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 8AEFD5028C; Tue, 21 Jan 2025 17:16:42 +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=1737479807; cv=none; b=ZsXH1+pN1G8FZNd3JdSSsQzjjJdaZivQFj055ryi8yrka6Y1ynbFvQdCryj/tsjCzaIbWv7alc9snWMkCWBKal+4sGmNOpQr5tjrydSZhQ1lE0QFdCaxvQHdF8a0MRIlRsyHkY0DUwfxWgXR9EXtE8gehHVRZAy5OkMdSjClAig= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737479807; c=relaxed/simple; bh=WT4lfoojV+LzmxIdY0+4vd69gSGGUWQRcjO8sTzpgIw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=jwfBEppTXK2lFUKPKxKbrEIKaXO4wqQnlPy5q/b0pX1f8iQHCxWVgeZi1bg85KP7R2EjDFTWzmRHkaN7UI60eJLzGphYm+yH5jwtIE8endBpJShQ3v7Famp2I6F560B1bPUpaTQCRuP0SYsd8VdoaMdMsHPHK5B4XUICFqEDHlM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=qfleM7Ai; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="qfleM7Ai" 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=WT4lfoojV+LzmxIdY0+4vd69gSGGUWQRcjO8sTzpgIw=; b=qfleM7AiDMoTb6reSChVwsoZf7 gpEdxQ1RvG70BD6p+OpetKyn7yztYG6mZAANsMWpFq6h5mUzNgCubAh7rEFe5+B7+dRm+kZr349WJ 6uPvk7h+KARJ6E49nwuY82dB2UfLQMCYK9AvMpxldZAcq/OEstItSfbjiTWySZPDfbDj7M3mqp5tK HyHOWBO+3NSRgBsvfBxzNFSM9d84tOq4tMtv94/5bOeodgpmhfoVGNiMUVfS3f5jNGP4XqiRuWcJL 4VFSBCjNE9rfV1NwACdGEt1Nwges0bR9iiQ/NlRgpQ8zlqk5soM6U/6W6LuCQiQHFWW3UklTX4P4T hcwMnIEA==; Received: from [205.251.233.110] (helo=freeip.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1taHre-00000000eWl-0pQ1; Tue, 21 Jan 2025 17:16:34 +0000 Message-ID: Subject: Re: [PATCH 09/10] KVM: x86: Setup Hyper-V TSC page before Xen PV clocks (during clock update) From: David Woodhouse To: paul@xen.org, Sean Christopherson , Vitaly Kuznetsov Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+352e553a86e0d75f5120@syzkaller.appspotmail.com, Paul Durrant Date: Tue, 21 Jan 2025 09:16:29 -0800 In-Reply-To: References: <20250118005552.2626804-1-seanjc@google.com> <20250118005552.2626804-10-seanjc@google.com> <8734hd8rrx.fsf@redhat.com> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-mSTtn7q1jMfQGNwkWIxK" User-Agent: Evolution 