;
> +	}
> +	doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
> +	doorbell->base = v2m->res.start;
> +	doorbell->size = 4;
> +	doorbell->prot = IOMMU_WRITE;

You probably need to also have something that says IOMMU_DEVICE or
something similar, because I'm afraid you're getting a memory mapping
here. I've had a quick look at the two other series, but couldn't find
anything that would force the memory attributes.

> +	v2m->doorbell_info.nb_doorbells = 1;
> +
>  	v2m->base = ioremap(v2m->res.start, resource_size(&v2m->res));
>  	if (!v2m->base) {
>  		pr_err("Failed to map GICv2m resource\n");
>  		ret = -ENOMEM;
> -		goto err_free_v2m;
> +		goto err_free_v2m_doorbells;
>  	}
>  
>  	if (spi_start && nr_spis) {
> @@ -359,6 +387,8 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>  
>  err_iounmap:
>  	iounmap(v2m->base);
> +err_free_v2m_doorbells:
> +	free_percpu(v2m->doorbell_info.percpu_doorbells);
>  err_free_v2m:
>  	kfree(v2m);
>  	return ret;
> 

Thanks,

	M.
Eric Auger April 20, 2016, 12:33 p.m. UTC | #2
Marc,
On 04/20/2016 11:27 AM, Marc Zyngier wrote:
> On 19/04/16 18:13, Eric Auger wrote:
>> This patch implements the msi_doorbell_info callback in the
>> gicv2m driver.
>>
>> The driver now is able to return its doorbell characteristics
>> (base, size, prot). A single doorbell is exposed.
>>
>> This will allow the msi layer to iommu_map this doorbell when
>> requested.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>
>> ---
>>
>> v7: creation
>> ---
>>  drivers/irqchip/irq-gic-v2m.c | 32 +++++++++++++++++++++++++++++++-
>>  1 file changed, 31 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
>> index 28f047c..54690b9 100644
>> --- a/drivers/irqchip/irq-gic-v2m.c
>> +++ b/drivers/irqchip/irq-gic-v2m.c
>> @@ -24,6 +24,8 @@
>>  #include <linux/of_pci.h>
>>  #include <linux/slab.h>
>>  #include <linux/spinlock.h>
>> +#include <linux/percpu.h>
>> +#include <linux/iommu.h>
>>  
>>  /*
>>  * MSI_TYPER:
>> @@ -64,6 +66,7 @@ struct v2m_data {
>>  	u32 nr_spis;		/* The number of SPIs for MSIs */
>>  	unsigned long *bm;	/* MSI vector bitmap */
>>  	u32 flags;		/* v2m flags for specific implementation */
>> +	struct irq_chip_msi_doorbell_info doorbell_info;
>>  };
>>  
>>  static void gicv2m_mask_msi_irq(struct irq_data *d)
>> @@ -105,6 +108,16 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
>>  		msg->data -= v2m->spi_start;
>>  }
>>  
>> +static const struct irq_chip_msi_doorbell_info *
>> +gicv2m_msi_doorbell_info(struct irq_data *data)
>> +{
>> +	struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
>> +
>> +	if (!v2m)
>> +		return NULL;
> 
> How can this ever be NULL? I think you can drop that test.
OK
> 
>> +	return (const struct irq_chip_msi_doorbell_info *)(&v2m->doorbell_info);
> 
> Please don't do that. Use "const" in the functions that are using
> irq_chip_msi_doorbell_info, but do not make this "const" here.
It definitively compiles without casting so obviously this is not needed
but is there any other wrong thing I don't see?
we still want this function to return a pointer to a const?
> 
>> +}
>> +
>>  static struct irq_chip gicv2m_irq_chip = {
>>  	.name			= "GICv2m",
>>  	.irq_mask		= irq_chip_mask_parent,
>> @@ -112,6 +125,7 @@ static struct irq_chip gicv2m_irq_chip = {
>>  	.irq_eoi		= irq_chip_eoi_parent,
>>  	.irq_set_affinity	= irq_chip_set_affinity_parent,
>>  	.irq_compose_msi_msg	= gicv2m_compose_msi_msg,
>> +	.msi_doorbell_info	= gicv2m_msi_doorbell_info,
>>  };
>>  
>>  static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
>> @@ -247,6 +261,7 @@ static void gicv2m_teardown(void)
>>  
>>  	list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
>>  		list_del(&v2m->entry);
>> +		free_percpu(v2m->doorbell_info.percpu_doorbells);
>>  		kfree(v2m->bm);
>>  		iounmap(v2m->base);
>>  		of_node_put(to_of_node(v2m->fwnode));
>> @@ -299,6 +314,7 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>>  {
>>  	int ret;
>>  	struct v2m_data *v2m;
>> +	struct irq_chip_msi_doorbell __percpu *doorbell;
>>  
>>  	v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
>>  	if (!v2m) {
>> @@ -311,11 +327,23 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>>  
>>  	memcpy(&v2m->res, res, sizeof(struct resource));
>>  
>> +	v2m->doorbell_info.percpu_doorbells =
>> +		alloc_percpu(struct irq_chip_msi_doorbell);
>> +	if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
>> +		ret = -ENOMEM;
>> +		goto err_free_v2m;
>> +	}
>> +	doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
>> +	doorbell->base = v2m->res.start;
>> +	doorbell->size = 4;
>> +	doorbell->prot = IOMMU_WRITE;
> 
> You probably need to also have something that says IOMMU_DEVICE or
> something similar, because I'm afraid you're getting a memory mapping
> here. I've had a quick look at the two other series, but couldn't find
> anything that would force the memory attributes.
Yes you're right I currently just enforce the direction (which is
checked against what VFIO user registered). Do you refer to IOMMU_MMIO,
latterly proposed on the ML. In the positive, yes I intend to add it
once it gets upstreamed.

