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

Re: [PATCH v2 2/2] x86/xen: Allow per-domain usage of hardware virtualized APIC


  • To: Jane Malalane <jane.malalane@xxxxxxxxxx>
  • From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
  • Date: Thu, 10 Feb 2022 11:09:10 +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=7RjCmAc7agmyzI0yWa//DZ3lhJzsYLLGRDvR+wra0yo=; b=jhgmlX26EEAujTJgi6I1A2jxAoGlPS00oU+4SbyzbO2cQYvgiLtPeZfhHN21qUpayTu2WJYxmvB18VT5dK6g3SrnvNfQIjYfGkbnj4fvROgmqXxfE7Pby4AmosGuQGMl7laKczU2gWUGlbv1m4IR5ON7WHyxuaN1fnXaYixuy+blGN239wUTu6q/8cLF6SnMqFBYO/zcuAgp8CAr23KEFcm0FNbuqFyhkh8nf+34rGWfj0rjWA/roDa/ASs3d628lfY6eDcnpSLxtj2R/hT2/E2vdT9HgaV+XzBddq2aAoweSuDFcRnaPK+S5QAXxDJ/EbX7UrmrV6u1Xu6nDTqa1w==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=kUG2DGMTvqhCtpbSSkHtF19OhUQI01r7T7oeNLIEttsF+XJxCoZJ2sFaEqd1HSTOnkbm7FoyFROUi+Hlfw7WVnE6HsX0MahogYHyFeXyEfqPO9pn1CVB8Tkkjae/LrO0C7lI+qqYw0BZT502t4UOHiWdBISTixNYImBfAe0xThtYGHfkTrKkwHU9jUclE24CtqXN7Nily2I73S+aIhsiiinI3PE2jV2z/2ePnvjTSF0g9K4d7EFjbjelYsqOit5QlscrOM7cN6GD874QLkQP+dpZlrGpHN3tNLiohdxEgG2e+wtY/upWiqsdJfoJvKcTlpvJ0RB4IPEmxcWH2pUmOw==
  • Authentication-results: esa2.hc3370-68.iphmx.com; dkim=pass (signature verified) header.i=@citrix.onmicrosoft.com
  • Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Anthony PERARD <anthony.perard@xxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Julien Grall <julien@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Christian Lindig <christian.lindig@xxxxxxxxxx>, David Scott <dave@xxxxxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
  • Delivery-date: Thu, 10 Feb 2022 10:09:28 +0000
  • Ironport-data: A9a23:PjUQcajl8VDOh9YXmCPWEGMhX1612BcKZh0ujC45NGQN5FlHY01je htvW2rVP6yNNzD9edh+OYni9UNQ75LVnYM2GwZkqStnRS4b9cadCdqndUqhZCn6wu8v7a5EA 2fyTvGacajYm1eF/k/F3oAMKRCQ7InQLlbGILes1htZGEk0GE/NtTo5w7Rj2tQx2YDga++wk YiaT/P3aQfNNwFcagr424rbwP+4lK2v0N+wlgVWicFj5DcypVFMZH4sDfjZw0/DaptVBoaHq 9Prl9lVyI97EyAFUbtJmp6jGqEDryW70QKm0hK6UID66vROS7BbPg/W+5PwZG8O4whlkeydx /108qahRh14NZHHmedebUBVTxkiFqhZreqvzXiX6aR/zmXDenrohf5vEFs3LcsT/eMf7WNmr KJCbmpXN1ba2rzwkOnTpupE36zPKOHxO4wSoDd4xCzxBvc6W5HTBa7N4Le02R9u3ZEXRKeOO qL1bxJiVC6bMxxAEW06AaAyvM6yq1PtTyVH/Qf9Sa0fvDGIkV0ZPKLWGMHOZtWASMFRn0CZj mHL5WL0BlcdLtP34TiY9nOhgMffkCW9X5gdfJWG8fptjEyW13YkIhQcXlumotG0kke7HdlYL iQ89iMwoIAo+UesT927WAe3yFabujYMVtwWFPc1gCmdx6yR7wuHC2wsSj9adMdgpMIwXSYt1 FKCg5XuHzMHmL+fRG+Z97yUhSivIiVTJmgHDQcGQhEC+MLLu5wog1TESdMLLUKupoSrQ3eqm WnM9XVgweVI5SIW60ml1WmAuSOjvMnCcgU05UbpB2/51l9SYZHwMuRE9mPnxfpHKY+YSHyIs 34Fh9WS4YgyMH2dqMCeaL5TRe/0vp5pJBWZ2AcyRMd5q1xB7lb+Jdg43d1oGKt+3i/okxfNa VSbhw5e7YQ70JCCPf4uONLZ5yjHIMHd+TXZuhL8M4ImjntZLlbvEMRSiai4hDmFfK8Ey/9XB HtjWZzwZUv28Iw+pNZMe88T0KUw2gc1zn7JSJbwwnyPiOTCOCLOE+9dawvRP4jVCZ9oRi2Oq r6z0OPQlX1ivBDWOHGLoeb/03hWRZTEOXwGg5MOLbPSSuaXMGogF+XQ0dscl39NxMxoehPz1 