[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH v2 1/9] x86/cpuid: Advertise SSB_NO to guests by default


  • To: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
  • Date: Mon, 31 Jan 2022 10:41:00 +0100
  • Arc-authentication-results: i=1; mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none
  • Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=/7Du2E7wi75A31DeeLGa8shaeraeo9TRnNjdP34ENnE=; b=UOVxetsTDahxys/3oDWvvm/gyU9DU1MJx3IE/5syjGwlysEVjgcG5xDBW4VGGxoX8YPss6iT6OSghmuBcZzb5Yukr7Br8KxuuJ4gSwCzSJ2nQbo3TeoMryhOwQljWchIhdhmndoUDQ3qRPi0vR3RI8UEQyrZIBqFOcX8BuF7hxhudXJMdVpO6WFhoFLSDNzjMqkYbEamIVxXPM+k3wcRmYM2eScBQYBEQ3ae8veqwuQpMhHJoOCqLqwAxwSKNZOHYBUXqnGLcoYvTNxwDfRXWlIwC1Pn8cLUKf8KAjZJdnC2KsIWmns+21q8kIVEfdNXj5IndG+Z3FgpQqQqtP36qA==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=KW57M7lBStlqw6ZdFgD3w1InipABIsCbClTaGN630mOVuMeenEnbY4rHtWyEzjtHQMAcMz50KDql4LVlYKF1/cgtw3MV7hYxLrzMy0gbUXHMF7R57O2ayNdX+ouayqr8kAZ6MipvLg0SxvDhQ2iVKxJQSsltjQwcNtoKsb1Cq920Bk628ZsTkJvmERGO9baEZnLryEtOSSuZJgfmCzNEhax44xWgpFwuydwWwG8171yvbjeZ9fe8qponxKXm08cbxP57VL6HRalL86KS5nXxq0dpyZfUN7jfMp+Re/k4PUaLXQSAPzeDk7mB7+1vC2BChvufEl3W8yOXxoR3x508MQ==
  • Authentication-results: esa3.hc3370-68.iphmx.com; dkim=pass (signature verified) header.i=@citrix.onmicrosoft.com
  • Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxx>, Wei Liu <wl@xxxxxxx>
  • Delivery-date: Mon, 31 Jan 2022 09:41:15 +0000
  • Ironport-data: A9a23:HPIA0qO7CGtbxe7vrR1DkMFynXyQoLVcMsEvi/4bfWQNrUoggTxRy 2pND2CEOqneNDOnL4t0PN/l9klUu56ByNFrSAto+SlhQUwRpJueD7x1DKtR0wB+jCHnZBg6h ynLQoCYdKjYdpJYz/uUGuCJQUNUjMlkfZKhTr6UUsxNbVU8En150Ek6w7dRbrNA2rBVPSvc4 bsenOWHULOV82Yc3rU8sv/rRLtH5ZweiRtA1rAMTakjUGz2zhH5OKk3N6CpR0YUd6EPdgKMq 0Qv+5nilo/R109F5tpICd8XeGVSKlLZFVDmZna7x8FOK/WNz8A/+v9TCRYSVatYoyjOpN1Y1 f9PjoPzWEQGburCo98MQSANRkmSPYUekFPGCX22sMjVxEzaaXr8hf5pCSnaP6VBpLwxWzsXs 6VFdnZdNXhvhMrvqF6/YvNrick5atHiIasUu216zCGfBvEjKXzGa/uRvIcEhWlv7ixINf2DY pA0eBMxVxDrQTxVMVsUKrExk+j90xETdBUH8QnI9MLb+VP70whZwLXrdt3PdbSiZ+9Yg0KZr WLu5HniD1cRM9n34SqI9Degi/HCmQv/WZkOD/uo+/hymlqRy2cPThoMWjOGTeKR0xDkHYgFc gpNp3Ro/fNaGFGXosfVQlqDrVeZlBwnRJlBUMJqrw+28bvG2lPMboQbdQJpZNsjvc4wYDUl0 