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path: root/drivers/vfio/pci/vfio_pci_nvlink2.c
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Diffstat (limited to 'drivers/vfio/pci/vfio_pci_nvlink2.c')
-rw-r--r--drivers/vfio/pci/vfio_pci_nvlink2.c482
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;
+}