From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E9FFB38AC91 for ; Sun, 14 Jun 2026 23:37:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781480264; cv=none; b=EiKcTh6qPPFto8hnwzEhWgrN4pEihfi/d6sd4/1s6hrB8cqjKOCgUnJ/4G1TGPekzSkByYLOn+7+0ncZ/0rMBws+wT6j6lEVlGbjKDM1lPC3Lj2e8grCpeYffVAcwkCU7W8OOSBFyWEovDrAAM+x+iZ0o+zJbKvTQJl31Ux5zQk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781480264; c=relaxed/simple; bh=pJANR27TCwzM6P7JUjCO8NVSON5V5PQjS7w9IaURvgE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=OeIbX6zXESSw+cpfkDjujC1ytrwWfD+MZADGcqCDt43Dcq3w/ciZFLTsyG0vCtQJ7r9yAO732NvnxLFj+Vrxqq0ibMFYppOOfBGy272n02/7+eNzZRfMGGaX8fGOquchDQHbXVkUDWmHXHQzbYb6En0YfEKvtN5GIfYTucCXndY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--skhawaja.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Ep17HGcj; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--skhawaja.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Ep17HGcj" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-36d99181eaaso3494893a91.3 for ; Sun, 14 Jun 2026 16:37:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1781480261; x=1782085061; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=l4jEXc7eb319TzKfJMN/jxkEzmPY1X3dZJzTvkIvfjE=; b=Ep17HGcjnOOnoo0lpIFw5FR9symZiUcu3ygJtg2sbH3YSJ0crlzuzUMNtXOtJQ0WYY GVDM9ff4uBhfu9D5r55LHSyI4IrFeKz05Vq9ovT/UeuE9VWBe/ZS1tDbmxscHhhrpBvJ dnc4qUP7FAwdZ1GmmVAuWNqg/4MTiYfzvKaAZk+wMpxrJcc0XitqbKEQ4HnX5iR30Uyo CGckc8zapBEFLsUzEiBjiB9kffjAFPgtWq8ZTmZWSf8da5QMMHohv1OoQI/hDA4gjJcL qfDMgeoNuyQGljnlEE3lUAdiH84/z6C/P6++2wQisLvrFRiJw4fKcZGvMic5M3gLZpam dBBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1781480261; x=1782085061; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=l4jEXc7eb319TzKfJMN/jxkEzmPY1X3dZJzTvkIvfjE=; b=CkgjS2rfseikc87REzwMmjHWx37fF8DP3eYi8WV2a0klKxBlr/Wn3fMAGS0slv/SIc ijcIY6amc0PB0GRx3TybfkAYmybX3qg9D4liKJ6et6CYQn8424k6ZJ+FiweHRxnfB23C YiEW+b6Iom68rnH9KbCUwb99iZYtnB1OMeC1oqJCiY5CLAb1Q487WE0VYtfmc5DTKZ6k 3paDMpibnD+gDwA8IyQLlcr/rf0kn18zWSJrVRd8XP+Dwn+IxXwol3O0jum3uT+US/N+ vEs7ruMFaUxM5OYxW/p1FI2okkj4PosS7iP6Z7ATyXcHOmu9Y1bBI9ntg0Ir5QJJzxce xxEQ== X-Forwarded-Encrypted: i=1; AFNElJ+1AEdYDwAn5C5HEsq8Sc4fQ0odeCUetyF8FrPlGipXv4u7l26ZnXXtQNyaY5vXcx5GtL+Z5X12TQXX+zA=@vger.kernel.org X-Gm-Message-State: AOJu0YwoqefNyJljlVct2m+rS5CqQhvon5IwUW8XKDVhlutipuZRft9X FABbZKoX89Mxwl3OKprFasFj5XQ9TQHQ0tl3XlL/6UV6Q/+qfXu7y5TlU/aSWFXzAnwJwphOrdi mIhkahbE7xF994Q== X-Received: from pgah15.prod.google.com ([2002:a05:6a02:4e8f:b0:c79:7757:4178]) (user=skhawaja job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:1808:b0:36b:bec8:94cf with SMTP id 98e67ed59e1d1-37c2bc87071mr8712791a91.9.1781480260992; Sun, 14 Jun 2026 16:37:40 -0700 (PDT) Date: Sun, 14 Jun 2026 23:37:24 +0000 In-Reply-To: <20260614233728.2212104-1-skhawaja@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260614233728.2212104-1-skhawaja@google.com> X-Mailer: git-send-email 2.54.0.1136.gdb2ca164c4-goog