Messages in this thread | | | Date | Tue, 10 Nov 2020 15:24:52 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH v1 07/24] kvm: arm64: Create nVHE copy of cpu_logical_map |
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On 2020-11-09 11:32, David Brazdil wrote: > When KVM starts validating host's PSCI requests, it will need to map > MPIDR back to the CPU ID. To this end, copy cpu_logical_map into nVHE > hyp memory when KVM is initialized. > > Only copy the information for CPUs that are online at the point of KVM > initialization so that KVM rejects CPUs whose features were not checked > against the finalized capabilities. > > Signed-off-by: David Brazdil <dbrazdil@google.com> > --- > arch/arm64/kvm/arm.c | 17 +++++++++++++++++ > arch/arm64/kvm/hyp/nvhe/percpu.c | 16 ++++++++++++++++ > 2 files changed, 33 insertions(+) > > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c > index 9ba9db2aa7f8..b85b4294b72d 100644 > --- a/arch/arm64/kvm/arm.c > +++ b/arch/arm64/kvm/arm.c > @@ -1481,6 +1481,21 @@ static inline void hyp_cpu_pm_exit(void) > } > #endif > > +static void init_cpu_logical_map(void) > +{ > + extern u64 kvm_nvhe_sym(__cpu_logical_map)[NR_CPUS]; > + int cpu; > + > + /* > + * Copy the MPIDR <-> logical CPU ID mapping to hyp. > + * Only copy the set of online CPUs whose features have been chacked > + * against the finalized system capabilities. The hypervisor will not > + * allow any other CPUs from the `possible` set to boot. > + */ > + for_each_online_cpu(cpu) > + CHOOSE_NVHE_SYM(__cpu_logical_map)[cpu] = cpu_logical_map(cpu); > +} > + > static int init_common_resources(void) > { > return kvm_set_ipa_limit(); > @@ -1659,6 +1674,8 @@ static int init_hyp_mode(void) > } > } > > + init_cpu_logical_map(); > + > return 0; > > out_err: > diff --git a/arch/arm64/kvm/hyp/nvhe/percpu.c > b/arch/arm64/kvm/hyp/nvhe/percpu.c > index 5fd0c5696907..d0b9dbc2df45 100644 > --- a/arch/arm64/kvm/hyp/nvhe/percpu.c > +++ b/arch/arm64/kvm/hyp/nvhe/percpu.c > @@ -8,6 +8,22 @@ > #include <asm/kvm_hyp.h> > #include <asm/kvm_mmu.h> > > +/* > + * nVHE copy of data structures tracking available CPU cores. > + * Only entries for CPUs that were online at KVM init are populated. > + * Other CPUs should not be allowed to boot because their features > were > + * not checked against the finalized system capabilities. > + */ > +u64 __ro_after_init __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] > = INVALID_HWID };
I'm not sure what __ro_after_init means once we get S2 isolation.
> + > +u64 cpu_logical_map(int cpu)
nit: is there any reason why "cpu" cannot be unsigned? The thought of a negative CPU number makes me shiver...
> +{ > + if (cpu < 0 || cpu >= ARRAY_SIZE(__cpu_logical_map)) > + hyp_panic(); > + > + return __cpu_logical_map[cpu]; > +} > + > unsigned long __hyp_per_cpu_offset(unsigned int cpu) > { > unsigned long *cpu_base_array;
Overall, this patch would make more sense closer it its use case (in patch 19). I also don't understand why this lives in percpu.c...
Thanks,
M. -- Jazz is not dead. It just smells funny...
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