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 AF199194AF9; Wed, 26 Feb 2025 15:07:51 +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=1740582471; cv=none; b=pW07g3wvLEv7U8Pr5/jtlfNLLJew7IQnUVDIZAoCGskiZuqm9K7iY8HATHN8YxljURob9/XyevRKNue4ntOUChoVlLIO37MSeaqmVzpLInRECfP+4idctgLwHt8l1l5v+v93Ukfu0AjQheAZxB9jpGizK+DAkHiX4SmA/pYo6RM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740582471; c=relaxed/simple; bh=B9XcjEPM+jhCbMj4W001+uMUwpvu1a7JWj4XEnZFlac=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rFenPevJVxF5TlGd6qhkpQ8C3rH0tCgxN+PC6F/fmkd3kkPb/qTJk0LQXudJIyxqzLnNz1cHQUmHzA/OURtKFL4vHi+uJG90a+C29XId3yzjh7fMJmwdZgy0f4IlUucbkTeZccUj9IYQ4Nuuu3qUF+bUxw37yEpp0SclnllUBPY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IZ+aUmnG; 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="IZ+aUmnG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 130D7C4CED6; Wed, 26 Feb 2025 15:07:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740582471; bh=B9XcjEPM+jhCbMj4W001+uMUwpvu1a7JWj4XEnZFlac=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IZ+aUmnGf45RfCarvX357sQ0Upo/AdKZqHhBt4oOqwP8TPtAfjR6zWOS8m3TuOSAU UY7ZgRODLPPOjC1epR1nf8EdlAkZ7DV+R3o92iqNS+rakx5GYMAm7rjdoRPaJr0wT2 XJRto9IdXDtU21j80XiD6UnO/7j9w6+g/mRdRXpuJdk5Z91fAkR+xsFEWe2jG2MZU+ /BXkBXe4NieukmbhY0hKKiYMychTz4bvorcVf+kvl0WDZPfyjNlqpb4TjhsDbVqepN qeNXv68dlFM2vWFvVAJ3tGv9G9L7ZUv2zDvsqbo9JmIWhpXJPNCKzD7sHWj2QTND+s O3oEvGjOQUOyA== Date: Wed, 26 Feb 2025 16:07:37 +0100 From: Ingo Molnar To: Rostyslav Khudolii Cc: Yazen Ghannam , Borislav Petkov , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, "bhelgaas@google.com" , "tglx@linutronix.de" Subject: Re: PCI IO ECS access is no longer possible for AMD family 17h Message-ID: References: <20241219112125.GAZ2QBteug3I1Sb46q@fat_crate.local> <20241219164408.GA1454146@yaz-khff2.amd.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: * Rostyslav Khudolii wrote: > > My understanding, based on the above info, is that ACPI should be > > used. The direct register enablement is still possible for > > backwards compatibility, if needed. > > > > I think your observation proves a good point. The registers were > > moved starting in Zen. But this is not an issue on modern OSes > > since ACPI is used by default. > > This is my understanding too. However, what is the desired behavior > on Zen if the CONFIG_ACPI_MCFG and CONFIG_PCI_MMCONFIG are both > disabled? ECS should not be possible since the registers were moved, > right? If that's the case then, at the very least, it would be great > to have a warning message. > > > For your specific issue, I think we should determine if there is a > > configuration or a firmware problem. > > To give a bit more context: I am porting the kernel which works on > the AMD Ryzen™ Embedded V1000-based device. On that system, it seems > like the firmware doesn't disable IO access to ECS (which is wrong), > hence we have never experienced this issue before. Now, the > R2000-based device's firmware disables IO access to ECS (correctly) > and that's when the issue starts to happen. [ Sorry about the late reply. ] So what is the practical impact here? Do things start breaking unexpectedly if CONFIG_ACPI_MCFG and CONFIG_PCI_MMCONFIG are disabled? Then I'd suggest fixing that in the Kconfig space, either by adding a dependency on ACPI_MCFG && PCI_MMCONFIG, or by selecting those must-have pieces of infrastructure. Thanks, Ingo