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 ED243221FBB; Mon, 27 Apr 2026 23:21:02 +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=1777332063; cv=none; b=k2o9YoIrATvuJlnsr8gsx4+cA18NdwGkj2K1OqLZ0klYUCak6AYj5f3MLCCUFKKzpzeEcTAzTeJWittxDIRsXMg09rFzQb28Aln4TRVhN6Q0yDy08nhqZFzLCOBa9NkHbbEx0JtlM6/VRO2Ur/CgllXOfVD7yYboimALt3u9cT8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777332063; c=relaxed/simple; bh=kJhtciu421O7ueHQhqPqW6F64apq6WD9S/98PUZ0xhE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hrxSjfwKtVMhpMckRMEjpytiZa9SmP7RhcJ61lV8bYB3Y+O/gITKsEPx9JwgzB/Rql0r8Aopj76NQ5pyNPUbz7fTV8Y71VVDCx0469uFjjvt8KjLbWwi8Q0O2MMvVXqv9C07ZNzC1AxLZHJQdtMj+4oBfl/c+IcbhkfyXV76WIk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gEdcdVm7; 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="gEdcdVm7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46B83C19425; Mon, 27 Apr 2026 23:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777332062; bh=kJhtciu421O7ueHQhqPqW6F64apq6WD9S/98PUZ0xhE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gEdcdVm7xpKZrEsM+oT2xb2RFKvUXaok9tghYeXA7iP9kB7K+w2s4DbBe5oKKUfrv fF1d5+1vlcDyPNI6YZtxo4SbLgqcQWZUK4SpZ9ogkpIP8TSoG8nXgzSDFKuLAkZHWL NSaClz1SmkpxtucZOHTWV7GVqFYV/rTUWOqZd6X/NjG/5+94iIk1kXL9FA2lWrM24d xgEFYhLjplK8N3sN8lH2QDc72BGF1pmwJPXjQy7WCRrOkunQmRQxnsypD1sK8vz03x 73ppN0ijH8W7S+/IIN/Hd6YbRGLx3ZV/pZv4h+tvRA0sXDDtVJKKrlXaMGkHT0LxO8 5q1Wa9usw9fJw== Date: Mon, 27 Apr 2026 16:21:00 -0700 From: Jakub Kicinski To: Dipayaan Roy Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, leon@kernel.org, longli@microsoft.com, kotaranov@microsoft.com, horms@kernel.org, shradhagupta@linux.microsoft.com, ssengar@linux.microsoft.com, ernis@linux.microsoft.com, shirazsaleem@microsoft.com, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, stephen@networkplumber.org, jacob.e.keller@intel.com, dipayanroy@microsoft.com, leitao@debian.org, kees@kernel.org, john.fastabend@gmail.com, hawk@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org, sdf@fomichev.me, yury.norov@gmail.com Subject: Re: [PATCH net-next] net: mana: Force single RX buffer per page for CVM/encrypted guest memory Message-ID: <20260427162100.5f731228@kernel.org> In-Reply-To: References: 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-Transfer-Encoding: 7bit On Mon, 27 Apr 2026 06:51:02 -0700 Dipayaan Roy wrote: > When page_pool allocates sub-page RX buffer fragments, the bounce buffer > granularity may not align with these smaller fragment sizes, leading to > failure in mana driver rx path. > > Refactor the RX buffer decision into mana_use_single_rxbuf_per_page(). > When cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) is true, the driver is > forced to use a single RX buffer per page. This ensures: > - Each RX buffer is exactly one PAGE_SIZE. > - The DMA offset is always 0. > - SWIOTLB maps full, page-aligned blocks. As commented on your RFC - I'm not sure why you need this.