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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"Ian Jackson" <Ian.Jackson@citrix.com>
Subject: Re: [Xen-devel] [PATCH v2 08/10] tools/libxc: Rework xc_cpuid_apply_policy() to use {get, set}_cpu_policy()
Date: Mon, 16 Sep 2019 16:49:40 +0100	[thread overview]
Message-ID: <da0e9474-1467-ef45-6946-256e8c3149d4@citrix.com> (raw)
In-Reply-To: <a48bd401-32e1-0b7e-4c0b-3509630652ce@suse.com>

On 16/09/2019 12:17, Jan Beulich wrote:
> On 13.09.2019 21:27, Andrew Cooper wrote:
>> -static void intel_xc_cpuid_policy(const struct cpuid_domain_info *info,
>> -                                  const unsigned int *input, unsigned int *regs)
>> -{
>> -    switch ( input[0] )
>> -    {
>> -    case 0x00000004:
>> -        /*
>> -         * EAX[31:26] is Maximum Cores Per Package (minus one).
>> -         * Update to reflect vLAPIC_ID = vCPU_ID * 2.
>> -         */
>> -        regs[0] = (((regs[0] & 0x7c000000u) << 1) | 0x04000000u |
>> -                   (regs[0] & 0x3ffu));
>> -        regs[3] &= 0x3ffu;
> I think you want to mention that the removal of this masking is
> intentional, for it looking bogus. With an appropriate addition to
> the description
> Reviewed-by: Jan Beulich <jbeulich@suse.com>

As I said before, I fail to see how that isn't covered by the blanket
"almost all of this is redundant" statement.

There are other masks which are dropped, and calling this one out in
isolation seems wrong.  Observe that the comment discussing topology
only talks about eax, and not edx.

~Andrew

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  parent reply	other threads:[~2019-09-16 15:49 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-13 19:27 [Xen-devel] [PATCH v2 00/10] x86/cpuid: Switch to using XEN_DOMCTL_set_cpumsr_policy Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 01/10] x86/msr: Offer CPUID Faulting to PVH control domains Andrew Cooper
2019-09-16 10:53   ` Jan Beulich
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 02/10] libx86: Proactively initialise error pointers Andrew Cooper
     [not found]   ` <527f33ad-3de1-15c7-eb4b-603eaf65f3c5@suse.com>
     [not found]     ` <65f18521-15c5-72a9-29f6-cd5d621e1283@citrix.com>
2019-09-16 15:46       ` Jan Beulich
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 03/10] libx86: Introduce x86_cpu_policies_are_compatible() Andrew Cooper
2019-09-16 10:59   ` Jan Beulich
2019-09-16 15:31     ` Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 04/10] x86/cpuid: Split update_domain_cpuid_info() in half Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 05/10] x86/domctl: Implement XEN_DOMCTL_set_cpumsr_policy Andrew Cooper
2019-09-16 11:04   ` Jan Beulich
2019-09-16 15:40     ` Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 06/10] tools/libxc: Pre-cleanup for xc_cpuid_{set, apply_policy}() Andrew Cooper
2019-09-16 11:09   ` Jan Beulich
2019-09-16 15:42     ` Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 07/10] tools/libxc: Rework xc_cpuid_set() to use {get, set}_cpu_policy() Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 08/10] tools/libxc: Rework xc_cpuid_apply_policy() " Andrew Cooper
2019-09-16 11:17   ` Jan Beulich
2019-09-16 13:41     ` Wei Liu
2019-09-16 15:49     ` Andrew Cooper [this message]
2019-09-16 16:05       ` Jan Beulich
2019-09-18 16:09   ` Jan Beulich
2019-09-19  8:48     ` Andrew Cooper
2019-09-25 18:11   ` [Xen-devel] [PATCH v3 " Andrew Cooper
2019-09-26  8:04     ` Jan Beulich
2019-09-26 12:25       ` Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 09/10] x86/domctl: Drop XEN_DOMCTL_set_cpuid Andrew Cooper
2019-09-13 19:27 ` [Xen-devel] [PATCH v2 10/10] x86/cpuid: Enable CPUID Faulting for PV control domains by default Andrew Cooper
2019-09-16 11:22   ` Jan Beulich
2019-09-16 15:52     ` Andrew Cooper

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