Message-ID: <20260614233728.2212104-15-skhawaja@google.com> Subject: [PATCH v3 14/18] iommufd: Implement ioctl to mark HWPT for preservation From: Samiullah Khawaja To: David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Jason Gunthorpe Cc: YiFei Zhu , Samiullah Khawaja , Robin Murphy , Kevin Tian , Alex Williamson , Shuah Khan , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Pratyush Yadav , Pasha Tatashin , David Matlack , Andrew Morton , Pranjal Shrivastava , Vipin Sharma Content-Type: text/plain; charset="UTF-8" From: YiFei Zhu Userspace provides a token to mark the HWPT for preservation. Note that this token is not the LUO token that is used to preserve the iommufd. Once all the required HWPT are marked for preservation, the user can preserve the iommufd into LUO. The iommufd will preserve the HWPTs that are marked for preservation. The marked HWPTs are tracked using a new XArray mark protected by a new liveupdate mutex. This mutex will also be used during iommufd preservation to protect against any race with the mark preserve ioctl. The HWPT token will be used during restore to identify this HWPT. The restoration logic is not implemented and will be added later. Reviewed-by: Pranjal Shrivastava Signed-off-by: YiFei Zhu Signed-off-by: Samiullah Khawaja --- MAINTAINERS | 1 + drivers/iommu/iommufd/Makefile | 2 + drivers/iommu/iommufd/iommufd_private.h | 18 ++++++++ drivers/iommu/iommufd/liveupdate.c | 56 +++++++++++++++++++++++++ drivers/iommu/iommufd/main.c | 9 ++++ include/uapi/linux/iommufd.h | 26 ++++++++++++ 6 files changed, 112 insertions(+) create mode 100644 drivers/iommu/iommufd/liveupdate.c diff --git a/MAINTAINERS b/MAINTAINERS index 4dfb56962426..9ef9f2b75d6f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13498,6 +13498,7 @@ M: Samiullah Khawaja R: Pranjal Shrivastava L: iommu@lists.linux.dev S: Maintained +F: drivers/iommu/iommufd/liveupdate.c F: drivers/iommu/liveupdate.c F: include/linux/iommu-liveupdate.h F: include/linux/kho/abi/iommu.h diff --git a/drivers/iommu/iommufd/Makefile b/drivers/iommu/iommufd/Makefile index 71d692c9a8f4..d765fc10e3b2 100644 --- a/drivers/iommu/iommufd/Makefile +++ b/drivers/iommu/iommufd/Makefile @@ -11,9 +11,11 @@ iommufd-y := \ viommu.o iommufd-$(CONFIG_IOMMUFD_TEST) += selftest.o +iommufd-$(CONFIG_IOMMU_LIVEUPDATE) += liveupdate.o obj-$(CONFIG_IOMMUFD) += iommufd.o obj-$(CONFIG_IOMMUFD_DRIVER) += iova_bitmap.o iommufd_driver-y := driver.o obj-$(CONFIG_IOMMUFD_DRIVER_CORE) += iommufd_driver.o + diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index 6ac1965199e9..111f4d42e210 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -44,6 +44,11 @@ struct iommufd_ctx { struct file *file; struct xarray objects; struct xarray groups; +#ifdef CONFIG_IOMMU_LIVEUPDATE +#define IOMMUFD_OBJ_LIVEUPDATE_MARK XA_MARK_1 + /* @liveupdate_mutex: Protects the preservation of HWPTs. */ + struct mutex liveupdate_mutex; +#endif wait_queue_head_t