From: Chao Gao <chao.gao@intel.com>
To: Sergey Dyasli <sergey.dyasli@citrix.com>
Cc: "Kevin Tian" <kevin.tian@intel.com>,
"Ashok Raj" <ashok.raj@intel.com>, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Jan Beulich" <jbeulich@suse.com>,
"Jun Nakajima" <jun.nakajima@intel.com>,
xen-devel@lists.xenproject.org,
"Thomas Gleixner" <tglx@linutronix.de>,
"Borislav Petkov" <bp@suse.de>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v9 13/15] x86/microcode: Synchronize late microcode loading
Date: Mon, 19 Aug 2019 22:49:36 +0800 [thread overview]
Message-ID: <20190819144934.GA12597@gao-cwp> (raw)
In-Reply-To: <ea4e0bee-7151-82da-c293-fec2532f9b92@citrix.com>
On Mon, Aug 19, 2019 at 11:27:36AM +0100, Sergey Dyasli wrote:
>> +static int master_thread_fn(const struct microcode_patch *patch)
>> +{
>> + unsigned int cpu = smp_processor_id();
>> + int ret = 0;
>> +
>> + while ( loading_state != LOADING_CALLIN )
>> + cpu_relax();
>> +
>> + cpumask_set_cpu(cpu, &cpu_callin_map);
>> +
>> + while ( loading_state != LOADING_ENTER )
>> + cpu_relax();
>
>If I'm reading it right, this will wait forever in case when...
>
>> +
>> + /*
>> + * If an error happened, control thread would set 'loading_state'
>> + * to LOADING_EXIT. Don't perform ucode loading for this case
>> + */
>> + if ( loading_state == LOADING_EXIT )
>> + return ret;
I tried to check whether there was an error here. But as you said, we
cannot reach here if 'control thread' set loading_state from LOADING_CALLIN
to LOADING_EXIT. I will do this check in the while-loop right above.
>> +
>> + ret = microcode_ops->apply_microcode(patch);
>> + if ( !ret )
>> + atomic_inc(&cpu_updated);
>> + atomic_inc(&cpu_out);
>> +
>> + while ( loading_state != LOADING_EXIT )
>> + cpu_relax();
>> +
>> + return ret;
>> +}
>> +
>> +static int control_thread_fn(const struct microcode_patch *patch)
>> {
>> - unsigned int cpu;
>> + unsigned int cpu = smp_processor_id(), done;
>> + unsigned long tick;
>> + int ret;
>>
>> - /* Store the patch after a successful loading */
>> - if ( !microcode_update_cpu(patch) && patch )
>> + /* Allow threads to call in */
>> + loading_state = LOADING_CALLIN;
>> + smp_mb();
>> +
>> + cpumask_set_cpu(cpu, &cpu_callin_map);
>> +
>> + /* Waiting for all threads calling in */
>> + ret = wait_for_condition(wait_cpu_callin,
>> + (void *)(unsigned long)num_online_cpus(),
>> + MICROCODE_CALLIN_TIMEOUT_US);
>> + if ( ret ) {
>> + loading_state = LOADING_EXIT;
>> + return ret;
>> + }
>
>...this condition holds. Have you actually tested this case?
I didn't craft a case to verify the error-handling path. And I believe
that you are right.
Thanks
Chao
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2019-08-19 14:46 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 1:25 [Xen-devel] [PATCH v9 00/15] improve late microcode loading Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 01/15] microcode/intel: extend microcode_update_match() Chao Gao
2019-08-28 15:12 ` Jan Beulich
2019-08-29 7:15 ` Chao Gao
2019-08-29 7:14 ` Jan Beulich
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 02/15] microcode/amd: fix memory leak Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 03/15] microcode/amd: distinguish old and mismatched ucode in microcode_fits() Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 04/15] microcode: introduce a global cache of ucode patch Chao Gao
2019-08-22 11:11 ` Roger Pau Monné
2019-08-28 15:21 ` Jan Beulich
2019-08-29 10:18 ` Jan Beulich
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 05/15] microcode: clean up microcode_resume_cpu Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 06/15] microcode: remove struct ucode_cpu_info Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 07/15] microcode: remove pointless 'cpu' parameter Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 08/15] microcode/amd: call svm_host_osvw_init() in common code Chao Gao
2019-08-22 13:08 ` Roger Pau Monné
2019-08-28 15:26 ` Jan Beulich
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 09/15] microcode: pass a patch pointer to apply_microcode() Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 10/15] microcode: split out apply_microcode() from cpu_request_microcode() Chao Gao
2019-08-22 13:59 ` Roger Pau Monné
2019-08-29 10:06 ` Jan Beulich
2019-08-30 3:22 ` Chao Gao
2019-08-30 7:25 ` Jan Beulich
2019-08-29 10:19 ` Jan Beulich
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 11/15] microcode: unify loading update during CPU resuming and AP wakeup Chao Gao
2019-08-22 14:10 ` Roger Pau Monné
2019-08-22 16:44 ` Chao Gao
2019-08-23 9:09 ` Roger Pau Monné
2019-08-29 7:37 ` Chao Gao
2019-08-29 8:16 ` Roger Pau Monné
2019-08-29 10:26 ` Jan Beulich
2019-08-29 10:29 ` Jan Beulich
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 12/15] microcode: reduce memory allocation and copy when creating a patch Chao Gao
2019-08-23 8:11 ` Roger Pau Monné
2019-08-26 7:03 ` Chao Gao
2019-08-26 8:11 ` Roger Pau Monné
2019-08-29 10:47 ` Jan Beulich
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 13/15] x86/microcode: Synchronize late microcode loading Chao Gao
2019-08-19 10:27 ` Sergey Dyasli
2019-08-19 14:49 ` Chao Gao [this message]
2019-08-29 12:06 ` Jan Beulich
2019-08-30 3:30 ` Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 14/15] microcode: remove microcode_update_lock Chao Gao
2019-08-19 1:25 ` [Xen-devel] [PATCH v9 15/15] microcode: block #NMI handling when loading an ucode Chao Gao
2019-08-23 8:46 ` Sergey Dyasli
2019-08-26 8:07 ` Chao Gao
2019-08-27 4:52 ` Chao Gao
2019-08-28 8:52 ` Sergey Dyasli
2019-08-29 12:11 ` Jan Beulich
2019-08-30 6:35 ` Chao Gao
2019-09-09 5:52 ` Chao Gao
2019-09-09 6:16 ` Jan Beulich
2019-08-29 12:22 ` Jan Beulich
2019-08-30 6:33 ` Chao Gao
2019-08-30 7:30 ` Jan Beulich
2019-08-22 7:51 ` [Xen-devel] [PATCH v9 00/15] improve late microcode loading Sergey Dyasli
2019-08-22 15:39 ` Chao Gao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190819144934.GA12597@gao-cwp \
--to=chao.gao@intel.com \
--cc=andrew.cooper3@citrix.com \
--cc=ashok.raj@intel.com \
--cc=bp@suse.de \
--cc=jbeulich@suse.com \
--cc=jun.nakajima@intel.com \
--cc=kevin.tian@intel.com \
--cc=roger.pau@citrix.com \
--cc=sergey.dyasli@citrix.com \
--cc=tglx@linutronix.de \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).