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

Re: [PATCH] docs: correct x86 MCE command line option info


  • To: Jan Beulich <jbeulich@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • From: Andrew Cooper <Andrew.Cooper3@xxxxxxxxxx>
  • Date: Mon, 28 Feb 2022 13:19:40 +0000
  • Accept-language: en-GB, en-US
  • Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=citrix.com; dmarc=pass action=none header.from=citrix.com; dkim=pass header.d=citrix.com; 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=0kRc8gBjLkYgEVkXNntJvOvykn3mZ64v01dlovW2AXw=; b=XOPZv1L9Cq8Y5prbfat5V3rB7nv4YVzDZt4okQC4Ndf9jBO1dKDuW+GJTaXGqmuDeNL3WP83mhTxYejB+iMV8PyxhcEi8q1rr1Fke0hXXQQzvB3bT8NjJXcsUjI+tWv5BkJjs99FdELb+p8+d2TIBzFlftqa+Ytrads8jsnr7o0J4QEMqDqshYf5+BTOCRm5zIXRqxGHeKokrTy0FLNUnTDug1+RBvQxtcMCA/YMFSjjKZMax57if1tWLCga3l0BQXHZXa/4TylxGqwaPxXkRwwNc5fXKJfFUT8FPaPsntrtNPw5zCigfng4NwcBw1qBQzBoj4XGs8Bh/BuKsHlbrQ==
  • Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=MNlv2XXghfsbtQ6T0rLOFI56OoqBCr/38JUNIcMmjLCF5GBKOPZwHRKeGBhxG0Z1E8d+Q83Qo3/8UsSz9fDbfRilib1zeFi+vGZqegGsPyYHlK0pW3HuYfFv9DVxzc8si+eUvSOHDfwm9Gv7SH01YrwN4dnnFQWRD6I5TW3m8yrPW1zQHC4/2S9R3kL5EQeaE/C8Rz5AV0K4pGCxHv4bX72SrGv1mwMgwoQyyp53rPAi9wg+nXn7VyOEZBNZGbCfnjlW6zmWQWgWf4tqVygHJMnr/ZCImyk7kVSzsVF5TBgDsk54DCpZxTXjLytS42h+kECToILGYZjkYalqr9FPdg==
  • Authentication-results: esa6.hc3370-68.iphmx.com; dkim=pass (signature verified) header.i=@citrix.onmicrosoft.com
  • Cc: George Dunlap <George.Dunlap@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, "Roger Pau Monne" <roger.pau@xxxxxxxxxx>
  • Delivery-date: Mon, 28 Feb 2022 13:19:55 +0000
  • Ironport-data: A9a23:q/kDkKoGvLGXd8WvNTQUXuo/v3ReBmLdZRIvgKrLsJaIsI4StFCzt garIBmHb/+KYjGmftgib4uwpE1T6sTTzNRlHgA/riFkRXxB8ZuZCYyVIHmrMnLJJKUvbq7GA +byyDXkBJppJpMJjk71atANlVEliefQAOCU5NfsYkidfyc9IMsaoU8lyrZRbrJA24DjWVvX4 4Oq+qUzBXf+s9JKGjNMg068gEsHUMTa4Fv0aXRnOJinFHeH/5UkJMp3yZOZdhMUcaENdgKOf M7RzanRw4/s10xF5uVJMFrMWhZirrb6ZWBig5fNMkSoqkAqSicais7XOBeAAKv+Zvrgc91Zk b1wWZKMpQgBOZbCycAWckZiKDB/E78F5Zj2BFGYiJnGp6HGWyOEL/RGCUg3OcsT+/ptAHEI/ vsdQNwPRknd3aTsmuv9E7QywJR4RCXoFNp3VnVI5DfVF/s5B7vERL3H/4Rw1zYsnMFeW/3ZY qL1bBIxMUyaO0cRZj/7DroRkNqWr2egWQF5l0iph/o7znL11C9Yhe2F3N39JYXRGJQ9clyjj nnd423zDxUeNdqe4TmI6HShgqnIhyyTcJ0WPK218LhtmlL77m4ODBwbU3OrrP//jVSxM/pdI UEJ/islrYAp6VemCNL6WnWQsHOC+xIRRddUO+k78x2WjLrZ5R6DAWoJRSIHb8Yp3PLaXhRzi AXPxYmwQ2Uy7vvFEhpx64t4sxu1AiZECWQjOhU/XAor8Zr+h7AWpzX2G4ML/LGOsvX5HjT5w javpSc4hqkOgcNj65hX7WwrkBr3+MGXE1ddChH/Gzv8s1gnPNLNi5mAtACDhcusOrp1WbVoU JIsv8GFpN4DApiW/MBmaLVcRer5jxpp3dC1vLKOI3XD32n3k5JAVdoJiN2bGKuPGpxZEdMOS BWO0T69HLcJYBOXgVZfOupd8fgCw6n6DsjCXfvJdNdIaZUZXFbZoHw/NRHJhjyzyBhEfUQD1 XGzK5vE4ZEyU/kP8dZLb71Fje9DKt4Wnws/uqwXPzz4iOHDNRZ5uJ8OMUeUb/BR0U93iF69z jqrDOPTk083eLSnOkH/qNdPRXhXfSlTLc2n8KR/K7/cSjeK7Ul8Upc9N5t6INc790mU/8+Vl kyAtrhwkwKu1SWaclzRMhiOqtrHBP5CkJ7yBgR1VX6A0Hk/e4e/qqAZcpo8Z7488+J/i/VzS pE4lw+oWJyjlhyvF+whUKTA
  • Ironport-hdrordr: A9a23:rF4kiq6mICx/rMeh2QPXwWaBI+orL9Y04lQ7vn2ZFiY7TiXIra yTdaoguCMc0AxhJU3Jmbi7Scy9qeu1z+873WBjB8bfYOCAghrnEGgC1/qv/9SEIUPDH4FmpN 5dmsRFeb7N5B1B/LzHCWqDYpcdKbu8gdiVbI7lph8HJ2ALV0gj1XYDNu/yKDwseOAsP+tcKH Po3Lsgm9PWQwVxUi3UPAhmY8Hz4/nw0L72ax8PABAqrCOUiymz1bL8Gx+Emj8DTjJm294ZgC j4uj28wp/mn+Cwyxfa2WOWxY9RgsHdxtxKA9HJotQJKw/rlh2jaO1aKv6/VXEO0aOSAWQR4Z 3xSiQbToNOArTqDyeISC7WqkzdOfAVmibfIBGj8CPeSIfCNU0H4oJ69Pxkm13imhAdVZhHod J2NyjyjesnMTrQ2Cv6/NTGTBdsiw69pmcji/caizhFXZIZc6I5l/1VwKp5KuZIIMvB0vFuLA CuNrCp2N9GNVeBK3zJtGhmx9KhGnw1AxedW0AH/siYySJfknx1x1YRgJV3pAZMyLstD51fo+ jUOKVhk79DCscQcKJmHe8EBc+6EHbETx7AOH+bZV7nCKYEMXTQrIOf2sR+2Mi6PJgTiJcikp XIV11V8WY0ZkL1EMWLmIZG9xjcKV/NKwgFCvsukKSRloeMNoYDaxfzO2zGu/HQ1skiPg==
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
  • Thread-index: AQHYLIzH3mLmwWw5aEm0tUCG/sGwH6yo8pOA
  • Thread-topic: [PATCH] docs: correct x86 MCE command line option info

