From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f193.google.com (mail-qk1-f193.google.com [209.85.222.193]) (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 EA98B33D6F6 for ; Thu, 22 Jan 2026 18:02:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.193 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769104989; cv=none; b=ekVCCYSr6XkHXP/eCPoM88+v2JHR168mXVNoPnlx7PtR1EbSRQ7CU6DXODiAK5kXXLOiBNRuPjDat8ZejqluftJm6b7O1XnxQXkC1baISBeGbIj2nv8KR6z6AvAfkaDOViHS/uZZ0f/BmzqkQpdVr2U995Ku/PG4VvlkHmXf3FQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769104989; c=relaxed/simple; bh=HnQGF+GQp2hqS7/UCHcdVaF6HDlO/rgXAhOIogT0hbY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A4f5u7oQOZPsvZhHJPF7rMjQzX49SnV3WazD1ZMI9IQ2rrt9RsJ7ZLQqIz+8zBacESmv89FRaUECCqX+RsqVtcqaEa39Ayfnkh9916oBP4WYdXTbhgIxobwW6z5YKlhUljtCwqOVShWKDCXQbFBqK8VQ9rWX2zhYgsNoYipVURw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=e+ioyvD5; arc=none smtp.client-ip=209.85.222.193 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="e+ioyvD5" Received: by mail-qk1-f193.google.com with SMTP id af79cd13be357-8c5389c3cd2so130107085a.0 for ; Thu, 22 Jan 2026 10:02:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1769104975; x=1769709775; 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=Lk0DadVMYIedGPbXp5WhX8kegjjbwpGdfj2a8a3noKw=; b=e+ioyvD5mh1+7tOT8IK9uxQSA/8K/fj1ugC7ALfhyl7CGOvsAUAbCSe5UZvkCj8lGi RlQo/vElbPcwjw2FdOf8BjXqyNxIHb57qwr0HxgBshZUBP2UfnuxvnIoJBsP9fdonccI A/A49gVzdTm2KMyeMzJSfF0u8pa64FX77cLEM/4nGZIquoxR1baiO4ooaH1lL9ex2Q/4 LFXT2zGdLiA1W+GY6RWZeAE8+a6ATWNY9YlOzgJklNysQS3Ruc5uYRJxt4DPpSj5RfXd Tf55THYRDTBlEbFxerHkY7BZJTOboTl3Tz+dV6X1jO05fvoYcF30kK9JBvQ1wZ/3v0L6 5FMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769104975; x=1769709775; 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=Lk0DadVMYIedGPbXp5WhX8kegjjbwpGdfj2a8a3noKw=; b=XPZ0yr0Oi4ngP//mM9hXs8WCg1Dfrx8mirF8y4+FPtnRhzYK+OyAjedl0DC3mFxcvh 0qR3ORGNFCsuAC5uugb7uAmNMZttUuszFKEq8irbOMBUH0GLU2VrID0usMk9Uis4FBJS XVWynFqaQQUIvBth6Rs0lqWQ85JspUQ19bjVr3Tcyop/ZDoOVOTRKHHi7KD9V+rHy1Ec JufsOq6tj6EH2k3JMS5PZDUKn+9R66qmjabz9qm/jpcfNvq63zFAOng3Edo4B3JHW8g/ emdrkpg08IdtbWqqT4ajWxv/TCAEwsMYTluaOcWgdfZw/+5PvANIdXrwqVcxFKQUchas jv/A== X-Forwarded-Encrypted: i=1; AJvYcCVK4AzEwHsOTDZwEhZoK13Q++dTYG+yGe+dn6tLKAQz02X2tnvwnFEYmhlWm6AMMHmN0ZsrYYCbu9k=@vger.kernel.org X-Gm-Message-State: AOJu0Yx0nAN1cuiXXFoIF/b4G4F7htSqyEChObyGIPcMlqo+3egeXUwh j8Ee8g0kN76APsR7jIFE0oeSt+bvCidv0DqNFXQDf8F1CziCPLR5sT0hWilbsAC6RHc= X-Gm-Gg: AZuq6aI7BejkES5gbVN5Bt2pcj5qOEHKUQU3GArF9+b0tlB6YvCgswQDkRN/O/FXLO4 7oGr5u+uGHxYZWcvhKHL52qICYQQY6luD3X+JgDy7AY0hJQ3gt85OXKn9IUp1g+8rODbLNBL/S9 hgRFephlka8ao+qagRJXyh7Z7wZgjJ8AAZ3Fe9/cIghP/oNW+vLbByYULlpyeTzVY1GMGSHDGn5 xhmRqO3QSAxONwR2/LthAm+58b19bCO/C5YgUXYMxcZqMwApcv2+K1zdYkCbc218uLSpJOUnJwn qOWZ2YduBR6jpUN//ysrvPGi/G/n+iBTaQdHm2E46CVAnJBpR54NiSNsDRazd6wNyT7ElEJVNKr x5DuBEwLarjmWsc97snE1cf88osal2mRK92Ln0+vMcQN90Vpj1k8OzjzBYgOr/nIqeiq3QCyKN7 CQXVacCOVwR4xPAiMg8hXGihJwR6PNOoWuXtTBZBiM9hKr4uNRC6vQYSyrDl0PzlwwWsf7zw== X-Received: by 2002:a05:620a:410a:b0:8b2:3371:e9d6 with SMTP id af79cd13be357-8c6e2e44d03mr38296485a.62.1769104974462; Thu, 22 Jan 2026 10:02:54 -0800 (PST) Received: from gourry-fedora-PF4VCD3F (pool-96-255-20-138.washdc.ftas.verizon.net. [96.255.20.138]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8c6a71c083esm1471036185a.17.2026.01.22.10.02.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Jan 2026 10:02:53 -0800 (PST) Date: Thu, 22 Jan 2026 13:02:52 -0500 From: Gregory Price To: Robert Richter Cc: Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , Jonathan Cameron , Dave Jiang , Davidlohr Bueso , Jonathan Corbet , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, "Fabio M. De Francesco" , Terry Bowman , Joshua Hahn , linux-doc@vger.kernel.org Subject: Re: [PATCH v4 3/3] Documentation/driver-api/cxl: ACPI PRM Address Translation Support and AMD Zen5 enablement Message-ID: References: <20260122172432.369215-1-rrichter@amd.com> <20260122172432.369215-3-rrichter@amd.com> Precedence: bulk X-Mailing-List: linux-cxl@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: <20260122172432.369215-3-rrichter@amd.com> On Thu, Jan 22, 2026 at 06:24:29PM +0100, Robert Richter wrote: > + > +The following changes to the specification are needed: > + > +* Allow a CXL device to be in an HPA space other than the host's address space. > + > +* Allow the platform to use implementation-specific address translation when > + crossing memory domains on the CXL.mem path between the host and the device. > + > +* Recommend that the platform provide a method for the OS to convert device > + addresses to SPAs, such as a PRM handler or _DSM. Document _DSM as the > + preferred method. > + > +* Specify that the kernel (Operating System) determines Endpoint SPA ranges and > + interleaving configurations using platform-specific address translation > + methods. > + As-written for the state of things - this is fine. Just making a note given feedback on the translation patch set here: https://lore.kernel.org/linux-cxl/697186008aa26_1d6f10061@dwillia2-mobl4.notmuch/ If the spec is updated to include such translation tables as described in the discussion above, then this should probably be updated to say: --- Platform shall provide the appropriate CEDT translation tables. If the translation mechanism can't be encoded into tables, then it's on the platform to justify this and provide PRM or _DSM (etc etc.). --- ~Gregory