From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 F113B3EDAB3; Wed, 15 Jul 2026 15:44:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784130299; cv=none; b=etZHj7mbzUfEbCAh2VMP9b2C9lv/vxCkYiXmtyFw0Yp8kkhgkqkq1R/ziWxJpfdpo6ynlwiEHDwqc05nE6MYqadMlpTtuYBRpH45gYSrnG8PI4CiIPlFQpecBZoj7Wg2fALSrUgLs69rwLK6QElfhkNyEIdD625ol8WXzGsmo38= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784130299; c=relaxed/simple; bh=OV68crIr086whsjEANXs+13UCKCVMq/8FeONoVgg8Dk=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=aJAD+PVh1pssD7r4QjkqcvQEtTKQjBnph1m51Q9lIe3k7SDmkp1kmkPUlGUNJukJBMTPDBbuVXppZT+IK4veeiT3ABdRQlXdldrqkWeyC9dyxB4XczPSoUxqg4babkd3Y9Aem0YUf6quTqtF6xkX5vbEzDp5ewFQhrAM7kVvJH0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Lsv8Xsar; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Lsv8Xsar" 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) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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.