[Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

[Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

[Jiang Liu]

Finally enhance pci_root driver to support DMAR device hotplug when
hot-plugging PCI host bridges.

Signed-off-by: Jiang Liu <jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
---
 drivers/acpi/pci_root.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index d388f13d48b4..aa8f549869f3 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -33,6 +33,7 @@
 #include <linux/pci.h>
 #include <linux/pci-acpi.h>
 #include <linux/pci-aspm.h>
+#include <linux/dmar.h>
 #include <linux/acpi.h>
 #include <linux/slab.h>
 #include <acpi/apei.h>	/* for acpi_hest_init() */
@@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	struct acpi_pci_root *root;
 	acpi_handle handle = device->handle;
 	int no_aspm = 0, clear_aspm = 0;
+	bool hotadd = (system_state != SYSTEM_BOOTING);
 
 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 	if (!root)
@@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 	device->driver_data = root;
 
+	if (hotadd && dmar_device_hotplug(handle, true)) {
+		result = -ENXIO;
+		goto end;
+	}
+
 	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
 	       acpi_device_name(device), acpi_device_bid(device),
 	       root->segment, &root->secondary);
@@ -583,7 +590,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 			root->segment, (unsigned int)root->secondary.start);
 		device->driver_data = NULL;
 		result = -ENODEV;
-		goto end;
+		goto remove_dmar;
 	}
 
 	if (clear_aspm) {
@@ -597,7 +604,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	if (device->wakeup.flags.run_wake)
 		device_set_run_wake(root->bus->bridge, true);
 
-	if (system_state != SYSTEM_BOOTING) {
+	if (hotadd) {
 		pcibios_resource_survey_bus(root->bus);
 		pci_assign_unassigned_root_bus_resources(root->bus);
 	}
@@ -607,6 +614,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	pci_unlock_rescan_remove();
 	return 1;
 
+remove_dmar:
+	if (hotadd)
+		dmar_device_hotplug(handle, false);
 end:
 	kfree(root);
 	return result;
@@ -625,6 +635,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
 
 	pci_remove_root_bus(root->bus);
 
+	dmar_device_hotplug(device->handle, false);
+
 	pci_unlock_rescan_remove();
 
 	kfree(root);
-- 
1.7.10.4

Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

[Rafael J. Wysocki]

On Tuesday, April 22, 2014 03:07:28 PM Jiang Liu wrote:
> Finally enhance pci_root driver to support DMAR device hotplug when
> hot-plugging PCI host bridges.
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---
>  drivers/acpi/pci_root.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d388f13d48b4..aa8f549869f3 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -33,6 +33,7 @@
>  #include <linux/pci.h>
>  #include <linux/pci-acpi.h>
>  #include <linux/pci-aspm.h>
> +#include <linux/dmar.h>
>  #include <linux/acpi.h>
>  #include <linux/slab.h>
>  #include <acpi/apei.h>	/* for acpi_hest_init() */
> @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	struct acpi_pci_root *root;
>  	acpi_handle handle = device->handle;
>  	int no_aspm = 0, clear_aspm = 0;
> +	bool hotadd = (system_state != SYSTEM_BOOTING);

The parens are not necessary in the above instruction.

>  	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
>  	if (!root)
> @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
>  	device->driver_data = root;
>  
> +	if (hotadd && dmar_device_hotplug(handle, true)) {
> +		result = -ENXIO;
> +		goto end;
> +	}
> +
>  	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
>  	       acpi_device_name(device), acpi_device_bid(device),
>  	       root->segment, &root->secondary);
> @@ -583,7 +590,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  			root->segment, (unsigned int)root->secondary.start);
>  		device->driver_data = NULL;
>  		result = -ENODEV;
> -		goto end;
> +		goto remove_dmar;
>  	}
>  
>  	if (clear_aspm) {
> @@ -597,7 +604,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	if (device->wakeup.flags.run_wake)
>  		device_set_run_wake(root->bus->bridge, true);
>  
> -	if (system_state != SYSTEM_BOOTING) {
> +	if (hotadd) {
>  		pcibios_resource_survey_bus(root->bus);
>  		pci_assign_unassigned_root_bus_resources(root->bus);
>  	}
> @@ -607,6 +614,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	pci_unlock_rescan_remove();
>  	return 1;
>  
> +remove_dmar:
> +	if (hotadd)
> +		dmar_device_hotplug(handle, false);

I suppose that works if dmar_device_hotplug() returned false before?

>  end:
>  	kfree(root);
>  	return result;
> @@ -625,6 +635,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
>  
>  	pci_remove_root_bus(root->bus);
>  
> +	dmar_device_hotplug(device->handle, false);
> +
>  	pci_unlock_rescan_remove();
>  
>  	kfree(root);
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

[Bjorn Helgaas]

On Tue, Apr 22, 2014 at 03:07:28PM +0800, Jiang Liu wrote:
> Finally enhance pci_root driver to support DMAR device hotplug when
> hot-plugging PCI host bridges.
> 
> Signed-off-by: Jiang Liu <jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> ---
>  drivers/acpi/pci_root.c |   16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d388f13d48b4..aa8f549869f3 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -33,6 +33,7 @@
>  #include <linux/pci.h>
>  #include <linux/pci-acpi.h>
>  #include <linux/pci-aspm.h>
> +#include <linux/dmar.h>
>  #include <linux/acpi.h>
>  #include <linux/slab.h>
>  #include <acpi/apei.h>	/* for acpi_hest_init() */
> @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	struct acpi_pci_root *root;
>  	acpi_handle handle = device->handle;
>  	int no_aspm = 0, clear_aspm = 0;
> +	bool hotadd = (system_state != SYSTEM_BOOTING);
>  
>  	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
>  	if (!root)
> @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
>  	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
>  	device->driver_data = root;
>  
> +	if (hotadd && dmar_device_hotplug(handle, true)) {

Apparently "dmar_device_hotplug(handle, true)" means "add a DMAR device,"
and "dmar_device_hotplug(device->handle, false)" means "remove a DMAR
device."  I'm not really a fan of interfaces where one of the arguments
selects between two completely different actions, because it's harder for a
casual reader to see what's going on.

