diff options
Diffstat (limited to 'drivers/vfio/pci/vfio_pci_nvlink2.c')
| -rw-r--r-- | drivers/vfio/pci/vfio_pci_nvlink2.c | 482 |
1 files changed, 482 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci_nvlink2.c b/drivers/vfio/pci/vfio_pci_nvlink2.c new file mode 100644 index 000000000000..054a2cf9dd8e --- /dev/null +++ b/drivers/vfio/pci/vfio_pci_nvlink2.c @@ -0,0 +1,482 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * VFIO PCI NVIDIA Whitherspoon GPU support a.k.a. NVLink2. + * + * Copyright (C) 2018 IBM Corp. All rights reserved. + * Author: Alexey Kardashevskiy <aik@ozlabs.ru> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Register an on-GPU RAM region for cacheable access. + * + * Derived from original vfio_pci_igd.c: + * Copyright (C) 2016 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + */ + +#include <linux/io.h> +#include <linux/pci.h> +#include <linux/uaccess.h> +#include <linux/vfio.h> +#include <linux/sched/mm.h> +#include <linux/mmu_context.h> +#include <asm/kvm_ppc.h> +#include "vfio_pci_private.h" + +#define CREATE_TRACE_POINTS +#include "trace.h" + +EXPORT_TRACEPOINT_SYMBOL_GPL(vfio_pci_nvgpu_mmap_fault); +EXPORT_TRACEPOINT_SYMBOL_GPL(vfio_pci_nvgpu_mmap); +EXPORT_TRACEPOINT_SYMBOL_GPL(vfio_pci_npu2_mmap); + +struct vfio_pci_nvgpu_data { + unsigned long gpu_hpa; /* GPU RAM physical address */ + unsigned long gpu_tgt; /* TGT address of corresponding GPU RAM */ + unsigned long useraddr; /* GPU RAM userspace address */ + unsigned long size; /* Size of the GPU RAM window (usually 128GB) */ + struct mm_struct *mm; + struct mm_iommu_table_group_mem_t *mem; /* Pre-registered RAM descr. */ + struct pci_dev *gpdev; + struct notifier_block group_notifier; +}; + +static size_t vfio_pci_nvgpu_rw(struct vfio_pci_device *vdev, + char __user *buf, size_t count, loff_t *ppos, bool iswrite) +{ + unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) - VFIO_PCI_NUM_REGIONS; + struct vfio_pci_nvgpu_data *data = vdev->region[i].data; + loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK; + loff_t posaligned = pos & PAGE_MASK, posoff = pos & ~PAGE_MASK; + size_t sizealigned; + void __iomem *ptr; + + if (pos >= vdev->region[i].size) + return -EINVAL; + + count = min(count, (size_t)(vdev->region[i].size - pos)); + + /* + * We map only a bit of GPU RAM for a short time instead of mapping it + * for the guest lifetime as: + * + * 1) we do not know GPU RAM size, only aperture which is 4-8 times + * bigger than actual RAM size (16/32GB RAM vs. 128GB aperture); + * 2) mapping GPU RAM allows CPU to prefetch and if this happens + * before NVLink bridge is reset (which fences GPU RAM), + * hardware management interrupts (HMI) might happen, this + * will freeze NVLink bridge. + * + * This is not fast path anyway. + */ + sizealigned = _ALIGN_UP(posoff + count, PAGE_SIZE); + ptr = ioremap_cache(data->gpu_hpa + posaligned, sizealigned); + if (!ptr) + return -EFAULT; + + if (iswrite) { + if (copy_from_user(ptr + posoff, buf, count)) + count = -EFAULT; + else + *ppos += count; + } else { + if (copy_to_user(buf, ptr + posoff, count)) + count = -EFAULT; + else + *ppos += count; + } + + iounmap(ptr); + + return count; +} + +static void vfio_pci_nvgpu_release(struct vfio_pci_device *vdev, + struct vfio_pci_region *region) +{ + struct vfio_pci_nvgpu_data *data = region->data; + long ret; + + /* If there were any mappings at all... */ + if (data->mm) { + ret = mm_iommu_put(data->mm, data->mem); + WARN_ON(ret); + + mmdrop(data->mm); + } + + vfio_unregister_notifier(&data->gpdev->dev, VFIO_GROUP_NOTIFY, + &data->group_notifier); + + pnv_npu2_unmap_lpar_dev(data->gpdev); + + kfree(data); +} + +static vm_fault_t vfio_pci_nvgpu_mmap_fault(struct vm_fault *vmf) +{ + vm_fault_t ret; + struct vm_area_struct *vma = vmf->vma; + struct vfio_pci_region *region = vma->vm_private_data; + struct vfio_pci_nvgpu_data *data = region->data; + unsigned long vmf_off = (vmf->address - vma->vm_start) >> PAGE_SHIFT; + unsigned long nv2pg = data->gpu_hpa >> PAGE_SHIFT; + unsigned long vm_pgoff = vma->vm_pgoff & + ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1); + unsigned long pfn = nv2pg + vm_pgoff + vmf_off; + + ret = vmf_insert_pfn(vma, vmf->address, pfn); + trace_vfio_pci_nvgpu_mmap_fault(data->gpdev, pfn << PAGE_SHIFT, + vmf->address, ret); + + return ret; +} + +static const struct vm_operations_struct vfio_pci_nvgpu_mmap_vmops = { + .fault = vfio_pci_nvgpu_mmap_fault, +}; + +static int vfio_pci_nvgpu_mmap(struct vfio_pci_device *vdev, + struct vfio_pci_region *region, struct vm_area_struct *vma) +{ + int ret; + struct vfio_pci_nvgpu_data *data = region->data; + + if (data->useraddr) + return -EPERM; + + if (vma->vm_end - vma->vm_start > data->size) + return -EINVAL; + + vma->vm_private_data = region; + vma->vm_flags |= VM_PFNMAP; + vma->vm_ops = &vfio_pci_nvgpu_mmap_vmops; + + /* + * Calling mm_iommu_newdev() here once as the region is not + * registered yet and therefore right initialization will happen now. + * Other places will use mm_iommu_find() which returns + * registered @mem and does not go gup(). + */ + data->useraddr = vma->vm_start; + data->mm = current->mm; + + atomic_inc(&data->mm->mm_count); + ret = (int) mm_iommu_newdev(data->mm, data->useraddr, + (vma->vm_end - vma->vm_start) >> PAGE_SHIFT, + data->gpu_hpa, &data->mem); + + trace_vfio_pci_nvgpu_mmap(vdev->pdev, data->gpu_hpa, data->useraddr, + vma->vm_end - vma->vm_start, ret); + + return ret; +} + +static int vfio_pci_nvgpu_add_capability(struct vfio_pci_device *vdev, + struct vfio_pci_region *region, struct vfio_info_cap *caps) +{ + struct vfio_pci_nvgpu_data *data = region->data; + struct vfio_region_info_cap_nvlink2_ssatgt cap = { 0 }; + + cap.header.id = VFIO_REGION_INFO_CAP_NVLINK2_SSATGT; + cap.header.version = 1; + cap.tgt = data->gpu_tgt; + + return vfio_info_add_capability(caps, &cap.header, sizeof(cap)); +} + +static const struct vfio_pci_regops vfio_pci_nvgpu_regops = { + .rw = vfio_pci_nvgpu_rw, + .release = vfio_pci_nvgpu_release, + .mmap = vfio_pci_nvgpu_mmap, + .add_capability = vfio_pci_nvgpu_add_capability, +}; + +static int vfio_pci_nvgpu_group_notifier(struct notifier_block *nb, + unsigned long action, void *opaque) +{ + struct kvm *kvm = opaque; + struct vfio_pci_nvgpu_data *data = container_of(nb, + struct vfio_pci_nvgpu_data, + group_notifier); + + if (action == VFIO_GROUP_NOTIFY_SET_KVM && kvm && + pnv_npu2_map_lpar_dev(data->gpdev, + kvm->arch.lpid, MSR_DR | MSR_PR)) + return NOTIFY_BAD; + + return NOTIFY_OK; +} + +int vfio_pci_nvdia_v100_nvlink2_init(struct vfio_pci_device *vdev) +{ + int ret; + u64 reg[2]; + u64 tgt = 0; + struct device_node *npu_node, *mem_node; + struct pci_dev *npu_dev; + struct vfio_pci_nvgpu_data *data; + uint32_t mem_phandle = 0; + unsigned long events = VFIO_GROUP_NOTIFY_SET_KVM; + + /* + * PCI config space does not tell us about NVLink presense but + * platform does, use this. + */ + npu_dev = pnv_pci_get_npu_dev(vdev->pdev, 