3.52.3-0ubuntu1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org 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 --=-mSTtn7q1jMfQGNwkWIxK Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2025-01-21 at 15:59 +0000, Paul Durrant wrote: > On 21/01/2025 15:44, Sean Christopherson wrote: > [snip] > >=20 > > I think it's ok to keep the Hyper-V TSC page in this case.=C2=A0 It's n= ot that the Xen > > PV clock is truly unstable, it's that some guests get tripped up by the= STABLE > > flag.=C2=A0 A guest that can't handle the STABLE flag has bigger proble= ms than the > > existence of a completely unrelated clock that is implied to be stable. > >=20 >=20 > Agreed. >=20 > > > I don't know if anyone combines Xen and Hyper-V emulation capabilitie= s for > > > the same guest on KVM though.) > >=20 > > That someone would have to be quite "brave" :-D >=20 > Maybe :-) Xen itself does offer some Hyper-V enlightenments, and we might reasonably expect KVM-based hypervisors to offer the same. We explicitly do account for the KVM CPUID leaves moving up to let the Hyper-V ones exist. I don't recall if Xen's Hyper-V support includes the TSC page though. --=-mSTtn7q1jMfQGNwkWIxK Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCD9Aw ggSOMIIDdqADAgECAhAOmiw0ECVD4cWj5DqVrT9PMA0GCSqGSIb3DQEBCwUAMGUxCzAJBgNVBAYT AlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xJDAi BgNVBAMTG0RpZ2lDZXJ0IEFzc3VyZWQgSUQgUm9vdCBDQTAeFw0yNDAxMzAwMDAwMDBaFw0zMTEx MDkyMzU5NTlaMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYDVQQDExdWZXJv a2V5IFNlY3VyZSBFbWFpbCBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMjvgLKj jfhCFqxYyRiW8g3cNFAvltDbK5AzcOaR7yVzVGadr4YcCVxjKrEJOgi7WEOH8rUgCNB5cTD8N/Et GfZI+LGqSv0YtNa54T9D1AWJy08ZKkWvfGGIXN9UFAPMJ6OLLH/UUEgFa+7KlrEvMUupDFGnnR06 aDJAwtycb8yXtILj+TvfhLFhafxroXrflspavejQkEiHjNjtHnwbZ+o43g0/yxjwnarGI3kgcak7 nnI9/8Lqpq79tLHYwLajotwLiGTB71AGN5xK+tzB+D4eN9lXayrjcszgbOv2ZCgzExQUAIt98mre 8EggKs9mwtEuKAhYBIP/0K6WsoMnQCcCAwEAAaOCAVwwggFYMBIGA1UdEwEB/wQIMAYBAf8CAQAw