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 F29F5C44501 for ; Wed, 15 Jul 2026 15:45:05 +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-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID: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=oScIehFNLVV6Ks2K1Q/+8RY9UPPqDbzPiGCzLfB1ONk=; b=uIgjddl2hvQidPwW3xHcxnUr1e vYPxHmf0FJ4nuss8q3X4aaSFM+/eczb7UjIX2Dlfo7hPqyt4m0A2gwM/li4STzhOoGrWQFGMW4lqq NGRQ2WkJBKeREcjMcKyoJn6qyVxclqraoUCTTENtaAyYiMV6NxJPBP2LwZYCYrpVKYbHgyWF1GJJ9 PU57GRfLnY35sdedrR0XlBeOV+OtkwyTXuYXy8OM0PkTHdctRZDy//+205GG1OkAKl5qZIFn/fkHE 2FO15qcGYXS3cVIWdDVJKgPWb7aks91OVsRvy4YYwuMJKjFj6DkGbhzuuIm+GvRIHpGEx4HHV4Hoi ZDtim0hg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wk1n9-0000000FM3g-2QK7; Wed, 15 Jul 2026 15:44:59 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wk1n8-0000000FM3F-2f2p for linux-arm-kernel@lists.infradead.org; Wed, 15 Jul 2026 15:44:58 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id C9B9F6001D; Wed, 15 Jul 2026 15:44:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7ACC11F000E9; Wed, 15 Jul 2026 15:44:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784130297; bh=oScIehFNLVV6Ks2K1Q/+8RY9UPPqDbzPiGCzLfB1ONk=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=Lsv8XsarAjwRmT5pSLAM4xb1jKVASVgI//6qChlF8vms9nalzS+IYOPSadkp231pZ n14OOb+e1+fDZBasxdyAFtLYFQwZt1Tja85uQMBP5SNG5djGBGnRdhp1KApA3g9PxW B6MXHob+FpM6M3l0pFN3mwQa1R/TETjfNnuurjVsqkkoSpzECfZtMtAwe5dKHxqLRU v/ydBeczqHpCCgZVPdTWUFemud7sFswPzBTeaG2gZQUvmvma+KXXbqSymx3VaipF/m 8PwZHALsLm0utsRH5IFDl51iKYHmyu9WeizolTYBTCOSijJfwUQ8tiggmcNpA6ptg7 Q/uy/ua42au1A== Received: from [194.56.92.2] (helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wk1n5-00000005NeP-1TpK; Wed, 15 Jul 2026 15:44:55 +0000 Date: Wed, 15 Jul 2026 16:46:44 +0100 Message-ID: <8733xk5k7v.wl-maz@kernel.org> From: Marc Zyngier To: Steven Price Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , 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 , WeiLin.Chang@arm.com, Lorenzo Pieralisi Subject: Re: [PATCH v15 26/37] KVM: arm64: WARN on injected undef exceptions In-Reply-To: <20260715142841.80544-27-steven.price@arm.com> References: <20260715142841.80544-1-steven.price@arm.com> <20260715142841.80544-27-steven.price@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 194.56.92.2 X-SA-Exim-Rcpt-To: steven.price@arm.com, kvm@vger.kernel.org, kvmarm@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, oliver.upton@linux.dev, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, joey.gouly@arm.com, alexandru.elisei@arm.com, christoffer.dall@arm.com, tabba@google.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, gshan@redhat.com, sdonthineni@nvidia.com, alpergun@google.com, aneesh.kumar@kernel.org, fj0570is@fujitsu.com, vannapurve@google.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false 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, 15 Jul 2026 15:28:28 +0100, Steven Price wrote: > > The RMM doesn't allow injection of a undefined exception into a realm > guest. Add a WARN to catch if this ever happens. > > Signed-off-by: Steven Price > Reviewed-by: Gavin Shan > Reviewed-by: Suzuki K Poulose > --- > Changes since v6: > * if (x) WARN(1, ...) makes no sense, just WARN(x, ...)! > --- > arch/arm64/kvm/inject_fault.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c > index 6492397b73d7..613f223bc7a3 100644 > --- a/arch/arm64/kvm/inject_fault.c > +++ b/arch/arm64/kvm/inject_fault.c > @@ -327,6 +327,7 @@ void kvm_inject_size_fault(struct kvm_vcpu *vcpu) > */ > void kvm_inject_undefined(struct kvm_vcpu *vcpu) > { > + WARN(vcpu_is_rec(vcpu), "Unexpected undefined exception injection to REC"); > if (vcpu_el1_is_32bit(vcpu)) > inject_undef32(vcpu); > else No. WARN_ONCE at a push, but even then, this looks dodgy. Exceptions must be injectable. Otherwise, how do you respond to, for example, a sysreg access for a feature that is hidden from the guest? Will the RMM perform this in KVM's stead? M. -- Jazz isn't dead. It just smells funny.