On Thu, Sep 30, 2021 at 11:05 PM Reiji Watanabe <reijiw@xxxxxxxxxx> wrote:
>
> On Thu, Sep 23, 2021 at 12:16 PM Oliver Upton <oupton@xxxxxxxxxx> wrote:
> >
> > In its implementation of the PSCI function, KVM needs to request that a
> > target vCPU resets before its next entry into the guest. Wrap the logic
> > for requesting a reset in a function for later use by other implemented
> > PSCI calls.
> >
> > No functional change intended.
> >
> > Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
> > ---
> > arch/arm64/kvm/psci.c | 59 +++++++++++++++++++++++++------------------
> > 1 file changed, 35 insertions(+), 24 deletions(-)
> >
> > diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
> > index 310b9cb2b32b..bb59b692998b 100644
> > --- a/arch/arm64/kvm/psci.c
> > +++ b/arch/arm64/kvm/psci.c
> > @@ -64,9 +64,40 @@ static inline bool kvm_psci_valid_affinity(unsigned long affinity)
> > return !(affinity & ~MPIDR_HWID_BITMASK);
> > }
> >
> > -static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> > +static void kvm_psci_vcpu_request_reset(struct kvm_vcpu *vcpu,
> > + unsigned long entry_addr,
> > + unsigned long context_id,
> > + bool big_endian)
> > {
> > struct vcpu_reset_state *reset_state;
> > +
> > + lockdep_assert_held(&vcpu->kvm->lock);
> > +
> > + reset_state = &vcpu->arch.reset_state;
> > + reset_state->pc = entry_addr;
> > +
> > + /* Propagate caller endianness */
> > + reset_state->be = big_endian;
> > +
> > + /*
> > + * NOTE: We always update r0 (or x0) because for PSCI v0.1
> > + * the general purpose registers are undefined upon CPU_ON.
> > + */
> > + reset_state->r0 = context_id;
> > +
> > + WRITE_ONCE(reset_state->reset, true);
> > + kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);
> > +
> > + /*
> > + * Make sure the reset request is observed if the change to
> > + * power_state is observed.
> > + */
> > + smp_wmb();
> > + vcpu->arch.power_off = false;
> > +}
> > +
> > +static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> > +{
> > struct kvm *kvm = source_vcpu->kvm;
> > struct kvm_vcpu *vcpu = NULL;
> > unsigned long cpu_id;
> > @@ -90,29 +121,9 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> > return PSCI_RET_INVALID_PARAMS;
> > }
> >
> > - reset_state = &vcpu->arch.reset_state;
> > -
> > - reset_state->pc = smccc_get_arg2(source_vcpu);
> > -
> > - /* Propagate caller endianness */
> > - reset_state->be = kvm_vcpu_is_be(source_vcpu);
> > -
> > - /*
> > - * NOTE: We always update r0 (or x0) because for PSCI v0.1
> > - * the general purpose registers are undefined upon CPU_ON.
> > - */
> > - reset_state->r0 = smccc_get_arg3(source_vcpu);
> > -
> > - WRITE_ONCE(reset_state->reset, true);
> > - kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);
> > -
> > - /*
> > - * Make sure the reset request is observed if the change to
> > - * power_state is observed.
> > - */
> > - smp_wmb();
> > -
> > - vcpu->arch.power_off = false;
> > + kvm_psci_vcpu_request_reset(vcpu, smccc_get_arg2(source_vcpu),
> > + smccc_get_arg3(source_vcpu),
> > + kvm_vcpu_is_be(source_vcpu));
> > kvm_vcpu_wake_up(vcpu);
> >
> > return PSCI_RET_SUCCESS;
> > --
> > 2.33.0.685.g46640cef36-goog
>
> Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
>
> Not directly related to the patch, but the (original) code doesn't
> do any sanity checking for the entry address although the PSCI spec says:
>
> "INVALID_ADDRESS is returned when the entry point address is known
> by the implementation to be invalid, because it is in a range that
> is known not to be available to the caller."
Right, I had noticed the same but was a tad too lazy to address in
this series :) Thanks for the review, Reji!
--
Best,
Oliver
