From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (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 9F2D213AF2; Mon, 22 Jun 2026 03:12:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782097927; cv=none; b=TJL2mczdSNEgE4+Kn6CKnM6oFEGTbBJ+a+3VZyYuluyz8qk7Uh9/MV1/CTI9FDIZodM2CbJPD1uFXngETUoDPDgFfik2Fs9Qoza6FvCs7Mwq3hBbXh3el9G1T7tabXM6WDAeWisS4J/yXsdacUiUlcRgw7tBjR02m4VZPQpEwr8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782097927; c=relaxed/simple; bh=zImvOuePFdZg7H+6UnjoJXpQ1HYUUu1uXxUhmcu5Hgk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kFsky5VLf13pi5Szvek1CyLgDHgokbbAp0oWqOyPVm07OJrrMD1jczdoJmqT1TbRZ8quW5KUfAaQui5Lb5jmPkkHB7/6v+7Bub9n288DIaOWmiRGH0+Dms47a24ip9f//K4d+YafDpvcXnBN/Y7izKBrlmompltuzuyvBoqBmRs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=E+6yeSA6; arc=none smtp.client-ip=198.175.65.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="E+6yeSA6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1782097926; x=1813633926; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=zImvOuePFdZg7H+6UnjoJXpQ1HYUUu1uXxUhmcu5Hgk=; b=E+6yeSA6zeHMZxbJS1zge4eN0Jm3P8ObZQa1r6qi4A0UMAre9+Be7/H6 JSSpYB7hzCMGcdOrZj4FyUCKF4TgN2UD/7dbOrM9K5S2CFtwAjZ+O3Mzx /kLOjRknyfRr2AI92pHUXnmxH7j1vGOq+VyLBpPVlhIkY2O/+zqHWsymR fkBrtmAnbd5X93y7OBgXzzEgmxVp6epTScEEf6S+oIJs02Th/luGIVpxs O8UwIlz5TeTijHwVzWK9RxYaK/LxTqTspPIIa/A7ClM7oVj/7W0wLxBFl JxTpMH7vDMljBpPnLKzT1JoJT0rSnr/eVAyoQCzTem/Q5qum/0crUDuf5 A==; X-CSE-ConnectionGUID: XlbCIgByQgG119nxnnH8Xw== X-CSE-MsgGUID: uF/D34sqSSa/UWwcX53akA== X-IronPort-AV: E=McAfee;i="6800,10657,11824"; a="82917233" X-IronPort-AV: E=Sophos;i="6.24,218,1774335600"; d="scan'208";a="82917233" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jun 2026 20:12:06 -0700 X-CSE-ConnectionGUID: Cbb/fnU2QkKb6OW5SH7kpw== X-CSE-MsgGUID: 0XFVuEElRQ++Vq9NMIZINw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,218,1774335600"; d="scan'208";a="248959104" Received: from allen-sbox.sh.intel.com (HELO [10.239.159.30]) ([10.239.159.30]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jun 2026 20:12:01 -0700 Message-ID: Date: Mon, 22 Jun 2026 11:10:55 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 09/18] iommu: Add APIs to get iommu and device preserved state To: Samiullah Khawaja , David Woodhouse , Joerg Roedel , Will Deacon , Jason Gunthorpe Cc: 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 References: <20260614233728.2212104-1-skhawaja@google.com> <20260614233728.2212104-10-skhawaja@google.com> Content-Language: en-US From: Baolu Lu In-Reply-To: <20260614233728.2212104-10-skhawaja@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/15/26 07:37, Samiullah Khawaja wrote: > The preserved state of the device and IOMMU needs to be fetched during > shutdown and boot in the next kernel. Add APIs that can be used to fetch > the preserved state of a device and IOMMU. The APIs will only be used > during shutdown and after liveupdate so no locking needed. > > Reviewed-by: Pranjal Shrivastava > Signed-off-by: Samiullah Khawaja > --- > drivers/iommu/liveupdate.c | 75 ++++++++++++++++++++++++++++++++ > include/linux/iommu-liveupdate.h | 31 +++++++++++++ > 2 files changed, 106 insertions(+) > > diff --git a/drivers/iommu/liveupdate.c b/drivers/iommu/liveupdate.c > index 2d782023407d..90750e78cd2a 100644 > --- a/drivers/iommu/liveupdate.c > +++ b/drivers/iommu/liveupdate.c > @@ -18,6 +18,17 @@ > #define iommu_max_objs_per_page(_array) \ > ((PAGE_SIZE - sizeof(struct iommu_array_hdr_ser)) / sizeof((_array)->objects[0])) > > +#define iommu_liveupdate_for_each_obj(_arr, _obj, _idx) \ > + for ((_idx) = 0, (_obj) = (_arr)->objects; \ > + (_idx) < (_arr)->hdr.nr_objects; (_idx)++, (_obj)++) \ > + if (((_obj)->hdr.flags & IOMMU_SER_FLAG_DELETED)) \ > + continue; \ > + else > + > +#define iommu_liveupdate_for_each_arr(_arr) \ > + for (; (_arr); (_arr) = (_arr)->hdr.next_array_phys ? \ > + phys_to_virt((_arr)->hdr.next_array_phys) : NULL) > + > struct iommu_flb_obj { > struct mutex lock; > struct iommu_flb_ser *ser; > @@ -216,6 +227,70 @@ void iommu_liveupdate_unregister_flb(struct