From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D807329D26E; Fri, 1 May 2026 00:42:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777596138; cv=none; b=cQsNZGkA5U4SIuNgOjVxB9RN1ovEZJR9z+LI7Xhmq6gHW4mkdAKyf/i8kNBT6eycqzxuySjmLVTVTGwWX9fK72u0TvX0zzGdKUppAFbH/D8RUxiLq8Kz2iIvJ8sTqGdlfdpLEKn5cjv4ins1PdtOZ+jtE+RbIb+C7O3rmLYLdxI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777596138; c=relaxed/simple; bh=jYrebEGyLACqbZL/w3y9a7O0xWgw6FHchfvbYBMKEM0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JG5azDiLHzS0McDObbeYBOE8uOG2K/PoyfNGhFF833lcBBOjj0kzG/T5TuelkyqvlO5GqE6ELpWVo1kYVDShIjwHZ5KpYAgvTD74E+kc+I0fX4dvvc4UuhoMVi61ZM07yssRrfcUcf4IstIb2BxSxlJbZ9CPvZjttVSLdfWKD9k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=M2woPDPU; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="M2woPDPU" Received: from mrdev.corp.microsoft.com (unknown [40.86.183.173]) by linux.microsoft.com (Postfix) with ESMTPSA id E073920B7172; Thu, 30 Apr 2026 17:42:15 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E073920B7172 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1777596136; bh=YnF+uI+QwqeYTK6oQpqBg7HAiFmqfGlkyQt6D84StzY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M2woPDPUVdS9NeB1SvEI95f9f67vYOHf0bdchGfAnnczATXJUsd3Yceu8VF7i/UpP 7DgPhd5zkRdX9oeAT1xw9YBVkGj0ljox6Cp1YhGs5U0U95RxUn4K6+GsojTxirfkzI t4yb2645Dak1/3wEswZ2pTGHC12MMmW2OxGVmXWc= From: Mukesh R To: hpa@zytor.com, robin.murphy@arm.com, robh@kernel.org, wei.liu@kernel.org, mrathor@linux.microsoft.com, mhklinux@outlook.com, muislam@microsoft.com, namjain@linux.microsoft.com, magnuskulke@linux.microsoft.com, anbelski@linux.microsoft.com, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, iommu@lists.linux.dev, linux-pci@vger.kernel.org, linux-arch@vger.kernel.org Cc: kys@microsoft.com, haiyangz@microsoft.com, decui@microsoft.com, longli@microsoft.com, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, joro@8bytes.org, will@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org, bhelgaas@google.com, arnd@arndb.de Subject: [PATCH V2 05/11] mshv: Implement mshv bridge device for VFIO Date: Thu, 30 Apr 2026 17:41:51 -0700 Message-ID: <20260501004157.3108202-6-mrathor@linux.microsoft.com> X-Mailer: git-send-email 2.51.2.vfs.0.1 In-Reply-To: <20260501004157.3108202-1-mrathor@linux.microsoft.com> References: <20260501004157.3108202-1-mrathor@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a new file to implement VFIO-MSHV bridge pseudo device. These functions are called in the VFIO framework, and credits to kvm/vfio.c as this file was adapted from it. Co-developed-by: Wei Liu Signed-off-by: Wei Liu Signed-off-by: Mukesh R --- drivers/hv/Makefile | 3 +- drivers/hv/mshv_vfio.c | 211 ++++++++++++++++++++++++++++++++++++++ include/uapi/linux/mshv.h | 1 + 3 files changed, 214 insertions(+), 1 deletion(-) create mode 100644 drivers/hv/mshv_vfio.c diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile index 888a748cc7cb..9ab6fc254c38 100644 --- a/drivers/hv/Makefile +++ b/drivers/hv/Makefile @@ -14,7 +14,8 @@ hv_vmbus-y := vmbus_drv.o \ hv_vmbus-$(CONFIG_HYPERV_TESTING) += hv_debugfs.o hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_utils_transport.o mshv_root-y := mshv_root_main.o mshv_synic.o mshv_eventfd.o mshv_irq.o \ - mshv_root_hv_call.o mshv_portid_table.o mshv_regions.o + mshv_root_hv_call.o mshv_portid_table.o mshv_regions.o \ + mshv_vfio.o mshv_root-$(CONFIG_DEBUG_FS) += mshv_debugfs.o mshv_root-$(CONFIG_TRACEPOINTS) += mshv_trace.o mshv_vtl-y := mshv_vtl_main.o diff --git a/drivers/hv/mshv_vfio.c b/drivers/hv/mshv_vfio.c new file mode 100644 index 000000000000..00a97920e25b --- /dev/null +++ b/drivers/hv/mshv_vfio.