destroy_wait; struct rw_semaphore ioas_creation_lock; struct maple_tree mt_mmap; @@ -373,6 +378,10 @@ struct iommufd_hwpt_paging { bool auto_domain : 1; bool enforce_cache_coherency : 1; bool nest_parent : 1; +#ifdef CONFIG_IOMMU_LIVEUPDATE + bool liveupdate_preserve : 1; + u64 liveupdate_token; +#endif /* Head at iommufd_ioas::hwpt_list */ struct list_head hwpt_item; struct iommufd_sw_msi_maps present_sw_msi; @@ -706,6 +715,15 @@ iommufd_get_vdevice(struct iommufd_ctx *ictx, u32 id) struct iommufd_vdevice, obj); } +#ifdef CONFIG_IOMMU_LIVEUPDATE +int iommufd_hwpt_liveupdate_mark_preserve(struct iommufd_ucmd *ucmd); +#else +static inline int iommufd_hwpt_liveupdate_mark_preserve(struct iommufd_ucmd *ucmd) +{ + return -ENOTTY; +} +#endif + #ifdef CONFIG_IOMMUFD_TEST int iommufd_test(struct iommufd_ucmd *ucmd); void iommufd_selftest_destroy(struct iommufd_object *obj); diff --git a/drivers/iommu/iommufd/liveupdate.c b/drivers/iommu/iommufd/liveupdate.c new file mode 100644 index 000000000000..e0d2c4aa2466 --- /dev/null +++ b/drivers/iommu/iommufd/liveupdate.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * Copyright (C) 2026, Google LLC + * Author: Samiullah Khawaja + */ + +#define pr_fmt(fmt) "iommufd: " fmt + +#include +#include +#include + +#include "iommufd_private.h" + +int iommufd_hwpt_liveupdate_mark_preserve(struct iommufd_ucmd *ucmd) +{ + struct iommu_hwpt_liveupdate_mark_preserve *cmd = ucmd->cmd; + struct iommufd_hwpt_paging *hwpt_target; + struct iommufd_hwpt_paging *hwpt_paging; + struct iommufd_ctx *ictx = ucmd->ictx; + struct iommufd_object *obj; + unsigned long index; + int rc = 0; + + hwpt_target = iommufd_get_hwpt_paging(ucmd, cmd->hwpt_id); + if (IS_ERR(hwpt_target)) + return PTR_ERR(hwpt_target); + + mutex_lock(&ictx->liveupdate_mutex); + + xa_lock(&ictx->objects); + xa_for_each_marked(&ictx->objects, index, obj, IOMMUFD_OBJ_LIVEUPDATE_MARK) { + if (WARN_ON_ONCE(obj->type != IOMMUFD_OBJ_HWPT_PAGING)) + continue; + + hwpt_paging = to_hwpt_paging(container_of(obj, struct iommufd_hw_pagetable, obj)); + if (hwpt_paging->liveupdate_token == cmd->hwpt_token) { + rc = -EADDRINUSE; + goto out_unlock; + } + } + + __xa_set_mark(&ictx->objects, hwpt_target->common.obj.id, IOMMUFD_OBJ_LIVEUPDATE_MARK); + + if (hwpt_target->liveupdate_token != 0) + pr_warn_ratelimited("Overwriting HWPT liveupdate token from: %llu to %llu\n", + hwpt_target->liveupdate_token, cmd->hwpt_token); + hwpt_target->liveupdate_token = cmd->hwpt_token; + +out_unlock: + xa_unlock(&ictx->objects); + mutex_unlock(&ictx->liveupdate_mutex); + iommufd_put_object(ictx, &hwpt_target->common.obj); + return rc; +} diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 8c6d43601afb..0114c1520db4 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -313,6 +313,9 @@ static int iommufd_fops_open(struct inode *inode, struct file *filp) init_rwsem(&ictx->ioas_creation_lock); xa_init_flags(&ictx->objects, XA_FLAGS_ALLOC1 | XA_FLAGS_ACCOUNT); xa_init(&ictx->groups); +#ifdef CONFIG_IOMMU_LIVEUPDATE + mutex_init(&ictx->liveupdate_mutex); +#endif ictx->file = filp; mt_init_flags(&ictx->mt_mmap, MT_FLAGS_ALLOC_RANGE); init_waitqueue_head(&ictx->destroy_wait); @@ -375,6 +378,9 @@ static int iommufd_fops_release(struct inode *inode, struct file *filp) * iommufd_object_tombstone_user() */ xa_destroy(&ictx->objects); +#ifdef CONFIG_IOMMU_LIVEUPDATE + mutex_destroy(&ictx->liveupdate_mutex); +#endif WARN_ON(!xa_empty(&ictx->groups)); @@ -420,6 +426,7 @@ union ucmd_buffer { struct iommu_hwpt_alloc hwpt; struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap; struct iommu_hwpt_invalidate cache; + struct iommu_hwpt_liveupdate_mark_preserve mark_preserve; struct iommu_hwpt_set_dirty_tracking set_dirty_tracking; struct iommu_ioas_alloc alloc; struct iommu_ioas_allow_iovas allow_iovas; @@ -493,6 +500,8 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = { __reserved), IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl, struct iommu_viommu_alloc, out_viommu_id), + IOCTL_OP(IOMMU_HWPT_LIVEUPDATE_MARK_PRESERVE, iommufd_hwpt_liveupdate_mark_preserve, + struct iommu_hwpt_liveupdate_mark_preserve, hwpt_token), #ifdef CONFIG_IOMMUFD_TEST IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last), #endif diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h index e998dfbd6960..d96a74b43c9d 100644 --- a/include/uapi/linux/iommufd.h +++ b/include/uapi/linux/iommufd.h @@ -57,6 +57,7 @@ enum { IOMMUFD_CMD_IOAS_CHANGE_PROCESS = 0x92, IOMMUFD_CMD_VEVENTQ_ALLOC = 0x93, IOMMUFD_CMD_HW_QUEUE_ALLOC = 0x94, + IOMMUFD_CMD_HWPT_LU_MARK_PRESERVE = 0x95, }; /** @@ -1347,4 +1348,29 @@ struct iommu_hw_queue_alloc { __aligned_u64 length; }; #define IOMMU_HW_QUEUE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HW_QUEUE_ALLOC) + +/** + * struct iommu_hwpt_liveupdate_mark_preserve - ioctl(IOMMU_HWPT_LIVEUPDATE_MARK_PRESERVE) + * @size: sizeof(struct iommu_hwpt_liveupdate_mark_preserve) + * @hwpt_id: Iommufd object ID of the target HWPT + * @hwpt_token: Token to identify this hwpt upon restore + * + * The target HWPT will be preserved during iommufd preservation. + * Only file-based memory mappings (e.g. memfd) are supported for HWPTs marked + * for preservation. Mapping anonymous memory into a preserved HWPT will result + * in a failure during the preservation phase. + * + * The hwpt_token is provided by userspace. If userspace enters a token + * already in use within this iommufd, -EADDRINUSE is returned from this ioctl. + * + * Note: There is no 'unmark' operation, so any HWPTs pooled in userspace that + * are marked for preservation must be destroyed after use. + */ +struct iommu_hwpt_liveupdate_mark_preserve { + __u32 size; + __u32 hwpt_id; + __u64 hwpt_token; +}; +#define IOMMU_HWPT_LIVEUPDATE_MARK_PRESERVE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_LU_MARK_PRESERVE) + #endif -- 2.54.0.1136.gdb2ca164c4-goog