Received: by 2002:a05:6a10:f3d0:0:0:0:0 with SMTP id a16csp240465pxv; Thu, 24 Jun 2021 07:01:14 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxcscHDPr5c/KZW/kxbe53SftveOrFAD+ojwFwJfdw5IYnn4ZCkqkSIMiCPLBDfEBnzDJF0 X-Received: by 2002:a17:906:a108:: with SMTP id t8mr5355538ejy.407.1624543273879; Thu, 24 Jun 2021 07:01:13 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1624543273; cv=none; d=google.com; s=arc-20160816; b=MdjdzSozZjnEs24Oeco24xQaYokVrZuK6E5POtt0rMRnfG6CAzcdSDTYaUEkpxHF4q NMP4Pxh6iTVOWrZ6lJUpjzQ0X9T21g6EfwuREf2NpeelhlerN95nHJZ7FiOFLZ8e3zTI cIe3mpw6NP69vjxqMmc+AC70NegFcOt43cT3gZDDGIfVTqStCQIm5EE0zMq4sJSrOUK1 CnLo5te9zncUKbJx+jo0iLIG4hm5TQk781XSujw8JoDpztJxKxm6/9uCiR6ih8bNX6oc eHN3eN2aZtepMxgqh54gWU9bc5xtc89uI85vCIiC/DNEKop5AwOqsEPmKKcVKKmvgmNx wQnw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version:date :message-id:subject:references:in-reply-to:cc:to:from; bh=Zkvqv8mdLSwrXN4xCM2ENUUtQ3I2UydmzWHEfQeb5wQ=; b=gT9gOH2bhjrXJBrEQ/EEJFGLCCcNC9XNLdl6rKk7Q032p8anXC9JKK1y2qIYFy/bL6 aYKApDKLLrLzIXizqNqxlbRA1DJMNdSdZzBF3aPeLAIVbMxviPECzmKG06GInEPjWujE Vd5xU6WgBO7Db+GJnQKO0eY5S02TYAlbFiUBKiwW7voi1I04rXUKtxnk6fNxwQWiOmTO nUIlxsgPNpWuXKUw09/akwxz9nWlrUPTzvCaeWMCaC8HBRuDBiX0EX8vkKAvdsrLdlcx LlxD/b1DrBUyeFH8PDoz0FxVOjp6q3WE2tSPJIqYpvL3WKhebsbyMP+p0TrzobFZ8umq uSkg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id 13si2846557ejg.731.2021.06.24.07.00.48; Thu, 24 Jun 2021 07:01:13 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230087AbhFXOCN (ORCPT + 99 others); Thu, 24 Jun 2021 10:02:13 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:38331 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229878AbhFXOCN (ORCPT ); Thu, 24 Jun 2021 10:02:13 -0400 Received: by ozlabs.org (Postfix, from userid 1034) id 4G9hbD5jzzz9sVt; Thu, 24 Jun 2021 23:59:52 +1000 (AEST) From: Michael Ellerman To: Paul Mackerras , Michael Ellerman , Nathan Chancellor Cc: kernel test robot , Nicholas Piggin , clang-built-linux@googlegroups.com, kvm-ppc@vger.kernel.org, Arnd Bergmann , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Benjamin Herrenschmidt , Nick Desaulniers In-Reply-To: <20210621182440.990242-1-nathan@kernel.org> References: <20210621182440.990242-1-nathan@kernel.org> Subject: Re: [PATCH] KVM: PPC: Book3S HV: Workaround high stack usage with clang Message-Id: <162454315620.2927609.2836123364412705213.b4-ty@ellerman.id.au> Date: Thu, 24 Jun 2021 23:59:16 +1000 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Jun 2021 11:24:40 -0700, Nathan Chancellor wrote: > LLVM does not emit optimal byteswap assembly, which results in high > stack usage in kvmhv_enter_nested_guest() due to the inlining of > byteswap_pt_regs(). With LLVM 12.0.0: > > arch/powerpc/kvm/book3s_hv_nested.c:289:6: error: stack frame size of > 2512 bytes in function 'kvmhv_enter_nested_guest' [-Werror,-Wframe-larger-than=] > long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu) > ^ > 1 error generated. > > [...] Applied to powerpc/topic/ppc-kvm. [1/1] KVM: PPC: Book3S HV: Workaround high stack usage with clang https://git.kernel.org/powerpc/c/51696f39cbee5bb684e7959c0c98b5f54548aa34 cheers