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 0469E3E5EEC; Tue, 6 Oct 2026 08:47:29 +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=1791276451; cv=none; b=GcvkJqzQfbWIrR84jDx8OGaSkTrr9qWKP1ABy+gGcwSirpOGjc6C2ep06z/u3VrP71sBLVHH8kVV+CFyrDsGdDXHeZ4XE3gNKVLG67NmnxHPJJK+GEoETWeBRRGSJ4uaVJP06TwfnSnUIzYbKy05z6G6sbf2cI8F+okKhdbYkbM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791276451; c=relaxed/simple; bh=rgP0MkX2WPTW6UmkASwpgVPkkaUtV2XiRPw3eu7FjL0=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=PjmG7TxHYqX2wUKlDQfmpBnQ2KPMX+jW3D9+FjQ1eQwAPFTpbel4eu+dMWzpl6GUKTAQMgUeB28GLyVeRGn1NacbH6GcDqr/gasDtX3/D5ftdwcxZIQqBMLcGTQwsy2s86KHWcxL8SmyAI5xef3gj7Lc/NIte7l8PbkcDlXOUWg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lF09HEqh; 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="lF09HEqh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2CBA1F000FF; Tue, 6 Oct 2026 08:47:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791276449; bh=VKhn4EloVtEWtPSbv6ns+F1in9VJjNcsDUeazF9vXNI=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=lF09HEqhTUOX4gf5PoapSj7ESItyOnLZXWFhTvZSG2oxLhrVcYgi8epP8Du/Gy9g1 vaZ/+yqk/ZIvHc6NNq0xWzOi7i6hzH/0pgu4o7lK/JkxbdxEtt32OssV+2snJ6A3mw SYHGk08Bggi01O4zObeNXuqeXjI1jhWyPxtf9LhPtAJUczh4Lw7QrhC/Ar8KkHa9G6 8UqTU+/3MihjgKGf+wmYmyOoob7Sn242ROgnjDLwJKH/78k/oqRGF8vnoBgsefOlN1 +1xEZiGhQe1kQCJX0UXwOc+jjsPMFntejjoCyION0h1UxSIEwPEra8i7JtXCJwnv/0 omOjOeABKDhag== Received: from sofa.misterjones.org ([185.219.108.64] 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 1xE0pa-0000000HLcV-3RVB; Tue, 06 Oct 2026 08:47:27 +0000 Date: Tue, 06 Oct 2026 09:50:33 +0100 Message-ID: <87bj972ox2.wl-maz@kernel.org> From: Marc Zyngier To: Suzuki K Poulose Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.com Subject: Re: [PATCH v22 09/23] KVM: arm64: Prevent unsupported vcpu features for VM types In-Reply-To: <20261005090754.2140522-10-suzuki.poulose@arm.com> References: <20261005090754.2140522-1-suzuki.poulose@arm.com> <20261005090754.2140522-10-suzuki.poulose@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: 185.219.108.64 X-SA-Exim-Rcpt-To: suzuki.poulose@arm.com, kvm@vger.kernel.org, kvmarm@lists.linux.dev, will@kernel.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, steven.price@arm.com, aneesh.kumar@kernel.org, oupton@kernel.org, gshan@redhat.com, joey.gouly@arm.com, tabba@google.com, yuzenghui@huawei.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, sdonthineni@nvidia.com, alpergun@google.com, fj0570is@fujitsu.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org, enju.kohei@fujitsu.com, sudeep.holla@arm.com, jonathan.cameron@oss.qualcomm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Mon, 05 Oct 2026 10:07:40 +0100, Suzuki K Poulose wrote: > > Prevent unsupported VCPU features for the protected VCPUs. Realms and pVMs > not support 32bit EL1 or NV yet. pKVM doesn't rely on the host vcpu > features and it clears the unsupported features while hyp_vcpu is > initialised. Block the features early in the vcpu init if we detect > incompatible features. > > Signed-off-by: Suzuki K Poulose > --- > arch/arm64/kvm/arm.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index f31d31fa27ad9..9c2ef7ca6a961 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -1668,11 +1668,12 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, > return -EINVAL; > } > > -static unsigned long system_supported_vcpu_features(void) > +static unsigned long system_supported_vcpu_features(struct kvm_vcpu *vcpu) > { > unsigned long features = KVM_VCPU_VALID_FEATURES; > > - if (!cpus_have_final_cap(ARM64_HAS_32BIT_EL1)) > + if (vcpu_is_protected(vcpu) || > + !cpus_have_final_cap(ARM64_HAS_32BIT_EL1)) > clear_bit(KVM_ARM_VCPU_EL1_32BIT, &features); > This looks a bit daft. Why don't you simply use different base feature sets for the various backends? The nothing else need to change. M. -- Jazz isn't dead. It just smells funny.