From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Auger Subject: [PATCH v4 20/22] vfio_pci: Allow to mmap the fault queue Date: Mon, 18 Feb 2019 14:55:01 +0100 Message-ID: <20190218135504.25048-21-eric.auger@redhat.com> References: <20190218135504.25048-1-eric.auger@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190218135504.25048-1-eric.auger@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: eric.auger.pro@gmail.com, eric.auger@redhat.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, joro@8bytes.org, alex.williamson@redhat.com, jacob.jun.pan@linux.intel.com, yi.l.liu@linux.intel.com, jean-philippe.brucker@arm.com, will.deacon@arm.com, robin.murphy@arm.com Cc: marc.zyngier@arm.com, kevin.tian@intel.com, ashok.raj@intel.com List-Id: iommu@lists.linux-foundation.org The Producer Fault region contains the fault queue in the second page. There is benefit to let the userspace mmap this area. So let's expose this mmappable area through a sparse mmap entry and implement the mmap operation. Signed-off-by: Eric Auger --- drivers/vfio/pci/vfio_pci.c | 61 +++++++++++++++++++++++++++++++++++-- 1 file changed, 59 insertions(+), 2 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 019c9fd380a5..3aaa14eb5518 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -223,15 +223,70 @@ static const struct vfio_pci_fault_abi fault_abi_versions[] = { #define NR_FAULT_ABIS ARRAY_SIZE(fault_abi_versions) +static int vfio_pci_fault_mmap(struct vfio_pci_device *vdev, + struct vfio_pci_region *region, + struct vm_area_struct *vma) +{ + u64 phys_len, req_len, pgoff, req_start; + unsigned long long addr; + unsigned int index, ret; + + index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT); + + phys_len = region->size; + + req_len = vma->vm_end - vma->vm_start; + pgoff = vma->vm_pgoff & + ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1); + req_start = pgoff << PAGE_SHIFT; + + /* only the second page of the producer fault region is mmappable */ + if (req_start < PAGE_SIZE) + return -EINVAL; + + if (req_start + req_len > phys_len) + return -EINVAL; + + addr = virt_to_phys(vdev->fault_pages); + vma->vm_private_data = vdev; + vma->vm_pgoff = (addr >> PAGE_SHIFT) + pgoff; + + ret = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, + req_len, vma->vm_page_prot); + return ret; +} + static int vfio_pci_fault_prod_add_capability(struct vfio_pci_device *vdev, struct vfio_pci_region *region, struct vfio_info_cap *caps) { + struct vfio_region_info_cap_sparse_mmap *sparse = NULL; struct vfio_region_info_cap_fault cap = { .header.id = VFIO_REGION_INFO_CAP_PRODUCER_FAULT, .header.version = 1, .version = NR_FAULT_ABIS, }; - return vfio_info_add_capability(caps, &cap.header, sizeof(cap)); + size_t size = sizeof(*sparse) + sizeof(*sparse->areas); + int ret; + + ret = vfio_info_add_capability(caps, &cap.header, sizeof(cap)); + if (ret) + return ret; + + sparse = kzalloc(size, GFP_KERNEL); + if (!sparse) + return -ENOMEM; + + sparse->header.id = VFIO_REGION_INFO_CAP_SPARSE_MMAP; + sparse->header.version = 1; + sparse->nr_areas = 1; + sparse->areas[0].offset = PAGE_SIZE; + sparse->areas[0].size = PAGE_SIZE; + + ret = vfio_info_add_capability(caps, &sparse->header, size); + if (ret) + kfree(sparse); + + return ret; } static const struct vfio_pci_regops vfio_pci_fault_cons_regops = { @@ -242,6 +297,7 @@ static const struct vfio_pci_regops vfio_pci_fault_cons_regops = { static const struct vfio_pci_regops vfio_pci_fault_prod_regops = { .rw = vfio_pci_fault_prod_rw, .release = vfio_pci_fault_release, + .mmap = vfio_pci_fault_mmap, .add_capability = vfio_pci_fault_prod_add_capability, }; @@ -300,7 +356,8 @@ static int vfio_pci_init_fault_region(struct vfio_pci_device *vdev) VFIO_REGION_TYPE_NESTED, VFIO_REGION_SUBTYPE_NESTED_FAULT_PROD, &vfio_pci_fault_prod_regops, 2 * PAGE_SIZE, - VFIO_REGION_INFO_FLAG_READ, vdev->fault_pages); + VFIO_REGION_INFO_FLAG_READ | VFIO_REGION_INFO_FLAG_MMAP, + vdev->fault_pages); if (ret) goto out; -- 2.20.1