From: Jan Beulich <jbeulich@suse.com>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH 14/21] libs/guest: introduce helper to check cpu policy compatibility
Date: Wed, 31 Mar 2021 16:57:38 +0200 [thread overview]
Message-ID: <958bf9f5-8481-b7fe-c29f-6eb971c6e2f1@suse.com> (raw)
In-Reply-To: <YGRtzlUmuRjKh6er@Air-de-Roger>
On 31.03.2021 14:40, Roger Pau Monné wrote:
> On Tue, Mar 30, 2021 at 06:02:45PM +0200, Jan Beulich wrote:
>> On 23.03.2021 10:58, Roger Pau Monne wrote:
>>> --- a/tools/libs/guest/xg_cpuid_x86.c
>>> +++ b/tools/libs/guest/xg_cpuid_x86.c
>>> @@ -1098,3 +1098,20 @@ int xc_cpu_policy_update_msrs(xc_interface *xch, xc_cpu_policy_t policy,
>>> return rc;
>>>
>>> }
>>> +
>>> +bool xc_cpu_policy_is_compatible(xc_interface *xch, const xc_cpu_policy_t p1,
>>> + const xc_cpu_policy_t p2)
>>> +{
>>> + struct cpu_policy_errors err;
>>
>> Don't you need an initializer here for ...
>>
>>> + int rc = x86_cpu_policies_are_compatible(p1, p2, &err);
>>> +
>>> + if ( !rc )
>>> + return true;
>>> +
>>> + if ( err.leaf != -1 )
>>> + ERROR("Leaf %#x subleaf %#x is not compatible", err.leaf, err.subleaf);
>>> + if ( err.msr != -1 )
>>> + ERROR("MSR index %#x is not compatible", err.msr);
>>
>> ... these checks to have a chance of actually triggering? (I'm also
>> not certain -1 is a good indicator, but I guess we have been using it
>> elsewhere as well.)
>
> Well, this is strictly the error path, at which point I would expect
> err to be properly set by x86_cpu_policies_are_compatible. I can
> however initialize err for safety here.
Aiui in the error case one of the two, but not both fields would
be set. Without initializer you'd likely find both of them != -1,
though.
Jan
next prev parent reply other threads:[~2021-03-31 14:57 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 9:58 [PATCH 00/21] libs/guest: new CPUID/MSR interface Roger Pau Monne
2021-03-23 9:58 ` [PATCH 01/21] libxl: don't ignore the return value from xc_cpuid_apply_policy Roger Pau Monne
2021-03-30 15:21 ` Jan Beulich
2021-03-30 15:38 ` Andrew Cooper
2021-03-31 18:12 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 02/21] libs/guest: rename xc_get_cpu_policy_size to xc_cpu_policy_get_size Roger Pau Monne
2021-03-31 19:03 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 03/21] libs/guest: introduce xc_cpu_policy_t Roger Pau Monne
2021-03-31 20:10 ` Andrew Cooper
2021-04-01 8:48 ` Roger Pau Monné
2021-03-23 9:58 ` [PATCH 04/21] libs/guest: introduce helper to fetch a system cpu policy Roger Pau Monne
2021-03-30 15:35 ` Jan Beulich
2021-04-01 13:56 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 05/21] libs/guest: introduce helper to fetch a domain " Roger Pau Monne
2021-03-30 15:37 ` Jan Beulich
2021-03-31 11:06 ` Roger Pau Monné
2021-04-01 13:32 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 06/21] libs/guest: introduce helper to serialize a " Roger Pau Monne
2021-03-23 9:58 ` [PATCH 07/21] tools: switch existing users of xc_get_{system,domain}_cpu_policy Roger Pau Monne
2021-03-23 9:58 ` [PATCH 08/21] libs/guest: introduce a helper to apply a cpu policy to a domain Roger Pau Monne
2021-03-23 9:58 ` [PATCH 09/21] libs/guest: allow fetching a specific CPUID leaf from a cpu policy Roger Pau Monne
2021-04-01 14:47 ` Andrew Cooper
2021-04-08 15:53 ` Roger Pau Monné
2021-03-23 9:58 ` [PATCH 10/21] libs/guest: allow fetching a specific MSR entry " Roger Pau Monne
2021-03-23 9:58 ` [PATCH 11/21] libs/guest: allow updating a cpu policy CPUID data Roger Pau Monne
2021-03-30 15:56 ` Jan Beulich
2021-03-31 12:47 ` Roger Pau Monné
2021-04-01 14:55 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 12/21] libs/guest: allow updating a cpu policy MSR data Roger Pau Monne
2021-03-23 9:58 ` [PATCH 13/21] libs/guest: switch users of xc_set_domain_cpu_policy Roger Pau Monne
2021-04-01 15:04 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 14/21] libs/guest: introduce helper to check cpu policy compatibility Roger Pau Monne
2021-03-30 16:02 ` Jan Beulich
2021-03-31 12:40 ` Roger Pau Monné
2021-03-31 14:57 ` Jan Beulich [this message]
2021-04-01 16:14 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 15/21] libs/guest: obtain a compatible cpu policy from two input ones Roger Pau Monne
2021-03-31 15:24 ` Jan Beulich
2021-04-01 16:26 ` Andrew Cooper
2021-04-09 10:56 ` Roger Pau Monné
2021-03-23 9:58 ` [PATCH 16/21] libs/guest: make a cpu policy compatible with older Xen versions Roger Pau Monne
2021-03-31 15:29 ` Jan Beulich
2021-04-01 16:31 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 17/21] libs/guest: introduce helper set cpu topology in cpu policy Roger Pau Monne
2021-04-01 17:22 ` Andrew Cooper
2021-03-23 9:58 ` [PATCH 18/21] libs/guest: rework xc_cpuid_xend_policy Roger Pau Monne
2021-03-23 9:58 ` [PATCH 19/21] libs/guest: apply a featureset into a cpu policy Roger Pau Monne
2021-03-23 9:58 ` [PATCH 20/21] libs/{light,guest}: implement xc_cpuid_apply_policy in libxl Roger Pau Monne
2021-04-01 17:44 ` Andrew Cooper
2021-04-09 14:57 ` Roger Pau Monné
2021-03-23 9:58 ` [PATCH 21/21] libs/guest: (re)move xc_cpu_policy_apply_cpuid Roger Pau Monne
2021-04-01 17:53 ` Andrew Cooper
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