Re: [PATCH 02/11] KVM: arm/arm64: Convert kvm_host_cpu_state to a static per-cpu allocation

Christoffer Dall
2017-06-06T19:59:57Z

On Mon, May 15, 2017 at 06:43:50PM +0100, James Morse wrote:
> kvm_host_cpu_state is a per-cpu allocation made from kvm_arch_init()
> used to store the host EL1 registers when KVM switches to a guest.
>
> Make it easier for ASM to generate pointers into this per-cpu memory
> by making it a static allocation.
>

Acked-by: Christoffer Dall <cdall-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

> Signed-off-by: James Morse <james.morse-5wv7dgnIgG8@public.gmane.org>
> ---
> virt/kvm/arm/arm.c | 18 +++---------------
> 1 file changed, 3 insertions(+), 15 deletions(-)
>
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 3417e184c8e1..3a776ec99181 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -51,8 +51,8 @@
> __asm__(".arch_extension virt");
> #endif
>
> +DEFINE_PER_CPU(kvm_cpu_context_t, kvm_host_cpu_state);
> static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
> -static kvm_cpu_context_t __percpu *kvm_host_cpu_state;
>
> /* Per-CPU variable containing the currently running vcpu. */
> static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_arm_running_vcpu);
> @@ -351,7 +351,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
> }
>
> vcpu->cpu = cpu;
> - vcpu->arch.host_cpu_context = this_cpu_ptr(kvm_host_cpu_state);
> + vcpu->arch.host_cpu_context = this_cpu_ptr(&kvm_host_cpu_state);
>
> kvm_arm_set_running_vcpu(vcpu);
>
> @@ -1226,19 +1226,8 @@ static inline void hyp_cpu_pm_exit(void)
> }
> #endif
>
> -static void teardown_common_resources(void)
> -{
> - free_percpu(kvm_host_cpu_state);
> -}
> -
> static int init_common_resources(void)
> {
> - kvm_host_cpu_state = alloc_percpu(kvm_cpu_context_t);
> - if (!kvm_host_cpu_state) {
> - kvm_err("Cannot allocate host CPU state\n");
> - return -ENOMEM;
> - }
> -
> /* set size of VMID supported by CPU */
> kvm_vmid_bits = kvm_get_vmid_bits();
> kvm_info("%d-bit VMID\n", kvm_vmid_bits);
> @@ -1383,7 +1372,7 @@ static int init_hyp_mode(void)
> for_each_possible_cpu(cpu) {
> kvm_cpu_context_t *cpu_ctxt;
>
> - cpu_ctxt = per_cpu_ptr(kvm_host_cpu_state, cpu);
> + cpu_ctxt = per_cpu_ptr(&kvm_host_cpu_state, cpu);
> err = create_hyp_mappings(cpu_ctxt, cpu_ctxt + 1, PAGE_HYP);
>
> if (err) {
> @@ -1461,7 +1450,6 @@ int kvm_arch_init(void *opaque)
> out_hyp:
> teardown_hyp_mode();
> out_err:
> - teardown_common_resources();
> return err;
> }
>
> --
> 2.10.1