F6Vgt/kbQBSXK2ppWG1renN827rUcQBBSpbPHJfE1NZizX2iNxr1nryosBf/LlZZzEfMRX52 Hi0oSc3nN3/ZuZbhvzgrTgrb99Bz6UlrzLZBC2KBApJDSsjPeZJgrBED3CBt56sy67CFjG8U IAswZT20Qz3JcjleNaxaOsMBqq1wP2OLSfRh1Vid7F4qWj2pi78JdAOsW0vTKuMDiriUWWzC KM0kVgJjKK/wVPwNfMnC25PI5lCIVfc+STNCamPM4smjmlZfw6b5iB+DXN8LEi2+HXAZZoXY M/BGe71VC5yIf0+kFKeGrlBuZd2mHFW7T6DFPjTkkX8uZLDNSH9dFvwGAbUBgzPxPna8Fy9H hc2H5bi9iizp8WnPHGPr9ZPfA9bRZX5bLivw/Fqmie4ClMOMEkqCuPLwKNnfIpgnq9PkfzP8 G37UUhdoGcTT1WeQelTQnw8Or7pQ7hlqnc3YX4lMVqygiBxaoez9qYPMZAweOB/puBkyPd1S dgDetmBXasTGmiWpWxFYMmvtpFmeTSqmRmKY3ivbg8gcsMyXAfO4NLlIFfirXFcEiqtuMIii LS8zQeHE4EbTgFvAZ+OOvKixl+8p1YHn+d2UxeaK9VfYhy0ooNrNzbwnrk8JMRVcUfPwT6T1 gC3BxYEpLaS/99poYeR3a3d9tWnCepzGEZeDlL317fuOHmI5HenzK9BTP2MIWLXWlTr9fjwf u5S1fz9bqEKxQ4Yr4pmHr935qsi/N+z9aRCxwFpEXiXPVSmDrRsfiuP0cVV7/Afw7ZYvU29W 16V+8kcMrKMYZu3HFkULQsjT+KCyfBLxWWCsaVreB33tH1t4b6KcUROJB3d2iVSIYx8PJ4h3 ep86tUd7Bayi0ZyP9uL5syOG79g8pDUv30bi6wn
  • Ironport-hdrordr: A9a23:fgWs0q2msqlhwXSs7Dkg7wqjBLokLtp133Aq2lEZdPU1SK2lfq +V9sjzuSWYtN9zYhEdcLK7V5VoKEm0nfVICOIqU4tKMjOLhEKYaKxj94Hmyz3lFyCWzJ8+6U 8YGJIOa+HNMQ==
  • Ironport-sdr: KX824/Qo1pImywTqlN2FXxlYv930yhNFV9qrr48YHylJ3MMl6jUsQsPyH5HG2PeE4k33ermMhO cf/w8TUMLVgtEPsSgOJzu3I+HXy4GzvEQaZGGl+MW7Du/yrc6tZJvCK0oTyzi1CncxxfCfQB+F JP/8ONUYLipGpCAAeHiGTef2EE7EDPJR4epIpgqOQ4kyqxD8uqA3N/Ko/HBpR+L6lKTIkci3vm /8Fj162A77ru+pwoceUZzmHEM0Ft8MKaDLsITtC2tboM2gQ4Gaig4HA70v0TFZ1yvIOopUcrLx PyimQg82mHB8N/o8qwyfNHia
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On Fri, Jan 28, 2022 at 01:29:19PM +0000, Andrew Cooper wrote:
> This is a statement of hardware behaviour, and not related to controls for the
> guest kernel to use.  Pass it straight through from hardware.
> 

Not really related to this patch per se, but I think we should expose
AMD_SSBD unconditionally for SPEC_CTRL (and VIRT_SSBD for
VIRT_SPEC_CTRL when supported) in the max policies and implement them
as noop for compatibility reasons?

I would expect CPUs exposing SSB_NO to drop AMD_SSBD and VIRT_SSBD at
some point.

Thanks, Roger.



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.