vfio-pci/zdev: Add zPCI capabilities to VFIO_DEVICE_GET_INFO

Define a new configuration entry VFIO_PCI_ZDEV for VFIO/PCI.

When this s390-only feature is configured we add capabilities to the
VFIO_DEVICE_GET_INFO ioctl that describe features of the associated
zPCI device and its underlying hardware.

This patch is based on work previously done by Pierre Morel.

Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig
index ac3c1dd..40a2233 100644 (file)
--- a/drivers/vfio/pci/Kconfig
+++ b/drivers/vfio/pci/Kconfig
@@ -45,3 +45,15 @@ config VFIO_PCI_NVLINK2
        depends on VFIO_PCI && PPC_POWERNV
        help
          VFIO PCI support for P9 Witherspoon machine with NVIDIA V100 GPUs
+
+config VFIO_PCI_ZDEV
+       bool "VFIO PCI ZPCI device CLP support"
+       depends on VFIO_PCI && S390
+       default y
+       help
+         Enabling this option exposes VFIO capabilities containing hardware
+         configuration for zPCI devices. This enables userspace (e.g. QEMU)
+         to supply proper configuration values instead of hard-coded defaults
+         for zPCI devices passed through via VFIO on s390.
+
+         Say Y here.

diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile
index f027f8a..781e080 100644 (file)
--- a/drivers/vfio/pci/Makefile
+++ b/drivers/vfio/pci/Makefile
@@ -3,5 +3,6 @@
 vfio-pci-y := vfio_pci.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o
 vfio-pci-$(CONFIG_VFIO_PCI_IGD) += vfio_pci_igd.o
 vfio-pci-$(CONFIG_VFIO_PCI_NVLINK2) += vfio_pci_nvlink2.o
+vfio-pci-$(CONFIG_VFIO_PCI_ZDEV) += vfio_pci_zdev.o
 
 obj-$(CONFIG_VFIO_PCI) += vfio-pci.o

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 1ab1f5c..208dea5 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -807,15 +807,25 @@ static long vfio_pci_ioctl(void *device_data,
 
        if (cmd == VFIO_DEVICE_GET_INFO) {
                struct vfio_device_info info;
+               struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
+               unsigned long capsz;
 
                minsz = offsetofend(struct vfio_device_info, num_irqs);
 
+               /* For backward compatibility, cannot require this */
+               capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
+
                if (copy_from_user(&info, (void __user *)arg, minsz))
                        return -EFAULT;
 
                if (info.argsz < minsz)
                        return -EINVAL;
 
+               if (info.argsz >= capsz) {
+                       minsz = capsz;
+                       info.cap_offset = 0;
+               }
+
                info.flags = VFIO_DEVICE_FLAGS_PCI;
 
                if (vdev->reset_works)
@@ -824,6 +834,33 @@ static long vfio_pci_ioctl(void *device_data,
                info.num_regions = VFIO_PCI_NUM_REGIONS + vdev->num_regions;
                info.num_irqs = VFIO_PCI_NUM_IRQS;
 
+               if (IS_ENABLED(CONFIG_VFIO_PCI_ZDEV)) {
+                       int ret = vfio_pci_info_zdev_add_caps(vdev, &caps);
+
+                       if (ret && ret != -ENODEV) {
+                               pci_warn(vdev->pdev, "Failed to setup zPCI info capabilities\n");
+                               return ret;
+                       }
+               }
+
+               if (caps.size) {
+                       info.flags |= VFIO_DEVICE_FLAGS_CAPS;
+                       if (info.argsz < sizeof(info) + caps.size) {
+                               info.argsz = sizeof(info) + caps.size;
+                       } else {
+                               vfio_info_cap_shift(&caps, sizeof(info));
+                               if (copy_to_user((void __user *)arg +
+                                                 sizeof(info), caps.buf,
+                                                 caps.size)) {
+                                       kfree(caps.buf);
+                                       return -EFAULT;
+                               }
+                               info.cap_offset = sizeof(info);
+                       }
+
+                       kfree(caps.buf);
+               }
+
                return copy_to_user((void __user *)arg, &info, minsz) ?
                        -EFAULT : 0;
 

diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 61ca8ab..5c90e56 100644 (file)
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -213,4 +213,16 @@ static inline int vfio_pci_ibm_npu2_init(struct vfio_pci_device *vdev)
        return -ENODEV;
 }
 #endif
+
+#ifdef CONFIG_VFIO_PCI_ZDEV
+extern int vfio_pci_info_zdev_add_caps(struct vfio_pci_device *vdev,
+                                      struct vfio_info_cap *caps);
+#else
+static inline int vfio_pci_info_zdev_add_caps(struct vfio_pci_device *vdev,
+                                             struct vfio_info_cap *caps)
+{
+       return -ENODEV;
+}
+#endif
+
 #endif /* VFIO_PCI_PRIVATE_H */

diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c
new file mode 100644 (file)
index 0000000..2296856
--- /dev/null
+++ b/drivers/vfio/pci/vfio_pci_zdev.c
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * VFIO ZPCI devices support
+ *
+ * Copyright (C) IBM Corp. 2020.  All rights reserved.
+ *     Author(s): Pierre Morel <pmorel@linux.ibm.com>
+ *                 Matthew Rosato <mjrosato@linux.ibm.com>
+ *
+ * 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.
+ *
+ */
+#include <linux/io.h>
+#include <linux/pci.h>
+#include <linux/uaccess.h>
+#include <linux/vfio.h>
+#include <linux/vfio_zdev.h>
+#include <asm/pci_clp.h>
+#include <asm/pci_io.h>
+
+#include "vfio_pci_private.h"
+
+/*
+ * Add the Base PCI Function information to the device info region.
+ */
+static int zpci_base_cap(struct zpci_dev *zdev, struct vfio_pci_device *vdev,
+                        struct vfio_info_cap *caps)
+{
+       struct vfio_device_info_cap_zpci_base cap = {
+               .header.id = VFIO_DEVICE_INFO_CAP_ZPCI_BASE,
+               .header.version = 1,
+               .start_dma = zdev->start_dma,
+               .end_dma = zdev->end_dma,
+               .pchid = zdev->pchid,
+               .vfn = zdev->vfn,
+               .fmb_length = zdev->fmb_length,
+               .pft = zdev->pft,
+               .gid = zdev->pfgid
+       };
+
+       return vfio_info_add_capability(caps, &cap.header, sizeof(cap));
+}
+
+/*
+ * Add the Base PCI Function Group information to the device info region.
+ */
+static int zpci_group_cap(struct zpci_dev *zdev, struct vfio_pci_device *vdev,
+                         struct vfio_info_cap *caps)
+{
+       struct vfio_device_info_cap_zpci_group cap = {
+               .header.id = VFIO_DEVICE_INFO_CAP_ZPCI_GROUP,
+               .header.version = 1,
+               .dasm = zdev->dma_mask,
+               .msi_addr = zdev->msi_addr,
+               .flags = VFIO_DEVICE_INFO_ZPCI_FLAG_REFRESH,
+               .mui = zdev->fmb_update,
+               .noi = zdev->max_msi,
+               .maxstbl = ZPCI_MAX_WRITE_SIZE,
+               .version = zdev->version
+       };
+
+       return vfio_info_add_capability(caps, &cap.header, sizeof(cap));
+}
+
+/*
+ * Add the device utility string to the device info region.
+ */
+static int zpci_util_cap(struct zpci_dev *zdev, struct vfio_pci_device *vdev,
+                        struct vfio_info_cap *caps)
+{
+       struct vfio_device_info_cap_zpci_util *cap;
+       int cap_size = sizeof(*cap) + CLP_UTIL_STR_LEN;
+       int ret;
+
+       cap = kmalloc(cap_size, GFP_KERNEL);
+
+       cap->header.id = VFIO_DEVICE_INFO_CAP_ZPCI_UTIL;
+       cap->header.version = 1;
+       cap->size = CLP_UTIL_STR_LEN;
+       memcpy(cap->util_str, zdev->util_str, cap->size);
+
+       ret = vfio_info_add_capability(caps, &cap->header, cap_size);
+
+       kfree(cap);
+
+       return ret;
+}
+
+/*
+ * Add the function path string to the device info region.
+ */
+static int zpci_pfip_cap(struct zpci_dev *zdev, struct vfio_pci_device *vdev,
+                        struct vfio_info_cap *caps)
+{
+       struct vfio_device_info_cap_zpci_pfip *cap;
+       int cap_size = sizeof(*cap) + CLP_PFIP_NR_SEGMENTS;
+       int ret;
+
+       cap = kmalloc(cap_size, GFP_KERNEL);
+
+       cap->header.id = VFIO_DEVICE_INFO_CAP_ZPCI_PFIP;
+       cap->header.version = 1;
+       cap->size = CLP_PFIP_NR_SEGMENTS;
+       memcpy(cap->pfip, zdev->pfip, cap->size);
+
+       ret = vfio_info_add_capability(caps, &cap->header, cap_size);
+
+       kfree(cap);
+
+       return ret;
+}
+
+/*
+ * Add all supported capabilities to the VFIO_DEVICE_GET_INFO capability chain.
+ */
+int vfio_pci_info_zdev_add_caps(struct vfio_pci_device *vdev,
+                               struct vfio_info_cap *caps)
+{
+       struct zpci_dev *zdev = to_zpci(vdev->pdev);
+       int ret;
+
+       if (!zdev)
+               return -ENODEV;
+
+       ret = zpci_base_cap(zdev, vdev, caps);
+       if (ret)
+               return ret;
+
+       ret = zpci_group_cap(zdev, vdev, caps);
+       if (ret)
+               return ret;
+
+       if (zdev->util_str_avail) {
+               ret = zpci_util_cap(zdev, vdev, caps);
+               if (ret)
+                       return ret;
+       }
+
+       ret = zpci_pfip_cap(zdev, vdev, caps);
+
+       return ret;
+}