HQYDVR0OBBYEFIlICOogTndrhuWByNfhjWSEf/xwMB8GA1UdIwQYMBaAFEXroq/0ksuCMS1Ri6en IZ3zbcgPMA4GA1UdDwEB/wQEAwIBhjAdBgNVHSUEFjAUBggrBgEFBQcDBAYIKwYBBQUHAwIweQYI KwYBBQUHAQEEbTBrMCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5kaWdpY2VydC5jb20wQwYIKwYB BQUHMAKGN2h0dHA6Ly9jYWNlcnRzLmRpZ2ljZXJ0LmNvbS9EaWdpQ2VydEFzc3VyZWRJRFJvb3RD QS5jcnQwRQYDVR0fBD4wPDA6oDigNoY0aHR0cDovL2NybDMuZGlnaWNlcnQuY29tL0RpZ2lDZXJ0 QXNzdXJlZElEUm9vdENBLmNybDARBgNVHSAECjAIMAYGBFUdIAAwDQYJKoZIhvcNAQELBQADggEB ACiagCqvNVxOfSd0uYfJMiZsOEBXAKIR/kpqRp2YCfrP4Tz7fJogYN4fxNAw7iy/bPZcvpVCfe/H /CCcp3alXL0I8M/rnEnRlv8ItY4MEF+2T/MkdXI3u1vHy3ua8SxBM8eT9LBQokHZxGUX51cE0kwa uEOZ+PonVIOnMjuLp29kcNOVnzf8DGKiek+cT51FvGRjV6LbaxXOm2P47/aiaXrDD5O0RF5SiPo6 xD1/ClkCETyyEAE5LRJlXtx288R598koyFcwCSXijeVcRvBB1cNOLEbg7RMSw1AGq14fNe2cH1HG W7xyduY/ydQt6gv5r21mDOQ5SaZSWC/ZRfLDuEYwggWbMIIEg6ADAgECAhAH5JEPagNRXYDiRPdl c1vgMA0GCSqGSIb3DQEBCwUAMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYD VQQDExdWZXJva2V5IFNlY3VyZSBFbWFpbCBHMjAeFw0yNDEyMzAwMDAwMDBaFw0yODAxMDQyMzU5 NTlaMB4xHDAaBgNVBAMME2R3bXcyQGluZnJhZGVhZC5vcmcwggIiMA0GCSqGSIb3DQEBAQUAA4IC DwAwggIKAoICAQDali7HveR1thexYXx/W7oMk/3Wpyppl62zJ8+RmTQH4yZeYAS/SRV6zmfXlXaZ sNOE6emg8WXLRS6BA70liot+u0O0oPnIvnx+CsMH0PD4tCKSCsdp+XphIJ2zkC9S7/yHDYnqegqt w4smkqUqf0WX/ggH1Dckh0vHlpoS1OoxqUg+ocU6WCsnuz5q5rzFsHxhD1qGpgFdZEk2/c//ZvUN i12vPWipk8TcJwHw9zoZ/ZrVNybpMCC0THsJ/UEVyuyszPtNYeYZAhOJ41vav1RhZJzYan4a1gU0 kKBPQklcpQEhq48woEu15isvwWh9/+5jjh0L+YNaN0I//nHSp6U9COUG9Z0cvnO8FM6PTqsnSbcc 0j+GchwOHRC7aP2t5v2stVx3KbptaYEzi4MQHxm/0+HQpMEVLLUiizJqS4PWPU6zfQTOMZ9uLQRR ci+c5xhtMEBszlQDOvEQcyEG+hc++fH47K+MmZz21bFNfoBxLP6bjR6xtPXtREF5lLXxp+CJ6KKS blPKeVRg/UtyJHeFKAZXO8Zeco7TZUMVHmK0ZZ1EpnZbnAhKE19Z+FJrQPQrlR0gO3lBzuyPPArV hvWxjlO7S4DmaEhLzarWi/ze7EGwWSuI2eEa/8zU0INUsGI4ywe7vepQz7IqaAovAX0d+f1YjbmC VsAwjhLmveFjNwIDAQABo4IBsDCCAawwHwYDVR0jBBgwFoAUiUgI6iBOd2uG5YHI1+GNZIR//HAw HQYDVR0OBBYEFFxiGptwbOfWOtMk5loHw7uqWUOnMDAGA1UdEQQpMCeBE2R3bXcyQGluZnJhZGVh ZC5vcmeBEGRhdmlkQHdvb2Rob3Uuc2UwFAYDVR0gBA0wCzAJBgdngQwBBQEBMA4GA1UdDwEB/wQE