Messages in this thread | | | Subject | Re: [PATCH v4 6/8] vfio/mdev: Add iommu place holders in mdev_device | From | Lu Baolu <> | Date | Wed, 7 Nov 2018 09:48:51 +0800 |
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Hi Alex,
On 11/7/18 7:53 AM, Alex Williamson wrote: > On Mon, 5 Nov 2018 15:34:06 +0800 > Lu Baolu <baolu.lu@linux.intel.com> wrote: > >> A parent device might create different types of mediated >> devices. For example, a mediated device could be created >> by the parent device with full isolation and protection >> provided by the IOMMU. One usage case could be found on >> Intel platforms where a mediated device is an assignable >> subset of a PCI, the DMA requests on behalf of it are all >> tagged with a PASID. Since IOMMU supports PASID-granular >> translations (scalable mode in vt-d 3.0), this mediated >> device could be individually protected and isolated by an >> IOMMU. >> >> This patch adds two new members in struct mdev_device: >> * iommu_device >> - This, if set, indicates that the mediated device could >> be fully isolated and protected by IOMMU via attaching >> an iommu domain to this device. If empty, it indicates >> using vendor defined isolation. >> >> * iommu_domain >> - This is a place holder for an iommu domain. A domain >> could be store here for later use once it has been >> attached to the iommu_device of this mdev. >> >> Below helpers are added to set and get above iommu device >> and iommu domain pointers. >> >> * mdev_set/get_iommu_device(dev, iommu_device) >> - Set or get the iommu device which represents this mdev >> in IOMMU's device scope. Drivers don't need to set the >> iommu device if it uses vendor defined isolation. >> >> * mdev_set/get_iommu_domain(domain) >> - A iommu domain which has been attached to the iommu >> device in order to protect and isolate the mediated >> device will be kept in the mdev data structure and >> could be retrieved later. >> >> Cc: Ashok Raj <ashok.raj@intel.com> >> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com> >> Cc: Kevin Tian <kevin.tian@intel.com> >> Cc: Liu Yi L <yi.l.liu@intel.com> >> Suggested-by: Kevin Tian <kevin.tian@intel.com> >> Suggested-by: Alex Williamson <alex.williamson@redhat.com> >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> >> --- >> drivers/vfio/mdev/mdev_core.c | 36 ++++++++++++++++++++++++++++++++ >> drivers/vfio/mdev/mdev_private.h | 2 ++ >> include/linux/mdev.h | 23 ++++++++++++++++++++ >> 3 files changed, 61 insertions(+) >> >> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c >> index 0212f0ee8aea..5119809225c5 100644 >> --- a/drivers/vfio/mdev/mdev_core.c >> +++ b/drivers/vfio/mdev/mdev_core.c >> @@ -390,6 +390,42 @@ int mdev_device_remove(struct device *dev, bool force_remove) >> return 0; >> } >> >> +int mdev_set_iommu_device(struct device *dev, struct device *iommu_device) >> +{ >> + struct mdev_device *mdev = to_mdev_device(dev); >> + >> + mdev->iommu_device = iommu_device; >> + >> + return 0; >> +} >> +EXPORT_SYMBOL(mdev_set_iommu_device); >> + >> +struct device *mdev_get_iommu_device(struct device *dev) >> +{ >> + struct mdev_device *mdev = to_mdev_device(dev); >> + >> + return mdev->iommu_device; >> +} >> +EXPORT_SYMBOL(mdev_get_iommu_device); >> + >> +int mdev_set_iommu_domain(struct device *dev, void *domain) >> +{ >> + struct mdev_device *mdev = to_mdev_device(dev); >> + >> + mdev->iommu_domain = domain; >> + >> + return 0; >> +} >> +EXPORT_SYMBOL(mdev_set_iommu_domain); >> + >> +void *mdev_get_iommu_domain(struct device *dev) >> +{ >> + struct mdev_device *mdev = to_mdev_device(dev); >> + >> + return mdev->iommu_domain; >> +} >> +EXPORT_SYMBOL(mdev_get_iommu_domain); >> + >> static int __init mdev_init(void) >> { >> return mdev_bus_register(); >> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h >> index b5819b7d7ef7..c01518068e84 100644 >> --- a/drivers/vfio/mdev/mdev_private.h >> +++ b/drivers/vfio/mdev/mdev_private.h >> @@ -34,6 +34,8 @@ struct mdev_device { >> struct list_head next; >> struct kobject *type_kobj; >> bool active; >> + struct device *iommu_device; >> + void *iommu_domain; >> }; >> >> #define to_mdev_device(dev) container_of(dev, struct mdev_device, dev) >> diff --git a/include/linux/mdev.h b/include/linux/mdev.h >> index b6e048e1045f..c46777d3e568 100644 >> --- a/include/linux/mdev.h >> +++ b/include/linux/mdev.h >> @@ -14,6 +14,29 @@ >> #define MDEV_H >> >> struct mdev_device; >> +struct iommu_domain; >> + >> +/* >> + * Called by the parent device driver to set the PCI device which represents > > s/PCI // > > There is no requirement or expectation that the device is PCI. >
Fair enough.
>> + * this mdev in iommu protection scope. By default, the iommu device is NULL, >> + * that indicates using vendor defined isolation. >> + * >> + * @dev: the mediated device that iommu will isolate. >> + * @iommu_device: a pci device which represents the iommu for @dev. >> + * >> + * Return 0 for success, otherwise negative error value. >> + */ >> +int mdev_set_iommu_device(struct device *dev, struct device *iommu_device); >> + >> +struct device *mdev_get_iommu_device(struct device *dev); >> + >> +/* >> + * Called by vfio iommu modules to save the iommu domain after a domain being >> + * attached to the mediated device. >> + */ >> +int mdev_set_iommu_domain(struct device *dev, void *domain); >> + >> +void *mdev_get_iommu_domain(struct device *dev); > > I can't say I really understand the purpose of this, the cover letter > indicates this is a placeholder, should we add it separately when we > have a requirement for it?
Oh, I am sorry that I used a wrong word. It's not a placeholder for something designed for future, but adding two members that will be used in the following patches. Since they will be used in anther modules (like vfio_iommu), we need function interfaces to get and set them.
mdev->iommu_device: - This, if set, indicates that the mediated device could be fully isolated and protected by IOMMU via attaching an iommu domain to this device. If empty, it indicates using vendor defined isolation.
mdev->iommu_domain: - This is used to save the pointer of an iommu domain. Once a domain has been attached to the iommu_device, it should be stored here.
Sorry for the confusion.
Best regards, Lu Baolu
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