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Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqfgp-0000000FdID-3Ui5; Fri, 07 Mar 2025 21:57:07 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqffD-0000000FcxW-07UN for linux-arm-kernel@lists.infradead.org; Fri, 07 Mar 2025 21:55:28 +0000 Received: from [192.168.35.166] (c-24-22-154-137.hsd1.wa.comcast.net [24.22.154.137]) by linux.microsoft.com (Postfix) with ESMTPSA id E30EB2038F3B; Fri, 7 Mar 2025 13:55:23 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com E30EB2038F3B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1741384524; bh=BYiqT5jddIJjKfv2s/zeQhMm81+sjONX7rRhWau6sX8=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=SnZFHeoT4mDZsn5Rlyo65kO8j7OrCyFjXp+yUsoaUMwBj04Pv8Hr4YbS0zY1M5JBI KzbKWXQF8/IhMnTVs9LQmBaZigJf+/bNz8HHHuNKFlreUORpgb5AXo51iKtcbOmmA6 dV2IMIxGY2uY01fbJKBPdec4cij7cYKcHmJG8rSE= Message-ID: <9cd97b0e-dfd3-4923-961e-00ba09eb6cef@linux.microsoft.com> Date: Fri, 7 Mar 2025 13:55:22 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: Michael Kelley , eahariha@linux.microsoft.com, "linux-hyperv@vger.kernel.org" , "x86@kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "kys@microsoft.com" , "haiyangz@microsoft.com" , "wei.liu@kernel.org" , "decui@microsoft.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "hpa@zytor.com" , "daniel.lezcano@linaro.org" , "joro@8bytes.org" , "robin.murphy@arm.com" , "arnd@arndb.de" , "jinankjain@linux.microsoft.com" , "muminulrussell@gmail.com" , "skinsburskii@linux.microsoft.com" , "mrathor@linux.microsoft.com" , "ssengar@linux.microsoft.com" , "apais@linux.microsoft.com" , "Tianyu.Lan@microsoft.com" , "stanislav.kinsburskiy@gmail.com" , "gregkh@linuxfoundation.org" , "vkuznets@redhat.com" , "prapal@linux.microsoft.com" , "muislam@microsoft.com" , "anrayabh@linux.microsoft.com" , "rafael@kernel.org" , "lenb@kernel.org" , "corbet@lwn.net" Subject: Re: [PATCH v5 03/10] arm64/hyperv: Add some missing functions to arm64 To: Nuno Das Neves References: <1740611284-27506-1-git-send-email-nunodasneves@linux.microsoft.com> <1740611284-27506-4-git-send-email-nunodasneves@linux.microsoft.com> <5f3d660d-fe2e-4ac1-94a7-66d6c8ffe579@linux.microsoft.com> <2fee888a-4f81-40aa-9545-617a49a7fb30@linux.microsoft.com> <7f689725-f676-4465-974d-ca2477d445f7@linux.microsoft.com> From: Easwar Hariharan Content-Language: en-US In-Reply-To: <7f689725-f676-4465-974d-ca2477d445f7@linux.microsoft.com> 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-20250307_135527_146374_50A90A2B X-CRM114-Status: GOOD ( 19.25 ) 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 3/7/2025 1:36 PM, Nuno Das Neves wrote: > On 3/6/2025 11:05 AM, Michael Kelley wrote: >> From: Nuno Das Neves Sent: Thursday, February 27, 2025 4:21 PM >>> >>> On 2/26/2025 9:56 PM, Easwar Hariharan wrote: >>>> On 2/26/2025 3:07 PM, Nuno Das Neves wrote: >>>>> These non-nested msr and fast hypercall functions are present in x86, >>>>> but they must be available in both architetures for the root partition >>>> >>>> nit: *architectures* >>>> >>>> >>> Thanks! >>> >>>>> driver code. >>>>> >>>>> Signed-off-by: Nuno Das Neves >>>>> --- >>>>> arch/arm64/hyperv/hv_core.c | 17 +++++++++++++++++ >>>>> arch/arm64/include/asm/mshyperv.h | 12 ++++++++++++ >>>>> include/asm-generic/mshyperv.h | 2 ++ >>>>> 3 files changed, 31 insertions(+) >>>>> >>>>> diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c >>>>> index 69004f619c57..e33a9e3c366a 100644 >>>>> --- a/arch/arm64/hyperv/hv_core.c >>>>> +++ b/arch/arm64/hyperv/hv_core.c >>>>> @@ -53,6 +53,23 @@ u64 hv_do_fast_hypercall8(u16 code, u64 input) >>>>> } >>>>> EXPORT_SYMBOL_GPL(hv_do_fast_hypercall8); >>>>> >>>>> +/* >>>>> + * hv_do_fast_hypercall16 -- Invoke the specified hypercall >>>>> + * with arguments in registers instead of physical memory. >>>>> + * Avoids the overhead of virt_to_phys for simple hypercalls. >>>>> + */ >>>>> +u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2) >>>>> +{ >>>>> + struct arm_smccc_res res; >>>>> + u64 control; >>>>> + >>>>> + control = (u64)code | HV_HYPERCALL_FAST_BIT; >>>>> + >>>>> + arm_smccc_1_1_hvc(HV_FUNC_ID, control, input1, input2, &res); >>>>> + return res.a0; >>>>> +} >>>>> +EXPORT_SYMBOL_GPL(hv_do_fast_hypercall16); >>>>> + >>>> >>>> I'd like this to have been in arch/arm64/include/asm/mshyperv.h like its x86 >>>> counterpart, but that's just my personal liking of symmetry. I see why it's here >>>> with its slow and 8-byte brethren. >>>> >>> Good point, I don't see a good reason this can't be in the header. >> >> I was trying to remember if there was some reason I originally put >> hv_do_hypercall() and hv_do_fast_hypercall8() in the .c file instead of >> the header like on x86. But I don't remember a reason. During >> development, the code changed several times, and there might have >> been a reason that didn't persistent in the version that was finally >> accepted upstream. >> >> My only comment is that hv_do_hypercall() and the 8 and 16 "fast" >> versions should probably stay together one place on the arm64 side, >> even if it doesn't match x86. >> > > I think I'll just keep them together here for now then. They > could be moved to the header in future if it seems worth doing. > I was really hoping the answer here would be to move all of them together to the header, but oh well.