AwIF4DAdBgNVHSUEFjAUBggrBgEFBQcDAgYIKwYBBQUHAwQwewYDVR0fBHQwcjA3oDWgM4YxaHR0 cDovL2NybDMuZGlnaWNlcnQuY29tL1Zlcm9rZXlTZWN1cmVFbWFpbEcyLmNybDA3oDWgM4YxaHR0 cDovL2NybDQuZGlnaWNlcnQuY29tL1Zlcm9rZXlTZWN1cmVFbWFpbEcyLmNybDB2BggrBgEFBQcB AQRqMGgwJAYIKwYBBQUHMAGGGGh0dHA6Ly9vY3NwLmRpZ2ljZXJ0LmNvbTBABggrBgEFBQcwAoY0 aHR0cDovL2NhY2VydHMuZGlnaWNlcnQuY29tL1Zlcm9rZXlTZWN1cmVFbWFpbEcyLmNydDANBgkq hkiG9w0BAQsFAAOCAQEAQXc4FPiPLRnTDvmOABEzkIumojfZAe5SlnuQoeFUfi+LsWCKiB8Uextv iBAvboKhLuN6eG/NC6WOzOCppn4mkQxRkOdLNThwMHW0d19jrZFEKtEG/epZ/hw/DdScTuZ2m7im 8ppItAT6GXD3aPhXkXnJpC/zTs85uNSQR64cEcBFjjoQDuSsTeJ5DAWf8EMyhMuD8pcbqx5kRvyt JPsWBQzv1Dsdv2LDPLNd/JUKhHSgr7nbUr4+aAP2PHTXGcEBh8lTeYea9p4d5k969pe0OHYMV5aL xERqTagmSetuIwolkAuBCzA9vulg8Y49Nz2zrpUGfKGOD0FMqenYxdJHgDCCBZswggSDoAMCAQIC EAfkkQ9qA1FdgOJE92VzW+AwDQYJKoZIhvcNAQELBQAwQTELMAkGA1UEBhMCQVUxEDAOBgNVBAoT B1Zlcm9rZXkxIDAeBgNVBAMTF1Zlcm9rZXkgU2VjdXJlIEVtYWlsIEcyMB4XDTI0MTIzMDAwMDAw MFoXDTI4MDEwNDIzNTk1OVowHjEcMBoGA1UEAwwTZHdtdzJAaW5mcmFkZWFkLm9yZzCCAiIwDQYJ KoZIhvcNAQEBBQADggIPADCCAgoCggIBANqWLse95HW2F7FhfH9bugyT/danKmmXrbMnz5GZNAfj Jl5gBL9JFXrOZ9eVdpmw04Tp6aDxZctFLoEDvSWKi367Q7Sg+ci+fH4KwwfQ8Pi0IpIKx2n5emEg nbOQL1Lv/IcNiep6Cq3DiyaSpSp/RZf+CAfUNySHS8eWmhLU6jGpSD6hxTpYKye7PmrmvMWwfGEP WoamAV1kSTb9z/9m9Q2LXa89aKmTxNwnAfD3Ohn9mtU3JukwILRMewn9QRXK7KzM+01h5hkCE4nj W9q/VGFknNhqfhrWBTSQoE9CSVylASGrjzCgS7XmKy/BaH3/7mOOHQv5g1o3Qj/+cdKnpT0I5Qb1 nRy+c7wUzo9OqydJtxzSP4ZyHA4dELto/a3m/ay1XHcpum1pgTOLgxAfGb/T4dCkwRUstSKLMmpL g9Y9TrN9BM4xn24tBFFyL5znGG0wQGzOVAM68RBzIQb6Fz758fjsr4yZnPbVsU1+gHEs/puNHrG0 9e1EQXmUtfGn4InoopJuU8p5VGD9S3Ikd4UoBlc7xl5yjtNlQxUeYrRlnUSmdlucCEoTX1n4UmtA 9CuVHSA7eUHO7I88CtWG9bGOU7tLgOZoSEvNqtaL/N7sQbBZK4jZ4Rr/zNTQg1SwYjjLB7u96lDP sipoCi8BfR35/ViNuYJWwDCOEua94WM3AgMBAAGjggGwMIIBrDAfBgNVHSMEGDAWgBSJSAjqIE53 a4blgcjX4Y1khH/8cDAdBgNVHQ4EFgQUXGIam3Bs59Y60yTmWgfDu6pZQ6cwMAYDVR0RBCkwJ4ET ZHdtdzJAaW5mcmFkZWFkLm9yZ4EQZGF2aWRAd29vZGhvdS5zZTAUBgNVHSAEDTALMAkGB2eBDAEF AQEwDgYDVR0PAQH/BAQDAgXgMB0GA1UdJQQWMBQGCCsGAQUFBwMCBggrBgEFBQcDBDB7BgNVHR8E