{"id":2226030,"url":"http://patchwork.ozlabs.org/api/patches/2226030/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260422023239.1171963-7-mrathor@linux.microsoft.com/","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/projects/28/?format=json","name":"Linux PCI development","link_name":"linux-pci","list_id":"linux-pci.vger.kernel.org","list_email":"linux-pci@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260422023239.1171963-7-mrathor@linux.microsoft.com>","list_archive_url":null,"date":"2026-04-22T02:32:32","name":"[V1,06/13] mshv: Implement mshv bridge device for VFIO","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"57b83c081036d8fc9d0851be3139095762050fd0","submitter":{"id":91512,"url":"http://patchwork.ozlabs.org/api/people/91512/?format=json","name":"Mukesh R","email":"mrathor@linux.microsoft.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260422023239.1171963-7-mrathor@linux.microsoft.com/mbox/","series":[{"id":500915,"url":"http://patchwork.ozlabs.org/api/series/500915/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/list/?series=500915","date":"2026-04-22T02:32:26","name":"PCI passthru on Hyper-V (Part I)","version":1,"mbox":"http://patchwork.ozlabs.org/series/500915/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2226030/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2226030/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.microsoft.com header.i=@linux.microsoft.com\n header.a=rsa-sha256 header.s=default header.b=GgLzpdJZ;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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These\nfunctions are called in the VFIO framework, and credits to kvm/vfio.c\nas this file was adapted from it.\n\nCo-developed-by: Wei Liu \nSigned-off-by: Wei Liu \nSigned-off-by: Mukesh R \n---\n drivers/hv/Makefile | 3 +-\n drivers/hv/mshv_vfio.c | 211 ++++++++++++++++++++++++++++++++++++++\n include/uapi/linux/mshv.h | 1 +\n 3 files changed, 214 insertions(+), 1 deletion(-)\n create mode 100644 drivers/hv/mshv_vfio.c","diff":"diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile\nindex 888a748cc7cb..9ab6fc254c38 100644\n--- a/drivers/hv/Makefile\n+++ b/drivers/hv/Makefile\n@@ -14,7 +14,8 @@ hv_vmbus-y := vmbus_drv.o \\\n hv_vmbus-$(CONFIG_HYPERV_TESTING)\t+= hv_debugfs.o\n hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_utils_transport.o\n mshv_root-y := mshv_root_main.o mshv_synic.o mshv_eventfd.o mshv_irq.o \\\n-\t mshv_root_hv_call.o mshv_portid_table.o mshv_regions.o\n+\t mshv_root_hv_call.o mshv_portid_table.o mshv_regions.o \\\n+ mshv_vfio.o\n mshv_root-$(CONFIG_DEBUG_FS) += mshv_debugfs.o\n mshv_root-$(CONFIG_TRACEPOINTS) += mshv_trace.o\n mshv_vtl-y := mshv_vtl_main.o\ndiff --git a/drivers/hv/mshv_vfio.c b/drivers/hv/mshv_vfio.c\nnew file mode 100644\nindex 000000000000..00a97920e25b\n--- /dev/null\n+++ b/drivers/hv/mshv_vfio.c\n@@ -0,0 +1,211 @@\n+// SPDX-License-Identifier: GPL-2.0-only\n+/*\n+ * VFIO-MSHV bridge pseudo device\n+ *\n+ * Heavily inspired by the VFIO-KVM bridge pseudo device.\n+ */\n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+#include \n+\n+#include \"mshv.h\"\n+#include \"mshv_root.h\"\n+\n+struct mshv_vfio_file {\n+\tstruct list_head node;\n+\tstruct file *file;\t/* list of struct mshv_vfio_file */\n+};\n+\n+struct mshv_vfio {\n+\tstruct list_head file_list;\n+\tstruct mutex lock;\n+};\n+\n+static bool mshv_vfio_file_is_valid(struct file *file)\n+{\n+\tbool (*fn)(struct file *file);\n+\tbool ret;\n+\n+\tfn = symbol_get(vfio_file_is_valid);\n+\tif (!fn)\n+\t\treturn false;\n+\n+\tret = fn(file);\n+\n+\tsymbol_put(vfio_file_is_valid);\n+\n+\treturn ret;\n+}\n+\n+static long mshv_vfio_file_add(struct mshv_device *mshvdev, unsigned int fd)\n+{\n+\tstruct mshv_vfio *mshv_vfio = mshvdev->device_private;\n+\tstruct mshv_vfio_file *mvf;\n+\tstruct file *filp;\n+\tlong ret = 0;\n+\n+\tfilp = fget(fd);\n+\tif (!filp)\n+\t\treturn -EBADF;\n+\n+\t/* Ensure the FD is a vfio FD. */\n+\tif (!mshv_vfio_file_is_valid(filp)) {\n+\t\tret = -EINVAL;\n+\t\tgoto