Hi Ilya, On Thu, Feb 04, 2016 at 10:28:53AM +0200, Ilya Lesokhin wrote: > Changes from v1: > Due to the security concern raised in v1, we add two patches > to make sure the VFs belong to the same IOMMU group as > the PF and are probed by VFIO. > > Today the QEMU hypervisor allows assigning a physical device to a VM, > facilitating driver development. However, it does not support enabling > SR-IOV by the VM kernel driver. Our goal is to implement such support, > allowing developers working on SR-IOV physical function drivers to work > inside VMs as well. > > This patch series implements the kernel side of our solution. It extends > the VFIO driver to support the PCIE SRIOV extended capability with > following features: > 1. The ability to probe SRIOV BAR sizes. > 2. The ability to enable and disable sriov. > > This patch series is going to be used by QEMU to expose sriov capabilities > to VM. We already have an early prototype based on Knut Omang's patches for > SRIOV[1]. > > Open issues: > 1. How to tell if it is safe to disable SRIOV? > In the current implementation, a userspace can enable sriov, grab one of > the VFs and then call disable sriov without releasing the device. This > will result in a deadlock where the user process is stuck inside disable > sriov waiting for itself to release the device. Killing the process leaves > it in a zombie state. > We also get a strange warning saying: > [ 181.668492] WARNING: CPU: 22 PID: 3684 at kernel/sched/core.c:7497 __might_sleep+0x77/0x80() > [ 181.668502] do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff810aa193>] prepare_to_wait_event+0x63/0xf0 > > 2. How to expose the Supported Page Sizes and System Page Size registers in > the SRIOV capability? > Presently the hypervisor initializes Supported Page Sizes once and assumes > it doesn't change therefore we cannot allow user space to change this > register at will. The first solution that comes to mind is to expose a > device that only supports the page size selected by the hypervisor. > Unfourtently, Per SR-IOV spec section 3.3.12, PFs are required to support > 4-KB, 8-KB, 64-KB, 256-KB, 1-MB, and 4-MB page sizes. We currently map both > registers as virtualized and read only and leave user space to worry about > this problem. > > 3. Other SRIOV capabilities. > Do we want to hide capabilities we do not support in the SR-IOV > Capabilities register? or leave it to the userspace application? > > [1] https://github.com/knuto/qemu/tree/sriov_patches_v6 > > Ilya Lesokhin (4): > VFIO: Probe new devices in a live VFIO group with the VFIO driver > IOMMU: Force the VFs of an untrusted PF device to be in the PFs IOMMU > group > PCI: Expose iov_set_numvfs and iov_resource_size for modules. > VFIO: Add support for SRIOV extended capablity > > drivers/iommu/iommu.c | 4 + > drivers/pci/iov.c | 4 +- > drivers/vfio/pci/vfio_pci.c | 3 + > drivers/vfio/pci/vfio_pci_config.c | 169 +++++++++++++++++++++++++++++++++---- > drivers/vfio/vfio.c | 18 +++- > include/linux/pci.h | 5 ++ > 6 files changed, 182 insertions(+), 21 deletions(-) This is mostly a VFIO series, so I'm going to defer to Alex. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
