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 597D5F4487B for ; Mon, 13 Apr 2026 11:44:42 +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=cGNuEHkArBiNiNVxwIRGSAzaCURMpjmGdsqqc7Hqft0=; b=NM0JXjpV+3R4rVguxk2eDAZ/Xb hocnCdzu1sYzDwPBPnBX91539F0k4lDRgktBv6FC/NSh2+5n4ZxochkG77m4NDkfyeQLy0yw2a8S/ t2znBHCXhHH1mrAl0FmA46vK4kdmMwfcctgM86PK1CwTCseKR8y1r7CkFDjjykKep8EjOGFS2j64/ IMf3tCtF+/umQ0fgHf/lifaV0P15nmijw/Yrnh4e2dP71vAWHusHNZdkY91OY8TroiGjOSu7NRchX c8c1SPxKsWs7gdCBUtm7vDD8ZziZVIVnRTFy+EnGPswUcO+0W62n48cZpbYlb8blNXfsUnkeSfvQE 3I52O9uA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wCFiX-0000000Fac3-1UuY; Mon, 13 Apr 2026 11:44:37 +0000 Received: from linux.microsoft.com ([13.77.154.182]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wCFiU-0000000FabZ-35km; Mon, 13 Apr 2026 11:44:35 +0000 Received: from [192.168.0.106] (unknown [49.205.253.198]) by linux.microsoft.com (Postfix) with ESMTPSA id ED2F320B7128; Mon, 13 Apr 2026 04:44:21 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com ED2F320B7128 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1776080668; bh=cGNuEHkArBiNiNVxwIRGSAzaCURMpjmGdsqqc7Hqft0=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=GdpGvPY6u6Kxlr3Gwj9vd3P3c+ECIc35+EwWAEp1VNH4UT26kmYkva+RZR3iv/Msg uMIxbkofXzjxjwMRBnOSfMzfdKXz8nqUEP5WL2mOZ0gf2qqY16we/vfeRP9v29dxnY GSqaZM25iXA12FMSgbcU8MrMWBs5cmsQkREpOLoM= Message-ID: <7c6e721e-d8e1-45b5-99a3-a8104c212983@linux.microsoft.com> Date: Mon, 13 Apr 2026 17:14:16 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 01/11] arch: arm64: Export arch_smp_send_reschedule for mshv_vtl module To: Michael Kelley , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "x86@kernel.org" , "H . Peter Anvin" , Arnd Bergmann , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti Cc: Marc Zyngier , Timothy Hayes , Lorenzo Pieralisi , mrigendrachaubey , "ssengar@linux.microsoft.com" , "linux-hyperv@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-riscv@lists.infradead.org" References: <20260316121241.910764-1-namjain@linux.microsoft.com> <20260316121241.910764-2-namjain@linux.microsoft.com> Content-Language: en-US From: Naman Jain In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260413_044434_818311_8E7B545A X-CRM114-Status: GOOD ( 15.78 ) 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 4/1/2026 10:24 PM, Michael Kelley wrote: > From: Naman Jain Sent: Monday, March 16, 2026 5:13 AM >> > > Nit: For the patch "Subject", the most common prefix for the file > arch/arm64/kernel/smp.c is "arm64: smp:". I'd suggest using that > prefix for historical consistency. Acked. Will change in v2. > >> mshv_vtl_main.c calls smp_send_reschedule() which expands to >> arch_smp_send_reschedule(). When CONFIG_MSHV_VTL=m, the module cannot >> access this symbol since it is not exported on arm64. >> >> smp_send_reschedule() is used in mshv_vtl_cancel() to interrupt a vCPU >> thread running on another CPU. When a vCPU is looping in >> mshv_vtl_ioctl_return_to_lower_vtl(), it checks a per-CPU cancel flag >> before each VTL0 entry. Setting cancel=1 alone is not enough if the >> target CPU thread is sleeping - the IPI from smp_send_reschedule() kicks >> the remote CPU out of idle/sleep so it re-checks the cancel flag and >> exits the loop promptly. >> >> Other architectures (riscv, loongarch, powerpc) already export this >> symbol. Add the same EXPORT_SYMBOL_GPL for arm64. This is required >> for adding arm64 support in MSHV_VTL. >> >> Signed-off-by: Naman Jain >> --- >> arch/arm64/kernel/smp.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c >> index 1aa324104afb..26b1a4456ceb 100644 >> --- a/arch/arm64/kernel/smp.c >> +++ b/arch/arm64/kernel/smp.c >> @@ -1152,6 +1152,7 @@ void arch_smp_send_reschedule(int cpu) >> { >> smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); >> } >> +EXPORT_SYMBOL_GPL(arch_smp_send_reschedule); >> >> #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL >> void arch_send_wakeup_ipi(unsigned int cpu) >> -- >> 2.43.0 >> > > The "Subject" nit notwithstanding, > > Reviewed-by: Michael Kelley Thanks, Naman