out_fput;\n+\t}\n+\n+\tmutex_lock(&mshv_vfio->lock);\n+\n+\tlist_for_each_entry(mvf, &mshv_vfio->file_list, node) {\n+\t\tif (mvf->file == filp) {\n+\t\t\tret = -EEXIST;\n+\t\t\tgoto out_unlock;\n+\t\t}\n+\t}\n+\n+\tmvf = kzalloc(sizeof(*mvf), GFP_KERNEL_ACCOUNT);\n+\tif (!mvf) {\n+\t\tret = -ENOMEM;\n+\t\tgoto out_unlock;\n+\t}\n+\n+\tmvf->file = get_file(filp);\n+\tlist_add_tail(&mvf->node, &mshv_vfio->file_list);\n+\n+out_unlock:\n+\tmutex_unlock(&mshv_vfio->lock);\n+out_fput:\n+\tfput(filp);\n+\treturn ret;\n+}\n+\n+static long mshv_vfio_file_del(struct mshv_device *mshvdev, unsigned int fd)\n+{\n+\tstruct mshv_vfio *mshv_vfio = mshvdev->device_private;\n+\tstruct mshv_vfio_file *mvf;\n+\tlong ret;\n+\n+\tCLASS(fd, f)(fd);\n+\n+\tif (fd_empty(f))\n+\t\treturn -EBADF;\n+\n+\tret = -ENOENT;\n+\tmutex_lock(&mshv_vfio->lock);\n+\n+\tlist_for_each_entry(mvf, &mshv_vfio->file_list, node) {\n+\t\tif (mvf->file != fd_file(f))\n+\t\t\tcontinue;\n+\n+\t\tlist_del(&mvf->node);\n+\t\tfput(mvf->file);\n+\t\tkfree(mvf);\n+\t\tret = 0;\n+\t\tbreak;\n+\t}\n+\n+\tmutex_unlock(&mshv_vfio->lock);\n+\treturn ret;\n+}\n+\n+static long mshv_vfio_set_file(struct mshv_device *mshvdev, long attr,\n+\t\t\t void __user *arg)\n+{\n+\tint32_t __user *argp = arg;\n+\tint32_t fd;\n+\n+\tswitch (attr) {\n+\tcase MSHV_DEV_VFIO_FILE_ADD:\n+\t\tif (get_user(fd, argp))\n+\t\t\treturn -EFAULT;\n+\t\treturn mshv_vfio_file_add(mshvdev, fd);\n+\n+\tcase MSHV_DEV_VFIO_FILE_DEL:\n+\t\tif (get_user(fd, argp))\n+\t\t\treturn -EFAULT;\n+\t\treturn mshv_vfio_file_del(mshvdev, fd);\n+\t}\n+\n+\treturn -ENXIO;\n+}\n+\n+static long mshv_vfio_set_attr(struct mshv_device *mshvdev,\n+\t\t\t struct mshv_device_attr *attr)\n+{\n+\tswitch (attr->group) {\n+\tcase MSHV_DEV_VFIO_FILE:\n+\t\treturn mshv_vfio_set_file(mshvdev, attr->attr,\n+\t\t\t\t\t u64_to_user_ptr(attr->addr));\n+\t}\n+\n+\treturn -ENXIO;\n+}\n+\n+static long mshv_vfio_has_attr(struct mshv_device *mshvdev,\n+\t\t\t struct mshv_device_attr *attr)\n+{\n+\tswitch (attr->group) {\n+\tcase MSHV_DEV_VFIO_FILE:\n+\t\tswitch (attr->attr) {\n+\t\tcase MSHV_DEV_VFIO_FILE_ADD:\n+\t\tcase MSHV_DEV_VFIO_FILE_DEL:\n+\t\t\treturn 0;\n+\t\t}\n+\n+\t\tbreak;\n+\t}\n+\n+\treturn -ENXIO;\n+}\n+\n+static long mshv_vfio_create_device(struct mshv_device *mshvdev)\n+{\n+\tstruct mshv_device *tmp;\n+\tstruct mshv_vfio *mshv_vfio;\n+\n+\t/* Only one VFIO \"device\" per VM */\n+\thlist_for_each_entry(tmp, &mshvdev->device_pt->pt_devices,\n+\t\t\t device_ptnode)\n+\t\tif (tmp->device_ops == &mshv_vfio_device_ops)\n+\t\t\treturn -EBUSY;\n+\n+\tmshv_vfio = kzalloc(sizeof(*mshv_vfio), GFP_KERNEL_ACCOUNT);\n+\tif (mshv_vfio == NULL)\n+\t\treturn -ENOMEM;\n+\n+\tINIT_LIST_HEAD(&mshv_vfio->file_list);\n+\tmutex_init(&mshv_vfio->lock);\n+\n+\tmshvdev->device_private = mshv_vfio;\n+\n+\treturn 0;\n+}\n+\n+/* This is called from mshv_device_fop_release() */\n+static void mshv_vfio_release_device(struct mshv_device *mshvdev)\n+{\n+\tstruct mshv_vfio *mv = mshvdev->device_private;\n+\tstruct mshv_vfio_file *mvf, *tmp;\n+\n+\tlist_for_each_entry_safe(mvf, tmp, &mv->file_list, node) {\n+\t\tfput(mvf->file);\n+\t\tlist_del(&mvf->node);\n+\t\tkfree(mvf);\n+\t}\n+\n+\tkfree(mv);\n+\tkfree(mshvdev);\n+}\n+\n+struct mshv_device_ops mshv_vfio_device_ops = {\n+\t.device_name = \"mshv-vfio\",\n+\t.device_create = mshv_vfio_create_device,\n+\t.device_release = mshv_vfio_release_device,\n+\t.device_set_attr = mshv_vfio_set_attr,\n+\t.device_has_attr = mshv_vfio_has_attr,\n+};\ndiff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h\nindex 4373a8243951..6404e8a98237 100644\n--- a/include/uapi/linux/mshv.h\n+++ b/include/uapi/linux/mshv.h\n@@ -254,6 +254,7 @@ struct mshv_root_hvcall {\n #define MSHV_GET_GPAP_ACCESS_BITMAP\t_IOWR(MSHV_IOCTL, 0x06, struct mshv_gpap_access_bitmap)\n /* Generic hypercall */\n #define MSHV_ROOT_HVCALL\t\t_IOWR(MSHV_IOCTL, 0x07, struct mshv_root_hvcall)\n+#define MSHV_CREATE_DEVICE _IOWR(MSHV_IOCTL, 0x08, struct mshv_create_device)\n \n /*\n ********************************\n","prefixes":["V1","06/13"]}