liveupdate_file_handler *handler) > } > EXPORT_SYMBOL(iommu_liveupdate_unregister_flb); > > +int iommu_for_each_preserved_device(iommu_preserved_device_iter_fn fn, > + void *arg) > +{ > + struct iommu_flb_obj *flb_obj; > + struct iommu_device_array_ser *array; > + struct iommu_device_ser *device_ser; > + int ret, idx; > + > + ret = liveupdate_flb_get_incoming(&iommu_flb, (void **)&flb_obj); > + if (ret) > + return -ENOENT; > + > + if (!flb_obj->ser->device_array_phys) > + return -ENOENT; > + > + array = phys_to_virt(flb_obj->ser->device_array_phys); > + iommu_liveupdate_for_each_arr(array) { > + iommu_liveupdate_for_each_obj(array, device_ser, idx) { > + ret = fn(device_ser, arg); > + if (ret) > + goto out; > + } > + } > + > +out: > + liveupdate_flb_put_incoming(&iommu_flb); > + return ret; > +} > +EXPORT_SYMBOL(iommu_for_each_preserved_device); > + > +struct iommu_hw_ser *iommu_get_preserved_data(u64 token, enum iommu_type_ser type) > +{ > + struct iommu_hw_ser *iommu_ser = NULL; > + struct iommu_hw_array_ser *array; > + struct iommu_flb_obj *flb_obj; > + int ret, idx; > + > + ret = liveupdate_flb_get_incoming(&iommu_flb, (void **)&flb_obj); > + if (ret == -ENODATA || ret == -ENOENT) > + return NULL; > + > + if (ret) > + return ERR_PTR(ret); Why does this helper return both NULL and an ERR_PTR()? Is NULL considered an error case here? Also, why are -ENODATA and -ENOENT treated differently? > + > + if (!flb_obj->ser->iommu_array_phys) { > + iommu_ser = ERR_PTR(-EINVAL); > + goto out; > + } > + > + array = phys_to_virt(flb_obj->ser->iommu_array_phys); > + iommu_liveupdate_for_each_arr(array) { > + iommu_liveupdate_for_each_obj(array, iommu_ser, idx) { > + if (iommu_ser->token == token && iommu_ser->type == type) > + goto out; > + } > + } > + > + iommu_ser = NULL; > +out: > + liveupdate_flb_put_incoming(&iommu_flb); > + return iommu_ser; > +} > +EXPORT_SYMBOL(iommu_get_preserved_data); These two helpers are intended for use by IOMMU drivers, correct? If so, please add kernel-doc style comments to document their usage and guide how drivers should use them. > + > static int alloc_object_ser(void **curr_array_ptr, u64 max_objs) > { > struct iommu_array_hdr_ser *curr_array = *curr_array_ptr; > diff --git a/include/linux/iommu-liveupdate.h b/include/linux/iommu-liveupdate.h > index f9528c94979d..5ad006892cbd 100644 > --- a/include/linux/iommu-liveupdate.h > +++ b/include/linux/iommu-liveupdate.h > @@ -13,6 +13,8 @@ > #include > #include > > +typedef int (*iommu_preserved_device_iter_fn)(struct iommu_device_ser *ser, > + void *arg); > #ifdef CONFIG_IOMMU_LIVEUPDATE > static inline void *dev_iommu_preserved_state(struct device *dev) > { > @@ -28,6 +30,20 @@ static inline void *dev_iommu_preserved_state(struct device *dev) > return NULL; > } > > +static inline void *iommu_domain_restored_state(struct iommu_domain *domain) > +{ > + struct iommu_domain_ser *ser; > + > + ser = domain->preserved_state; > + if (ser && (ser->hdr.flags & IOMMU_SER_FLAG_INCOMING)) > + return ser; > + > + return NULL; > +} > + > +int iommu_for_each_preserved_device(iommu_preserved_device_iter_fn fn, > + void *arg); > +struct iommu_hw_ser *iommu_get_preserved_data(u64 token, enum iommu_type_ser type); > int iommu_preserve_domain(struct iommu_domain *domain, struct iommu_domain_ser **ser); > void iommu_unpreserve_domain(struct iommu_domain *domain); > int iommu_preserve_device(struct iommu_domain *domain, > @@ -44,6 +60,21 @@ static inline void *dev_iommu_preserved_state(struct device *dev) > return NULL; > } > > +static inline void *iommu_domain_restored_state(struct iommu_domain *domain) > +{ > + return NULL; > +} > + > +static inline int iommu_for_each_preserved_device(iommu_preserved_device_iter_fn fn, void *arg) > +{ > + return -EOPNOTSUPP; > +} > + > +static inline struct iommu_hw_ser *iommu_get_preserved_data(u64 token, enum iommu_type_ser type) > +{ > + return NULL; > +} > + > static inline int iommu_preserve_domain(struct iommu_domain *domain, struct iommu_domain_ser **ser) > { > return -EOPNOTSUPP; Thanks, baolu