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 A30ECC6FD20 for ; Fri, 24 Mar 2023 20:43:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232210AbjCXUnt (ORCPT ); Fri, 24 Mar 2023 16:43:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35566 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232157AbjCXUnr (ORCPT ); Fri, 24 Mar 2023 16:43:47 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6921B5B8F for ; Fri, 24 Mar 2023 13:43:45 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id h4-20020a170902f54400b001a1f5f00f3fso1790785plf.2 for ; Fri, 24 Mar 2023 13:43:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1679690625; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=g9FsH5f+Xb8IXPDsf4Vq2M9YTg13c83UJ3Vl9FncU8A=; b=R1CJAKUEiFUCOywhblEqKTuQ5/frQjfKCPjzY4EmGXnG/FZ8Mvl74UQXykJLT4izLW AC8Ga8LOADJ9jErvWBObdzLpjfKSPgoezDRFEkJI+4xJ5sSwPLpjJcb7SsFf/JZedd4g M44BNIsx8ZTxhshB1B0CI0siKLtgDNfkPvGG7N2Ltv9n6WO9Z8elgJ+MiA3TfoJh/lXb JHYrBxc46scu7edRhrqSNAK8P2K7QTVZz49wi6pdGRicPOuhFPDwlgc/Y5+QUUx66s4L q6FLJj9urtUdO4i5coFLMS/Q3yDAjLJmSNap9VFNAx4RPAoZXofFgNlMgFXkC48AVw93 jQhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679690625; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=g9FsH5f+Xb8IXPDsf4Vq2M9YTg13c83UJ3Vl9FncU8A=; b=n0KaR+7AL3XR5N/UTsaCy/gzdwAmj2GF0AYaNLziaFoCzsSlylaS/DozEihwfAJ7SF +hhxW0bZ1aapFpwhqgvOk5ZN2zX99hyGJM5nC3fdVEctDz04YVZztdV6OUyhn998QA8q XLKuscikgzJqDKpdf2nziJvxZDO9jJmqc5fEIyDiwgMncxqSMmS8NoWlkKcWsgXpAB0d 880wlAgmTJVfWdThidVXB8/ePHDvauIOD/lLSXbdUsf2GR/WvRQo81cTfyztUNJ7Lx0/ 7HPD1uBCW+hglF88/aGLo7FAHT6aYQGPDz7f7MxUkbbH2Q5/XE74VsP6iZl7PJqCX/vg BWKQ== X-Gm-Message-State: AAQBX9f7h5RFM3tcHQFxAMfORL2pYNSqPSqDz3c97YKF+cObqrsC8W47 68VW5gqSAqinwuEoFH22G4B7rPhiR2s= X-Google-Smtp-Source: AKy350Ymjfg+3M3Dv4LBikspPO3ElnhrQ/Ms1LmMDrfGv3OrehR2cc7M3jW6S4kdjDad2P2FdlyI1gKgqVo= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:5141:b0:23d:50d0:4ba4 with SMTP id k1-20020a17090a514100b0023d50d04ba4mr1256858pjm.3.1679690624943; Fri, 24 Mar 2023 13:43:44 -0700 (PDT) Date: Fri, 24 Mar 2023 13:43:43 -0700 In-Reply-To: <20230221163655.920289-12-mizhang@google.com> Mime-Version: 1.0 References: <20230221163655.920289-1-mizhang@google.com> <20230221163655.920289-12-mizhang@google.com> Message-ID: Subject: Re: [PATCH v3 11/13] KVM: selftests: x86: Remove redundant check that XSAVE is supported From: Sean Christopherson To: Mingwei Zhang Cc: Paolo Bonzini , Thomas Gleixner , "H. Peter Anvin" , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Jim Mattson , Venkatesh Srinivas , Aaron Lewis , "Chang S. Bae" , Chao Gao Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 21, 2023, Mingwei Zhang wrote: > From: Aaron Lewis > > In amx_test, userspace requires that XSAVE is supported before running > the test, then the guest checks that it is supported after enabling > AMX. Remove the redundant check in the guest that XSAVE is supported. It's a bit paranoid, but I actually don't mind the extra check. It's not redundant per se, just useless in its current location. If the check is moved _before_ CR4 is set, then it actually provides value, e.g. if something does go sideways, will fire an assert instead of getting a #GP on set_cr4().