Thanks

Eric
> 
>> +	v2m->doorbell_info.nb_doorbells = 1;
>> +
>>  	v2m->base = ioremap(v2m->res.start, resource_size(&v2m->res));
>>  	if (!v2m->base) {
>>  		pr_err("Failed to map GICv2m resource\n");
>>  		ret = -ENOMEM;
>> -		goto err_free_v2m;
>> +		goto err_free_v2m_doorbells;
>>  	}
>>  
>>  	if (spi_start && nr_spis) {
>> @@ -359,6 +387,8 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>>  
>>  err_iounmap:
>>  	iounmap(v2m->base);
>> +err_free_v2m_doorbells:
>> +	free_percpu(v2m->doorbell_info.percpu_doorbells);
>>  err_free_v2m:
>>  	kfree(v2m);
>>  	return ret;
>>
> 
> Thanks,
> 
> 	M.
>
Marc Zyngier April 20, 2016, 5:56 p.m. UTC | #3
On Wed, 20 Apr 2016 14:33:17 +0200
Eric Auger <eric.auger@linaro.org> wrote:

> Marc,
> On 04/20/2016 11:27 AM, Marc Zyngier wrote:
> > On 19/04/16 18:13, Eric Auger wrote:
> >> This patch implements the msi_doorbell_info callback in the
> >> gicv2m driver.
> >>
> >> The driver now is able to return its doorbell characteristics
> >> (base, size, prot). A single doorbell is exposed.
> >>
> >> This will allow the msi layer to iommu_map this doorbell when
> >> requested.
> >>
> >> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> >>
> >> ---
> >>
> >> v7: creation
> >> ---
> >>  drivers/irqchip/irq-gic-v2m.c | 32 +++++++++++++++++++++++++++++++-
> >>  1 file changed, 31 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
> >> index 28f047c..54690b9 100644
> >> --- a/drivers/irqchip/irq-gic-v2m.c
> >> +++ b/drivers/irqchip/irq-gic-v2m.c
> >> @@ -24,6 +24,8 @@
> >>  #include <linux/of_pci.h>
> >>  #include <linux/slab.h>
> >>  #include <linux/spinlock.h>
> >> +#include <linux/percpu.h>
> >> +#include <linux/iommu.h>
> >>  
> >>  /*
> >>  * MSI_TYPER:
> >> @@ -64,6 +66,7 @@ struct v2m_data {
> >>  	u32 nr_spis;		/* The number of SPIs for MSIs */
> >>  	unsigned long *bm;	/* MSI vector bitmap */
> >>  	u32 flags;		/* v2m flags for specific implementation */
> >> +	struct irq_chip_msi_doorbell_info doorbell_info;
> >>  };
> >>  
> >>  static void gicv2m_mask_msi_irq(struct irq_data *d)
> >> @@ -105,6 +108,16 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
> >>  		msg->data -= v2m->spi_start;
> >>  }
> >>  
> >> +static const struct irq_chip_msi_doorbell_info *
> >> +gicv2m_msi_doorbell_info(struct irq_data *data)
> >> +{
> >> +	struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
> >> +
> >> +	if (!v2m)
> >> +		return NULL;
> > 
> > How can this ever be NULL? I think you can drop that test.
> OK
> > 
> >> +	return (const struct irq_chip_msi_doorbell_info *)(&v2m->doorbell_info);
> > 
> > Please don't do that. Use "const" in the functions that are using
> > irq_chip_msi_doorbell_info, but do not make this "const" here.
> It definitively compiles without casting so obviously this is not needed
> but is there any other wrong thing I don't see?
> we still want this function to return a pointer to a const?

