| Message ID | 20200226202221.6555-2-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: Default vs Max policies | expand |
On 26.02.2020 21:22, Andrew Cooper wrote: > Just as with c/s 96dc77b4b1 for XEN_SYSCTL_get_cpu_policy, > XEN_SYSCTL_get_cpu_featureset needs to become conditional. > > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Albeit I'd say "want", not "needs" in the description. Jan
On 27/02/2020 07:38, Jan Beulich wrote: > On 26.02.2020 21:22, Andrew Cooper wrote: >> Just as with c/s 96dc77b4b1 for XEN_SYSCTL_get_cpu_policy, >> XEN_SYSCTL_get_cpu_featureset needs to become conditional. >> >> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> > Reviewed-by: Jan Beulich <jbeulich@suse.com> > > Albeit I'd say "want", not "needs" in the description. It occurs to me that XEN_SYSCTL_get_cpu_featureset is strictly a subset of XEN_SYSCTL_get_cpu_policy, and that now I've adjusted the toolstack onto get_cpu_policy, the sole remaining user is xen-cpuid. get_cpu_policy already has separate default and max indices, whereas get_cpu_featureset was written before the need for this has become obvious. This leads to an asymmetry in xen-cpuid, where the -p (policy) option provides two more sets of information than the featureset listing. Instead, I think I'd like to drop XEN_SYSCTL_get_cpu_featureset and update the sole user to the more complete interface. Thoughts? ~Andrew
On 27.02.2020 10:33, Andrew Cooper wrote: > On 27/02/2020 07:38, Jan Beulich wrote: >> On 26.02.2020 21:22, Andrew Cooper wrote: >>> Just as with c/s 96dc77b4b1 for XEN_SYSCTL_get_cpu_policy, >>> XEN_SYSCTL_get_cpu_featureset needs to become conditional. >>> >>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> >> Reviewed-by: Jan Beulich <jbeulich@suse.com> >> >> Albeit I'd say "want", not "needs" in the description. > > It occurs to me that XEN_SYSCTL_get_cpu_featureset is strictly a subset > of XEN_SYSCTL_get_cpu_policy, and that now I've adjusted the toolstack > onto get_cpu_policy, the sole remaining user is xen-cpuid. > > get_cpu_policy already has separate default and max indices, whereas > get_cpu_featureset was written before the need for this has become obvious. > > This leads to an asymmetry in xen-cpuid, where the -p (policy) option > provides two more sets of information than the featureset listing. > > Instead, I think I'd like to drop XEN_SYSCTL_get_cpu_featureset and > update the sole user to the more complete interface. Sounds like a good move to me. Jan
On 27/02/2020 09:40, Jan Beulich wrote: > On 27.02.2020 10:33, Andrew Cooper wrote: >> On 27/02/2020 07:38, Jan Beulich wrote: >>> On 26.02.2020 21:22, Andrew Cooper wrote: >>>> Just as with c/s 96dc77b4b1 for XEN_SYSCTL_get_cpu_policy, >>>> XEN_SYSCTL_get_cpu_featureset needs to become conditional. >>>> >>>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> >>> Reviewed-by: Jan Beulich <jbeulich@suse.com> >>> >>> Albeit I'd say "want", not "needs" in the description. >> It occurs to me that XEN_SYSCTL_get_cpu_featureset is strictly a subset >> of XEN_SYSCTL_get_cpu_policy, and that now I've adjusted the toolstack >> onto get_cpu_policy, the sole remaining user is xen-cpuid. >> >> get_cpu_policy already has separate default and max indices, whereas >> get_cpu_featureset was written before the need for this has become obvious. >> >> This leads to an asymmetry in xen-cpuid, where the -p (policy) option >> provides two more sets of information than the featureset listing. >> >> Instead, I think I'd like to drop XEN_SYSCTL_get_cpu_featureset and >> update the sole user to the more complete interface. > Sounds like a good move to me. Actually, after having spent almost a day trying to disentangle the remains of this, I'm going to leave it for now. It turns out it is still used by the legacy CPUID logic, and I could do with getting a few other pieces of infrastructure before it is easy to take out. ~Andrew
