From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0F57EC3DA61 for ; Sat, 27 Jul 2024 09:21:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lN07q+H5ikyR24FZXcPG3GkVzFrpfLcjnoisu0rjkuA=; b=qDtBLxKzl978Fyybr4/N152hEq LZTIgSV95RJonwS0hiIi4lqA7SaFcjUDtVqDE+a5/FyqaZ9oIEXJPdJmjt8DPCvfLp8ivxh9v3jy1 P5gOOKygcZ8fmstaF9zS+/L0xcUxn421aMXtzCdSeSJcDQGcf7Io3gy3rJ/C4cx94nbfIYD5Md5+p RtRMzcnd315zpmYDmRIvyCW2peFBt4raq7lkWm5z5snVZ56w6COO1Ts08GqsWGRqhga1gZ6ltI6u1 xcKMqcnk5Xb76D94hw/Q1NDE/6GiBnDyMczLHaYXIlDX8HMD0woxXuejVTwfcorIlQnAVSJfAKe45 8al9Wsmg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sXdcG-00000006OKI-0hec; Sat, 27 Jul 2024 09:21:28 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sXdbq-00000006OCo-0l6D for linux-arm-kernel@lists.infradead.org; Sat, 27 Jul 2024 09:21:03 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 3CD31609FA; Sat, 27 Jul 2024 09:21:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EB52C32786; Sat, 27 Jul 2024 09:20:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722072060; bh=ThQdrmdK+EMALR/mguXOUSvlEXDj9D2TPtTM/KgqOgM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=iUfStM4g3uD8cr+8hZS7Lj2VMa31bZNh3aRUWTTbUIUBpEobmm07Z1IEUo/ISgA8c 4SOb4h8YK+pWAaDrmL2YMY3rgNTqSqIq+ZetaSz/yewhrsVIIeIULiAj0A061kSb2O GonIbl0dk02BEs+5SSpZOsZDvIwT96vcB294IK8mSF2UdRydmIizpDNrWPbBv304Hj mVREeIIbfQx4KFGQM7ZEWSIZ6DcnVc5T/xRY5GPFmNBZ3Jo9JaKdRDjCLU7UlPmIRV v9tC3H5scWjr9BVs78YeUQUtCxtSJ7KjCtIQDQ1VSuHcaI3Jjf2NoTUP8BGiDDgNOZ s16e21m6madQA== Message-ID: <1e3dbe67-5210-4b76-b1de-c1afaf4c9fcc@kernel.org> Date: Sat, 27 Jul 2024 11:20:49 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 6/7] Drivers: hv: vmbus: Get the IRQ number from DT To: Arnd Bergmann , Roman Kisel , bhelgaas@google.com, Borislav Petkov , Catalin Marinas , Dave Hansen , Dexuan Cui , Haiyang Zhang , "H. Peter Anvin" , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , "K. Y. Srinivasan" , Len Brown , Lorenzo Pieralisi , Ingo Molnar , "Rafael J . Wysocki" , Rob Herring , Thomas Gleixner , Wei Liu , Will Deacon , linux-acpi@vger.kernel.org, Linux-Arch , linux-arm-kernel@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org Cc: apais@microsoft.com, benhill@microsoft.com, ssengar@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev References: <20240726225910.1912537-1-romank@linux.microsoft.com> <20240726225910.1912537-7-romank@linux.microsoft.com> <7418bfcd-c572-4574-accc-7f2ae117529f@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; keydata= xsFNBFVDQq4BEAC6KeLOfFsAvFMBsrCrJ2bCalhPv5+KQF2PS2+iwZI8BpRZoV+Bd5kWvN79 