On Sun, Jul 17, 2022 at 11:56 PM Marc Zyngier <maz@xxxxxxxxxx> wrote: > > [- Drew and android-mm, as both addresses bounce] > > On Fri, 15 Jul 2022 07:10:17 +0100, > Kalesh Singh <kaleshsingh@xxxxxxxxxx> wrote: > > > > This can be used to disable stacktrace for the protected KVM > > nVHE hypervisor, in order to save on the associated memory usage. > > > > This option is disabled by default, since protected KVM is not widely > > used on platforms other than Android currently. > > > > Signed-off-by: Kalesh Singh <kaleshsingh@xxxxxxxxxx> > > --- > > arch/arm64/kvm/Kconfig | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > > index 8a5fbbf084df..1edab6f8a3b8 100644 > > --- a/arch/arm64/kvm/Kconfig > > +++ b/arch/arm64/kvm/Kconfig > > @@ -46,6 +46,21 @@ menuconfig KVM > > > > If unsure, say N. > > > > +config PROTECTED_NVHE_STACKTRACE > > + bool "Protected KVM hypervisor stacktraces" > > + depends on KVM > > + default n > > + help > > + Say Y here to enable pKVM hypervisor stacktraces on hyp_panic() > > + > > + If you are not using protected nVHE (pKVM), say N. > > + > > + If using protected nVHE mode, but cannot afford the associated > > + memory cost (less than 0.75 page per CPU) of pKVM stacktraces, > > + say N. > > + > > + If unsure, say N. > > + > > Can we make this depend on NVHE_EL2_DEBUG instead? I'd like to keep > the disclosing of EL2 information in protected mode a strict debug > feature. Hi Marc, An earlier version was similar to what you propose. The unwinding depended on NVHE_EL2_DEBUG and all unwinding was done from EL1 with host stage 2 being disabled. The reason the design was changed is because Android expressed the need for pKVM hyp stacktraces in production environments. [1] [1] https://lore.kernel.org/all/CAC_TJveNRaDFcQGo9-eqKa3=1DnuVDs4U+ye795VcJ1ozVkMyg@xxxxxxxxxxxxxx/ --Kalesh > > > config NVHE_EL2_DEBUG > > bool "Debug mode for non-VHE EL2 object" > > depends on KVM > > Thanks, > > M. > > -- > Without deviation from the norm, progress is not possible. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
