| Message ID | 20200226202221.6555-9-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: > For now, the default and max policies remain identical, but this will change > in the future. Write calculate_{pv,hvm}_def_policy() in a way which will cope > with simple feature differences for now. > > Update XEN_SYSCTL_get_cpu_policy and init_domain_cpuid_policy() to use the > default policies. For the sysctl the statement looks to be broader than reality, as (of course) you don't touch XEN_SYSCTL_cpu_policy_*_max. > @@ -381,6 +386,23 @@ static void __init calculate_pv_max_policy(void) > p->extd.raw[0xa] = EMPTY_LEAF; /* No SVM for PV guests. */ > } > > +static void __init calculate_pv_def_policy(void) > +{ > + struct cpuid_policy *p = &pv_def_cpuid_policy; > + uint32_t pv_featureset[FSCAPINTS]; > + unsigned int i; > + > + *p = pv_max_cpuid_policy; > + cpuid_policy_to_featureset(p, pv_featureset); > + > + for ( i = 0; i < ARRAY_SIZE(pv_featureset); ++i ) > + pv_featureset[i] &= pv_def_featuremask[i]; > + > + sanitise_featureset(pv_featureset); > + cpuid_featureset_to_policy(pv_featureset, p); > + recalculate_xstate(p); > +} Is there a reason the call to guest_common_feature_adjustments() is missing here? If so, I think you want to say a word on the why in the description. If not, with it added Reviewed-by: Jan Beulich <jbeulich@suse.com> Jan
On 27/02/2020 08:19, Jan Beulich wrote: > On 26.02.2020 21:22, Andrew Cooper wrote: >> For now, the default and max policies remain identical, but this will change >> in the future. Write calculate_{pv,hvm}_def_policy() in a way which will cope >> with simple feature differences for now. >> >> Update XEN_SYSCTL_get_cpu_policy and init_domain_cpuid_policy() to use the >> default policies. > For the sysctl the statement looks to be broader than reality, > as (of course) you don't touch XEN_SYSCTL_cpu_policy_*_max. I'm afraid I don't understand what you mean here. What would I need to touch in XEN_SYSCTL_cpu_policy_*_max at all? >> @@ -381,6 +386,23 @@ static void __init calculate_pv_max_policy(void) >> p->extd.raw[0xa] = EMPTY_LEAF; /* No SVM for PV guests. */ >> } >> >> +static void __init calculate_pv_def_policy(void) >> +{ >> + struct cpuid_policy *p = &pv_def_cpuid_policy; >> + uint32_t pv_featureset[FSCAPINTS]; >> + unsigned int i; >> + >> + *p = pv_max_cpuid_policy; >> + cpuid_policy_to_featureset(p, pv_featureset); >> + >> + for ( i = 0; i < ARRAY_SIZE(pv_featureset); ++i ) >> + pv_featureset[i] &= pv_def_featuremask[i]; >> + >> + sanitise_featureset(pv_featureset); >> + cpuid_featureset_to_policy(pv_featureset, p); >> + recalculate_xstate(p); >> +} > Is there a reason the call to guest_common_feature_adjustments() > is missing here? Yes, for the same reason that other logic is dropped. Inheriting from pv_max_cpuid_policy means that it has already been run on this object. The host to *_max derivation is non-trivial. Some features get added in, others are conditional on external factors. The *_max to *_def derivation is much more simple in comparison. Long term, I expect this logic to move into libx86 and further simplify cpuid.c However, I'm not sure why guest_common_feature_adjustments() is special compared to the other removed logic, and why it should be called out. ~Andrew
