From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Roger Pau Monne <roger.pau@citrix.com>, <xen-devel@lists.xenproject.org>
Cc: Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH 09/21] libs/guest: allow fetching a specific CPUID leaf from a cpu policy
Date: Thu, 1 Apr 2021 15:47:20 +0100 [thread overview]
Message-ID: <bb7b8cd2-97ae-09d9-61c8-1f84616256f5@citrix.com> (raw)
In-Reply-To: <20210323095849.37858-10-roger.pau@citrix.com>
On 23/03/2021 09:58, Roger Pau Monne wrote:
> diff --git a/tools/libs/guest/xg_cpuid_x86.c b/tools/libs/guest/xg_cpuid_x86.c
> index 48351f1c4c6..a1e1bf10d5c 100644
> --- a/tools/libs/guest/xg_cpuid_x86.c
> +++ b/tools/libs/guest/xg_cpuid_x86.c
> @@ -883,3 +883,45 @@ int xc_cpu_policy_serialise(xc_interface *xch, const xc_cpu_policy_t p,
> errno = 0;
> return 0;
> }
> +
> +int xc_cpu_policy_get_cpuid(xc_interface *xch, const xc_cpu_policy_t policy,
> + uint32_t leaf, uint32_t subleaf,
> + xen_cpuid_leaf_t *out)
> +{
> + unsigned int nr_leaves, nr_msrs, i;
> + xen_cpuid_leaf_t *leaves;
> + int rc = xc_cpu_policy_get_size(xch, &nr_leaves, &nr_msrs);
> +
> + if ( rc )
> + {
> + PERROR("Failed to obtain policy info size");
> + return -1;
> + }
> +
> + leaves = calloc(nr_leaves, sizeof(*leaves));
> + if ( !leaves )
> + {
> + PERROR("Failed to allocate resources");
> + errno = ENOMEM;
> + return -1;
> + }
> +
> + rc = xc_cpu_policy_serialise(xch, policy, leaves, &nr_leaves, NULL, 0);
> + if ( rc )
> + goto out;
> +
> + for ( i = 0; i < nr_leaves; i++ )
> + if ( leaves[i].leaf == leaf && leaves[i].subleaf == subleaf )
> + {
> + *out = leaves[i];
> + goto out;
> + }
Please adapt find_leaf(), probably by dropping xc_xend_cpuid and passing
in leaf/subleaf parameters.
Serialised leaves are sorted and there are plenty of them, so a log
search is better.
How frequent is this call going to be for the same policy? With the
arrays embedded in a policy, they're still around, and serialise is an
expensive operation.
I wonder if it makes sense to try and keep both forms in sync, so we can
avoid redundant calls like this?
~Andrew
next prev parent reply other threads:[~2021-04-01 14:47 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 [this message]
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
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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