Hi James,
On 30/03/16 16:56, 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 an
> 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@xxxxxxx>
> ---
> arch/arm/kvm/arm.c | 51 +++++++++++++++++++++++++++++++++------------------
> 1 file changed, 33 insertions(+), 18 deletions(-)
>
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 6accd66d26f0..cf0184edf4f5 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -1067,8 +1067,16 @@ static int hyp_init_cpu_notify(struct notifier_block *self,
> switch (action) {
> case CPU_STARTING:
> case CPU_STARTING_FROZEN:
> - if (__hyp_get_vectors() == hyp_default_vectors)
> - cpu_init_hyp_mode(NULL);
> + 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);
> + }
> break;
> }
>
> @@ -1084,9 +1092,13 @@ 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) {
> + if (is_kernel_in_hyp_mode()) {
> + cpu_init_stage2(NULL);
> + } else {
> + if (__hyp_get_vectors() == hyp_default_vectors)
> + cpu_init_hyp_mode(NULL);
> + }
Any reason why we can't isolate that snippet in a separate function and
use it in both locations?
> return NOTIFY_OK;
> }
>
> @@ -1128,6 +1140,22 @@ 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 +1298,6 @@ 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);
>
Otherwise looks good to me.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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