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * VFIO-MSHV bridge pseudo device + * + * Heavily inspired by the VFIO-KVM bridge pseudo device. + */ +#include +#include +#include +#include +#include +#include +#include +#include + +#include "mshv.h" +#include "mshv_root.h" + +struct mshv_vfio_file { + struct list_head node; + struct file *file; /* list of struct mshv_vfio_file */ +}; + +struct mshv_vfio { + struct list_head file_list; + struct mutex lock; +}; + +static bool mshv_vfio_file_is_valid(struct file *file) +{ + bool (*fn)(struct file *file); + bool ret; + + fn = symbol_get(vfio_file_is_valid); + if (!fn) + return false; + + ret = fn(file); + + symbol_put(vfio_file_is_valid); + + return ret; +} + +static long mshv_vfio_file_add(struct mshv_device *mshvdev, unsigned int fd) +{ + struct mshv_vfio *mshv_vfio = mshvdev->device_private; + struct mshv_vfio_file *mvf; + struct file *filp; + long ret = 0; + + filp = fget(fd); + if (!filp) + return -EBADF; + + /* Ensure the FD is a vfio FD. */ + if (!mshv_vfio_file_is_valid(filp)) { + ret = -EINVAL; + goto out_fput; + } + + mutex_lock(&mshv_vfio->lock); + + list_for_each_entry(mvf, &mshv_vfio->file_list, node) { + if (mvf->file == filp) { + ret = -EEXIST; + goto out_unlock; + } + } + + mvf = kzalloc(sizeof(*mvf), GFP_KERNEL_ACCOUNT); + if (!mvf) { + ret = -ENOMEM; + goto out_unlock; + } + + mvf->file = get_file(filp); + list_add_tail(&mvf->node, &mshv_vfio->file_list); + +out_unlock: + mutex_unlock(&mshv_vfio->lock); +out_fput: + fput(filp); + return ret; +} + +static long mshv_vfio_file_del(struct mshv_device *mshvdev, unsigned int fd) +{ + struct mshv_vfio *mshv_vfio = mshvdev->device_private; + struct mshv_vfio_file *mvf; + long ret; + + CLASS(fd, f)(fd); + + if (fd_empty(f)) + return -EBADF; + + ret = -ENOENT; + mutex_lock(&mshv_vfio->lock); + + list_for_each_entry(mvf, &mshv_vfio->file_list, node) { + if (mvf->file != fd_file(f)) + continue; + + list_del(&mvf->node); + fput(mvf->file); + kfree(mvf); + ret = 0; + break; + } + + mutex_unlock(&mshv_vfio->lock); + return ret; +} + +static long mshv_vfio_set_file(struct mshv_device *mshvdev, long attr, + void __user *arg) +{ + int32_t __user *argp = arg; + int32_t fd; + + switch (attr) { + case MSHV_DEV_VFIO_FILE_ADD: + if (get_user(fd, argp)) + return -EFAULT; + return mshv_vfio_file_add(mshvdev, fd); + + case MSHV_DEV_VFIO_FILE_DEL: + if (get_user(fd, argp)) + return -EFAULT; + return mshv_vfio_file_del(mshvdev, fd); + } + + return -ENXIO; +} + +static long mshv_vfio_set_attr(struct mshv_device *mshvdev, + struct mshv_device_attr *attr) +{ + switch (attr->group) { + case MSHV_DEV_VFIO_FILE: + return mshv_vfio_set_file(mshvdev, attr->attr, + u64_to_user_ptr(attr->addr)); + } + + return -ENXIO; +} + +static long mshv_vfio_has_attr(struct mshv_device *mshvdev, + struct mshv_device_attr *attr) +{ + switch (attr->group) { + case MSHV_DEV_VFIO_FILE: + switch (attr->attr) { + case MSHV_DEV_VFIO_FILE_ADD: + case MSHV_DEV_VFIO_FILE_DEL: + return 0; + } + + break; + } + + return -ENXIO; +} + +static long mshv_vfio_create_device(struct mshv_device *mshvdev) +{ + struct mshv_device *tmp; + struct mshv_vfio *mshv_vfio; + + /* Only one VFIO "device" per VM */ + hlist_for_each_entry(tmp, &mshvdev->device_pt->pt_devices, + device_ptnode) + if (tmp->device_ops == &mshv_vfio_device_ops) + return -EBUSY; + + mshv_vfio = kzalloc(sizeof(*mshv_vfio), GFP_KERNEL_ACCOUNT); + if (mshv_vfio == NULL) + return -ENOMEM; + + INIT_LIST_HEAD(&mshv_vfio->file_list); + mutex_init(&mshv_vfio->lock); + + mshvdev->device_private = mshv_vfio; + + return 0; +} + +/* This is called from mshv_device_fop_release() */ +static void mshv_vfio_release_device(struct mshv_device *mshvdev) +{ + struct mshv_vfio *mv = mshvdev->device_private; + struct mshv_vfio_file *mvf, *tmp; + + list_for_each_entry_safe(mvf, tmp, &mv->file_list, node) { + fput(mvf->file); + list_del(&mvf->node); + kfree(mvf); + } + + kfree(mv); + kfree(mshvdev); +} + +struct mshv_device_ops mshv_vfio_device_ops = { + .device_name = "mshv-vfio", + .device_create = mshv_vfio_create_device, + .device_release = mshv_vfio_release_device, + .device_set_attr = mshv_vfio_set_attr, + .device_has_attr = mshv_vfio_has_attr, +}; diff --git a/include/uapi/linux/mshv.h b/include/uapi/linux/mshv.h index 4373a8243951..6404e8a98237 100644 --- a/include/uapi/linux/mshv.h +++ b/include/uapi/linux/mshv.h @@ -254,6 +254,7 @@ struct mshv_root_hvcall { #define MSHV_GET_GPAP_ACCESS_BITMAP _IOWR(MSHV_IOCTL, 0x06, struct mshv_gpap_access_bitmap) /* Generic hypercall */ #define MSHV_ROOT_HVCALL _IOWR(MSHV_IOCTL, 0x07, struct mshv_root_hvcall) +#define MSHV_CREATE_DEVICE _IOWR(MSHV_IOCTL, 0x08, struct mshv_create_device) /* ******************************** -- 2.51.2.vfs.0.1