On 27.02.2020 11:55, Andrew Cooper wrote: > On 27/02/2020 08:19, Jan Beulich wrote: >> On 26.02.2020 21:22, Andrew Cooper wrote: >>> For now, the default and max policies remain identical, but this will change >>> in the future. Write calculate_{pv,hvm}_def_policy() in a way which will cope >>> with simple feature differences for now. >>> >>> Update XEN_SYSCTL_get_cpu_policy and init_domain_cpuid_policy() to use the >>> default policies. >> For the sysctl the statement looks to be broader than reality, >> as (of course) you don't touch XEN_SYSCTL_cpu_policy_*_max. > > I'm afraid I don't understand what you mean here. What would I need to > touch in XEN_SYSCTL_cpu_policy_*_max at all? Nothing, and hence my "too broad" response. Only part of XEN_SYSCTL_get_cpu_policy gets updated. But yes, thinking about it again, I think I see now how you mean this. So never mind. >>> @@ -381,6 +386,23 @@ static void __init calculate_pv_max_policy(void) >>> p->extd.raw[0xa] = EMPTY_LEAF; /* No SVM for PV guests. */ >>> } >>> >>> +static void __init calculate_pv_def_policy(void) >>> +{ >>> + struct cpuid_policy *p = &pv_def_cpuid_policy; >>> + uint32_t pv_featureset[FSCAPINTS]; >>> + unsigned int i; >>> + >>> + *p = pv_max_cpuid_policy; >>> + cpuid_policy_to_featureset(p, pv_featureset); >>> + >>> + for ( i = 0; i < ARRAY_SIZE(pv_featureset); ++i ) >>> + pv_featureset[i] &= pv_def_featuremask[i]; >>> + >>> + sanitise_featureset(pv_featureset); >>> + cpuid_featureset_to_policy(pv_featureset, p); >>> + recalculate_xstate(p); >>> +} >> Is there a reason the call to guest_common_feature_adjustments() >> is missing here? > > Yes, for the same reason that other logic is dropped. Inheriting from > pv_max_cpuid_policy means that it has already been run on this object. > > The host to *_max derivation is non-trivial. Some features get added > in, others are conditional on external factors. The *_max to *_def > derivation is much more simple in comparison. > > Long term, I expect this logic to move into libx86 and further simplify > cpuid.c > > However, I'm not sure why guest_common_feature_adjustments() is special > compared to the other removed logic, and why it should be called out. Well, the oddity isn't with removed logic (and in fact in this patch I can't see much of a removal of anything), but with the call being there in calculate_hvm_def_policy(). This difference, if intentional, is what I think needs calling out. Jan
diff --git a/xen/arch/x86/cpuid.c b/xen/arch/x86/cpuid.c index cd9a02143c..6e01394fd2 100644 --- a/xen/arch/x86/cpuid.c +++ b/xen/arch/x86/cpuid.c @@ -18,6 +18,9 @@ const uint32_t special_features[] = INIT_SPECIAL_FEATURES; static const uint32_t pv_max_featuremask[] = INIT_PV_MAX_FEATURES; static const uint32_t hvm_shadow_max_featuremask[] = INIT_HVM_SHADOW_MAX_FEATURES; static const uint32_t hvm_hap_max_featuremask[] = INIT_HVM_HAP_MAX_FEATURES; +static const uint32_t pv_def_featuremask[] = INIT_PV_DEF_FEATURES; +static const uint32_t hvm_shadow_def_featuremask[] = INIT_HVM_SHADOW_DEF_FEATURES; +static const uint32_t hvm_hap_def_featuremask[] = INIT_HVM_HAP_DEF_FEATURES; static const uint32_t deep_features[] = INIT_DEEP_FEATURES; static int __init parse_xen_cpuid(const char *s) @@ -99,9 +102,11 @@ struct cpuid_policy __read_mostly raw_cpuid_policy, __read_mostly host_cpuid_policy; #ifdef CONFIG_PV struct cpuid_policy __read_mostly pv_max_cpuid_policy; +struct cpuid_policy __read_mostly pv_def_cpuid_policy; #endif #ifdef CONFIG_HVM struct cpuid_policy __read_mostly hvm_max_cpuid_policy; +struct cpuid_policy __read_mostly hvm_def_cpuid_policy; #endif static void sanitise_featureset(uint32_t *fs) @@ -381,6 +386,23 @@ static void __init calculate_pv_max_policy(void) p->extd.raw[0xa] = EMPTY_LEAF; /* No SVM for PV guests. */ } +static void __init calculate_pv_def_policy(void) +{ + struct cpuid_policy *p = &pv_def_cpuid_policy; + uint32_t pv_featureset[FSCAPINTS]; + unsigned int i; + + *p = pv_max_cpuid_policy; + cpuid_policy_to_featureset(p, pv_featureset); + + for ( i = 0; i < ARRAY_SIZE(pv_featureset); ++i ) + pv_featureset[i] &= pv_def_featuremask[i]; + + sanitise_featureset(pv_featureset); + cpuid_featureset_to_policy(pv_featureset, p); + recalculate_xstate(p); +} + static void __init calculate_hvm_max_policy(void) { struct cpuid_policy *p = &hvm_max_cpuid_policy; @@ -440,16 +462,45 @@ static void __init calculate_hvm_max_policy(void) recalculate_xstate(p); } +static void __init calculate_hvm_def_policy(void) +{ + struct cpuid_policy *p = &hvm_def_cpuid_policy; + uint32_t hvm_featureset[FSCAPINTS]; + unsigned int i; + const uint32_t *hvm_featuremask; + + *p = hvm_max_cpuid_policy; + cpuid_policy_to_featureset(p, hvm_featureset); + + hvm_featuremask = hvm_hap_supported() ? + hvm_hap_def_featuremask : hvm_shadow_def_featuremask; + + for ( i = 0; i < ARRAY_SIZE(hvm_featureset); ++i ) + hvm_featureset[i] &= hvm_featuremask[i]; + + guest_common_feature_adjustments(hvm_featureset); + + sanitise_featureset(hvm_featureset); + cpuid_featureset_to_policy(hvm_featureset, p); + recalculate_xstate(p); +} + void __init init_guest_cpuid(void) { calculate_raw_policy(); calculate_host_policy(); if ( IS_ENABLED(CONFIG_PV) ) + { calculate_pv_max_policy(); + calculate_pv_def_policy(); + } if ( hvm_enabled ) + { calculate_hvm_max_policy(); + calculate_hvm_def_policy(); + } } bool recheck_cpu_features(unsigned int cpu) @@ -625,8 +676,8 @@ void recalculate_cpuid_policy(struct domain *d) int init_domain_cpuid_policy(struct domain *d) { struct cpuid_policy *p = is_pv_domain(d) - ? (IS_ENABLED(CONFIG_PV) ? &pv_max_cpuid_policy : NULL) - : (IS_ENABLED(CONFIG_HVM) ? &hvm_max_cpuid_policy : NULL); + ? (IS_ENABLED(CONFIG_PV) ? &pv_def_cpuid_policy : NULL) + : (IS_ENABLED(CONFIG_HVM) ? &hvm_def_cpuid_policy : NULL); if ( !p ) { diff --git a/xen/arch/x86/sysctl.c b/xen/arch/x86/sysctl.c index cad7534373..b7948f2663 100644 --- a/xen/arch/x86/sysctl.c +++ b/xen/arch/x86/sysctl.c @@ -48,7 +48,7 @@ const struct cpu_policy system_policies[6] = { &pv_max_msr_policy, }, [ XEN_SYSCTL_cpu_policy_pv_default ] = { - &pv_max_cpuid_policy, + &pv_def_cpuid_policy, &pv_def_msr_policy, }, #endif @@ -58,7 +58,7 @@ const struct cpu_policy system_policies[6] = { &hvm_max_msr_policy, }, [ XEN_SYSCTL_cpu_policy_hvm_default ] = { - &hvm_max_cpuid_policy, + &hvm_def_cpuid_policy, &hvm_def_msr_policy, }, #endif diff --git a/xen/include/asm-x86/cpuid.h b/xen/include/asm-x86/cpuid.h index 1b00e832d6..7baf6c9628 100644 --- a/xen/include/asm-x86/cpuid.h +++ b/xen/include/asm-x86/cpuid.h @@ -49,7 +49,8 @@ DECLARE_PER_CPU(struct cpuidmasks, cpuidmasks); extern struct cpuidmasks cpuidmask_defaults; extern struct cpuid_policy raw_cpuid_policy, host_cpuid_policy, - pv_max_cpuid_policy, hvm_max_cpuid_policy; + pv_max_cpuid_policy, pv_def_cpuid_policy, + hvm_max_cpuid_policy, hvm_def_cpuid_policy; extern const struct cpu_policy system_policies[];
For now, the default and max policies remain identical, but this will change in the future. Write calculate_{pv,hvm}_def_policy() in a way which will cope with simple feature differences for now. Update XEN_SYSCTL_get_cpu_policy and init_domain_cpuid_policy() to use the default policies. 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> --- xen/arch/x86/cpuid.c | 55 +++++++++++++++++++++++++++++++++++++++++++-- xen/arch/x86/sysctl.c | 4 ++-- xen/include/asm-x86/cpuid.h | 3 ++- 3 files changed, 57 insertions(+), 5 deletions(-)