Re: [RFC v2 14/20] iommu: introduce device fault data
On Wed, 12 Dec 2018 09:21:43 +0100 Auger Eric wrote: > Hi Jacob, > > On 9/21/18 12:06 AM, Jacob Pan wrote: > > On Tue, 18 Sep 2018 16:24:51 +0200 > > Eric Auger wrote: > > > >> From: Jacob Pan > >> > >> Device faults detected by IOMMU can be reported outside IOMMU > >> subsystem for further processing. This patch intends to provide > >> a generic device fault data such that device drivers can be > >> communicated with IOMMU faults without model specific knowledge. > >> > >> The proposed format is the result of discussion at: > >> https://lkml.org/lkml/2017/11/10/291 > >> Part of the code is based on Jean-Philippe Brucker's patchset > >> (https://patchwork.kernel.org/patch/9989315/). > >> > >> The assumption is that model specific IOMMU driver can filter and > >> handle most of the internal faults if the cause is within IOMMU > >> driver control. Therefore, the fault reasons can be reported are > >> grouped and generalized based common specifications such as PCI > >> ATS. > >> > >> Signed-off-by: Jacob Pan > >> Signed-off-by: Jean-Philippe Brucker > >> Signed-off-by: Liu, Yi L > >> Signed-off-by: Ashok Raj > >> Signed-off-by: Eric Auger > >> [moved part of the iommu_fault_event > >> struct in the uapi, enriched the fault reasons to be able to map > >> unrecoverable SMMUv3 errors] > > Sounds good to me. > > There are also other "enrichment" we need to do to support mdev or > > finer granularity fault reporting below physical device. e.g. PASID > > level. > > > > The current scheme works for PCIe physical device level, where each > > device registers a single handler only once. When device fault is > > detected by the IOMMU, it will find the matching handler and private > > data to report back. However, for devices partitioned by PASID and > > represented by mdev this may not work. Since IOMMU is not mdev aware > > and only works at physical device level. > > So I am thinking we should allow multiple registration of fault > > handler with different data and ID. i.e. > > > > int iommu_register_device_fault_handler(struct device *dev, > > iommu_dev_fault_handler_t > > handler, int id, > > void *data) > > > > where the new "id field" is > > * @id: Identification of the handler private data, will be used by > > fault > > * reporting code to match the handler data to be returned. > > For page > > * request, this can be the PASID. ID must be unique per > > device, i.e. > > * each ID can only be registered once per device. > > * - IOMMU_DEV_FAULT_ID_UNRECOVERY (~0U) is reserved for fault > > reporting > > * w/o ID. e.g. unrecoverable faults. > > > > I am still testing, but just wanted to have feedback on this idea. > > I am currently respinning this series. Do you have a respin for this > patch including iommu_register_device_fault_handler with the @id param > as you suggested above? Otherwise 2 solutions: I keep the code as is > or I do the modification myself implementing a list of fault_params? > you can keep the code as is if it fits your current needs. Yi and I have thought of some new cases for supporting mdev. We are thinking to support many to many handler vs PASID relationship. i.e. allow registration of many fault handlers per device, each associated with an ID and data. The use case is that a physical device may register a fault handler for its own PASID or non-PASID related faults. Such physical device can also be partitioned into sub-device, e.g. mdev, but fault handler registration is at physical device level in that IOMMU is not mdev aware. Anyway, still need some work to flush out the details. > Besides do you plans for "[PATCH v5 00/23] IOMMU and VT-d driver > support for Shared Virtual Address (SVA)" respin - hope I didn't miss > anything? - ? > You did not miss anything. Yes, we are still working on some internal integration issues. It should not affect the common interface much. Or I can send out a common API spin first once we have the functionality tested. Thanks for checking. > Thanks > > Eric > > > > Thanks, > > > > Jacob > > > > > >> --- > >> include/linux/iommu.h | 55 - > >> include/uapi/linux/iommu.h | 83 > >> ++ 2 files changed, 136 > >> insertions(+), 2 deletions(-) > >> > >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h > >> index 9bd3e63d562b..7529c14ff506 100644 > >> --- a/include/linux/iommu.h > >> +++ b/include/linux/iommu.h > >> @@ -49,13 +49,17 @@ struct bus_type; > >> struct device; > >> struct iommu_domain; > >> struct notifier_block; > >> +struct iommu_fault_event; > >> > >> /* iommu fault flags */ > >> -#define IOMMU_FAULT_READ 0x0 > >> -#define IOMMU_FAULT_WRITE 0x1 > >> +#define IOMMU_FAULT_READ (1 << 0) > >> +#define IOMMU_FAULT_WRITE (1 << 1) > >> +#define IOMMU_FAULT_EXEC (1 << 2) > >> +#define IOMMU_FAULT_PRIV (1 <<
Re: [RFC v2 14/20] iommu: introduce device fault data
Hi Jacob,
On 9/21/18 12:06 AM, Jacob Pan wrote:
> On Tue, 18 Sep 2018 16:24:51 +0200
> Eric Auger wrote:
>
>> From: Jacob Pan
>>
>> Device faults detected by IOMMU can be reported outside IOMMU
>> subsystem for further processing. This patch intends to provide
>> a generic device fault data such that device drivers can be
>> communicated with IOMMU faults without model specific knowledge.