On 28/02/2022 10:20, Jan Beulich wrote:
> Not even the types were correct,

Huh yes.  c/s 97638f08f4 was plain wrong.

>  let alone defaults being spelled out or
> the purpose of the options actually mentioned in any way.
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/docs/misc/xen-command-line.pandoc
> +++ b/docs/misc/xen-command-line.pandoc
> @@ -1681,10 +1681,21 @@ one pending bit to be allocated.
>  Defaults to 20 bits (to cover at most 1048576 interrupts).
>  
>  ### mce (x86)
> -> `= <integer>`
> +> `= <boolean>`
> +
> +> Default: `true`
> +
> +Allows to disable the use of Machine Check Exceptions.  Note that this
> +may result in silent shutdown of the system in case an event occurs
> +which would have resulted in raising a Machine Check Exception.

This description appears backwards.  Errors happen irrespective of MCE,
and will by default cause a system shutdown.

MCE offers the OS/VMM some ability to deal with certain
not-totally-fatal errors in a less impactful way than killing the whole
system.  Also, it allows reporting of corrected errors which are
indicative of failing components.

Also, it's not silent - the MCE registers explicitly don't clear on
reset so they can be recovered after warm reset.  Firmware collects
these and is supposed to do something useful with them, although
"useful" is a matter of opinion, and in some cases depends on how much
extra you're willing to pay your OEM.

~Andrew

 


Rackspace

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