| Message ID | 20190125180711.1970973-2-jeremy.linton@arm.com |
|---|---|
| State | Accepted |
| Commit | de19055564c8f8f9d366f8db3395836da0b2176c |
| Headers | show |
| Series | arm64: add system vulnerability sysfs entries | expand |
On Fri, 25 Jan 2019 12:07:00 -0600 Jeremy Linton <jeremy.linton@arm.com> wrote: Hi, > For a while Arm64 has been capable of force enabling > or disabling the kpti mitigations. Lets make sure the > documentation reflects that. > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: linux-doc@vger.kernel.org > --- > Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt > b/Documentation/admin-guide/kernel-parameters.txt index > b799bcf67d7b..9475f02c79da 100644 --- > a/Documentation/admin-guide/kernel-parameters.txt +++ > b/Documentation/admin-guide/kernel-parameters.txt @@ -1982,6 +1982,12 > @@ Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, > the default is off. > > + kpti= [ARM64] Control page table isolation of > user > + and kernel address spaces. > + Default: enabled on cores which need > mitigation. Would this be a good place to mention that we enable it when CONFIG_RANDOMIZE_BASE is enabled and we have a valid kaslr_offset? I found this somewhat surprising, also it's unrelated to the vulnerability. Cheers, Andre > + 0: force disabled > + 1: force enabled > + > kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled > MSRs. Default is 0 (don't ignore, but inject #GP) >
On Fri, 25 Jan 2019 12:07:00 -0600 Jeremy Linton <jeremy.linton@arm.com> wrote: > For a while Arm64 has been capable of force enabling > or disabling the kpti mitigations. Lets make sure the > documentation reflects that. > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: linux-doc@vger.kernel.org Reviewed-by: Andre Przywara <andre.przywara@arm.com> Cheers, Andre. > --- > Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt > b/Documentation/admin-guide/kernel-parameters.txt > index b799bcf67d7b..9475f02c79da 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1982,6 +1982,12 @@ > Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, > the default is off. > > + kpti= [ARM64] Control page table isolation of user > + and kernel address spaces. > + Default: enabled on cores which need mitigation. > + 0: force disabled > + 1: force enabled > + > kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. > Default is 0 (don't ignore, but inject #GP) >
Hi, I just realized I replied to this off-list. On 01/30/2019 12:02 PM, Andre Przywara wrote: > On Fri, 25 Jan 2019 12:07:00 -0600 > Jeremy Linton <jeremy.linton@arm.com> wrote: > > Hi, > >> For a while Arm64 has been capable of force enabling >> or disabling the kpti mitigations. Lets make sure the >> documentation reflects that. >> >> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> >> Cc: Jonathan Corbet <corbet@lwn.net> >> Cc: linux-doc@vger.kernel.org >> --- >> Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/Documentation/admin-guide/kernel-parameters.txt >> b/Documentation/admin-guide/kernel-parameters.txt index >> b799bcf67d7b..9475f02c79da 100644 --- >> a/Documentation/admin-guide/kernel-parameters.txt +++ >> b/Documentation/admin-guide/kernel-parameters.txt @@ -1982,6 +1982,12 >> @@ Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, >> the default is off. >> >> + kpti= [ARM64] Control page table isolation of >> user >> + and kernel address spaces. >> + Default: enabled on cores which need >> mitigation. > > Would this be a good place to mention that we enable it when > CONFIG_RANDOMIZE_BASE is enabled and we have a valid kaslr_offset? I > found this somewhat surprising, also it's unrelated to the > vulnerability. Maybe, but I tend to think since this command line forces it on/off regardless of RANDOMIZE_BASE, that a better place to mention that RANDOMIZE_BASE forces kpti on is the Kconfig option. BTW: Thanks for reviewing this. > > Cheers, > Andre > >> + 0: force disabled >> + 1: force enabled >> + >> kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled >> MSRs. Default is 0 (don't ignore, but inject #GP) >> >
On 06/02/2019 19:24, Jeremy Linton wrote: > Hi, > > > I just realized I replied to this off-list. > > On 01/30/2019 12:02 PM, Andre Przywara wrote: >> On Fri, 25 Jan 2019 12:07:00 -0600 >> Jeremy Linton <jeremy.linton@arm.com> wrote: >> >> Hi, >> >>> For a while Arm64 has been capable of force enabling >>> or disabling the kpti mitigations. Lets make sure the >>> documentation reflects that. >>> >>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> >>> Cc: Jonathan Corbet <corbet@lwn.net> >>> Cc: linux-doc@vger.kernel.org >>> --- >>> Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/Documentation/admin-guide/kernel-parameters.txt >>> b/Documentation/admin-guide/kernel-parameters.txt index >>> b799bcf67d7b..9475f02c79da 100644 --- >>> a/Documentation/admin-guide/kernel-parameters.txt +++ >>> b/Documentation/admin-guide/kernel-parameters.txt @@ -1982,6 +1982,12 >>> @@ Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, >>> the default is off. >>> + kpti= [ARM64] Control page table isolation of >>> user >>> + and kernel address spaces. >>> + Default: enabled on cores which need >>> mitigation. >> >> Would this be a good place to mention that we enable it when >> CONFIG_RANDOMIZE_BASE is enabled and we have a valid kaslr_offset? I >> found this somewhat surprising, also it's unrelated to the >> vulnerability. > > Maybe, but I tend to think since this command line forces it on/off > regardless of RANDOMIZE_BASE, that a better place to mention that > RANDOMIZE_BASE forces kpti on is the Kconfig option. True, kpti= takes precedence, in both ways. Disregard my comment then, this is indeed not the right place to mention RANDOMIZE_BASE. Cheers, Andre. > > BTW: Thanks for reviewing this. > > >> >> Cheers, >> Andre >> >>> + 0: force disabled >>> + 1: force enabled >>> + >>> kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled >>> MSRs. Default is 0 (don't ignore, but inject #GP) >>> >> >
On Fri, 25 Jan 2019 12:07:00 -0600 Jeremy Linton <jeremy.linton@arm.com> wrote: > For a while Arm64 has been capable of force enabling > or disabling the kpti mitigations. Lets make sure the > documentation reflects that. > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > Cc: Jonathan Corbet <corbet@lwn.net> > Cc: linux-doc@vger.kernel.org I've applied this, thanks. jon
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b799bcf67d7b..9475f02c79da 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1982,6 +1982,12 @@ Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, the default is off. + kpti= [ARM64] Control page table isolation of user + and kernel address spaces. + Default: enabled on cores which need mitigation. + 0: force disabled + 1: force enabled + kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs. Default is 0 (don't ignore, but inject #GP)
For a while Arm64 has been capable of force enabling or disabling the kpti mitigations. Lets make sure the documentation reflects that. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ 1 file changed, 6 insertions(+) -- 2.17.2