| Message ID | 1459359184-15601-1-git-send-email-james.morse@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 30/03/16 18:33, James Morse wrote: > When the kernel is running at EL2, it doesn't need init_hyp_mode() to > configure page tables for HYP. This function also registers the CPU > hotplug and lower power notifiers that cause HYP to be re-initialised > after the CPU has been reset. > > To avoid losing the register state that controls stage2 translation, move > the registering of these notifiers into init_subsystems(), and add a > is_kernel_in_hyp_mode() path to each callback. > > Fixes: 1e947bad0b6 ("arm64: KVM: Skip HYP setup when already running in HYP") > Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> M.
On Wed, Mar 30, 2016 at 06:33:04PM +0100, James Morse wrote: > When the kernel is running at EL2, it doesn't need init_hyp_mode() to > configure page tables for HYP. This function also registers the CPU > hotplug and lower power notifiers that cause HYP to be re-initialised > after the CPU has been reset. > > To avoid losing the register state that controls stage2 translation, move > the registering of these notifiers into init_subsystems(), and add a > is_kernel_in_hyp_mode() path to each callback. I had naively, or perhaps supidly, assumed that a VHE kernel would save/restore all EL2 state as part of its suspend/resume procedure, but I guess that wouldn't work for hotplug anyway. In any case: Acked-by: Christoffer Dall <christoffer.dall@linaro.org> And applied. Thanks, -Christoffer > > Fixes: 1e947bad0b6 ("arm64: KVM: Skip HYP setup when already running in HYP") > Signed-off-by: James Morse <james.morse@arm.com> > --- > > Change since v1: > * Moved common re-init code to cpu_hyp_reinit(). > > arch/arm/kvm/arm.c | 52 +++++++++++++++++++++++++++++++++------------------- > 1 file changed, 33 insertions(+), 19 deletions(-) > > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 6accd66d26f0..b5384311dec4 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -1061,15 +1061,27 @@ static void cpu_init_hyp_mode(void *dummy) > kvm_arm_init_debug(); > } > > +static void cpu_hyp_reinit(void) > +{ > + if (is_kernel_in_hyp_mode()) { > + /* > + * cpu_init_stage2() is safe to call even if the PM > + * event was cancelled before the CPU was reset. > + */ > + cpu_init_stage2(NULL); > + } else { > + if (__hyp_get_vectors() == hyp_default_vectors) > + cpu_init_hyp_mode(NULL); > + } > +} > + > static int hyp_init_cpu_notify(struct notifier_block *self, > unsigned long action, void *cpu) > { > switch (action) { > case CPU_STARTING: > case CPU_STARTING_FROZEN: > - if (__hyp_get_vectors() == hyp_default_vectors) > - cpu_init_hyp_mode(NULL); > - break; > + cpu_hyp_reinit(); > } > > return NOTIFY_OK; > @@ -1084,9 +1096,8 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self, > unsigned long cmd, > void *v) > { > - if (cmd == CPU_PM_EXIT && > - __hyp_get_vectors() == hyp_default_vectors) { > - cpu_init_hyp_mode(NULL); > + if (cmd == CPU_PM_EXIT) { > + cpu_hyp_reinit(); > return NOTIFY_OK; > } > > @@ -1128,6 +1139,22 @@ static int init_subsystems(void) > int err; > > /* > + * Register CPU Hotplug notifier > + */ > + cpu_notifier_register_begin(); > + err = __register_cpu_notifier(&hyp_init_cpu_nb); > + cpu_notifier_register_done(); > + if (err) { > + kvm_err("Cannot register KVM init CPU notifier (%d)\n", err); > + return err; > + } > + > + /* > + * Register CPU lower-power notifier > + */ > + hyp_cpu_pm_init(); > + > + /* > * Init HYP view of VGIC > */ > err = kvm_vgic_hyp_init(); > @@ -1270,19 +1297,6 @@ static int init_hyp_mode(void) > free_boot_hyp_pgd(); > #endif > > - cpu_notifier_register_begin(); > - > - err = __register_cpu_notifier(&hyp_init_cpu_nb); > - > - cpu_notifier_register_done(); > - > - if (err) { > - kvm_err("Cannot register HYP init CPU notifier (%d)\n", err); > - goto out_err; > - } > - > - hyp_cpu_pm_init(); > - > /* set size of VMID supported by CPU */ > kvm_vmid_bits = kvm_get_vmid_bits(); > kvm_info("%d-bit VMID\n", kvm_vmid_bits); > -- > 2.8.0.rc3 >
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 6accd66d26f0..b5384311dec4 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -1061,15 +1061,27 @@ static void cpu_init_hyp_mode(void *dummy) kvm_arm_init_debug(); } +static void cpu_hyp_reinit(void) +{ + if (is_kernel_in_hyp_mode()) { + /* + * cpu_init_stage2() is safe to call even if the PM + * event was cancelled before the CPU was reset. + */ + cpu_init_stage2(NULL); + } else { + if (__hyp_get_vectors() == hyp_default_vectors) + cpu_init_hyp_mode(NULL); + } +} + static int hyp_init_cpu_notify(struct notifier_block *self, unsigned long action, void *cpu) { switch (action) { case CPU_STARTING: case CPU_STARTING_FROZEN: - if (__hyp_get_vectors() == hyp_default_vectors) - cpu_init_hyp_mode(NULL); - break; + cpu_hyp_reinit(); } return NOTIFY_OK; @@ -1084,9 +1096,8 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd, void *v) { - if (cmd == CPU_PM_EXIT && - __hyp_get_vectors() == hyp_default_vectors) { - cpu_init_hyp_mode(NULL); + if (cmd == CPU_PM_EXIT) { + cpu_hyp_reinit(); return NOTIFY_OK; } @@ -1128,6 +1139,22 @@ static int init_subsystems(void) int err; /* + * Register CPU Hotplug notifier + */ + cpu_notifier_register_begin(); + err = __register_cpu_notifier(&hyp_init_cpu_nb); + cpu_notifier_register_done(); + if (err) { + kvm_err("Cannot register KVM init CPU notifier (%d)\n", err); + return err; + } + + /* + * Register CPU lower-power notifier + */ + hyp_cpu_pm_init(); + + /* * Init HYP view of VGIC */ err = kvm_vgic_hyp_init(); @@ -1270,19 +1297,6 @@ static int init_hyp_mode(void) free_boot_hyp_pgd(); #endif - cpu_notifier_register_begin(); - - err = __register_cpu_notifier(&hyp_init_cpu_nb); - - cpu_notifier_register_done(); - - if (err) { - kvm_err("Cannot register HYP init CPU notifier (%d)\n", err); - goto out_err; - } - - hyp_cpu_pm_init(); - /* set size of VMID supported by CPU */ kvm_vmid_bits = kvm_get_vmid_bits(); kvm_info("%d-bit VMID\n", kvm_vmid_bits);
When the kernel is running at EL2, it doesn't need init_hyp_mode() to configure page tables for HYP. This function also registers the CPU hotplug and lower power notifiers that cause HYP to be re-initialised after the CPU has been reset. To avoid losing the register state that controls stage2 translation, move the registering of these notifiers into init_subsystems(), and add a is_kernel_in_hyp_mode() path to each callback. Fixes: 1e947bad0b6 ("arm64: KVM: Skip HYP setup when already running in HYP") Signed-off-by: James Morse <james.morse@arm.com> --- Change since v1: * Moved common re-init code to cpu_hyp_reinit(). arch/arm/kvm/arm.c | 52 +++++++++++++++++++++++++++++++++------------------- 1 file changed, 33 insertions(+), 19 deletions(-)