>>
>> The proposed format is the result of discussion at:
>> https://lkml.org/lkml/2017/11/10/291
>> Part of the code is based on Jean-Philippe Brucker's patchset
>> (https://patchwork.kernel.org/patch/9989315/).
>>
>> The assumption is that model specific IOMMU driver can filter and
>> handle most of the internal faults if the cause is within IOMMU driver
>> control. Therefore, the fault reasons can be reported are grouped
>> and generalized based common specifications such as PCI ATS.
>>
>> Signed-off-by: Jacob Pan
>> Signed-off-by: Jean-Philippe Brucker
>> Signed-off-by: Liu, Yi L
>> Signed-off-by: Ashok Raj
>> Signed-off-by: Eric Auger
>> [moved part of the iommu_fault_event struct in the uapi, enriched
>> the fault reasons to be able to map unrecoverable SMMUv3 errors]
> Sounds good to me.
> There are also other "enrichment" we need to do to support mdev or
> finer granularity fault reporting below physical device. e.g. PASID
> level.
>
> The current scheme works for PCIe physical device level, where each
> device registers a single handler only once. When device fault is
> detected by the IOMMU, it will find the matching handler and private
> data to report back. However, for devices partitioned by PASID and
> represented by mdev this may not work. Since IOMMU is not mdev aware
> and only works at physical device level.
> So I am thinking we should allow multiple registration of fault handler
> with different data and ID. i.e.
>
> int iommu_register_device_fault_handler(struct device *dev,
> iommu_dev_fault_handler_t handler,
> int id,
> void *data)
>
> where the new "id field" is
> * @id: Identification of the handler private data, will be used by fault
> * reporting code to match the handler data to be returned. For page
> * request, this can be the PASID. ID must be unique per device, i.e.
> * each ID can only be registered once per device.
> * - IOMMU_DEV_FAULT_ID_UNRECOVERY (~0U) is reserved for fault reporting
> * w/o ID. e.g. unrecoverable faults.
>
> I am still testing, but just wanted to have feedback on this idea.
I am currently respinning this series. Do you have a respin for this
patch including iommu_register_device_fault_handler with the @id param
as you suggested above? Otherwise 2 solutions: I keep the code as is or
I do the modification myself implementing a list of fault_params?
Besides do you plans for "[PATCH v5 00/23] IOMMU and VT-d driver support
for Shared Virtual Address (SVA)" respin - hope I didn't miss anything? - ?
Thanks
Eric
>
> Thanks,
>
> Jacob
>
>
>> ---
>> include/linux/iommu.h | 55 -
>> include/uapi/linux/iommu.h | 83
>> ++ 2 files changed, 136
>> insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index 9bd3e63d562b..7529c14ff506 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -49,13 +49,17 @@ struct bus_type;
>> struct device;
>> struct iommu_domain;
>> struct notifier_block;
>> +struct iommu_fault_event;
>>
>> /* iommu fault flags */
>> -#define IOMMU_FAULT_READ0x0
>> -#define IOMMU_FAULT_WRITE 0x1
>> +#define IOMMU_FAULT_READ(1 << 0)
>> +#define IOMMU_FAULT_WRITE (1 << 1)
>> +#define IOMMU_FAULT_EXEC(1 << 2)
>> +#define IOMMU_FAULT_PRIV(1 << 3)
>>
>> typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
>> struct device *, unsigned long, int, void *);
>> +typedef int (*iommu_dev_fault_handler_t)(struct iommu_fault_event *,
>> void *);
>> struct iommu_domain_geometry {
>> dma_addr_t aperture_start; /* First address that can be
>> mapped*/ @@ -262,6 +266,52 @@ struct iommu_device {
>> struct device *dev;
>> };
>>
>> +/**
>> + * struct iommu_fault_event - Generic per device fault data
>> + *
>> + * - PCI and non-PCI devices
>> + * - Recoverable faults (e.g. page request), information based on
>> PCI ATS
>> + * and PASID spec.
>> + * - Un-recoverable faults of device interest
>> + * - DMA remapping and IRQ remapping faults
>> + *
>> + * @fault: fault descriptor
>> + * @device_private: if present, uniquely identify device-specific
>> + * private data for an individual page request.
