From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fhigh-b7-smtp.messagingengine.com (fhigh-b7-smtp.messagingengine.com [202.12.124.158]) (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 203953A6B73; Tue, 2 Jun 2026 19:14:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.12.124.158 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780427663; cv=none; b=geSd4QuWhTri21YojL2Gv0VTLi9P+ihj+GB2xXs8dD1VVpAbt5pV0gG/4fcEU2+nJmGWaNe8exVwnqSy69tupDwKOtgOorF7QBvaDj4Zej1/C7zjuBsc6FcS37kNj8V9k9dlLxZXibNBAl51fz2CkrexoIZwDlXdyWS9DH6cZQU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780427663; c=relaxed/simple; bh=tAzkKETTuRf48VD4z0ecJB0e+JzCLTbr80+eKXBKgI4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hgfwiOTQi0998oEraQioTn1lGEEn7DgVcnlbofItP+2CcLXaHAWrGN6teRgnzlcGiOAmw/1gJ31rnhYtqa5q++lzzw9Xraxa4qiocfy5Hi55fwT1k+eF3Mnxmcf10+fyR3rWyJ19J+uejFWYh5xPHhS6crpqxOqebO7qTLZTCtE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=shazbot.org; spf=pass smtp.mailfrom=shazbot.org; dkim=pass (2048-bit key) header.d=shazbot.org header.i=@shazbot.org header.b=fYi8WswM; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b=gHZnmppg; arc=none smtp.client-ip=202.12.124.158 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=shazbot.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=shazbot.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=shazbot.org header.i=@shazbot.org header.b="fYi8WswM"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="gHZnmppg" Received: from phl-compute-06.internal (phl-compute-06.internal [10.202.2.46]) by mailfhigh.stl.internal (Postfix) with ESMTP id DAE987A00A1; Tue, 2 Jun 2026 15:14:20 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-06.internal (MEProxy); Tue, 02 Jun 2026 15:14:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shazbot.org; h= cc:cc:content-transfer-encoding:content-type:content-type:date :date:from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to; s=fm3; t=1780427660; x=1780514060; bh=SpvDioedx7EBp7REkfmzqAAh1WhYtz7APHz8F+X6T5w=; b= fYi8WswM+/hkbi1Bd3EOzRsKS9w1UWkyvLNnwfILgyvyDaBqcCjA1b8c6n4DxuHQ Rufm0/3+n7fZ26/ntN0+xsHEmNNi3P8QbUAcLR8nsZUosIqvWis3u8AolZriPI5C YuWzbB1x/a5RsQQ1T3bRDmQy07wOdEr+RnzVSVcyClofhmTc1p89+VepqJFS1A2s boZQIsQD2T1hd72DAgKjy38GRJ3hZX/K0uCtHnvNzynsNlyEpmni5pyFIc3DvAA1 8mxM7s/xKW22LT3Tp2TeRal0XVGYLuqUPZFlA4P7fr3myk/3/p70msI7f0lMYXPR xsnJ7JUaM1wXfRmR3tavOg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding :content-type:content-type:date:date:feedback-id:feedback-id :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:subject:subject:to:to:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t=1780427660; x= 1780514060; bh=SpvDioedx7EBp7REkfmzqAAh1WhYtz7APHz8F+X6T5w=; b=g HZnmppgaNPwItEsd4IStTSIXHz/n3NR53RCJvTj0RmQJN0ZSzjnWudHLZVX8hvc0 yYJ/eY/QzBkPOiNbalDsZSWi42bWUKGCUmefFmVZ2IL1XHDBYKhAFOqHH37GSFd1 jC8iVrtGTTz/cfIOQnCTAmWEsJFY7EhljeRoSD+1k+zlg7G3Jf94qulTJTOesJv3 