0); + if (!npu_dev) + return -ENODEV; + + npu_node = pci_device_to_OF_node(npu_dev); + if (!npu_node) + return -EINVAL; + + if (of_property_read_u32(npu_node, "memory-region", &mem_phandle)) + return -EINVAL; + + mem_node = of_find_node_by_phandle(mem_phandle); + if (!mem_node) + return -EINVAL; + + if (of_property_read_variable_u64_array(mem_node, "reg", reg, + ARRAY_SIZE(reg), ARRAY_SIZE(reg)) != + ARRAY_SIZE(reg)) + return -EINVAL; + + if (of_property_read_u64(npu_node, "ibm,device-tgt-addr", &tgt)) { + dev_warn(&vdev->pdev->dev, "No ibm,device-tgt-addr found\n"); + return -EFAULT; + } + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->gpu_hpa = reg[0]; + data->gpu_tgt = tgt; + data->size = reg[1]; + + dev_dbg(&vdev->pdev->dev, "%lx..%lx\n", data->gpu_hpa, + data->gpu_hpa + data->size - 1); + + data->gpdev = vdev->pdev; + data->group_notifier.notifier_call = vfio_pci_nvgpu_group_notifier; + + ret = vfio_register_notifier(&data->gpdev->dev, VFIO_GROUP_NOTIFY, + &events, &data->group_notifier); + if (ret) + goto free_exit; + + /* + * We have just set KVM, we do not need the listener anymore. + * Also, keeping it registered means that if more than one GPU is + * assigned, we will get several similar notifiers notifying about + * the same device again which does not help with anything. + */ + vfio_unregister_notifier(&data->gpdev->dev, VFIO_GROUP_NOTIFY, + &data->group_notifier); + + ret = vfio_pci_register_dev_region(vdev, + PCI_VENDOR_ID_NVIDIA | VFIO_REGION_TYPE_PCI_VENDOR_TYPE, + VFIO_REGION_SUBTYPE_NVIDIA_NVLINK2_RAM, + &vfio_pci_nvgpu_regops, + data->size, + VFIO_REGION_INFO_FLAG_READ | + VFIO_REGION_INFO_FLAG_WRITE | + VFIO_REGION_INFO_FLAG_MMAP, + data); + if (ret) + goto free_exit; + + return 0; +free_exit: + kfree(data); + + return ret; +} + +/* + * IBM NPU2 bridge + */ +struct vfio_pci_npu2_data { + void *base; /* ATSD register virtual address, for emulated access */ + unsigned long mmio_atsd; /* ATSD physical address */ + unsigned long gpu_tgt; /* TGT address of corresponding GPU RAM */ + unsigned int link_speed; /* The link speed from DT's ibm,nvlink-speed */ +}; + +static size_t vfio_pci_npu2_rw(struct vfio_pci_device *vdev, + char __user *buf, size_t count, loff_t *ppos, bool iswrite) +{ + unsigned int i = VFIO_PCI_OFFSET_TO_INDEX(*ppos) - VFIO_PCI_NUM_REGIONS; + struct vfio_pci_npu2_data *data = vdev->region[i].data; + loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK; + + if (pos >= vdev->region[i].size) + return -EINVAL; + + count = min(count, (size_t)(vdev->region[i].size - pos)); + + if (iswrite) { + if (copy_from_user(data->base + pos, buf, count)) + return -EFAULT; + } else { + if (copy_to_user(buf, data->base + pos, count)) + return -EFAULT; + } + *ppos += count; + + return count; +} + +static int vfio_pci_npu2_mmap(struct vfio_pci_device *vdev, + struct vfio_pci_region *region, struct vm_area_struct *vma) +{ + int ret; + struct vfio_pci_npu2_data *data = region->data; + unsigned long req_len = vma->vm_end - vma->vm_start; + + if (req_len != PAGE_SIZE) + return -EINVAL; + + vma->vm_flags |= VM_PFNMAP; + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + ret = remap_pfn_range(vma, vma->vm_start, data->mmio_atsd >> PAGE_SHIFT, + req_len, vma->vm_page_prot); + trace_vfio_pci_npu2_mmap(vdev->pdev, data->mmio_atsd, vma->vm_start, + vma->vm_end - vma->vm_start, ret); + + return ret; +} + +static void vfio_pci_npu2_release(struct vfio_pci_device *vdev, + struct vfio_pci_region *region) +{ + struct vfio_pci_npu2_data *data = region->data; + + memunmap(data->base); + kfree(data); +} + +static int vfio_pci_npu2_add_capability(struct vfio_pci_device *vdev, + struct vfio_pci_region *region, struct vfio_info_cap *caps) +{ + struct vfio_pci_npu2_data *data = region->data; + struct vfio_region_info_cap_nvlink2_ssatgt captgt = { 0 }; + struct vfio_region_info_cap_nvlink2_lnkspd capspd = { 0 }; + int ret; + + captgt.header.id = VFIO_REGION_INFO_CAP_NVLINK2_SSATGT; + captgt.header.version = 1; + captgt.tgt = data->gpu_tgt; + + capspd.header.id = VFIO_REGION_INFO_CAP_NVLINK2_LNKSPD; + capspd.header.version = 1; + capspd.link_speed = data->link_speed; + + ret = vfio_info_add_capability(caps, &captgt.header, sizeof(captgt)); + if (ret) + return ret; + + return vfio_info_add_capability(caps, &capspd.header, sizeof(capspd)); +} + +static const struct vfio_pci_regops vfio_pci_npu2_regops = { + .rw = vfio_pci_npu2_rw, + .mmap = vfio_pci_npu2_mmap, + .release = vfio_pci_npu2_release, + .add_capability = vfio_pci_npu2_add_capability, +}; + +int vfio_pci_ibm_npu2_init(struct vfio_pci_device *vdev) +{ + int ret; + struct vfio_pci_npu2_data *data; + struct device_node *nvlink_dn; + u32 nvlink_index = 0; + struct pci_dev *npdev = vdev->pdev; + struct device_node *npu_node = pci_device_to_OF_node(npdev); + struct pci_controller *hose = pci_bus_to_host(npdev->bus); + u64 mmio_atsd = 0; + u64 tgt = 0; + u32 link_speed = 0xff; + + /* + * PCI config space does not tell us about NVLink presense but + * platform does, use this. + */ + if (!pnv_pci_get_gpu_dev(vdev->pdev)) + return -ENODEV; + + /* + * NPU2 normally has 8 ATSD registers (for concurrency) and 6 links + * so we can allocate one register per link, using nvlink index as + * a key. + * There is always at least one ATSD register so as long as at least + * NVLink bridge #0 is passed to the guest, ATSD will be available. + */ + nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0); + if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index", + &nvlink_index))) + return -ENODEV; + + if (of_property_read_u64_index(hose->dn, "ibm,mmio-atsd", nvlink_index, + &mmio_atsd)) { + dev_warn(&vdev->pdev->dev, "No available ATSD found\n"); + mmio_atsd = 0; + } + + if (of_property_read_u64(npu_node, "ibm,device-tgt-addr", &tgt)) { + dev_warn(&vdev->pdev->dev, "No ibm,device-tgt-addr found\n"); + return -EFAULT; + } + + if (of_property_read_u32(npu_node, "ibm,nvlink-speed", &link_speed)) { + dev_warn(&vdev->pdev->dev, "No ibm,nvlink-speed found\n"); + return -EFAULT; + } + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->mmio_atsd = mmio_atsd; + data->gpu_tgt = tgt; + data->link_speed = link_speed; + if (data->mmio_atsd) { + data->base = memremap(data->mmio_atsd, SZ_64K, MEMREMAP_WT); + if (!data->base) { + ret = -ENOMEM; + goto free_exit; + } + } + + /* + * We want to expose the capability even if this specific NVLink + * did not get its own ATSD register because capabilities + * belong to VFIO regions and normally there will be ATSD register + * assigned to the NVLink bridge. + */ + ret = vfio_pci_register_dev_region(vdev, + PCI_VENDOR_ID_IBM | + VFIO_REGION_TYPE_PCI_VENDOR_TYPE, + VFIO_REGION_SUBTYPE_IBM_NVLINK2_ATSD, + &vfio_pci_npu2_regops, + data->mmio_atsd ? PAGE_SIZE : 0, + VFIO_REGION_INFO_FLAG_READ | + VFIO_REGION_INFO_FLAG_WRITE | + VFIO_REGION_INFO_FLAG_MMAP, + data); + if (ret) + goto free_exit; + + return 0; + +free_exit: + kfree(data); + + return ret; +} |