* [Xen-devel] [PATCH for-4.13] docs: Extend with details about runtime microcode loading
@ 2019-10-12 18:18 Andrew Cooper
2019-10-14 13:44 ` Jürgen Groß
2019-10-23 13:56 ` Jan Beulich
0 siblings, 2 replies; 3+ messages in thread
From: Andrew Cooper @ 2019-10-12 18:18 UTC (permalink / raw)
To: Xen-devel
Cc: Juergen Gross, Lars Kurth, Stefano Stabellini, Julien Grall,
Wei Liu, Konrad Rzeszutek Wilk, George Dunlap, Andrew Cooper,
Tim Deegan, Jan Beulich, Ian Jackson
The xen-ucode utility is new with the late loading improvements in 4.13.
Update the documentation suitably.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Ian Jackson <ian.jackson@citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Tim Deegan <tim@xen.org>
CC: Wei Liu <wl@xen.org>
CC: Julien Grall <julien@xen.org>
CC: Juergen Gross <jgross@suse.com>
CC: Lars Kurth <lars.kurth@citrix.com>
For 4.13. This is documentation concerning new work.
The additions for choosing the application policy, and logic to rescan
CPUID/MSRs and start using the new functionatly will have to wait for 4.14 at
this point.
If anyone is curious about the wording of the warning, it should come as no
surprise that an individual blob of microcode might contain more than one
thing. On anything semi-modern system, there is Core microcode (the pipeline
itself), and Uncore microcode (the "rest" of the integrated functionality on
the chip), as well as other ancillary pieces.
---
docs/admin-guide/microcode-loading.rst | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/docs/admin-guide/microcode-loading.rst b/docs/admin-guide/microcode-loading.rst
index 8265b917a9..e83cadd2c2 100644
--- a/docs/admin-guide/microcode-loading.rst
+++ b/docs/admin-guide/microcode-loading.rst
@@ -103,3 +103,32 @@ which contains contains one of these two files::
The ``ucode=scan`` command line option will cause Xen to search through all
modules to find any CPIO archives, and search the archive for the applicable
file. Xen will stop searching at the first match.
+
+
+Run time microcode loading
+--------------------------
+
+.. warning::
+
+ If at all possible, microcode updates should be done by firmware updates,
+ or at boot time. Not all microcode updates (or parts thereof) can be
+ applied at runtime.
+
+The ``xen-ucode`` utility can be used to initiate a runtime microcode load.
+It will pass the blob to Xen, which will check to see whether the blob is
+correct for the processor, and newer than the running microcode.
+
+If these checks pass, the entire system will be rendezvoused and an update
+will be initiated on all CPUs in parallel. As with boot time loading,
+diagnostics will be put out onto the console::
+
+ [root@host ~]# xl dmesg | grep microcode
+ (XEN) microcode: CPU0 updated from revision 0x1a to 0x25, date = 2018-04-02
+ (XEN) microcode: CPU2 updated from revision 0x1a to 0x25, date = 2018-04-02
+ (XEN) microcode: CPU4 updated from revision 0x1a to 0x25, date = 2018-04-02
+ (XEN) microcode: CPU6 updated from revision 0x1a to 0x25, date = 2018-04-02
+ (XEN) 4 cores are to update their microcode
+ (XEN) microcode: CPU0 updated from revision 0x25 to 0x27, date = 2019-02-26
+ (XEN) microcode: CPU4 updated from revision 0x25 to 0x27, date = 2019-02-26
+ (XEN) microcode: CPU2 updated from revision 0x25 to 0x27, date = 2019-02-26
+ (XEN) microcode: CPU6 updated from revision 0x25 to 0x27, date = 2019-02-26
--
2.11.0
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [Xen-devel] [PATCH for-4.13] docs: Extend with details about runtime microcode loading
2019-10-12 18:18 [Xen-devel] [PATCH for-4.13] docs: Extend with details about runtime microcode loading Andrew Cooper
@ 2019-10-14 13:44 ` Jürgen Groß
2019-10-23 13:56 ` Jan Beulich
1 sibling, 0 replies; 3+ messages in thread
From: Jürgen Groß @ 2019-10-14 13:44 UTC (permalink / raw)
To: Andrew Cooper, Xen-devel
Cc: Lars Kurth, Stefano Stabellini, Julien Grall, WeiLiu,
Konrad Rzeszutek Wilk, George Dunlap, Tim Deegan, Jan Beulich,
Ian Jackson
On 12.10.19 20:18, Andrew Cooper wrote:
> The xen-ucode utility is new with the late loading improvements in 4.13.
> Update the documentation suitably.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
Juergen
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Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Xen-devel] [PATCH for-4.13] docs: Extend with details about runtime microcode loading
2019-10-12 18:18 [Xen-devel] [PATCH for-4.13] docs: Extend with details about runtime microcode loading Andrew Cooper
2019-10-14 13:44 ` Jürgen Groß
@ 2019-10-23 13:56 ` Jan Beulich
1 sibling, 0 replies; 3+ messages in thread
From: Jan Beulich @ 2019-10-23 13:56 UTC (permalink / raw)
To: Andrew Cooper
Cc: Juergen Gross, Lars Kurth, Stefano Stabellini, Julien Grall,
WeiLiu, Konrad Rzeszutek Wilk, George Dunlap, Tim Deegan,
Ian Jackson, Xen-devel
On 12.10.2019 20:18, Andrew Cooper wrote:
> The xen-ucode utility is new with the late loading improvements in 4.13.
> Update the documentation suitably.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
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Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
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2019-10-12 18:18 [Xen-devel] [PATCH for-4.13] docs: Extend with details about runtime microcode loading Andrew Cooper
2019-10-14 13:44 ` Jürgen Groß
2019-10-23 13:56 ` Jan Beulich
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