I see how it simplifies your implementation a little bit, but I think it's
more important to simplify for the reader.

Bjorn

Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

[Jiang Liu]

On 2014/4/25 1:33, Bjorn Helgaas wrote:
> On Tue, Apr 22, 2014 at 03:07:28PM +0800, Jiang Liu wrote:
>> Finally enhance pci_root driver to support DMAR device hotplug when
>> hot-plugging PCI host bridges.
>>
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>> ---
>>  drivers/acpi/pci_root.c |   16 ++++++++++++++--
>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> index d388f13d48b4..aa8f549869f3 100644
>> --- a/drivers/acpi/pci_root.c
>> +++ b/drivers/acpi/pci_root.c
>> @@ -33,6 +33,7 @@
>>  #include <linux/pci.h>
>>  #include <linux/pci-acpi.h>
>>  #include <linux/pci-aspm.h>
>> +#include <linux/dmar.h>
>>  #include <linux/acpi.h>
>>  #include <linux/slab.h>
>>  #include <acpi/apei.h>	/* for acpi_hest_init() */
>> @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  	struct acpi_pci_root *root;
>>  	acpi_handle handle = device->handle;
>>  	int no_aspm = 0, clear_aspm = 0;
>> +	bool hotadd = (system_state != SYSTEM_BOOTING);
>>  
>>  	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
>>  	if (!root)
>> @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
>>  	device->driver_data = root;
>>  
>> +	if (hotadd && dmar_device_hotplug(handle, true)) {
> 
> Apparently "dmar_device_hotplug(handle, true)" means "add a DMAR device,"
> and "dmar_device_hotplug(device->handle, false)" means "remove a DMAR
> device."  I'm not really a fan of interfaces where one of the arguments
> selects between two completely different actions, because it's harder for a
> casual reader to see what's going on.
> 
> I see how it simplifies your implementation a little bit, but I think it's
> more important to simplify for the reader.
Thanks Bjorn, I will rename it to dmar_device_add/remove() instead.

> 
> Bjorn
> 

Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

[Jiang Liu]

On 2014/4/22 17:49, Rafael J. Wysocki wrote:
> On Tuesday, April 22, 2014 03:07:28 PM Jiang Liu wrote:
>> Finally enhance pci_root driver to support DMAR device hotplug when
>> hot-plugging PCI host bridges.
>>
>> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
>> ---
>>  drivers/acpi/pci_root.c |   16 ++++++++++++++--
>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> index d388f13d48b4..aa8f549869f3 100644
>> --- a/drivers/acpi/pci_root.c
>> +++ b/drivers/acpi/pci_root.c
>> @@ -33,6 +33,7 @@
>>  #include <linux/pci.h>
>>  #include <linux/pci-acpi.h>
>>  #include <linux/pci-aspm.h>
>> +#include <linux/dmar.h>
>>  #include <linux/acpi.h>
>>  #include <linux/slab.h>
>>  #include <acpi/apei.h>	/* for acpi_hest_init() */
>> @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  	struct acpi_pci_root *root;
>>  	acpi_handle handle = device->handle;
>>  	int no_aspm = 0, clear_aspm = 0;
>> +	bool hotadd = (system_state != SYSTEM_BOOTING);
> 
> The parens are not necessary in the above instruction.
Hi Rafael,
	Thanks! Will fix it in next version.

> 
>>  	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
>>  	if (!root)
>> @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
>>  	device->driver_data = root;
>>  
>> +	if (hotadd && dmar_device_hotplug(handle, true)) {
>> +		result = -ENXIO;
>> +		goto end;
>> +	}
>> +
>>  	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
>>  	       acpi_device_name(device), acpi_device_bid(device),
>>  	       root->segment, &root->secondary);
>> @@ -583,7 +590,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  			root->segment, (unsigned int)root->secondary.start);
>>  		device->driver_data = NULL;
>>  		result = -ENODEV;
>> -		goto end;
>> +		goto remove_dmar;
>>  	}
>>  
>>  	if (clear_aspm) {
>> @@ -597,7 +604,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  	if (device->wakeup.flags.run_wake)
>>  		device_set_run_wake(root->bus->bridge, true);
>>  
>> -	if (system_state != SYSTEM_BOOTING) {
>> +	if (hotadd) {
>>  		pcibios_resource_survey_bus(root->bus);
>>  		pci_assign_unassigned_root_bus_resources(root->bus);
>>  	}
>> @@ -607,6 +614,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
>>  	pci_unlock_rescan_remove();
>>  	return 1;
>>  
>> +remove_dmar:
>> +	if (hotadd)
>> +		dmar_device_hotplug(handle, false);
> 
> I suppose that works if dmar_device_hotplug() returned false before?
Yes, it's for error recover only.

> 
>>  end:
>>  	kfree(root);
>>  	return result;
>> @@ -625,6 +635,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
>>  
>>  	pci_remove_root_bus(root->bus);
>>  
>> +	dmar_device_hotplug(device->handle, false);
>> +
>>  	pci_unlock_rescan_remove();
>>  
>>  	kfree(root);
>>
>