| Message ID | 9306d31184b8e714c3a10ccc6a2b2c6a80777ddb.1717410850.git.Sergiy_Kibrik@epam.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | x86: make cpu virtualization support configurable | expand |
On 03.06.2024 13:09, Sergiy Kibrik wrote: > @@ -38,9 +34,13 @@ static inline bool altp2m_active(const struct domain *d) > } > > /* Only declaration is needed. DCE will optimise it out when linking. */ > -uint16_t altp2m_vcpu_idx(const struct vcpu *v); > void altp2m_vcpu_disable_ve(struct vcpu *v); > > #endif > > +static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v) > +{ > + return altp2m_active(v->domain) ? vcpu_altp2m(v).p2midx : 0; > +} While perhaps okay this way as a first step, my general expectation would be that with ALTP2M=n there also wouldn't be any p2midx field in the respective struct. Which in turn will mean that this code would need re-doing again, and perhaps again splitting between an inline one and a decl-only one. With that I wonder whether that split wouldn't better be retained right away. Jan
On 07.06.2024 09:25, Jan Beulich wrote: > On 03.06.2024 13:09, Sergiy Kibrik wrote: >> @@ -38,9 +34,13 @@ static inline bool altp2m_active(const struct domain *d) >> } >> >> /* Only declaration is needed. DCE will optimise it out when linking. */ >> -uint16_t altp2m_vcpu_idx(const struct vcpu *v); >> void altp2m_vcpu_disable_ve(struct vcpu *v); >> >> #endif >> >> +static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v) >> +{ >> + return altp2m_active(v->domain) ? vcpu_altp2m(v).p2midx : 0; >> +} > > While perhaps okay this way as a first step, Hmm, or maybe not. 0 is a valid index, and hence could be misleading at call sites. Jan > my general expectation > would be that with ALTP2M=n there also wouldn't be any p2midx field > in the respective struct. Which in turn will mean that this code > would need re-doing again, and perhaps again splitting between an > inline one and a decl-only one. With that I wonder whether that split > wouldn't better be retained right away. > > Jan
07.06.24 10:50, Jan Beulich: > On 07.06.2024 09:25, Jan Beulich wrote: >> On 03.06.2024 13:09, Sergiy Kibrik wrote: >>> @@ -38,9 +34,13 @@ static inline bool altp2m_active(const struct domain *d) >>> } >>> >>> /* Only declaration is needed. DCE will optimise it out when linking. */ >>> -uint16_t altp2m_vcpu_idx(const struct vcpu *v); >>> void altp2m_vcpu_disable_ve(struct vcpu *v); >>> >>> #endif >>> >>> +static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v) >>> +{ >>> + return altp2m_active(v->domain) ? vcpu_altp2m(v).p2midx : 0; >>> +} >> >> While perhaps okay this way as a first step, > > Hmm, or maybe not. 0 is a valid index, and hence could be misleading > at call sites. I'm returning 0 index here because implementation of p2m_get_mem_access() for x86 & ARM expects it to be 0 when altp2m not active or not implemented. -Sergiy
On 07.06.2024 11:40, Sergiy Kibrik wrote: > 07.06.24 10:50, Jan Beulich: >> On 07.06.2024 09:25, Jan Beulich wrote: >>> On 03.06.2024 13:09, Sergiy Kibrik wrote: >>>> @@ -38,9 +34,13 @@ static inline bool altp2m_active(const struct domain *d) >>>> } >>>> >>>> /* Only declaration is needed. DCE will optimise it out when linking. */ >>>> -uint16_t altp2m_vcpu_idx(const struct vcpu *v); >>>> void altp2m_vcpu_disable_ve(struct vcpu *v); >>>> >>>> #endif >>>> >>>> +static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v) >>>> +{ >>>> + return altp2m_active(v->domain) ? vcpu_altp2m(v).p2midx : 0; >>>> +} >>> >>> While perhaps okay this way as a first step, >> >> Hmm, or maybe not. 0 is a valid index, and hence could be misleading >> at call sites. > > I'm returning 0 index here because implementation of > p2m_get_mem_access() for x86 & ARM expects it to be 0 when altp2m not > active or not implemented. Tamas, considering the comment in x86'es p2m_get_mem_access(), what purpose are d->arch.altp2m_p2m[0] and d->arch.altp2m_eptp[0] then? In case it indeed is unused, why would p2m_init_altp2m() set up slot 0 in the first place? Jan
diff --git a/xen/arch/x86/include/asm/altp2m.h b/xen/arch/x86/include/asm/altp2m.h index e5e59cbd68..2d36c5aa9b 100644 --- a/xen/arch/x86/include/asm/altp2m.h +++ b/xen/arch/x86/include/asm/altp2m.h @@ -26,10 +26,6 @@ void altp2m_vcpu_destroy(struct vcpu *v); int altp2m_vcpu_enable_ve(struct vcpu *v, gfn_t gfn); void altp2m_vcpu_disable_ve(struct vcpu *v); -static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v) -{ - return vcpu_altp2m(v).p2midx; -} #else static inline bool altp2m_active(const struct domain *d) @@ -38,9 +34,13 @@ static inline bool altp2m_active(const struct domain *d) } /* Only declaration is needed. DCE will optimise it out when linking. */ -uint16_t altp2m_vcpu_idx(const struct vcpu *v); void altp2m_vcpu_disable_ve(struct vcpu *v); #endif +static inline uint16_t altp2m_vcpu_idx(const struct vcpu *v) +{ + return altp2m_active(v->domain) ? vcpu_altp2m(v).p2midx : 0; +} + #endif /* __ASM_X86_ALTP2M_H */
Explicitly check whether altp2m is on for domain when getting altp2m index. The puspose of that is later to be able to disable altp2m support and exclude its code from the build completely, when not supported by target platform (as of now it's implemented for Intel EPT only). Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@epam.com> CC: Tamas K Lengyel <tamas@tklengyel.com> CC: Jan Beulich <jbeulich@suse.com> --- changes in v3: - move altp2m_active() check inside altp2m_vcpu_idx() - drop changes to monitor.c - changed patch description changes in v2: - patch description changed, removed VMX mentioning - guard by altp2m_active() instead of hvm_altp2m_supported() --- xen/arch/x86/include/asm/altp2m.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)