ijlACdwkQOn7VWecFniQi0zOdvHAMckxVpmbHNEALpd8yV6CWpZxPxELMVfkHhO3LEL8MOYu NFbJ5veUq4SFlwqOV01NPHAkWCrTzzy7SqmNCu5ejkvOZlmQg3C4Nj/eQXzsiIJC0KKWQEW+ dVMDyvXHsgOQRpMFsHTZK79xl+9pyFFyulzQ1HJMp9Yf0C1qNpmLCn4j/kWJcAQKEqcmmvGh ljOWRpI9/PQp4IV8cXSgfzWpYmeDOYjTFFRGHPW7OjqOHCCrHaj24JJTM2BYSvZCDHv4Kyna OgMl6P8PfQLkUxkqY15F7o3n6sy68G2/+1Rzxh+HWWNZFOuU+syLn6D1MhJl6tM2r4G5lfmB hPRooFXYOzbNtnkHVgdIBseQt6CjfxEyCPP6fkVIVnh4HMl9rSwTkgPbQKHjzZQLeUpPdp9k /shosMf9ye2lgEuboSdlilR+mmBci4AXqEgus1ICYPnkFN2mFRLYJiaAS7q+pCfLd5LNxByc DOTgaPDgZVax1bDLCVvRSScg7IFiMRcog1OwX8DO0+Ny4jMifIA1RFM9Sg6E1ZOxRJd3uMvY mVmOiWZ/0lVE+uEUCSbY12RJg==
  • Ironport-hdrordr: A9a23:iezya65s90zzu3cHLQPXwSqBI+orL9Y04lQ7vn2ZFiY7TiXIra yTdaoguCMc6AxxZJkh8erwX5VoZUmsj6KdgLNhRotKOTOJhILGFvAB0WKP+UyEJ8S6zJ8h6U 4CSdkBNDSTNykCsS+S2mDReLxBsbq6GeKT9J/jJh9WPH5XgspbnmFE42igYylLrF4sP+tEKH PQ3LsOmxOQPVAsKuirDHgMWObO4/XNiZLdeBYDQzoq8hOHgz+E4KPzV0Hw5GZVbxp/hZMZtU TVmQ3w4auu99m91x/nzmfWq7BbgsHoxNdvDNGFzuIVNjLvoAC1Y5kJYczIgBkF5MWUrHo6mt jFpBkte+x19nPqZ2mw5SDg3gHxuQxenEPK+Bu9uz/OsMb5TDU1B45qnoRCaCbU7EImoZVVzL 9L93jxjesZMTrw2ADGo/TYXRBjkUS55VA4l/QIsnBZWYwCLJdMsI0k+l9PGptoJlO31GkeKp guMCjg3ocXTbvDBEqp/VWHgebcE0jbJy32DHTr4aeuonprdHMQ9Tpt+CVQpAZEyHsHceg12w 3zCNUcqFh/dL5mUUtDPpZzfSKWMB26ffueChPaHbzYfJt3SU4l7aSHpIkI2A==
  • Ironport-sdr: MCwoY3U2H6aIsKoO+Jk3Ma2epybaU3uyWg/yh5HQTw8zNcSDMrsHAkgri5oQAO4K5j03Jf85/o bQ5KVTQZQ5NCvNnEPu9ft3YnFOC1xQa8hR/w4e48J2LEZr6OFVPXKXWMi1DlakR0qWm++3cKcy EiutqKznkbU8BZe6KlrdEUhiEMgNV0ORCf0yB9mpB7Jd3F4N0kaJzRG1sghpwDXIIVwa1XO3uD 8gg6IBRLzCarmv5K7NsN4VEP0Il/2shDIOCC0NgmNiN1+NimXzb//ySBv74m9iGC671Uk4rRZI n0Dxy2buc4IZBeNfTXwiea39
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On Mon, Feb 07, 2022 at 06:21:01PM +0000, Jane Malalane wrote:
> Introduce a new per-domain creation x86 specific flag to
> select whether hardware assisted virtualization should be used for
> x{2}APIC.
> 
> A per-domain option is added to xl in order to select the usage of
> x{2}APIC hardware assisted vitualization, as well as a global
> configuration option.
> 
> Having all APIC interaction exit to Xen for emulation is slow and can
> induce much overhead. Hardware can speed up x{2}APIC by running APIC
> read/write accesses without taking a VM exit.
> 
> Being able to disable x{2}APIC hardware assisted vitualization can be
> useful for testing and debugging purposes.

Might be worth adding a note to the commit log in order to note that
vmx_install_vlapic_mapping doesn't require modifications regardless of
whether the guest has virtualize_apic_accesses enabled or not.

Setting the APIC_ACCESS_ADDR VMCS field is fine even if
virtualize_apic_accesses is not enabled for the guest: as long as the
feature is supported by the CPU the field will exist.

Thanks, Roger.



 


Rackspace

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