| Message ID | 1415957488-27490-1-git-send-email-tiejun.chen@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 14/11/2014 10:31, Tiejun Chen wrote: > In some real scenarios 'start' may not be less than 'end' like > maxphyaddr = 52. > > Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> > --- > arch/x86/kvm/mmu.h | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h > index bde8ee7..0e98b5e 100644 > --- a/arch/x86/kvm/mmu.h > +++ b/arch/x86/kvm/mmu.h > @@ -58,6 +58,8 @@ > > static inline u64 rsvd_bits(int s, int e) > { > + if (unlikely(s > e)) > + return 0; > return ((1ULL << (e - s + 1)) - 1) << s; > } > > s == e + 1 is supported: (1ULL << (e - (e + 1) + 1)) - 1) << s == (1ULL << 0) << s == 0 Is there any case where s is even bigger? Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2014/11/14 18:06, Paolo Bonzini wrote: > > > On 14/11/2014 10:31, Tiejun Chen wrote: >> In some real scenarios 'start' may not be less than 'end' like >> maxphyaddr = 52. >> >> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> >> --- >> arch/x86/kvm/mmu.h | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h >> index bde8ee7..0e98b5e 100644 >> --- a/arch/x86/kvm/mmu.h >> +++ b/arch/x86/kvm/mmu.h >> @@ -58,6 +58,8 @@ >> >> static inline u64 rsvd_bits(int s, int e) >> { >> + if (unlikely(s > e)) >> + return 0; >> return ((1ULL << (e - s + 1)) - 1) << s; >> } >> >> > > s == e + 1 is supported: > > (1ULL << (e - (e + 1) + 1)) - 1) << s == (1ULL << (e - (e + 1) + 1)) - 1) << s = (1ULL << (e - e - 1) + 1)) - 1) << s = (1ULL << (-1) + 1)) - 1) << s = (1ULL << (0) - 1) << s = (1ULL << (- 1) << s Am I missing something? Thanks Tiejun > (1ULL << 0) << s == > 0 > > Is there any case where s is even bigger? > > Paolo > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 17/11/2014 02:34, Chen, Tiejun wrote: > On 2014/11/14 18:06, Paolo Bonzini wrote: >> >> >> On 14/11/2014 10:31, Tiejun Chen wrote: >>> In some real scenarios 'start' may not be less than 'end' like >>> maxphyaddr = 52. >>> >>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> >>> --- >>> arch/x86/kvm/mmu.h | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h >>> index bde8ee7..0e98b5e 100644 >>> --- a/arch/x86/kvm/mmu.h >>> +++ b/arch/x86/kvm/mmu.h >>> @@ -58,6 +58,8 @@ >>> >>> static inline u64 rsvd_bits(int s, int e) >>> { >>> + if (unlikely(s > e)) >>> + return 0; >>> return ((1ULL << (e - s + 1)) - 1) << s; >>> } >>> >>> >> >> s == e + 1 is supported: >> >> (1ULL << (e - (e + 1) + 1)) - 1) << s == > > (1ULL << (e - (e + 1) + 1)) - 1) << s > = (1ULL << (e - e - 1) + 1)) - 1) << s > = (1ULL << (-1) + 1)) - 1) << s no, ((1ULL << (-1 + 1)) - 1) << s > = (1ULL << (0) - 1) << s ((1ULL << (0)) - 1) << s > = (1ULL << (- 1) << s (1 - 1) << s 0 << s Paolo > > Am I missing something? > > Thanks > Tiejun > >> (1ULL << 0) << s == >> 0 >> >> Is there any case where s is even bigger? >> >> Paolo >> -- >> To unsubscribe from this list: send the line "unsubscribe kvm" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2014/11/17 17:22, Paolo Bonzini wrote: > > > On 17/11/2014 02:34, Chen, Tiejun wrote: >> On 2014/11/14 18:06, Paolo Bonzini wrote: >>> >>> >>> On 14/11/2014 10:31, Tiejun Chen wrote: >>>> In some real scenarios 'start' may not be less than 'end' like >>>> maxphyaddr = 52. >>>> >>>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> >>>> --- >>>> arch/x86/kvm/mmu.h | 2 ++ >>>> 1 file changed, 2 insertions(+) >>>> >>>> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h >>>> index bde8ee7..0e98b5e 100644 >>>> --- a/arch/x86/kvm/mmu.h >>>> +++ b/arch/x86/kvm/mmu.h >>>> @@ -58,6 +58,8 @@ >>>> >>>> static inline u64 rsvd_bits(int s, int e) >>>> { >>>> + if (unlikely(s > e)) >>>> + return 0; >>>> return ((1ULL << (e - s + 1)) - 1) << s; >>>> } >>>> >>>> >>> >>> s == e + 1 is supported: >>> >>> (1ULL << (e - (e + 1) + 1)) - 1) << s == >> >> (1ULL << (e - (e + 1) + 1)) - 1) << s >> = (1ULL << (e - e - 1) + 1)) - 1) << s >> = (1ULL << (-1) + 1)) - 1) << s > > no, You're right since I'm seeing "()" wrongly. Sorry to bother you. Thanks Tiejun -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index bde8ee7..0e98b5e 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -58,6 +58,8 @@ static inline u64 rsvd_bits(int s, int e) { + if (unlikely(s > e)) + return 0; return ((1ULL << (e - s + 1)) - 1) << s; }
In some real scenarios 'start' may not be less than 'end' like maxphyaddr = 52. Signed-off-by: Tiejun Chen <tiejun.chen@intel.com> --- arch/x86/kvm/mmu.h | 2 ++ 1 file changed, 2 insertions(+)