From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C62B1E7C11 for ; Fri, 21 Mar 2025 17:19:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742577587; cv=none; b=uyyIJmK5qRvFYd10ztwICOR/X9BJVPsws7Ew4pfUW1PenySyDX8txZUvSEW6FoL2ap1R2pak4Q1pRSN3uXoMr9fi+7DhKr3My+9KEeaV9zr5cru4Hs8vW+BzppSxNgiEmHJnzMD+BzUEWZYPn6YzvOyuwoO3eLU+/qXyRz8PGo8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742577587; c=relaxed/simple; bh=gVbbRrnGwNnGzrg0PcMWseIlbZd+2rOtKOWlutXmUcs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=t1+D9e2EDZC+EVVuXyt6De6TdfqohLqdUL6HNNSu35hkf1Fpa880TIHOSSC1dVLBJTtGe541trmO2cbp2/nQHUqsaMb+UzIhqktj8s28dca0tF0iwskMKis+D3+EGIpP5habmzdy0LaVnxmdrjctbYgGx2T8Gh8UU7vmdVigAA4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=AadYiU0g; arc=none smtp.client-ip=192.198.163.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="AadYiU0g" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1742577586; x=1774113586; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=gVbbRrnGwNnGzrg0PcMWseIlbZd+2rOtKOWlutXmUcs=; b=AadYiU0gxaUxlVoSMtESr/KSyl09elNgNrsdXCubeovDy9xMfWjIxx8A QCA5yXKwvMrzP1Phrngil+7GO7Vu+YgeNtfPlO9IAFKjfVtxDn9AWjVvo IXtCbU4xtIq8Pi+B49hB52j6aER27JUnWl0ozySPss6Zbcp1XyRKF6FIW /eyM8f5lY8IE/ErxDxkMTzL9NWbNajQxyq5ZHr38faJhxl6awEbiNn6xz gufcb7sjcTfMvGKRzY/+U5yzR6zx96aaCrkspR7J8zuNt+Fo26D53z3yU Iluu5AGymhKNu/237Tdrwto4Wn86VmLQOyyovxKrP7ZFZBh1Gwn3ByDDh g==; X-CSE-ConnectionGUID: Ndt9+d6kSZyA6OCanledwA== X-CSE-MsgGUID: Y+RCJtOkTxSlmfRs2Zyoaw== X-IronPort-AV: E=McAfee;i="6700,10204,11380"; a="43976783" X-IronPort-AV: E=Sophos;i="6.14,265,1736841600"; d="scan'208";a="43976783" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by fmvoesa109.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Mar 2025 10:19:43 -0700 X-CSE-ConnectionGUID: 7qCY3bGhTPC47xwJL20nuw== X-CSE-MsgGUID: G1+twzdjSSi1efJ4OTiarQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.14,265,1736841600"; d="scan'208";a="123914421" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by fmviesa010.fm.intel.com with ESMTP; 21 Mar 2025 10:19:42 -0700 From: Yi Liu To: kevin.tian@intel.com, jgg@nvidia.com Cc: joro@8bytes.org, baolu.lu@linux.intel.com, yi.l.liu@intel.com, iommu@lists.linux.dev, nicolinc@nvidia.com Subject: [PATCH v11 02/18] iommu: Introduce a replace API for device pasid Date: Fri, 21 Mar 2025 10:19:24 -0700 Message-Id: <20250321171940.7213-3-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250321171940.7213-1-yi.l.liu@intel.com> References: <20250321171940.7213-1-yi.l.liu@intel.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Provide a high-level API to allow replacements of one domain with another for specific pasid of a device. This is similar to iommu_replace_group_handle() and it is expected to be used only by IOMMUFD. Co-developed-by: Lu Baolu Signed-off-by: Lu Baolu Reviewed-by: Jason Gunthorpe Reviewed-by: Kevin Tian Reviewed-by: Nicolin Chen Signed-off-by: Yi Liu --- v10 -> v11: Drop redundant handle check as handle is always valid in iommu_replace_device_pasid(). No inline helper --- drivers/iommu/iommu-priv.h | 3 + drivers/iommu/iommu.c | 115 +++++++++++++++++++++++++++++++++++-- 2 files changed, 114 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h index c74fff25be78..b8528d5dd1e7 100644 --- a/drivers/iommu/iommu-priv.h +++ b/drivers/iommu/iommu-priv.h @@ -56,4 +56,7 @@ static inline int iommufd_sw_msi(struct iommu_domain *domain, } #endif /* CONFIG_IOMMUFD_DRIVER_CORE && CONFIG_IRQ_MSI_IOMMU */ +int iommu_replace_device_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t pasid, + struct iommu_attach_handle *handle); #endif /* __LINUX_IOMMU_PRIV_H */ diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 9f1db10645ee..c8c891f27e45 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -514,6 +514,13 @@ static void iommu_deinit_device(struct device *dev) dev_iommu_free(dev); } +static struct iommu_domain *pasid_array_entry_to_domain(void *entry) +{ + if (xa_pointer_tag(entry) == IOMMU_PASID_ARRAY_DOMAIN) + return xa_untag_pointer(entry); + return ((struct iommu_attach_handle *)xa_untag_pointer(entry))->domain; +} + DEFINE_MUTEX(iommu_probe_device_lock); static int __iommu_probe_device(struct device *dev, struct list_head *group_list) @@ -3324,14 +3331,15 @@ static void iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid, } static int __iommu_set_group_pasid(struct iommu_domain *domain, - struct iommu_group *group, ioasid_t pasid) + struct iommu_group *group, ioasid_t pasid, + struct iommu_domain *old) { struct group_device *device, *last_gdev; int ret; for_each_group_device(group, device) { ret = domain->ops->set_dev_pasid(domain, device->dev, - pasid, NULL); + pasid, old); if (ret) goto err_revert; } @@ -3343,7 +3351,15 @@ static int __iommu_set_group_pasid(struct iommu_domain *domain, for_each_group_device(group, device) { if (device == last_gdev) break; - iommu_remove_dev_pasid(device->dev, pasid, domain); + /* + * If no old domain, undo the succeeded devices/pasid. + * Otherwise, rollback the succeeded devices/pasid to the old + * domain. And it is a driver bug to fail attaching with a + * previously good domain. + */ + if (!old || WARN_ON(old->ops->set_dev_pasid(old, device->dev, + pasid, domain))) + iommu_remove_dev_pasid(device->dev, pasid, domain); } return ret; } @@ -3412,7 +3428,7 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, if (ret) goto out_unlock; - ret = __iommu_set_group_pasid(domain, group, pasid); + ret = __iommu_set_group_pasid(domain, group, pasid, NULL); if (ret) { xa_release(&group->pasid_array, pasid); goto out_unlock; @@ -3433,6 +3449,97 @@ int iommu_attach_device_pasid(struct iommu_domain *domain, } EXPORT_SYMBOL_GPL(iommu_attach_device_pasid); +/** + * iommu_replace_device_pasid - Replace the domain that a specific pasid + * of the device is attached to + * @domain: the new iommu domain + * @dev: the attached device. + * @pasid: the pasid of the device. + * @handle: the attach handle. + * + * This API allows the pasid to switch domains. The @pasid should have been + * attached. Otherwise, this fails. The pasid will keep the old configuration + * if replacement failed. + * + * Caller should always provide a new handle to avoid race with the paths + * that have lockless reference to handle if it intends to pass a valid handle. + * + * Return 0 on success, or an error. + */ +int iommu_replace_device_pasid(struct iommu_domain *domain, + struct device *dev, ioasid_t pasid, + struct iommu_attach_handle *handle) +{ + /* Caller must be a probed driver on dev */ + struct iommu_group *group = dev->iommu_group; + struct iommu_attach_handle *entry; + struct iommu_domain *curr_domain; + void *curr; + int ret; + + if (!group) + return -ENODEV; + + if (!domain->ops->set_dev_pasid) + return -EOPNOTSUPP; + + if (dev_iommu_ops(dev) != domain->owner || + pasid == IOMMU_NO_PASID || !handle) + return -EINVAL; + + mutex_lock(&group->mutex); + entry = iommu_make_pasid_array_entry(domain, handle); + curr = xa_cmpxchg(&group->pasid_array, pasid, NULL, + XA_ZERO_ENTRY, GFP_KERNEL); + if (xa_is_err(curr)) { + ret = xa_err(curr); + goto out_unlock; + } + + /* + * No domain (with or without handle) attached, hence not + * a replace case. + */ + if (!curr) { + xa_release(&group->pasid_array, pasid); + ret = -EINVAL; + goto out_unlock; + } + + /* + * Reusing handle is problematic as there are paths that refers + * the handle without lock. To avoid race, reject the callers that + * attempt it. + */ + if (curr == entry) { + WARN_ON(1); + ret = -EINVAL; + goto out_unlock; + } + + curr_domain = pasid_array_entry_to_domain(curr); + ret = 0; + + if (curr_domain != domain) { + ret = __iommu_set_group_pasid(domain, group, + pasid, curr_domain); + if (ret) + goto out_unlock; + } + + /* + * The above xa_cmpxchg() reserved the memory, and the + * group->mutex is held, this cannot fail. + */ + WARN_ON(xa_is_err(xa_store(&group->pasid_array, + pasid, entry, GFP_KERNEL))); + +out_unlock: + mutex_unlock(&group->mutex); + return ret; +} +EXPORT_SYMBOL_NS_GPL(iommu_replace_device_pasid, "IOMMUFD_INTERNAL"); + /* * iommu_detach_device_pasid() - Detach the domain from pasid of device * @domain: the iommu domain. -- 2.34.1