From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 85E2C20297C; Tue, 29 Jul 2025 08:29:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753777742; cv=none; b=qdTs56Xjkus9fOjFboIauaSMQYzNqi6PvVPcBfck+DaQUFB+yNBKdztADSWNzBV8MXrvpo1kQPDPmcDjOga3c5FO6YBapfAbiOAvfxLEOqARbbdKeUnlu/STDGmaM8Ydwp7mws9+v75hMyYOPS1KF9qscSb97iMViH7qqmINRkk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753777742; c=relaxed/simple; bh=K3BcUd/YctGhDw6vqaFn+ll0qNd9qomGN0pIy0wIoYs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=oWnA+h6W5+zb0HRhPHLjYChPkzodYXnDImFvCsqJ0oBmRuRkONzawhfVCGIktevWGqqBmqRBWpSFyvIBuWS8YImSL/s+X3Yf+EwBJU2ko+PVQ6y61refHPPUlD27mVGj3YmNlwLwvOllMKVsSYW4QEN2UPSldhk3cZKLBDhBhTk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H6VZf41W; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="H6VZf41W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAC0EC4CEF5; Tue, 29 Jul 2025 08:28:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753777742; bh=K3BcUd/YctGhDw6vqaFn+ll0qNd9qomGN0pIy0wIoYs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=H6VZf41WPH/OLHCLieY9YlBtbpK9t0RFg+/4zw2Qsf8pEmELzQMEkCDwM/IwvEF+P Ks6UkkDJh2d+gRAD/PWOwFkFfmU61wTVBtb064Y4/l1LCcLU9CEozAEnk223qKCmiv qjIc4QTogiEeTpr2MZfbtH8sj3O69THGjJQcePGQvXSmTgDQdRvXs9IZj/X6VfucTX afgxX1guhR/UkjGjCMVdE+JITWmoWQW+IlN4sNKzx1KevLBeec1QXr8Jqj0B2wI+lP szWqBlVNVCIHv1t14QZQH9SMapaH5pTyh4MfUplPaMJhrELUvvYS7QWkVYFkQa5lVj G1JyxBmahzg+Q== X-Mailer: emacs 30.1 (via feedmail 11-beta-1 I) From: Aneesh Kumar K.V To: Jason Gunthorpe Cc: linux-coco@lists.linux.dev, kvmarm@lists.linux.dev, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, aik@amd.com, lukas@wunner.de, Samuel Ortiz , Xu Yilun , Suzuki K Poulose , Steven Price , Catalin Marinas , Marc Zyngier , Will Deacon , Oliver Upton Subject: Re: [RFC PATCH v1 06/38] iommufd: Add and option to request for bar mapping with IORESOURCE_EXCLUSIVE In-Reply-To: <20250728140841.GA26511@ziepe.ca> References: <20250728135216.48084-1-aneesh.kumar@kernel.org> <20250728135216.48084-7-aneesh.kumar@kernel.org> <20250728140841.GA26511@ziepe.ca> Date: Tue, 29 Jul 2025 13:58:54 +0530 Message-ID: Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Jason Gunthorpe writes: > On Mon, Jul 28, 2025 at 07:21:43PM +0530, Aneesh Kumar K.V (Arm) wrote: >> Signed-off-by: Aneesh Kumar K.V (Arm) > > Why would we need this? > > I can sort of understand why Intel would need it due to their issues > with MCE, but ARM shouldn't care either way, should it? > > But also why is it an iommufd option? That doesn't seem right.. > > Jason This is based on our previous discussion https://lore.kernel.org/all/202506= 06120919.GH19710@nvidia.com IIUC, we intend to request the resource in exclusive mode for secure guests=E2=80=94regardless of whether the platform is Intel or ARM. Could you help clarify the MCE issue observed on Intel platforms in this context? -aneesh