cFgcqTTuNHjAvxtUG8pQgGTHAObYs6xeYJtjUH0ZX6ndJ33FJYf5V3yXqqjcZ30FgHzJCFUu JMp7PSyMPzpUXfU12yfcRYVEMQrmplNZssmYhiTeVicuOOypWugZKVLGNm0IweVCaZ/DJDIH gNbpvVwjcKYrx85m9cBVEBUGaQP6AT7qlVCkrf50v8bofSIyVa2xmubbAwwFA1oxoOusjPIE J3iadrwpFvsZjF5uHAKS+7wHLoW9hVzOnLbX6ajk5Hf8Pb1m+VH/E8bPBNNYKkfTtypTDUCj NYcd27tjnXfG+SDs/EXNUAIRefCyvaRG7oRYF3Ec+2RgQDRnmmjCjoQNbFrJvJkFHlPeHaeS BosGY+XWKydnmsfY7SSnjAzLUGAFhLd/XDVpb1Een2XucPpKvt9ORF+48gy12FA5GduRLhQU vK4tU7ojoem/G23PcowM1CwPurC8sAVsQb9KmwTGh7rVz3ks3w/zfGBy3+WmLg++C2Wct6nM Pd8/6CBVjEWqD06/RjI2AnjIq5fSEH/BIfXXfC68nMp9BZoy3So4ZsbOlBmtAPvMYX6U8VwD TNeBxJu5Ex0Izf1NV9CzC3nNaFUYOY8KfN01X5SExAoVTr09ewARAQABzSVLcnp5c3p0b2Yg S296bG93c2tpIDxrcnprQGtlcm5lbC5vcmc+wsGVBBMBCgA/AhsDBgsJCAcDAgYVCAIJCgsE FgIDAQIeAQIXgBYhBJvQfg4MUfjVlne3VBuTQ307QWKbBQJgPO8PBQkUX63hAAoJEBuTQ307 QWKbBn8P+QFxwl7pDsAKR1InemMAmuykCHl+XgC0LDqrsWhAH5TYeTVXGSyDsuZjHvj+FRP+ gZaEIYSw2Yf0e91U9HXo3RYhEwSmxUQ4Fjhc9qAwGKVPQf6YuQ5yy6pzI8brcKmHHOGrB3tP /MODPt81M1zpograAC2WTDzkICfHKj8LpXp45PylD99J9q0Y+gb04CG5/wXs+1hJy/dz0tYy iua4nCuSRbxnSHKBS5vvjosWWjWQXsRKd+zzXp6kfRHHpzJkhRwF6ArXi4XnQ+REnoTfM5Fk VmVmSQ3yFKKePEzoIriT1b2sXO0g5QXOAvFqB65LZjXG9jGJoVG6ZJrUV1MVK8vamKoVbUEe 0NlLl/tX96HLowHHoKhxEsbFzGzKiFLh7hyboTpy2whdonkDxpnv/H8wE9M3VW/fPgnL2nPe xaBLqyHxy9hA9JrZvxg3IQ61x7rtBWBUQPmEaK0azW+l3ysiNpBhISkZrsW3ZUdknWu87nh6 eTB7mR7xBcVxnomxWwJI4B0wuMwCPdgbV6YDUKCuSgRMUEiVry10xd9KLypR9Vfyn1AhROrq AubRPVeJBf9zR5UW1trJNfwVt3XmbHX50HCcHdEdCKiT9O+FiEcahIaWh9lihvO0ci0TtVGZ MCEtaCE80Q3Ma9RdHYB3uVF930jwquplFLNF+IBCn5JRzsFNBFVDXDQBEADNkrQYSREUL4D3 Gws46JEoZ9HEQOKtkrwjrzlw/tCmqVzERRPvz2Xg8n7+HRCrgqnodIYoUh5WsU84N03KlLue MNsWLJBvBaubYN4JuJIdRr4dS4oyF1/fQAQPHh8Thpiz0SAZFx6iWKB7Qrz3OrGCjTPcW6ei OMheesVS5hxietSmlin+SilmIAPZHx7n242u6kdHOh+/SyLImKn/dh9RzatVpUKbv34eP1wA GldWsRxbf3WP9pFNObSzI/Bo3kA89Xx2rO2roC+Gq4LeHvo7ptzcLcrqaHUAcZ3CgFG88CnA 6z6lBZn0WyewEcPOPdcUB2Q7D/NiUY+HDiV99rAYPJztjeTrBSTnHeSBPb+qn5ZZGQwIdUW9 YegxWKvXXHTwB5eMzo/RB6vffwqcnHDoe0q7VgzRRZJwpi6aMIXLfeWZ5Wrwaw2zldFuO4Dt 91pFzBSOIpeMtfgb/Pfe/a1WJ/GgaIRIBE+NUqckM+3zJHGmVPqJP/h2Iwv6nw8U+7Yyl6gU BLHFTg2hYnLFJI4Xjg+AX1hHFVKmvl3VBHIsBv0oDcsQWXqY+NaFahT0lRPjYtrTa1v3tem/ JoFzZ4B0p27K+qQCF2R96hVvuEyjzBmdq2esyE6zIqftdo4MOJho8uctOiWbwNNq2U9pPWmu 4vXVFBYIGmpyNPYzRm0QPwARAQABwsF8BBgBCgAmAhsMFiEEm9B+DgxR+NWWd7dUG5NDfTtB YpsFAmA872oFCRRflLYACgkQG5NDfTtBYpvScw/9GrqBrVLuJoJ52qBBKUBDo4E+5fU1bjt0 Gv0nh/hNJuecuRY6aemU6HOPNc2t8QHMSvwbSF+Vp9ZkOvrM36yUOufctoqON+wXrliEY0J4 