I don't think we can return a const pointer, because it is obviously
not (the memory has been kmalloc'ed, and you've written to it, so it is
not really "read-only").

Maybe I'm being overly zealous, but I've seen compilers taking amazing
shortcuts when offered a const qualifier...

> > 
> >> +}
> >> +
> >>  static struct irq_chip gicv2m_irq_chip = {
> >>  	.name			= "GICv2m",
> >>  	.irq_mask		= irq_chip_mask_parent,
> >> @@ -112,6 +125,7 @@ static struct irq_chip gicv2m_irq_chip = {
> >>  	.irq_eoi		= irq_chip_eoi_parent,
> >>  	.irq_set_affinity	= irq_chip_set_affinity_parent,
> >>  	.irq_compose_msi_msg	= gicv2m_compose_msi_msg,
> >> +	.msi_doorbell_info	= gicv2m_msi_doorbell_info,
> >>  };
> >>  
> >>  static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
> >> @@ -247,6 +261,7 @@ static void gicv2m_teardown(void)
> >>  
> >>  	list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
> >>  		list_del(&v2m->entry);
> >> +		free_percpu(v2m->doorbell_info.percpu_doorbells);
> >>  		kfree(v2m->bm);
> >>  		iounmap(v2m->base);
> >>  		of_node_put(to_of_node(v2m->fwnode));
> >> @@ -299,6 +314,7 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
> >>  {
> >>  	int ret;
> >>  	struct v2m_data *v2m;
> >> +	struct irq_chip_msi_doorbell __percpu *doorbell;
> >>  
> >>  	v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
> >>  	if (!v2m) {
> >> @@ -311,11 +327,23 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
> >>  
> >>  	memcpy(&v2m->res, res, sizeof(struct resource));
> >>  
> >> +	v2m->doorbell_info.percpu_doorbells =
> >> +		alloc_percpu(struct irq_chip_msi_doorbell);
> >> +	if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
> >> +		ret = -ENOMEM;
> >> +		goto err_free_v2m;
> >> +	}
> >> +	doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
> >> +	doorbell->base = v2m->res.start;
> >> +	doorbell->size = 4;
> >> +	doorbell->prot = IOMMU_WRITE;
> > 
> > You probably need to also have something that says IOMMU_DEVICE or
> > something similar, because I'm afraid you're getting a memory mapping
> > here. I've had a quick look at the two other series, but couldn't find
> > anything that would force the memory attributes.
> Yes you're right I currently just enforce the direction (which is
> checked against what VFIO user registered). Do you refer to IOMMU_MMIO,
> latterly proposed on the ML. In the positive, yes I intend to add it
> once it gets upstreamed.

Yeah, Robin's patches should become a dependency here, because there is
absolutely no guarantee that the device write to the doorbell won't be
treated a normal cacheable memory, with disastrous effects.

