From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 288E51EB5C2 for ; Mon, 30 Mar 2026 20:22:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774902132; cv=none; b=kYIvcAsDiA4KuJLcavi+2OR0tGkw4wuJtyWit1LFUgExaz8SNLk3GWzKy8poT9Wq8R/1kTGJROctRtG3CncFohQWlieHZxPOsdfdjnoI/nv2mZndy/DCk1AaI+PS/Scnn5i52DOWNDNSNh2HVhYWt8XCJAZdQFKF65B6x50MEwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774902132; c=relaxed/simple; bh=We4ZjVjNjOTol2XjP++h32vYdwZeglqE60eGXJG5PwM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HR73Ufu6Ol9uPgYfAfWo9//wDhNqh1ipWKFRLOYGZJp7+v/NO/wwbuuoY0FiRul7NX3w2DgNxvugeUQdDPO0o2zyvir0PgoN3syUyu8+0Jo3ZkGLlOCp1P+xvjonBaC+1AY1/FZ0jsYuoH6qqt54ijWMbsTDd0P3CI6r3297WPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=adStxN+h; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=nKwo6gSf; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="adStxN+h"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="nKwo6gSf" Date: Mon, 30 Mar 2026 22:22:06 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1774902129; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5A8tkX3YntkKwuWW7Ps0VVntxvwiR1iVI5TSScUuOdM=; b=adStxN+hQ29rmhgXIMzRqEjqk2LyfAwHMDkgqs8Sze2WJuaJ1pkHPtFnREQ+uKdlAl+E0r CTj5nTR41rV3H9m2oJ7APaZWDLLOmrwFaw4htl+6/fOaB9K75nOuvAfSy9687iMPAz9fQ5 C3+4GR+30JcFSSbaSWK55XxoE39Ep3TjrvaU0XhuWAPBnKfpYkwH/UYqWfKIU9xj53LjBj 2F/xrYWh10vdmbjUu98zwayv0SGn/dJ6JX8+CfO3GPOXze8sKB1yjVOp6R1R4OI2zGaX4s Cik4vqTMwUFX5f6A0SCyKJpkpZjEQdBMYwbWF/JfW7EmaF4EwaoQiSRN2sGXAA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1774902129; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5A8tkX3YntkKwuWW7Ps0VVntxvwiR1iVI5TSScUuOdM=; b=nKwo6gSfHDSv1pGjUwH3JPw+uCGwILmmgQS7xMLT2ibA7+YKDMQmzXB4i5I2yZNfGIMc2M m8t5NWMuPMCHZ/Dg== From: "Ahmed S. Darwish" To: David Woodhouse Cc: Borislav Petkov , Dave Hansen , Ingo Molnar , Thomas Gleixner , Andrew Cooper , "H. Peter Anvin" , Sean Christopherson , Peter Zijlstra , Christian Ludloff , Sohil Mehta , Maciej Wieczor-Retman , John Ogness , x86@kernel.org, x86-cpuid@lists.linux.dev, LKML Subject: Re: [ANNOUNCE] x86-cpuid-db: Release v3.0 Message-ID: References: <646c19398708901454c7336e408d80f8695060fe.camel@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <646c19398708901454c7336e408d80f8695060fe.camel@infradead.org> Hi! On Fri, 27 Mar 2026, David Woodhouse wrote: > > It still doesn't iterate over the hypervisor blocks at 0x4000_0x00 and > find all of them. Both Xen and KVM will advertise the Hyper-V leaves at > 0x4000_0000 and then their own get shifted to 0x4000_0100. And now we > can host HyperV-enlightened Xen guests under KVM, perhaps we could do > HyperV, then Xen, then KVM at 0x4000_0200? > > I was checking to see if it has all the ways to detect the Extended > Destination ID enlightenment documented in the last page ("Hypervisor > detection via CPUID") of https://david.woodhou.se/ExtDestId.pdf > > I think I see the Xen and KVM bits there, and I guess reporting them > with different strings in feature.c is kind of OK? The Bhyve and > Viridian bits are missing. > > Also, the leaf at 0x40000010 isn't necessarily VMware-specific; it's > seen elsewhere too. At least EC2 exposes it under KVM. See thread at > about https://lore.kernel.org/all/aLDo3F3KKW0MzlcH@google.com/ > Yes, it's in the plan. The priority is to get the CPUID model into the kernel: [PATCH v6 00/90] x86: Introduce a centralized CPUID data model https://lore.kernel.org/lkml/20260327021645.555257-1-darwi@linutronix.de including its newly-introduced X86_FEATURE synthetic and hardware-backed words routing to the CPUID tables. Then, convert the remaining call sites invoking CPUID, then begin tackling the guest code querying leaves at the 0x4000 range. Thanks, Ahmed