>> + * @iommu_private: used by the IOMMU driver for storing
>> fault-specific
>> + * data. Users should not modify this field before
>> + * sending
Re: [RFC v2 14/20] iommu: introduce device fault data
On Fri, 21 Sep 2018 11:54:56 +0200 Auger Eric wrote: > Hi Jacob, > > On 9/21/18 12:06 AM, Jacob Pan wrote: > > On Tue, 18 Sep 2018 16:24:51 +0200 > > Eric Auger wrote: > > > >> From: Jacob Pan > >> > >> Device faults detected by IOMMU can be reported outside IOMMU > >> subsystem for further processing. This patch intends to provide > >> a generic device fault data such that device drivers can be > >> communicated with IOMMU faults without model specific knowledge. > >> > >> The proposed format is the result of discussion at: > >> https://lkml.org/lkml/2017/11/10/291 > >> Part of the code is based on Jean-Philippe Brucker's patchset > >> (https://patchwork.kernel.org/patch/9989315/). > >> > >> The assumption is that model specific IOMMU driver can filter and > >> handle most of the internal faults if the cause is within IOMMU > >> driver control. Therefore, the fault reasons can be reported are > >> grouped and generalized based common specifications such as PCI > >> ATS. > >> > >> Signed-off-by: Jacob Pan > >> Signed-off-by: Jean-Philippe Brucker > >> Signed-off-by: Liu, Yi L > >> Signed-off-by: Ashok Raj > >> Signed-off-by: Eric Auger > >> [moved part of the iommu_fault_event > >> struct in the uapi, enriched the fault reasons to be able to map > >> unrecoverable SMMUv3 errors] > > Sounds good to me. > > There are also other "enrichment" we need to do to support mdev or > > finer granularity fault reporting below physical device. e.g. PASID > > level. > > Actually I intended to send you an email about those > iommu_fault_reason enum value changes. To attach this discussion to > your original series, I will send a separate email in the "[PATCH v5 > 00/23] IOMMU and VT-d driver support for Shared Virtual Address > (SVA)" thread. > > > > The current scheme works for PCIe physical device level, where each > > device registers a single handler only once. When device fault is > > detected by the IOMMU, it will find the matching handler and private > > data to report back. However, for devices partitioned by PASID and > > represented by mdev this may not work. Since IOMMU is not mdev aware > > and only works at physical device level. > > So I am thinking we should allow multiple registration of fault > > handler with different data and ID. i.e. > > > > int iommu_register_device_fault_handler(struct device *dev, > > iommu_dev_fault_handler_t > > handler, int id, > > void *data) > > > > where the new "id field" is > > * @id: Identification of the handler private data, will be used by > > fault > > * reporting code to match the handler data to be returned. > > For page > > * request, this can be the PASID. ID must be unique per > > device, i.e. > > * each ID can only be registered once per device. > > * - IOMMU_DEV_FAULT_ID_UNRECOVERY (~0U) is reserved for fault > > reporting > > * w/o ID. e.g. unrecoverable faults. > I don't get this last sentence. Don't you need the feature also for > unrecoverable faults, ie. isn't it requested to report an > unrecoverable fault on a specific id? > For unrecoverable faults which are not associated with a specific PASID, we reserve a range of special IDs for them. Let me rewrite the comments. The usage would be: For Handler registration by vfio or device driver 1. PRQ of PASID1 iommu_register_device_fault_handler(pdev, handler, pasid1, data1); 2. PRQ of PASID2 iommu_register_device_fault_handler(pdev, handler, pasid2, data2); 3. unrecoverable fault iommu_register_device_fault_handler(pdev, handler, IOMMU_DEV_FAULT_ID_UNRECOVERY, NULL); For IOMMU driver reporting fault back to vfio or kernel driver: 1. PRQ of PASID1 iommu_report_device_fault(dev, evt1) where evt1->data = data1, evt1->pasid = pasid1 2. PRQ of PASID2 iommu_report_device_fault(dev, evt2) where evt2->data = data2, evt2->pasid = pasid2 3. unrecoverable fault iommu_report_device_fault(dev, evt) where evt2->data = NULL, evt->pasid = IOMMU_DEV_FAULT_ID_UNRECOVERY where evt is of struct iommu_fault_event. > Otherwise looks OK; but I still need to carefully review "[RFC PATCH > v2 00/10] vfio/mdev: IOMMU aware mediated device". > > Thanks > > Eric > > > > I am still testing, but just wanted to have feedback on this idea. > > > > Thanks, > > > > Jacob > > > > > >> --- > >> include/linux/iommu.h | 55 - > >> include/uapi/linux/iommu.h | 83 > >> ++ 2 files changed, 136 > >> insertions(+), 2 deletions(-) > >> > >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h > >> index 9bd3e63d562b..7529c14ff506 100644 > >> --- a/include/linux/iommu.h > >> +++ b/include/linux/iommu.h > >> @@ -49,13 +49,17 @@ struct bus_type; > >> struct device; > >> struct iommu_domain; > >> struct notifier_block; > >> +struct iommu_fault_event; > >> > >> /* iommu fault flags */ > >> -#define IOMMU_FAULT_READ 0x0 > >> -#define
