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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8EF9C25B08 for ; Wed, 17 Aug 2022 14:40:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240385AbiHQOkX (ORCPT ); Wed, 17 Aug 2022 10:40:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240297AbiHQOkG (ORCPT ); Wed, 17 Aug 2022 10:40:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 633B87330C for ; Wed, 17 Aug 2022 07:39:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B235F614EC for ; Wed, 17 Aug 2022 14:39:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1AA31C433C1; Wed, 17 Aug 2022 14:39:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660747166; bh=D2F5rhQcvdQNsiT8HtBPBvUKoSwn9XOVx+QjpXWS2Bw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=N0tg25bb4yMVbc2/THbcZW6YZykHnEAvJ25bUxovHiM35NM3GrgF6VWqxAa5cbn6h iPxzqoNhqR/D23BBn3UaIWPe/+MrNiaUMcFTzrAWvJqjJzH/qwITp0K3feYHru+Kcd SMp90lCO0If5gfJjS3fEpfLW+PdpcBthUGRK0fOtEF8HbpFvAyqT9Z/WjYYPb7vI9o ig/SmCQU0s9LYO22TstjwWjAOov1nCMFmHuonI5SDpIpoJZGMPYMad53jjfaxE93S+ OXP9UyTBOmeuYzGImmAc0LG0hgUkB9COA39grfwiTb+rtqXEEeN2PghkTZ6TjjKblG 7gq06Qurh5nSQ== Date: Wed, 17 Aug 2022 22:30:07 +0800 From: Jisheng Zhang To: Palmer Dabbelt Cc: atishp@atishpatra.org, ajones@ventanamicro.com, linux-riscv@lists.infradead.org, kvm-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, daolu@rivosinc.com, Conor.Dooley@microchip.com, re@w6rz.net, apatel@ventanamicro.com Subject: Re: [PATCH] riscv: Ensure isa-ext static keys are writable Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 16, 2022 at 09:29:36PM -0700, Palmer Dabbelt wrote: > On Tue, 16 Aug 2022 16:41:46 PDT (-0700), atishp@atishpatra.org wrote: > > On Tue, Aug 16, 2022 at 9:31 AM Andrew Jones wrote: > > > > > > riscv_isa_ext_keys[] is an array of static keys used in the unified > > > ISA extension framework. The keys added to this array may be used > > > anywhere, including in modules. Ensure the keys remain writable by > > > placing them in the data section. > > > > > > The need to change riscv_isa_ext_keys[]'s section was found when the > > > kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv: > > > add Zihintpause support") adds a static branch check for a newly > > > added isa-ext key to cpu_relax(), which kvm uses. > >> > > > > > Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions") > > > Signed-off-by: Andrew Jones > > > > > --- > > > arch/riscv/kernel/cpufeature.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c > > > index 553d755483ed..3b5583db9d80 100644 > > > --- a/arch/riscv/kernel/cpufeature.c > > > +++ b/arch/riscv/kernel/cpufeature.c > > > @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly; > > > /* Host ISA bitmap */ > > > static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly; > > > > > > -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX); > > > +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX); > > > EXPORT_SYMBOL(riscv_isa_ext_keys); > > > > > > /** > > > -- > > > 2.37.1 > > > > > > > > > -- > > > kvm-riscv mailing list > > > kvm-riscv@lists.infradead.org > > > http://lists.infradead.org/mailman/listinfo/kvm-riscv > > > > Thanks for the quick fix. Tested with kvm guests booting in Qemu. > > > > Tested-by: Atish Patra Reviewed-by: Jisheng Zhang Thanks for catching the bug in my code. > > Thanks, I hadn't realized how static keys work but looks like having them as > __ro_after_init was always bogus. Sorry to break stuff, looks like I should be Sorry for breaking the static isa extension key usage in modules. It's a good idea to make them readonly, but need to cope with the usage in module properly. This may be a good improvement item. > loading some module (probably KVM, as it's in the defconfig) during testing. > > This is on fixes, I'm planning on sending it up later this week.