Hzhbzen7f4bxAYIByco1J7y33aGJDc/xd5c/co7lCx1KXDa6hc/gLo8Na6N+Pttt 0vW+LPbolONIOrIpL/GHLHus850xqwENSkNrZrJTbr1f6V9IdU4g0YuyK9cPKid4 lDWDW3cMun2To0zyPP+iQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTEbaR6LWAxxEP7bF1oueZFOpQlufeO72chHj023mPTzizOII6z5ldTM+xHFULHcJd KN0hIAhV7kszSpGu8UYILvRB9QwRkTWj6khZsy0V2rhu6mvc3076amoNLLnrXC8wle5U8k e19xr29yQwkD+fyr3WNDGif+swnmavasRDpBG5bCnmixecj00gr5lXamekgkoOQ078cPts CnXa3RTvGxPZyyfK6c2P8lMcR3Bqd7Dd7ndk2OxIQZ0W8xoZoK4MdeQC//3l03vQWShVsD EnUUq+uNCd37UWLpguugGlt1xZl9XZO9lvsgn8Ktzy5+1OPCSQ/Hf4drjV01A/xmVAV8CJ XpXvFZZpm977G6evGreJs5c5E24hbpdLz+gaYoOYEQSSTCNZea3/qiLwfKEbttRfEGlnH5 eUXReTuUjJSZw0Vjd1jXIAisrp6/6CqkroxMamWciT724xZYyeqP+Ou6NNohqsy1JhZxYY wZWHdg+ejxcOFd2TKlDcMQsLQWZ5XnT4kPV9vb0StqKqW//5ig/43r+FnPSQFBBGWf3uvi axl7yZ8MoHUEOb/wAdyn6SUir2uA6YCrKa/Q1QYRUeanFm58uZvdaCc2O2wVqV3rulFM8Y Pa1Mrg8R7jNWd7YPWht2zrHTwn4TzEafYAgL7BMKCrlHQjzA7rkyTd0Ts6Zg X-ME-Proxy: Feedback-ID: i03f14258:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 2 Jun 2026 15:14:18 -0400 (EDT) Date: Tue, 2 Jun 2026 13:14:17 -0600 From: Alex Williamson To: Matt Evans Cc: Leon Romanovsky , Jason Gunthorpe , Alex Mastro , Christian =?UTF-8?B?S8O2bmln?= , Bjorn Helgaas , Logan Gunthorpe , Mahmoud Adam , David Matlack , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Sumit Semwal , Kevin Tian , Ankit Agrawal , Pranjal Shrivastava , Alistair Popple , Vivek Kasireddy , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, kvm@vger.kernel.org, linux-pci@vger.kernel.org, alex@shazbot.org Subject: Re: [PATCH v2 9/9] vfio/pci: Add mmap() attributes to DMABUF feature Message-ID: <20260602131417.41366391@shazbot.org> In-Reply-To: <8854824e-06c2-43b3-86c2-8c2c28f9ad63@meta.com> References: <20260527102319.100128-1-mattev@meta.com> <20260527102319.100128-10-mattev@meta.com> <20260528171432.771a1a30@shazbot.org> <8854824e-06c2-43b3-86c2-8c2c28f9ad63@meta.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 2 Jun 2026 17:50:04 +0100 Matt Evans wrote: > On 29/05/2026 00:14, Alex Williamson wrote: > > On Wed, 27 May 2026 03:23:12 -0700 > > Matt Evans wrote: > >> + uint32_t old_attr = priv->memattr; > >> + > >> + if (flags & VFIO_DEVICE_FEATURE_SET) { > >> + switch(db_attr.memattr) { > >> + case VFIO_DEVICE_FEATURE_DMA_BUF_MEMATTR_NC: > >> + case VFIO_DEVICE_FEATURE_DMA_BUF_MEMATTR_WC: > >> + priv->memattr = db_attr.memattr; > >> + break; > >> + > >> + default: > >> + ret = -ENOTSUPP; > > > > -EINVAL > > I'd like to push back on this one; ENOTSUPP distinguishes trying to use > a wild attribute value from all manner of other screwups such as > trying to GET (with it no longer supported), passing an fd that isn't a > DMABUF, etc. > > I'm not wed to the value ENOTSUPP, just something distinctive versus the > other errors userspace might see, and that value seems appropriate. It needs to be a uAPI errno though, aiui ENOTSUPP is an internal NFS errno. How about EOPNOTSUPP? Thanks, Alex