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 CE4CDC433FE for ; Fri, 14 Oct 2022 20:04:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229968AbiJNUEt (ORCPT ); Fri, 14 Oct 2022 16:04:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34078 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229491AbiJNUEo (ORCPT ); Fri, 14 Oct 2022 16:04:44 -0400 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4FD6EC67 for ; Fri, 14 Oct 2022 13:04:38 -0700 (PDT) Received: by mail-pg1-x531.google.com with SMTP id u71so5247108pgd.2 for ; Fri, 14 Oct 2022 13:04:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=kbwkanpKDCzBUU6gmctb+QrCeHgMxWi09XjJZDjO5eQ=; b=X/8GV42PFEbwb1G42LBdmwiFnIlQkobhhcbf2afrVFAK/kAzcsrOrlGPim+kJih52X YEK9xn2aX6LsCZGwuadCycmbegoWPQD/TLpE4JOZDawCpM6yoovy4D+vbxkNNzK2bZ21 exkd6HtoXl7jie6ASLErpWPPxFqfelw3JeWKiuJjWIXClxMXVe0zl+f5Ob/DcEXoRqQG 5hrPH8uYnrRbMADhWTWiowZP49+fF6B4VtMJ5drYYBZEBIyiPdB2J+uoQnt/aDCDpxI6 bwIZmYKOLSn7ZXAHq8nLORAGhHIgfO7G8z0mfZzr9aVgi3FFCikocklfxoLkFTrgrXS7 vNcA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=kbwkanpKDCzBUU6gmctb+QrCeHgMxWi09XjJZDjO5eQ=; b=PAS9R8CX7/0MZ34U7vty7qk3u5YxjSGZ1AR7WlLYFzEJfhHvPurHgqoziv4JNlhR6v QQG+jJ1VZSj3gO2TQWrL7S2Ujno8LaMNBi5rC6p/Z+2gbdv96Lf0Gzpz0AdXi9EFDrrc WHs37xXAiz2l52naUZFhaQDv1OE7N8QQcLqn44GmQrpG7H3uritxyw5yCJgb8DDMwhXi vsVZlFTcnwkScWw07kfDaQV0lzfom/F3vDF7hquJnM8lUJ9qWpuAY6fgKr54GKzCj6ys j55HFdryFPdwdFIoFLytGdIpBRr9xduEu+3JoK6lmuPjCUfFE0Zo8JSZZgoIQQJAcYn8 DVUg== X-Gm-Message-State: ACrzQf10IxOanP+03+V9Da5/cS7g6zAYN/ed6jxiMk+MiVRdTZhjnzWM 34KeLotzCTXFHJc9NRf6rHSj6w== X-Google-Smtp-Source: AMsMyM7EBrEJiEtubCYTKLnlZSzu9M+zSixvrqFOxZtlxIoJYG4IoVQpLoMoGVuCpNVtnXuZY+vYvg== X-Received: by 2002:a62:1482:0:b0:55f:eb9a:38b2 with SMTP id 124-20020a621482000000b0055feb9a38b2mr7003442pfu.29.1665777877646; Fri, 14 Oct 2022 13:04:37 -0700 (PDT) Received: from google.com (7.104.168.34.bc.googleusercontent.com. [34.168.104.7]) by smtp.gmail.com with ESMTPSA id g18-20020aa79dd2000000b0056149203b60sm2136445pfq.46.2022.10.14.13.04.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Oct 2022 13:04:37 -0700 (PDT) Date: Fri, 14 Oct 2022 20:04:32 +0000 From: Sean Christopherson To: Vitaly Kuznetsov Cc: kvm@vger.kernel.org, Paolo Bonzini , Wanpeng Li , Jim Mattson , Michael Kelley , Maxim Levitsky , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 0/7] KVM: x86: Hyper-V invariant TSC control feature Message-ID: References: <20221013095849.705943-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221013095849.705943-1-vkuznets@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 13, 2022, Vitaly Kuznetsov wrote: > Normally, genuine Hyper-V doesn't expose architectural invariant TSC > (CPUID.80000007H:EDX[8]) to its guests by default. A special PV MSR > (HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x40000118) and corresponding CPUID > feature bit (CPUID.0x40000003.EAX[15]) were introduced. When bit 0 of the > PV MSR is set, invariant TSC bit starts to show up in CPUID. When the > feature is exposed to Hyper-V guests, reenlightenment becomes unneeded. > > Note: strictly speaking, KVM doesn't have to have the feature as exposing > raw invariant TSC bit (CPUID.80000007H:EDX[8]) also seems to work for > modern Windows versions. The feature is, however, tiny and straitforward > and gives additional flexibility so why not. > > Vitaly Kuznetsov (7): > x86/hyperv: Add HV_EXPOSE_INVARIANT_TSC define > KVM: x86: Add a KVM-only leaf for CPUID_8000_0007_EDX > KVM: x86: Hyper-V invariant TSC control > KVM: selftests: Rename 'msr->available' to 'msr->fault_exepected' in > hyperv_features test > KVM: selftests: Convert hyperv_features test to using > KVM_X86_CPU_FEATURE() > KVM: selftests: Test that values written to Hyper-V MSRs are preserved > KVM: selftests: Test Hyper-V invariant TSC control For the series, in case Paolo ends up grabbing this: Reviewed-by: Sean Christopherson