dDByMDegNaAzhjFodHRwOi8vY3JsMy5kaWdpY2VydC5jb20vVmVyb2tleVNlY3VyZUVtYWlsRzIu Y3JsMDegNaAzhjFodHRwOi8vY3JsNC5kaWdpY2VydC5jb20vVmVyb2tleVNlY3VyZUVtYWlsRzIu Y3JsMHYGCCsGAQUFBwEBBGowaDAkBggrBgEFBQcwAYYYaHR0cDovL29jc3AuZGlnaWNlcnQuY29t MEAGCCsGAQUFBzAChjRodHRwOi8vY2FjZXJ0cy5kaWdpY2VydC5jb20vVmVyb2tleVNlY3VyZUVt YWlsRzIuY3J0MA0GCSqGSIb3DQEBCwUAA4IBAQBBdzgU+I8tGdMO+Y4AETOQi6aiN9kB7lKWe5Ch 4VR+L4uxYIqIHxR7G2+IEC9ugqEu43p4b80LpY7M4KmmfiaRDFGQ50s1OHAwdbR3X2OtkUQq0Qb9 6ln+HD8N1JxO5nabuKbymki0BPoZcPdo+FeRecmkL/NOzzm41JBHrhwRwEWOOhAO5KxN4nkMBZ/w QzKEy4PylxurHmRG/K0k+xYFDO/UOx2/YsM8s138lQqEdKCvudtSvj5oA/Y8dNcZwQGHyVN5h5r2 nh3mT3r2l7Q4dgxXlovERGpNqCZJ624jCiWQC4ELMD2+6WDxjj03PbOulQZ8oY4PQUyp6djF0keA MYIDuzCCA7cCAQEwVTBBMQswCQYDVQQGEwJBVTEQMA4GA1UEChMHVmVyb2tleTEgMB4GA1UEAxMX VmVyb2tleSBTZWN1cmUgRW1haWwgRzICEAfkkQ9qA1FdgOJE92VzW+AwDQYJYIZIAWUDBAIBBQCg ggE3MBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTI1MDEyMTE3MTYy OVowLwYJKoZIhvcNAQkEMSIEIM22FUFoo5/ewiWmgkwmj8uQfYODwL5pN6ZSt5KXUV5gMGQGCSsG AQQBgjcQBDFXMFUwQTELMAkGA1UEBhMCQVUxEDAOBgNVBAoTB1Zlcm9rZXkxIDAeBgNVBAMTF1Zl cm9rZXkgU2VjdXJlIEVtYWlsIEcyAhAH5JEPagNRXYDiRPdlc1vgMGYGCyqGSIb3DQEJEAILMVeg VTBBMQswCQYDVQQGEwJBVTEQMA4GA1UEChMHVmVyb2tleTEgMB4GA1UEAxMXVmVyb2tleSBTZWN1 cmUgRW1haWwgRzICEAfkkQ9qA1FdgOJE92VzW+AwDQYJKoZIhvcNAQEBBQAEggIAijcXfRe+UEvy tDl0jvPknVIkN05R2tu5iYlHc4opqCjmelnjOVh4zBkqlb8E3PGeg1g4BulRVeN3sDvw7QG1ZG2D QEiDNdhIsfaHe9oaeb8xoiKft+b/X6Ea+qDy/hM75VtoW+uOFdOYnZsCCqANve6NgZDocbiqII1b gxVEimVAGsn4wKZUAcXUDI/h01hT2Crxgy6RV8P1BxHiyeXB38u8cB8ybNVy1k8w9nkSYpqmXIMc yVE0Jq2FXoSZ8gmtD7kPpERzZ6PJqJTvBGlQa1a8TAoT72cUOCGOC6J/PwNON+X5DoZhRnHFI1Gk ruR410HViM+EkoyQMAnhlNrEVHvOYduzHviOEDR2G7I9qQA+zRtI9jDHbBTf0VKt12AnDxF4gpy+ qMsw9KTuhJfn56RpCFMbzqxQUt8XOStPdllUIpKnCnw0SaQDVXJ9RNka7cGiCzPe8hLqdWNd36fo pdGYJqVpaSri6pzKUauE1kQHGVdQ6o51MCSb+xg5SZY1pXlbkwVugBz3ZmvYUgVeFqej28T+mTDh ojSXpFpIwE3w6uettYvAs1UZQMYK/tEhikLFGFVWYR6QEmb04Fde46eWpQ8+PTdhUHjqIg3X6y26 rPyHGRXACePJU8aRlhfgv6SJULF3J8QZU4JYqAI9STF4MiNVI/ylqOmajPPM74kAAAAAAAA= --=-mSTtn7q1jMfQGNwkWIxK--