From 6cdd97821322352b94bb92f271b4466ad38a2468 Mon Sep 17 00:00:00 2001 From: Alexey Kardashevskiy Date: Mon, 5 Aug 2013 10:52:36 -0600 Subject: vfio: add external user support VFIO is designed to be used via ioctls on file descriptors returned by VFIO. However in some situations support for an external user is required. The first user is KVM on PPC64 (SPAPR TCE protocol) which is going to use the existing VFIO groups for exclusive access in real/virtual mode on a host to avoid passing map/unmap requests to the user space which would made things pretty slow. The protocol includes: 1. do normal VFIO init operation: - opening a new container; - attaching group(s) to it; - setting an IOMMU driver for a container. When IOMMU is set for a container, all groups in it are considered ready to use by an external user. 2. User space passes a group fd to an external user. The external user calls vfio_group_get_external_user() to verify that: - the group is initialized; - IOMMU is set for it. If both checks passed, vfio_group_get_external_user() increments the container user counter to prevent the VFIO group from disposal before KVM exits. 3. The external user calls vfio_external_user_iommu_id() to know an IOMMU ID. PPC64 KVM uses it to link logical bus number (LIOBN) with IOMMU ID. 4. When the external KVM finishes, it calls vfio_group_put_external_user() to release the VFIO group. This call decrements the container user counter. Everything gets released. The "vfio: Limit group opens" patch is also required for the consistency. Signed-off-by: Alexey Kardashevskiy Signed-off-by: Alex Williamson --- include/linux/vfio.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include') diff --git a/include/linux/vfio.h b/include/linux/vfio.h index ac8d488e4372..24579a0312a0 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -90,4 +90,11 @@ extern void vfio_unregister_iommu_driver( TYPE tmp; \ offsetof(TYPE, MEMBER) + sizeof(tmp.MEMBER); }) \ +/* + * External user API + */ +extern struct vfio_group *vfio_group_get_external_user(struct file *filep); +extern void vfio_group_put_external_user(struct vfio_group *group); +extern int vfio_external_user_iommu_id(struct vfio_group *group); + #endif /* VFIO_H */ -- cgit v1.2.3 From 8b27ee60bfd6bbb84d2df28fa706c5c5081066ca Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Wed, 4 Sep 2013 11:28:04 -0600 Subject: vfio-pci: PCI hot reset interface The current VFIO_DEVICE_RESET interface only maps to PCI use cases where we can isolate the reset to the individual PCI function. This means the device must support FLR (PCIe or AF), PM reset on D3hot->D0 transition, device specific reset, or be a singleton device on a bus for a secondary bus reset. FLR does not have widespread support, PM reset is not very reliable, and bus topology is dictated by the system and device design. We need to provide a means for a user to induce a bus reset in cases where the existing mechanisms are not available or not reliable. This device specific extension to VFIO provides the user with this ability. Two new ioctls are introduced: - VFIO_DEVICE_PCI_GET_HOT_RESET_INFO - VFIO_DEVICE_PCI_HOT_RESET The first provides the user with information about the extent of devices affected by a hot reset. This is essentially a list of devices and the IOMMU groups they belong to. The user may then initiate a hot reset by calling the second ioctl. We must be careful that the user has ownership of all the affected devices found via the first ioctl, so the second ioctl takes a list of file descriptors for the VFIO groups affected by the reset. Each group must have IOMMU protection established for the ioctl to succeed. Signed-off-by: Alex Williamson --- include/uapi/linux/vfio.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'include') diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 916e444e6f74..0fd47f5bc146 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -324,6 +324,44 @@ enum { VFIO_PCI_NUM_IRQS }; +/** + * VFIO_DEVICE_GET_PCI_HOT_RESET_INFO - _IORW(VFIO_TYPE, VFIO_BASE + 12, + * struct vfio_pci_hot_reset_info) + * + * Return: 0 on success, -errno on failure: + * -enospc = insufficient buffer, -enodev = unsupported for device. + */ +struct vfio_pci_dependent_device { + __u32 group_id; + __u16 segment; + __u8 bus; + __u8 devfn; /* Use PCI_SLOT/PCI_FUNC */ +}; + +struct vfio_pci_hot_reset_info { + __u32 argsz; + __u32 flags; + __u32 count; + struct vfio_pci_dependent_device devices[]; +}; + +#define VFIO_DEVICE_GET_PCI_HOT_RESET_INFO _IO(VFIO_TYPE, VFIO_BASE + 12) + +/** + * VFIO_DEVICE_PCI_HOT_RESET - _IOW(VFIO_TYPE, VFIO_BASE + 13, + * struct vfio_pci_hot_reset) + * + * Return: 0 on success, -errno on failure. + */ +struct vfio_pci_hot_reset { + __u32 argsz; + __u32 flags; + __u32 count; + __s32 group_fds[]; +}; + +#define VFIO_DEVICE_PCI_HOT_RESET _IO(VFIO_TYPE, VFIO_BASE + 13) + /* -------- API for Type1 VFIO IOMMU -------- */ /** -- cgit v1.2.3