From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E594D2D12E4; Fri, 29 Aug 2025 11:38:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756467516; cv=none; b=BdlGWR2q+WawGM45zZ+CDMMYxPP0RjqP8wTGkrvJ9S+++J84e7RZoTSjz3QoHt+6aZ0Kt1lb9F8iBz7x9KvinWhpRQrUqv44ahs2YRlgI8wmKPuJMAZVHfSy+JXNU5RtR3Qf48iXsHthO738rXghH8540725gEYmQksYJZZGZMQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756467516; c=relaxed/simple; bh=RbED3PlV9vYyuIZxS54jBVlU5JqZD372U4HX1JRVHlA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bZLfKAaktxX8OpWS4drDEEBLsatuT9r44XHrxMZQLVkkwg8lQ4n2hrbm3NvROY5jLodlNaqPqpDzI1ieRC1kUMtx5fiuu+moRwe+hvdz851rs1cxu3m0YwYnL8oYTS/9U2+DGqT19DR9nzvlmszeiHr+hPrl6SEeCRQBypp9CWs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 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> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250820145606.180644-3-steven.price@arm.com> 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