From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 1DF5A270545; Wed, 20 May 2026 18:31:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301872; cv=none; b=j+rFIER1JGzqB4cUJOo1NytxoVZ9F5iRbsJYxKIwbNXnkIhElInyLFZS+0rYCtwNh5N9O7GQAmeRHJHb7/wvD5L4A7HkjSzFNFae7ZdvfFfeKhEB275j7boUTT9z2aq1caIMYn02XU4Db0qzfGfn0eM00zn7b7CYu4cTo4Hazy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301872; c=relaxed/simple; bh=38VjBVseDEfelALR1MiRTEA2WPwIZueCOuQcJA11DHw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=dMR99nRlEQQo45mFdQDGCevxVrIyqXm7S6Imtm7HvHjpZiitdQhKN4f9xS5ZYmzGmM2h3ujMKp0RIR+uZLbzswqjvxdQi6qU3qFya4Jsw0dGynyRtM//99JZCHCUdV7n1VTFte3uSEOdDzHs7eeVz2qS3anPYKkT8Zs9Djtgi2U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=okyxUeyj; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="okyxUeyj" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=38VjBVseDEfelALR1MiRTEA2WPwIZueCOuQcJA11DHw=; b=okyxUeyjtEfb4IL9N+H2s3fQ4l +FXGCOPfRMtSwfjsiCCErR/hqYIp5E43h19nlrt4LOcqkVnHdTnI4R4ixw9GM3byo64IZ/CfBk9zN QlG9oyCXRDp/W4Nv8hFGJ6REc4kp1SYAJvrFHC3S5281hyRFw/yATFCORBqbsYQ8DJcq4CyQo8OIn 9twCl0C6vXyDdlGu5IPu/RSlBANVuoNJZbRft5N+r2T/6avcFTE3Cm0V5uIZHyxK9DkX4PBh0jkkL ySMglljmFU2brGpAwqD/FpsMhr94TdQ3qTAs7ut6Ck8Y1oxrtBwReeEv+UYTIVdX7di2RShBiv2WW lkFhaaWQ==; Received: from 54-240-197-227.amazon.com ([54.240.197.227] helo=freeip.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wPlh5-00000007THG-3qKd; Wed, 20 May 2026 18:31:00 +0000 Message-ID: <6e80893d022b10110f520acf152f70ff6acf2e00.camel@infradead.org> Subject: Re: [PATCH v3 00/41] x86: Try to wrangle PV clocks vs. TSC From: David Woodhouse To: Sean Christopherson Cc: Kiryl Shutsemau , Paolo Bonzini , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Ajay Kaher , Alexey Makhalov , Jan Kiszka , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Juergen Gross , Daniel Lezcano , Thomas Gleixner , John Stultz , Rick Edgecombe , Vitaly Kuznetsov , Broadcom internal kernel review list , Boris Ostrovsky , Stephen Boyd , x86@kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Michael Kelley , Tom Lendacky , Nikunj A Dadhania , Thomas Gleixner Date: Wed, 20 May 2026 19:30:58 +0100 In-Reply-To: References: <20260515191942.1892718-1-seanjc@google.com> <7260682b21c28d1299e58400b9a2f4b8d23bd434.camel@infradead.org> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-nkQFBHechIC9A3sNo6/e" User-Agent: Evolution 3.52.3-0ubuntu1.1 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html --=-nkQFBHechIC9A3sNo6/e Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2026-05-20 at 10:59 -0700, Sean Christopherson wrote: >=20 > > And then it even spent some time at boot actually using the kvmclock as > > clocksource... when ideally I don't think it would even have *enabled* > > it at all? >=20 > Yeah, that's definitely the ideal state.=C2=A0 And I had all the same exp= ectations and > observations as you when digging in and testing this.=C2=A0 But unless th= is series > makes things worse, I want punt on achieving the ideal state for the mome= nt, as > it's proving to be a big lift just to get to a not-awful state. Ack. Just checking my understanding was correct. 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