Thanks,

	M.
Eric Auger April 20, 2016, 6:16 p.m. UTC | #4
Marc,
On 04/20/2016 07:56 PM, Marc Zyngier wrote:
> On Wed, 20 Apr 2016 14:33:17 +0200
> Eric Auger <eric.auger@linaro.org> wrote:
> 
>> Marc,
>> On 04/20/2016 11:27 AM, Marc Zyngier wrote:
>>> On 19/04/16 18:13, Eric Auger wrote:
>>>> This patch implements the msi_doorbell_info callback in the
>>>> gicv2m driver.
>>>>
>>>> The driver now is able to return its doorbell characteristics
>>>> (base, size, prot). A single doorbell is exposed.
>>>>
>>>> This will allow the msi layer to iommu_map this doorbell when
>>>> requested.
>>>>
>>>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>>>>
>>>> ---
>>>>
>>>> v7: creation
>>>> ---
>>>>  drivers/irqchip/irq-gic-v2m.c | 32 +++++++++++++++++++++++++++++++-
>>>>  1 file changed, 31 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
>>>> index 28f047c..54690b9 100644
>>>> --- a/drivers/irqchip/irq-gic-v2m.c
>>>> +++ b/drivers/irqchip/irq-gic-v2m.c
>>>> @@ -24,6 +24,8 @@
>>>>  #include <linux/of_pci.h>
>>>>  #include <linux/slab.h>
>>>>  #include <linux/spinlock.h>
>>>> +#include <linux/percpu.h>
>>>> +#include <linux/iommu.h>
>>>>  
>>>>  /*
>>>>  * MSI_TYPER:
>>>> @@ -64,6 +66,7 @@ struct v2m_data {
>>>>  	u32 nr_spis;		/* The number of SPIs for MSIs */
>>>>  	unsigned long *bm;	/* MSI vector bitmap */
>>>>  	u32 flags;		/* v2m flags for specific implementation */
>>>> +	struct irq_chip_msi_doorbell_info doorbell_info;
>>>>  };
>>>>  
>>>>  static void gicv2m_mask_msi_irq(struct irq_data *d)
>>>> @@ -105,6 +108,16 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
>>>>  		msg->data -= v2m->spi_start;
>>>>  }
>>>>  
>>>> +static const struct irq_chip_msi_doorbell_info *
>>>> +gicv2m_msi_doorbell_info(struct irq_data *data)
>>>> +{
>>>> +	struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
>>>> +
>>>> +	if (!v2m)
>>>> +		return NULL;
>>>
>>> How can this ever be NULL? I think you can drop that test.
>> OK
>>>
>>>> +	return (const struct irq_chip_msi_doorbell_info *)(&v2m->doorbell_info);
>>>
>>> Please don't do that. Use "const" in the functions that are using
>>> irq_chip_msi_doorbell_info, but do not make this "const" here.
>> It definitively compiles without casting so obviously this is not needed
>> but is there any other wrong thing I don't see?
>> we still want this function to return a pointer to a const?
> 
> I don't think we can return a const pointer, because it is obviously
> not (the memory has been kmalloc'ed, and you've written to it, so it is
> not really "read-only").
I see what you are afraid of now and I will remove it; will ask some
compiler guys ;-)

Have a nice evening

Eric

> 
> Maybe I'm being overly zealous, but I've seen compilers taking amazing
> shortcuts when offered a const qualifier...
> 
>>>
>>>> +}
>>>> +
>>>>  static struct irq_chip gicv2m_irq_chip = {
>>>>  	.name			= "GICv2m",
>>>>  	.irq_mask		= irq_chip_mask_parent,
>>>> @@ -112,6 +125,7 @@ static struct irq_chip gicv2m_irq_chip = {
>>>>  	.irq_eoi		= irq_chip_eoi_parent,
>>>>  	.irq_set_affinity	= irq_chip_set_affinity_parent,
>>>>  	.irq_compose_msi_msg	= gicv2m_compose_msi_msg,
>>>> +	.msi_doorbell_info	= gicv2m_msi_doorbell_info,
>>>>  };
>>>>  
>>>>  static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
>>>> @@ -247,6 +261,7 @@ static void gicv2m_teardown(void)
>>>>  
>>>>  	list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
>>>>  		list_del(&v2m->entry);
>>>> +		free_percpu(v2m->doorbell_info.percpu_doorbells);
>>>>  		kfree(v2m->bm);
>>>>  		iounmap(v2m->base);
>>>>  		of_node_put(to_of_node(v2m->fwnode));
>>>> @@ -299,6 +314,7 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>>>>  {
>>>>  	int ret;
>>>>  	struct v2m_data *v2m;
>>>> +	struct irq_chip_msi_doorbell __percpu *doorbell;
>>>>  
>>>>  	v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
>>>>  	if (!v2m) {
>>>> @@ -311,11 +327,23 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
>>>>  
>>>>  	memcpy(&v2m->res, res, sizeof(struct resource));
>>>>  
>>>> +	v2m->doorbell_info.percpu_doorbells =
>>>> +		alloc_percpu(struct irq_chip_msi_doorbell);
>>>> +	if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err_free_v2m;
>>>> +	}
>>>> +	doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
>>>> +	doorbell->base = v2m->res.start;
>>>> +	doorbell->size = 4;
>>>> +	doorbell->prot = IOMMU_WRITE;
>>>
>>> You probably need to also have something that says IOMMU_DEVICE or
>>> something similar, because I'm afraid you're getting a memory mapping
>>> here. I've had a quick look at the two other series, but couldn't find
>>> anything that would force the memory attributes.
>> Yes you're right I currently just enforce the direction (which is
>> checked against what VFIO user registered). Do you refer to IOMMU_MMIO,
>> latterly proposed on the ML. In the positive, yes I intend to add it
>> once it gets upstreamed.
> 
> Yeah, Robin's patches should become a dependency here, because there is
> absolutely no guarantee that the device write to the doorbell won't be
> treated a normal cacheable memory, with disastrous effects.
> 
> Thanks,
> 
> 	M.
>
diff mbox

