From patchwork Thu Dec 5 03:25:36 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yan Zhao X-Patchwork-Id: 11274099 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AF6346C1 for ; Thu, 5 Dec 2019 03:34:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8221F2073B for ; Thu, 5 Dec 2019 03:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728560AbfLEDd7 (ORCPT ); Wed, 4 Dec 2019 22:33:59 -0500 Received: from mga11.intel.com ([192.55.52.93]:22205 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728132AbfLEDd7 (ORCPT ); Wed, 4 Dec 2019 22:33:59 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Dec 2019 19:33:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,279,1571727600"; d="scan'208";a="243094895" Received: from joy-optiplex-7040.sh.intel.com ([10.239.13.9]) by fmsmga002.fm.intel.com with ESMTP; 04 Dec 2019 19:33:56 -0800 From: Yan Zhao To: alex.williamson@redhat.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, libvir-list@redhat.com, qemu-devel@nongnu.org, cohuck@redhat.com, zhenyuw@linux.intel.com, zhi.a.wang@intel.com, kevin.tian@intel.com, shaopeng.he@intel.com, Yan Zhao Subject: [RFC PATCH 1/9] vfio/pci: introduce mediate ops to intercept vfio-pci ops Date: Wed, 4 Dec 2019 22:25:36 -0500 Message-Id: <20191205032536.29653-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191205032419.29606-1-yan.y.zhao@intel.com> References: <20191205032419.29606-1-yan.y.zhao@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org when vfio-pci is bound to a physical device, almost all the hardware resources are passthroughed. Sometimes, vendor driver of this physcial device may want to mediate some hardware resource access for a short period of time, e.g. dirty page tracking during live migration. Here we introduce mediate ops in vfio-pci for this purpose. Vendor driver can register a mediate ops to vfio-pci. But rather than directly bind to the passthroughed device, the vendor driver is now either a module that does not bind to any device or a module binds to other device. E.g. when passing through a VF device that is bound to vfio-pci modules, PF driver that binds to PF device can register to vfio-pci to mediate VF's regions, hence supporting VF live migration. The sequence goes like this: 1. Vendor driver register its vfio_pci_mediate_ops to vfio-pci driver 2. vfio-pci maintains a list of those registered vfio_pci_mediate_ops 3. Whenever vfio-pci opens a device, it searches the list and call vfio_pci_mediate_ops->open() to check whether a vendor driver supports mediating this device. Upon a success return value of from vfio_pci_mediate_ops->open(), vfio-pci will stop list searching and store a mediate handle to represent this open into vendor driver. (so if multiple vendor drivers support mediating a device through vfio_pci_mediate_ops, only one will win, depending on their registering sequence) 4. Whenever a VFIO_DEVICE_GET_REGION_INFO ioctl is received in vfio-pci ops, it will chain into vfio_pci_mediate_ops->get_region_info(), so that vendor driver is able to override a region's default flags and caps, e.g. adding a sparse mmap cap to passthrough only sub-regions of a whole region. 5. vfio_pci_rw()/vfio_pci_mmap() first calls into vfio_pci_mediate_ops->rw()/vfio_pci_mediate_ops->mmaps(). if pt=true is rteturned, vfio_pci_rw()/vfio_pci_mmap() will further passthrough this read/write/mmap to physical device, otherwise it just returns without touch physical device. 6. When vfio-pci closes a device, vfio_pci_release() chains into vfio_pci_mediate_ops->release() to close the reference in vendor driver. 