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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C04FCC433EF for ; Mon, 16 May 2022 10:42:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242750AbiEPKm6 (ORCPT ); Mon, 16 May 2022 06:42:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236543AbiEPKmF (ORCPT ); Mon, 16 May 2022 06:42:05 -0400 Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A653B28 for ; Mon, 16 May 2022 03:42:03 -0700 (PDT) Received: by mail-ed1-x532.google.com with SMTP id c12so3947004eds.10 for ; Mon, 16 May 2022 03:42:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=erbXfCmeHocQjfL+rgDZPz13+JsufODTkqH4MW8FPkU=; b=P77DC0Il8yTtkstHIFJR8Nqlq8byFBHMvwFcvt4Nt22CzyvC/Fv+KdNgonw4S3OD3K 2LvZ1t/0q7xkgaqJ5UbQef9PLfEU7ibZjarM7y30f4syi3XrIkk66bNTygONFoWTGBsW T0zLbcuIOAC9Pea0Sj+b22Ih6ju5PVW+bGFZBfbQIQwsZ2smRedVpMeslKaL1/f8c8ws cpfStIYgXZGpFXthRtvUGpT3DV00iZ9sg3V6xgZDESod1iRqB5UonePNMTjP7uGf8dB4 IBqMuAHh6o186Vqyr9HRq/GyB3509vT7hUFGMlFByEIaa6lwVHd0K6KyZqrr3pKGyAHv dkfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=erbXfCmeHocQjfL+rgDZPz13+JsufODTkqH4MW8FPkU=; b=VsZTZpEMYq7vnAwPfc99al06uv2EMD5QBrt86F+bOB58eM2Duc0cfPS6dA5kVs+roG iLRo6tsvDbOZd9sKdDbrJxc9Mq6OJMuWXX2kdr0Emo7BJNzXBZccUTnyBXz6Dx3OX6Fy cUJ9JDe8Fj7V40ItImVUGJFvmfxGQ/jPKGHbHHK+XAtwi3Xs9O4Vi2d7zHkslBDempL7 vx5Fjc2QYJIb+ld06i7NDowiv+Gu6HrgXBEXGxgmJGmpMBOgTeYqPHqRR1hL6eBppxnv enYadsXR7l2xdGQBVjgxuGKRQiIxO99V7jIga04jhTMwHrPLuypYBhqD1HuAsUYrGSsy Oy8w== X-Gm-Message-State: AOAM531RIkU8lXScZhbE3SVCFVyLdUMwsvkxpxV3KL25xtNxE1z5XKVX DIvefRN61Qmaq5+7yUXtHjIQ+A== X-Google-Smtp-Source: ABdhPJwCmZ7TsADf4yBSO70bp+4Cv2yZYtgdUiE6w+q/M7boOVpmbsE2ZQrGrh1nN3VKR0CPmxFF2w== X-Received: by 2002:a05:6402:2710:b0:427:d087:b with SMTP id y16-20020a056402271000b00427d087000bmr12509532edd.11.1652697721952; Mon, 16 May 2022 03:42:01 -0700 (PDT) Received: from google.com (30.171.91.34.bc.googleusercontent.com. [34.91.171.30]) by smtp.gmail.com with ESMTPSA id ec33-20020a0564020d6100b0042ab48ea729sm1151662edb.88.2022.05.16.03.42.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 May 2022 03:42:01 -0700 (PDT) Date: Mon, 16 May 2022 10:41:58 +0000 From: Quentin Perret To: Marc Zyngier Cc: James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH] KVM: arm64: Don't hypercall before EL2 init Message-ID: References: <20220513092607.35233-1-qperret@google.com> <87sfpb59wj.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87sfpb59wj.wl-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sunday 15 May 2022 at 12:10:20 (+0100), Marc Zyngier wrote: > Can we simplify the condition? ARM64_SPECTRE_V3A is only set when > !VHE, and we already bail in kvm_patch_vector_branch() if we see > VHE+V3A, because the combination makes no sense at all. I think this > can be rewritten as: > > if (kvm_system_needs_idmapped_vectors() && > !is_protected_lvm_enabled()) > > Thoughts? Yup I think this works as both CPUs that are vulnerable to V3A aren't VHE-capable. But if we ever get a VHE-capable CPU that's vulnerable I think the next call to create_hyp_exec_mappings() will BUG(). Perhaps the alternative would be to have has_spectre_v3a() say no in VHE to be on the safe side? That is, prevent the cap from being set to begin with. Cheers, Quentin