From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (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 580B533C513 for ; Tue, 19 May 2026 15:52:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779205975; cv=none; b=obQ4+VMoh6kXT/x/1Crg/alO0Pw1BNx+X/Auu2kTuuJI7Kh6MhfmOSPOIo2DLwTK1nthFJRCZ2yH6LwXbhV1uyKjZxg/I6JTgl/32LJ/Gp3eZNxVdZuozbsrdqJJJ1ofSkRHExj+uIyWg5nAd5XpnehaWBT6s8Mi7fhB7gHg75E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779205975; c=relaxed/simple; bh=ObUUfsifRjlfBoeZadT6dAQY7dovdxNlTYoFkj2FnrY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gVN3DMsWcuyjPWbhBA5mq0zI3qnaymqtEBsAYFNWuv2blyWjuhxst1tTDp1fm++S4l9bc+BggFHT5jPSt8is1fj4C6U3QcdCA3HOor3e1/5e9Q+8MSN1AANICwwlPxFlq3OahtveeFqD4ovIRnrPw1nh7qzvv0NgVBQWnsXfsVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=ojUUegpp; arc=none smtp.client-ip=209.85.214.181 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=google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ojUUegpp" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-2b46da8c48eso755ad.1 for ; Tue, 19 May 2026 08:52:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779205973; x=1779810773; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=4yDtPc7IVu74fsWc9+gkWocaidYIl1HHcjSh1//EIiI=; b=ojUUegpp514TpqUNrGtfjNVG/3kkzJSp/gB5Ls3Mu+CUcoCNsU0aKkUIDaT8NG970Z W8fD5tgWJL/gewBoeZMm/Kjo68gjBDEbUjZOkdJlDrsp+WUp2lELtZm1nlP5Pivmn4Mt MwuWe3TSEu6hFeJ+z6rgqsSAJli1tFKjKw+OrbjZkS+IUKLYv0rmn2FHlGrjcuGb74gf od/BGnio58FXxbtLFeSuDrcc/dd2FyalmPeFyuv4PMP3vQRL+RtnDdJEwUkfRpUaLpus dzMGnUsBEyCM3ucJWyA4AyG2VpHOsxOBuPxQ6PZk9DDem8bKc5+30e/vRvQvtk8iAVHM 6QFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779205973; x=1779810773; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=4yDtPc7IVu74fsWc9+gkWocaidYIl1HHcjSh1//EIiI=; b=aKXo5+MbhOEt4AgDlXgRd4qIXz/W2xq5mBxTY07MLIbbAHF8G2gXpVSzpgpZ/NUUNH TN9c028I77cKoL7Ak8OzrL/flQfS3+n1/l0hQU7Vu574weCZnNeRYhiM2E3YFscaWHCB oluGeEs1gnzuRsB5ZnKd/FC+9TXn9Hlpc4sQ8Tsu893mKwnV/XDN8Kgknxh2nhmuXyxE KKilHBSGE5rIFVotxTpJBZ83e+AjPMhc7h2u3GSuNv0jNYKoixqoHE1HOpgZV4RzATLe GWo+Cnaj8KF11Nu5MkDmK0wsg5ERMzpql0LPocQS9W0bx4+9EkUbTHtF0XHI30PcEns5 RxIw== X-Forwarded-Encrypted: i=1; AFNElJ/AzaFp8Ti3n2si9TBPlOQEdgXYC7HZfbN0JIqL3+x4tE6xrs9UdHMFGtaz57Dnh+oj+L/d0an60xc5lPE=@vger.kernel.org X-Gm-Message-State: AOJu0Yz/v6LEDy/hFE0iBPrrAVcW1PAYB5YrKezRh2fmPFS0HIRtKxEk 4ynme8+PWtEHKv+MwOljn3T+DYHceCWrni7CysTt/eo4kUuIj0fvfejfQ1Y8lIsMdA== X-Gm-Gg: Acq92OHKQP1Dhp8QMu0JQt2BXo8v/hQOE8kuS15bXf6c/LRXirlmLVWkq8GRZo4+Gml rfnSoXZXGOdiePH+XHXvZLi8haN3bZf8Hlcl6nHE/NKQORKJ8V1EYv6+hIbHRrW6ik+O7arzNNH UetABIGHPyQwOAg6fZGSLNkjNPX6z+VBAxOg5xywp+39rdSIQYKDLS5lwa4ZwSqxsHa3jCAcqfU jKfS1qfmg5rOLrO0abStu9RLIzpjMDOvWknB2xjconIGDa3DExOuFOY1qsQgks4V2asWeiQxEj4 NXEW/ln1I+ny3+/ocqGGd7NbWHTmk6U44zMJU29kmHciJqSfpxJDSo/N5Ci0QyRfwB6mQcnNFD/ vUNey979IDO4KUDvnnsAelg+M3pU2v5Je3H/jzpS56B/OHn2zO2HY3dDtjhRTUedIOFVsCp76+r xbzMZf/6kP2Dcq117Pm2AXMaogLxkNrZ1xUq7FxAidKy6wL5VIBKnw+m3Y9TajHL5LWi2O X-Received: by 2002:a17:902:d4c4:b0:2ae:80a3:98a9 with SMTP id d9443c01a7336-2bdb32c2d37mr5627525ad.11.1779205972767; Tue, 19 May 2026 08:52:52 -0700 (PDT) Received: from google.com (44.234.124.34.bc.googleusercontent.com. [34.124.234.44]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2bd5bd5fe44sm195003525ad.11.2026.05.19.08.52.