7. Vendor driver unregister its vfio_pci_mediate_ops when driver exits Cc: Kevin Tian Signed-off-by: Yan Zhao --- drivers/vfio/pci/vfio_pci.c | 146 ++++++++++++++++++++++++++++ drivers/vfio/pci/vfio_pci_private.h | 2 + include/linux/vfio.h | 16 +++ 3 files changed, 164 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 02206162eaa9..55080ff29495 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -54,6 +54,14 @@ module_param(disable_idle_d3, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(disable_idle_d3, "Disable using the PCI D3 low power state for idle, unused devices"); +static LIST_HEAD(mediate_ops_list); +static DEFINE_MUTEX(mediate_ops_list_lock); +struct vfio_pci_mediate_ops_list_entry { + struct vfio_pci_mediate_ops *ops; + int refcnt; + struct list_head next; +}; + static inline bool vfio_vga_disabled(void) { #ifdef CONFIG_VFIO_PCI_VGA @@ -472,6 +480,10 @@ static void vfio_pci_release(void *device_data) if (!(--vdev->refcnt)) { vfio_spapr_pci_eeh_release(vdev->pdev); vfio_pci_disable(vdev); + if (vdev->mediate_ops && vdev->mediate_ops->release) { + vdev->mediate_ops->release(vdev->mediate_handle); + vdev->mediate_ops = NULL; + } } mutex_unlock(&vdev->reflck->lock); @@ -483,6 +495,7 @@ static int vfio_pci_open(void *device_data) { struct vfio_pci_device *vdev = device_data; int ret = 0; + struct vfio_pci_mediate_ops_list_entry *mentry; if (!try_module_get(THIS_MODULE)) return -ENODEV; @@ -495,6 +508,30 @@ static int vfio_pci_open(void *device_data) goto error; vfio_spapr_pci_eeh_open(vdev->pdev); + mutex_lock(&mediate_ops_list_lock); + list_for_each_entry(mentry, &mediate_ops_list, next) { + u64 caps; + u32 handle; + + memset(&caps, 0, sizeof(caps)); + ret = mentry->ops->open(vdev->pdev, &caps, &handle); + if (!ret) { + vdev->mediate_ops = mentry->ops; + vdev->mediate_handle = handle; + + pr_info("vfio pci found mediate_ops %s, caps=%llx, handle=%x for %x:%x\n", + vdev->mediate_ops->name, caps, + handle, vdev->pdev->vendor, + vdev->pdev->device); + /* + * only find the first matching mediate_ops, + * and add its refcnt + */ + mentry->refcnt++; + break; + } + } + mutex_unlock(&mediate_ops_list_lock); } vdev->refcnt++; error: @@ -736,6 +773,14 @@ static long vfio_pci_ioctl(void *device_data, info.size = pdev->cfg_size; info.flags = VFIO_REGION_INFO_FLAG_READ | VFIO_REGION_INFO_FLAG_WRITE; + + if (vdev->mediate_ops && + vdev->mediate_ops->get_region_info) { + vdev->mediate_ops->get_region_info( + vdev->mediate_handle, + &info, &caps, NULL); + } + break; case VFIO_PCI_BAR0_REGION_INDEX ... VFIO_PCI_BAR5_REGION_INDEX: info.offset = VFIO_PCI_INDEX_TO_OFFSET(info.index); @@ -756,6 +801,13 @@ static long vfio_pci_ioctl(void *device_data, } } + if (vdev->mediate_ops && + vdev->mediate_ops->get_region_info) { + vdev->mediate_ops->get_region_info( + vdev->mediate_handle, + &info, &caps, NULL); + } + break; case VFIO_PCI_ROM_REGION_INDEX: { @@ -794,6 +846,14 @@ static long vfio_pci_ioctl(void *device_data, } pci_write_config_word(pdev, PCI_COMMAND, orig_cmd); + + if (vdev->mediate_ops && + vdev->mediate_ops->get_region_info) { + vdev->mediate_ops->get_region_info( + vdev->mediate_handle, + &info, &caps, NULL); + } + break; } case VFIO_PCI_VGA_REGION_INDEX: @@ -805,6 +865,13 @@ static long vfio_pci_ioctl(void *device_data, info.flags = VFIO_REGION_INFO_FLAG_READ | VFIO_REGION_INFO_FLAG_WRITE; + if (vdev->mediate_ops && + vdev->mediate_ops->get_region_info) { + vdev->mediate_ops->get_region_info( + vdev->mediate_handle, + &info, &caps, NULL); + } + break; default: { @@ -839,6 +906,13 @@ static long vfio_pci_ioctl(void *device_data, if (ret) return ret; } + + if (vdev->mediate_ops && + vdev->mediate_ops->get_region_info) { + vdev->mediate_ops->get_region_info( + vdev->mediate_handle, + &info, &caps, &cap_type); + } } } @@ -1151,6 +1225,16 @@ static ssize_t vfio_pci_rw(void *device_data, char __user *buf, if (index >= VFIO_PCI_NUM_REGIONS + vdev->num_regions) return -EINVAL; + if (vdev->mediate_ops && vdev->mediate_ops->rw) { + int