Patch

diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
index 28f047c..54690b9 100644
--- a/drivers/irqchip/irq-gic-v2m.c
+++ b/drivers/irqchip/irq-gic-v2m.c
@@ -24,6 +24,8 @@ 
 #include <linux/of_pci.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/iommu.h>
 
 /*
 * MSI_TYPER:
@@ -64,6 +66,7 @@  struct v2m_data {
 	u32 nr_spis;		/* The number of SPIs for MSIs */
 	unsigned long *bm;	/* MSI vector bitmap */
 	u32 flags;		/* v2m flags for specific implementation */
+	struct irq_chip_msi_doorbell_info doorbell_info;
 };
 
 static void gicv2m_mask_msi_irq(struct irq_data *d)
@@ -105,6 +108,16 @@  static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		msg->data -= v2m->spi_start;
 }
 
+static const struct irq_chip_msi_doorbell_info *
+gicv2m_msi_doorbell_info(struct irq_data *data)
+{
+	struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
+
+	if (!v2m)
+		return NULL;
+	return (const struct irq_chip_msi_doorbell_info *)(&v2m->doorbell_info);
+}
+
 static struct irq_chip gicv2m_irq_chip = {
 	.name			= "GICv2m",
 	.irq_mask		= irq_chip_mask_parent,
@@ -112,6 +125,7 @@  static struct irq_chip gicv2m_irq_chip = {
 	.irq_eoi		= irq_chip_eoi_parent,
 	.irq_set_affinity	= irq_chip_set_affinity_parent,
 	.irq_compose_msi_msg	= gicv2m_compose_msi_msg,
+	.msi_doorbell_info	= gicv2m_msi_doorbell_info,
 };
 
 static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
@@ -247,6 +261,7 @@  static void gicv2m_teardown(void)
 
 	list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
 		list_del(&v2m->entry);
+		free_percpu(v2m->doorbell_info.percpu_doorbells);
 		kfree(v2m->bm);
 		iounmap(v2m->base);
 		of_node_put(to_of_node(v2m->fwnode));
@@ -299,6 +314,7 @@  static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 {
 	int ret;
 	struct v2m_data *v2m;
+	struct irq_chip_msi_doorbell __percpu *doorbell;
 
 	v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
 	if (!v2m) {
@@ -311,11 +327,23 @@  static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 
 	memcpy(&v2m->res, res, sizeof(struct resource));
 
+	v2m->doorbell_info.percpu_doorbells =
+		alloc_percpu(struct irq_chip_msi_doorbell);
+	if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
+		ret = -ENOMEM;
+		goto err_free_v2m;
+	}
+	doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
+	doorbell->base = v2m->res.start;
+	doorbell->size = 4;
+	doorbell->prot = IOMMU_WRITE;
+	v2m->doorbell_info.nb_doorbells = 1;
+
 	v2m->base = ioremap(v2m->res.start, resource_size(&v2m->res));
 	if (!v2m->base) {
 		pr_err("Failed to map GICv2m resource\n");
 		ret = -ENOMEM;
-		goto err_free_v2m;
+		goto err_free_v2m_doorbells;
 	}
 
 	if (spi_start && nr_spis) {
@@ -359,6 +387,8 @@  static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 
 err_iounmap:
 	iounmap(v2m->base);
+err_free_v2m_doorbells:
+	free_percpu(v2m->doorbell_info.percpu_doorbells);
 err_free_v2m:
 	kfree(v2m);
 	return ret;