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 08:52:52 -0700 (PDT) Date: Tue, 19 May 2026 15:52:43 +0000 From: Pranjal Shrivastava To: Samiullah Khawaja Cc: David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Jason Gunthorpe , Robin Murphy , Kevin Tian , Alex Williamson , Shuah Khan , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Saeed Mahameed , Adithya Jayachandran , Parav Pandit , Leon Romanovsky , William Tu , Pratyush Yadav , Pasha Tatashin , David Matlack , Andrew Morton , Chris Li , Vipin Sharma , YiFei Zhu Subject: Re: [PATCH v2 08/16] iommu: Add APIs to get iommu and device preserved state Message-ID: References: <20260427175633.1978233-1-skhawaja@google.com> <20260427175633.1978233-9-skhawaja@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260427175633.1978233-9-skhawaja@google.com> On Mon, Apr 27, 2026 at 05:56:25PM +0000, 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. > > Signed-off-by: Samiullah Khawaja > --- > drivers/iommu/liveupdate.c | 57 ++++++++++++++++++++++++++++++++ > include/linux/iommu-liveupdate.h | 31 +++++++++++++++++ > 2 files changed, 88 insertions(+) > > diff --git a/drivers/iommu/liveupdate.c b/drivers/iommu/liveupdate.c > index 765d042e22e3..60ee29b0c6bd 100644 > --- a/drivers/iommu/liveupdate.c > +++ b/drivers/iommu/liveupdate.c > @@ -17,6 +17,14 @@ > #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 (; (_arr); \ > + (_arr) = (_arr)->hdr.next_array_phys ? \ > + phys_to_virt((_arr)->hdr.next_array_phys) : NULL) \ > + for ((_idx) = 0, (_obj) = (_arr)->objects; \ > + (_idx) < (_arr)->hdr.nr_objects; (_idx)++, (_obj)++) \ > + if (!(_obj)->hdr.deleted) > + Nit: While the usage of this macro is safe right now because we use goto out; to short-circuit the scan. Such naked nested loops inside an iterator macro can be a bit of a trap for the future. If anyone tries to reuse this macro down the road and uses a break; statement, it will only break the innermost object loop and continue scanning subsequent array blocks. We could nest two macros or it as a helper fn to prevent such bugs. > static void *iommu_liveupdate_restore_array(u64 array_phys) > { > struct iommu_array_hdr_ser *array_hdr; > @@ -201,6 +209,55 @@ 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; > + > + array = phys_to_virt(flb_obj->ser->device_array_phys); Nit: phys_to_virt doesn't return an error for NULL. While we shouldn't be in a case where serialized ptrs are NULL. I'm wondering how painful catching such bugs would be.. should we check for NULL phys_addr here? (and at other places) > + 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); > + With those two nits, Reviewed-by: Pranjal Shrivastava