ret; + bool pt = true; + + ret = vdev->mediate_ops->rw(vdev->mediate_handle, + buf, count, ppos, iswrite, &pt); + if (!pt) + return ret; + } + switch (index) { case VFIO_PCI_CONFIG_REGION_INDEX: return vfio_pci_config_rw(vdev, buf, count, ppos, iswrite); @@ -1200,6 +1284,15 @@ static int vfio_pci_mmap(void *device_data, struct vm_area_struct *vma) u64 phys_len, req_len, pgoff, req_start; int ret; + if (vdev->mediate_ops && vdev->mediate_ops->mmap) { + int ret; + bool pt = true; + + ret = vdev->mediate_ops->mmap(vdev->mediate_handle, vma, &pt); + if (!pt) + return ret; + } + index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT); if (vma->vm_end < vma->vm_start) @@ -1629,8 +1722,17 @@ static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev) static void __exit vfio_pci_cleanup(void) { + struct vfio_pci_mediate_ops_list_entry *mentry, *n; + pci_unregister_driver(&vfio_pci_driver); vfio_pci_uninit_perm_bits(); + + mutex_lock(&mediate_ops_list_lock); + list_for_each_entry_safe(mentry, n, &mediate_ops_list, next) { + list_del(&mentry->next); + kfree(mentry); + } + mutex_unlock(&mediate_ops_list_lock); } static void __init vfio_pci_fill_ids(void) @@ -1697,6 +1799,50 @@ static int __init vfio_pci_init(void) return ret; } +int vfio_pci_register_mediate_ops(struct vfio_pci_mediate_ops *ops) +{ + struct vfio_pci_mediate_ops_list_entry *mentry; + + mutex_lock(&mediate_ops_list_lock); + mentry = kzalloc(sizeof(*mentry), GFP_KERNEL); + if (!mentry) { + mutex_unlock(&mediate_ops_list_lock); + return -ENOMEM; + } + + mentry->ops = ops; + mentry->refcnt = 0; + list_add(&mentry->next, &mediate_ops_list); + + pr_info("registered dm ops %s\n", ops->name); + mutex_unlock(&mediate_ops_list_lock); + + return 0; +} +EXPORT_SYMBOL(vfio_pci_register_mediate_ops); + +void vfio_pci_unregister_mediate_ops(struct vfio_pci_mediate_ops *ops) +{ + struct vfio_pci_mediate_ops_list_entry *mentry, *n; + + mutex_lock(&mediate_ops_list_lock); + list_for_each_entry_safe(mentry, n, &mediate_ops_list, next) { + if (mentry->ops != ops) + continue; + + mentry->refcnt--; + if (!mentry->refcnt) { + list_del(&mentry->next); + kfree(mentry); + } else + pr_err("vfio_pci unregister mediate ops %s error\n", + mentry->ops->name); + } + mutex_unlock(&mediate_ops_list_lock); + +} +EXPORT_SYMBOL(vfio_pci_unregister_mediate_ops); + module_init(vfio_pci_init); module_exit(vfio_pci_cleanup); diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h index ee6ee91718a4..bad4a254360e 100644 --- a/drivers/vfio/pci/vfio_pci_private.h +++ b/drivers/vfio/pci/vfio_pci_private.h @@ -122,6 +122,8 @@ struct vfio_pci_device { struct list_head dummy_resources_list; struct mutex ioeventfds_lock; struct list_head ioeventfds_list; + struct vfio_pci_mediate_ops *mediate_ops; + u32 mediate_handle; }; #define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX) diff --git a/include/linux/vfio.h b/include/linux/vfio.h index e42a711a2800..0265e779acd1 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -195,4 +195,20 @@ extern int vfio_virqfd_enable(void *opaque, void *data, struct virqfd **pvirqfd, int fd); extern void vfio_virqfd_disable(struct virqfd **pvirqfd); +struct vfio_pci_mediate_ops { + char *name; + int (*open)(struct pci_dev *pdev, u64 *caps, u32 *handle); + void (*release)(int handle); + void (*get_region_info)(int handle, + struct vfio_region_info *info, + struct vfio_info_cap *caps, + struct vfio_region_info_cap_type *cap_type); + ssize_t (*rw)(int handle, char __user *buf, + size_t count, loff_t *ppos, bool iswrite, bool *pt); + int (*mmap)(int handle, struct vm_area_struct *vma, bool *pt); + +}; +extern int vfio_pci_register_mediate_ops(struct vfio_pci_mediate_ops *ops); +extern void vfio_pci_unregister_mediate_ops(struct vfio_pci_mediate_ops *ops); + #endif /* VFIO_H */