From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.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 11/21] libs/guest: allow updating a cpu policy CPUID data
Date: Wed, 31 Mar 2021 14:47:42 +0200 [thread overview]
Message-ID: <YGRvbgQqyrWw4fjh@Air-de-Roger> (raw)
In-Reply-To: <ee841bd2-340e-aed4-2403-a655fbb13862@suse.com>
On Tue, Mar 30, 2021 at 05:56:35PM +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
> > @@ -966,3 +966,70 @@ int xc_cpu_policy_get_msr(xc_interface *xch, const xc_cpu_policy_t policy,
> > free(msrs);
> > return rc;
> > }
> > +
> > +int xc_cpu_policy_update_cpuid(xc_interface *xch, xc_cpu_policy_t policy,
> > + const xen_cpuid_leaf_t *leaves,
> > + uint32_t nr)
> > +{
> > + unsigned int err_leaf = -1, err_subleaf = -1;
> > + unsigned int nr_leaves, nr_msrs, i, j;
> > + xen_cpuid_leaf_t *current;
> > + int rc = xc_cpu_policy_get_size(xch, &nr_leaves, &nr_msrs);
> > +
> > + if ( rc )
> > + {
> > + PERROR("Failed to obtain policy info size");
> > + return -1;
> > + }
> > +
> > + current = calloc(nr_leaves, sizeof(*current));
> > + if ( !current )
> > + {
> > + PERROR("Failed to allocate resources");
> > + errno = ENOMEM;
> > + return -1;
> > + }
> > +
> > + rc = xc_cpu_policy_serialise(xch, policy, current, &nr_leaves, NULL, 0);
> > + if ( rc )
> > + goto out;
> > +
> > + for ( i = 0; i < nr; i++ )
> > + {
> > + const xen_cpuid_leaf_t *update = &leaves[i];
> > +
> > + for ( j = 0; j < nr_leaves; j++ )
> > + if ( current[j].leaf == update->leaf &&
> > + current[j].subleaf == update->subleaf )
> > + {
> > + /*
> > + * NB: cannot use an assignation because of the const vs
> > + * non-const difference.
> > + */
> > + memcpy(¤t[j], update, sizeof(*update));
>
> I'm having trouble understanding the comment. In
>
> current[j] = *update;
>
> the lvalue is xen_cpuid_leaf_t and the rvalue is const xen_cpuid_leaf_t.
> That the usual (and permitted) arrangement afaics.
I'm sure I was doing something really stupid, and as a bonus I failed
to properly parse the error message I got from the compiler. It's now
fixed here and below.
Thanks, Roger.
next prev parent reply other threads:[~2021-03-31 12:48 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 [this message]
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
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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