From nobody Mon Feb 9 12:08:42 2026 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BCCF29406 for ; Thu, 28 Nov 2024 01:34:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732757676; cv=none; b=W9keFsxz9QXjpRrV5uN5uED4Tk0qf0TBO4Ifrs+vMK2feUgGei2675CzcaK12xgUhOIT7zAbLNzJwDPe6HEC/AgGPB3VfXv1Ro5mu8ppuvolYjdtGKA3XgIShaB+v20QZlc58eynw6g0+vwE0fouKkGtaUSscgidXCxaWQRstWU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732757676; c=relaxed/simple; bh=qUOOQRdxqzW0iWtWBhZyxD40r+KxBbQyVzxJr0TNPM8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=GS7bUgHid/CFXH550ffFcQlmy+6RW5nyHKMG/Bb4bMgMjOQUdMZ/+p2nM2QS7kNpMWJTmwxYDBCdhC5S8GQEcOd5/VS7Z3D6FAOIjU9VdO+INyxoiQXKKNJ0D6SFHOCONjqArrnm2DkSR50Ekvb2ep21kAgJzQypvbCZggm9/Qo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=4C3zKq/e; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="4C3zKq/e" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-2eaf1a11078so452773a91.1 for ; Wed, 27 Nov 2024 17:34:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1732757674; x=1733362474; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=8PwmW/45ueQJahzHJJm7h5RjQBp4aZ3CpfBvMjYYokI=; b=4C3zKq/eL8aNPiGlFpon+1a7IxPxMNZtRN5E4LhXA/A99YMJU50nPSeh+Zy+CUsIMB 8/GTHMcPH/DCcKPbCcbE/V6vYwMSXTnUD+5vZlu5+E1Y9X3KfLVudNXZl0pf/rgrEEGe FJ5PDtV7Y690RD66ezgHlhOK+PFRKJZeMRK3P6hk/3sw8npIYlVvI3c5RZyvk4qMEpN3 3XbPfiMxfqlV2OIBjc1ZyEBYgrfQ7L1W6oz+LSgaFVJDpK3PO/Iar/FiohsDh4fsOjh6 GvVj0ZKdM06n67tF/ahUpGGnXJN7bXqMf+qZLlcPBWdxGA0OGryUdFzWAzsbndjkgX/t eznA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732757674; x=1733362474; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=8PwmW/45ueQJahzHJJm7h5RjQBp4aZ3CpfBvMjYYokI=; b=KZvpdGNG/oThlFtnLDJ2R5XOMSLZxtRIRm5Rw3qoAI02oCqjivJ8/lmEeaajTWt6Nh ql4Y2ABHP551GpShoKgH9WeBvF97DtDAKNbjHQMeAAzsUoqhQawSdyL9FbEdR0XnW4QS 8FTtE0P8ojKRKVka41JPZMMaV41jqHFOJ6VBA6gtgmLiPA23KnIFC6bjP17B4zKIyxrS mFZwkV59i89YPlKzWEjtPBoSVGCalgvD6/bL1pjS7Jt9QcWH/JVNr1nPOibhfggBU0hQ DsgPRm34G+8rjrK6fwnBoGKRx3hjQOI+51dN0L+ztYg5oLC5sskFcLjqJsum3HdntYva WsJw== X-Forwarded-Encrypted: i=1; AJvYcCUNWivYqZG3zGAomv2eD+7GmBr/EezSBKgX6y6NLuT00kpod9Kk0vaXJO+moA94eLjVfZN4SHPcptAR6Tk=@vger.kernel.org X-Gm-Message-State: AOJu0YzX6fw+PBpjGfiChFRT7yr4eMx8Os+rn/sOvTtVcUZewaDEYwRr dX6exnxL4faVys/ybweEyH27NYzFp8T+NMDZGYxAYRRhj/NGQGr04XYqaFvwT4C9kz1B2C2l4Of uzA== X-Google-Smtp-Source: AGHT+IHpXO85otaKd+k0LVF4CVKFisDTeercgU4ixevU+UUIJ0Tx7jcVkyEwl+8jlB2oryYpavN1dvJ2J/A= X-Received: from pjbqj4.prod.google.com ([2002:a17:90b:28c4:b0:2ea:839b:bb]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:35c9:b0:2ea:77d9:6345 with SMTP id 98e67ed59e1d1-2ee08ed4430mr5846693a91.22.1732757673761; Wed, 27 Nov 2024 17:34:33 -0800 (PST) Reply-To: Sean Christopherson Date: Wed, 27 Nov 2024 17:33:28 -0800 In-Reply-To: <20241128013424.4096668-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241128013424.4096668-1-seanjc@google.com> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog Message-ID: <20241128013424.4096668-2-seanjc@google.com> Subject: [PATCH v3 01/57] KVM: x86: Use feature_bit() to clear CONSTANT_TSC when emulating CPUID From: Sean Christopherson To: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Jarkko Sakkinen Cc: kvm@vger.kernel.org, linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org, Maxim Levitsky , Hou Wenlong , Xiaoyao Li , Kechen Lu , Oliver Upton , Binbin Wu , Yang Weijiang , Robert Hoo Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When clearing CONSTANT_TSC during CPUID emulation due to a Hyper-V quirk, use feature_bit() instead of SF() to ensure the bit is actually cleared. SF() evaluates to zero if the _host_ doesn't support the feature. I.e. KVM could keep the bit set if userspace advertised CONSTANT_TSC despite it not being supported in hardware. Note, translating from a scattered feature to a the hardware version is done by __feature_translate(), not SF(). The sole purpose of SF() is to check kernel support for the scattered feature, *before* translation. Cc: Vitaly Kuznetsov Signed-off-by: Sean Christopherson Reviewed-by: Vitaly Kuznetsov --- arch/x86/kvm/cpuid.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index 097bdc022d0f..776f24408fa3 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -1630,7 +1630,7 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *= ebx, *ebx &=3D ~(F(RTM) | F(HLE)); } else if (function =3D=3D 0x80000007) { if (kvm_hv_invtsc_suppressed(vcpu)) - *edx &=3D ~SF(CONSTANT_TSC); + *edx &=3D ~feature_bit(CONSTANT_TSC); } } else { *eax =3D *ebx =3D *ecx =3D *edx =3D 0; --=20 2.47.0.338.g60cca15819-goog