From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 92AA51A8F7B for ; Thu, 21 May 2026 22:30:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779402626; cv=none; b=IVztWCuna7fDQHS7ZMOhQb+iQZt8kZZOCTERya04ybv5p8diVJLWIu3KIJwDeA6+0xRz17knxsBCfwu2BwNtWMS8UVfKdDeXqxGmqlvrtBNZj0PEeNySeOCw9aInOFSfm3ZxdZwpPa2AfMWUb8nNvoLyMyk+BgxGgQAwl/JIyEA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779402626; c=relaxed/simple; bh=rbflla7xle2oiRwHeYhfStYOMc87R2Q835q8UhKjKro=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=hx1SN/+0DpU/pKYVWQ8nqSoKb2V9Zi2vEsNETkLQE+Y70FgaO3+LlEFLqNHyRErItE6QFVtfxSJkJVVrHJm4VWIIHphE0Cx7fWab2TVSZekmm+cys+jwUUVFjIrP0ii5itqch1Vqf5rpU5CvYkGrsAo15Ayjn37L2Im4TDvKB6A= 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=dsQARqOb; arc=none smtp.client-ip=209.85.214.202 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="dsQARqOb" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2ba718173d1so114076855ad.0 for ; Thu, 21 May 2026 15:30:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779402625; x=1780007425; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=+mwj630vVwEqi8mq4SZZW5tTSWOGwfC/65sZINb+5IQ=; b=dsQARqObuEFTteBeD8EZZkmR3mR+BaeWTW/5N3ij1iMrPuqwmludgo8bgkkq5SjjaG gXYtYxn5OsFs0TWqfUUa4VnM/nT//ipCUv7z6Bj/T9NWxXfshSqhP4Ba+xzPAGJZo6Zm Bixb6NOMzNRDOmECGLQEzVOWlE2xyWFnptm26uNZTkbQzAWCRzOYIglo8BkCfWXGdNtl I/UdX7C79e9WoMPoJrNDWLSR8PnVWMFFAt+AaRcWz1faZ3Ngb93adR0OhUovagzkwWpv b326ZDKtiJ2GoZuWlK144sVkx3z9MyeYh6IkQ3sxq0XjvTTzdg5yc0zu8w+ImcMmDDb0 ldmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779402625; x=1780007425; 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=+mwj630vVwEqi8mq4SZZW5tTSWOGwfC/65sZINb+5IQ=; b=XKekKnFlQQ/LqOdgNLQ324EDwF5W1grsbGV5xurOAq2Gk9aB2uwQUwR8o+HTeiA0ML Sm42wzeNZwuTfq4hR9MqoJMz/LUCO3LECY4Drig7yFB8sG3e9om19fLGyrpMwzuFX+0y 6TVUGB7iVWHH7ef74GJI/Rr5wfeS0LKjKkbASxippBYBW2YHN8OE70CCx/e63AiRm1MI J9xI68HiTYghLEumWEOZpeg/U1lSW6kF5Ih+v2GwsBblBF5l3S0fTVZeLVk0c++Rmfeo +Cmk//cztIFzHcazQdKoFv/4KDcEbSoBgmy+QeArULB5Y76c6XG0wbAJUf1+UyFGMkkR n5xQ== X-Forwarded-Encrypted: i=1; AFNElJ8sMIYToK3qCJBCUeiVXjs8TsvJ/KFK6v6klIenU/YoMiJJt1UBY3M64Nt1b6Qj9IW59LI=@vger.kernel.org X-Gm-Message-State: AOJu0YxuSU1ECYfdy/RyKYsuJ69sQy5Ldwua7H/IKCJYtLK8CZLcLJ// EIVFowog6xZPXVVxKQpca0gQOJp+F9Lq29YIGIzMu5fvSBlmLOtVJ3XelIMmdOAqZ55OXh75mp+ k8L+skw== X-Received: from pgbfl15.prod.google.com ([2002:a05:6a02:50cf:b0:c80:1541:9dfc]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:430e:b0:3a3:a55f:407c with SMTP id adf61e73a8af0-3b328cad3aemr900407637.16.1779402624505; Thu, 21 May 2026 15:30:24 -0700 (PDT) Date: Thu, 21 May 2026 15:30:23 -0700 In-Reply-To: <3ad6cd109480772ade3c11f23b9c1d7a9855d67e.camel@infradead.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260509224824.3264567-1-dwmw2@infradead.org> <20260509224824.3264567-28-dwmw2@infradead.org> <3ad6cd109480772ade3c11f23b9c1d7a9855d67e.camel@infradead.org> Message-ID: Subject: Re: [PATCH v4 27/30] KVM: x86: Add KVM_VCPU_TSC_EFFECTIVE_FREQ attribute From: Sean Christopherson To: David Woodhouse Cc: Paolo Bonzini , Jonathan Corbet , Shuah Khan , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Vitaly Kuznetsov , Juergen Gross , Boris Ostrovsky , Paul Durrant , Jonathan Cameron , Sascha Bischoff , Marc Zyngier , Joey Gouly , Jack Allister , Dongli Zhang , joe.jin@oracle.com, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="us-ascii" On Thu, May 21, 2026, David Woodhouse wrote: > On Sat, 2026-05-09 at 23:46 +0100, David Woodhouse wrote: > > From: David Woodhouse > That does leave userspace still needing a way to get the APIC bus > frequency, to populate CPUID. So maybe I'll just make an attribute > which returns that as a single value. Already exists, KVM_CAP_X86_APIC_BUS_CYCLES_NS. The TDX architecture decided that unconditionally telling guests the virtual APIC bus runs at 400Mhz was a brilliant idea.