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 B8EF6CA0FFD for ; Fri, 29 Aug 2025 15:43:39 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0HrNfo7K/g/yRUVVZCoI6en15lH4Fbz8rJFY8DPc1N8=; b=QdFeemnHmFR6hoBpcyuJWZ9Vwx qHXKt3CKQByx34mFN1kbMFlEGvGZ/Ma4QfVOMJRcB+cipMVS5DTkzM4+ury9I8zz8iK8IjEU0yoLn X2jNqGUbmtiJmHEGqRHu86zKs8FsxIydwTh582SqwZqt15ffxPKmCCcMxVK6+HkurrwtyxrM3b2Xf UBiq9SF4vrqCGBa3hv0k7yQ1ecVF57/7ybE3MQsA9g5X+ZFeSYP2V0GVe+R54mabHXwfvFYaNeD9C ZvZ3Vlp2zrFewlyRnDzaciM96ysvKJ+B0iCi1NeQgA0jWTpMicPhOmKrFWmjxhyk8HJV12Tg0led5 cX+dn53Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1us1G8-00000006FFA-0peC; Fri, 29 Aug 2025 15:43:24 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1urxRE-00000005VRJ-1FiA for linux-arm-kernel@lists.infradead.org; Fri, 29 Aug 2025 11:38:37 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 8C3A645280; Fri, 29 Aug 2025 11:38:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A227BC4CEF1; Fri, 29 Aug 2025 11:38:31 +0000 (UTC) Date: Fri, 29 Aug 2025 12:38:29 +0100 From: Catalin Marinas To: Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Marc Zyngier , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve Subject: Re: [PATCH v10 02/43] arm64: RME: Handle Granule Protection Faults (GPFs) Message-ID: References: <20250820145606.180644-1-steven.price@arm.com> <20250820145606.180644-3-steven.price@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250820145606.180644-3-steven.price@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250829_043836_356073_DF3CB1AD X-CRM114-Status: GOOD ( 22.46 ) 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 Wed, Aug 20, 2025 at 03:55:22PM +0100, Steven Price wrote: > If the host attempts to access granules that have been delegated for use > in a realm these accesses will be caught and will trigger a Granule > Protection Fault (GPF). > > A fault during a page walk signals a bug in the kernel and is handled by > oopsing the kernel. A non-page walk fault could be caused by user space > having access to a page which has been delegated to the kernel and will > trigger a SIGBUS to allow debugging why user space is trying to access a > delegated page. > > Reviewed-by: Suzuki K Poulose > Reviewed-by: Gavin Shan > Signed-off-by: Steven Price > --- > Changes since v2: > * Include missing "Granule Protection Fault at level -1" > --- > arch/arm64/mm/fault.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index d816ff44faff..e4237637cd8f 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -854,6 +854,25 @@ static int do_tag_check_fault(unsigned long far, unsigned long esr, > return 0; > } > > +static int do_gpf_ptw(unsigned long far, unsigned long esr, struct pt_regs *regs) > +{ > + const struct fault_info *inf = esr_to_fault_info(esr); > + > + die_kernel_fault(inf->name, far, esr, regs); > + return 0; > +} This is fine, it's irrelevant whether the fault happened at EL0 or EL1. > +static int do_gpf(unsigned long far, unsigned long esr, struct pt_regs *regs) > +{ > + const struct fault_info *inf = esr_to_fault_info(esr); > + > + if (!is_el1_instruction_abort(esr) && fixup_exception(regs, esr)) > + return 0; > + > + arm64_notify_die(inf->name, regs, inf->sig, inf->code, far, esr); > + return 0; > +} The end result is somewhat similar but why not just return 1 and avoid the arm64_notify_die() call? Let do_mem_abort() handle the oops vs user signal. With die_kernel_fault() we print the "Unable to handle kernel..." message and some more information. -- Catalin