diff --git a/tools/misc/xen-cpuid.c b/tools/misc/xen-cpuid.c index f55b67640a..36c17bf777 100644 --- a/tools/misc/xen-cpuid.c +++ b/tools/misc/xen-cpuid.c @@ -251,7 +251,7 @@ static void decode_featureset(const uint32_t *features, } } -static void get_featureset(xc_interface *xch, unsigned int idx) +static int get_featureset(xc_interface *xch, unsigned int idx) { struct fsinfo *f = &featuresets[idx]; @@ -261,8 +261,7 @@ static void get_featureset(xc_interface *xch, unsigned int idx) if ( !f->fs ) err(1, "calloc(, featureset)"); - if ( xc_get_cpu_featureset(xch, idx, &f->len, f->fs) ) - err(1, "xc_get_featureset()"); + return xc_get_cpu_featureset(xch, idx, &f->len, f->fs); } static void dump_info(xc_interface *xch, bool detail) @@ -294,7 +293,17 @@ static void dump_info(xc_interface *xch, bool detail) printf("\nDynamic sets:\n"); for ( i = 0; i < ARRAY_SIZE(featuresets); ++i ) { - get_featureset(xch, i); + if ( get_featureset(xch, i) ) + { + if ( errno == EOPNOTSUPP ) + { + printf("%s featureset not supported by Xen\n", + featuresets[i].name); + continue; + } + + err(1, "xc_get_featureset()"); + } decode_featureset(featuresets[i].fs, featuresets[i].len, featuresets[i].name, detail); diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c index 59a384023b..7ea8c38797 100644 --- a/xen/arch/x86/sysctl.c +++ b/xen/arch/x86/sysctl.c @@ -363,11 +363,15 @@ long arch_do_sysctl( case XEN_SYSCTL_get_cpu_featureset: { - static const struct cpuid_policy *const policy_table[] = { + static const struct cpuid_policy *const policy_table[4] = { [XEN_SYSCTL_cpu_featureset_raw] = &raw_cpuid_policy, [XEN_SYSCTL_cpu_featureset_host] = &host_cpuid_policy, +#ifdef CONFIG_PV [XEN_SYSCTL_cpu_featureset_pv] = &pv_max_cpuid_policy, +#endif +#ifdef CONFIG_HVM [XEN_SYSCTL_cpu_featureset_hvm] = &hvm_max_cpuid_policy, +#endif }; const struct cpuid_policy *p = NULL; uint32_t featureset[FSCAPINTS]; @@ -389,12 +393,17 @@ long arch_do_sysctl( /* Look up requested featureset. */ if ( sysctl->u.cpu_featureset.index < ARRAY_SIZE(policy_table) ) + { p = policy_table[sysctl->u.cpu_featureset.index]; - /* Bad featureset index? */ - if ( !p ) - ret = -EINVAL; + if ( !p ) + ret = -EOPNOTSUPP; + } else + /* Bad featureset index? */ + ret = -EINVAL; + + if ( !ret ) cpuid_policy_to_featureset(p, featureset); /* Copy the requested featureset into place. */ diff --git a/xen/include/public/sysctl.h b/xen/include/public/sysctl.h index 4dfba39ed8..3d72fab49f 100644 --- a/xen/include/public/sysctl.h +++ b/xen/include/public/sysctl.h @@ -796,6 +796,8 @@ struct xen_sysctl_cpu_levelling_caps { * - Host: The values Xen is using, (after command line overrides, etc). * - PV: Maximum set of features which can be given to a PV guest. * - HVM: Maximum set of features which can be given to a HVM guest. + * May fail with -EOPNOTSUPP if querying for PV or HVM data when support is + * compiled out of Xen. */ struct xen_sysctl_cpu_featureset { #define XEN_SYSCTL_cpu_featureset_raw 0
Just as with c/s 96dc77b4b1 for XEN_SYSCTL_get_cpu_policy, XEN_SYSCTL_get_cpu_featureset needs to become conditional. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Wei Liu <wl@xen.org> CC: Roger Pau Monné <roger.pau@citrix.com> --- tools/misc/xen-cpuid.c | 17 +++++++++++++---- xen/arch/x86/sysctl.c | 17 +++++++++++++---- xen/include/public/sysctl.h | 2 ++ 3 files changed, 28 insertions(+), 8 deletions(-)