ksR89ZILRRAold9Mh0YDqEJc1HmuxYLJ7lnbLYH1oui8bLbMBM8S2Uo9RKqV2GROLi44enVt vdrDvo+CxKj2K+d4cleCNiz5qbTxPUW/cgkwG0lJc4I4sso7l4XMDKn95c7JtNsuzqKvhEVS oic5by3fbUnuI0cemeizF4QdtX2uQxrP7RwHFBd+YUia7zCcz0//rv6FZmAxWZGy5arNl6Vm lQqNo7/Poh8WWfRS+xegBxc6hBXahpyUKphAKYkah+m+I0QToCfnGKnPqyYIMDEHCS/RfqA5 t8F+O56+oyLBAeWX7XcmyM6TGeVfb+OZVMJnZzK0s2VYAuI0Rl87FBFYgULdgqKV7R7WHzwD uZwJCLykjad45hsWcOGk3OcaAGQS6NDlfhM6O9aYNwGL6tGt/6BkRikNOs7VDEa4/HlbaSJo 7FgndGw1kWmkeL6oQh7wBvYll2buKod4qYntmNKEicoHGU+x91Gcan8mCoqhJkbqrL7+nXG2 5Q/GS5M9RFWS+nYyJh+c3OcfKqVcZQNANItt7+ULzdNJuhvTRRdC3g9hmCEuNSr+CLMdnRBY fv0= In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240727_022102_350645_F74867FF X-CRM114-Status: GOOD ( 19.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 27/07/2024 11:17, Arnd Bergmann wrote: > On Sat, Jul 27, 2024, at 10:56, Krzysztof Kozlowski wrote: >> On 27/07/2024 00:59, Roman Kisel wrote: >>> @@ -2338,6 +2372,21 @@ static int vmbus_device_add(struct platform_device *pdev) >>> cur_res = &res->sibling; >>> } >>> >>> + /* >>> + * Hyper-V always assumes DMA cache coherency, and the DMA subsystem >>> + * might default to 'not coherent' on some architectures. >>> + * Avoid high-cost cache coherency maintenance done by the CPU. >>> + */ >>> +#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ >>> + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ >>> + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) >>> + >>> + if (!of_property_read_bool(np, "dma-coherent")) >>> + pr_warn("Assuming cache coherent DMA transactions, no 'dma-coherent' node supplied\n"); >> >> Why do you need this property at all, if it is allways dma-coherent? Are >> you supporting dma-noncoherent somewhere? > > It's just a sanity check that the DT is well-formed. > > Since the dma-coherent property is interpreted by common code, it's > not up to hv to change the default for the platform. I'm not sure > if the presence of CONFIG_ARCH_HAS_SYNC_DMA_* options is the correct > check to determine that an architecture defaults to noncoherent > though, as the function may be needed to do something else. > > The global "dma_default_coherent' may be a better thing to check > for. This is e.g. set on powerpc64, riscv and on specific mips > platforms, but it's never set on arm64 as far as I can tell. Kernel's task is not to validate the DT. Even if it was, above code works poor. What if someone adds 'dma-noncoherent'? The job of the bindings and DT schema is to validate and check DT if is well formed. Best regards, Krzysztof