Hi Takahiro,
On Mon, 2015-03-23 at 20:53 +0900, AKASHI Takahiro wrote:
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index 3e6859b..428f41c 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
...
> +phys_addr_t kvm_get_stub_vectors(void)
> +{
> + return virt_to_phys(__hyp_stub_vectors);
> +}
The stub vectors are not part of KVM, but part of kernel,
so to me a routine get_hyp_stub_vectors() with a prototype
in asm/virt.h, then a definition in maybe
kernel/process.c, or a new file kernel/virt.c makes more
sense.
> +unsigned long kvm_reset_func_entry(void)
> +{
> + /* VA of __kvm_hyp_reset in trampline code */
> + return TRAMPOLINE_VA + (__kvm_hyp_reset - __hyp_idmap_text_start);
> +}
> +
> int kvm_mmu_init(void)
> {
> int err;
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 4f7310f..97ee2fc 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -116,8 +116,11 @@
> struct kvm;
> struct kvm_vcpu;
>
> +extern char __hyp_stub_vectors[];
I think this should at least be in asm/virt.h, or better,
have a get_hyp_stub_vectors().
> extern char __kvm_hyp_init[];
> extern char __kvm_hyp_init_end[];
> +extern char __kvm_hyp_reset[];
>
> extern char __kvm_hyp_vector[];
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 8ac3c70..97f88fe 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -199,6 +199,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
> struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
>
> u64 kvm_call_hyp(void *hypfn, ...);
> +void kvm_call_reset(unsigned long reset_func, ...);
kvm_call_reset() takes a fixed number of args, so we shouldn't
have it as a variadic here. I think a variadic routine
complicates things for my kvm_call_reset() suggestion below.
> void force_vm_exit(const cpumask_t *mask);
> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot);
>
> @@ -223,6 +224,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr,
> hyp_stack_ptr, vector_ptr);
> }
>
> +static inline void __cpu_reset_hyp_mode(unsigned long reset_func,
> + phys_addr_t boot_pgd_ptr,
> + phys_addr_t phys_idmap_start,
> + unsigned long stub_vector_ptr)
> + kvm_call_reset(reset_func, boot_pgd_ptr,
> + phys_idmap_start, stub_vector_ptr);
Why not switch the order of the args here to:
kvm_call_reset(boot_pgd_ptr, phys_idmap_start, stub_vector_ptr, reset_func)
This will eliminate the register shifting in the HVC_RESET
hcall vector which becomes just 'br x3'.
> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> index fd085ec..aee75f9 100644
> --- a/arch/arm64/kvm/hyp.S
> +++ b/arch/arm64/kvm/hyp.S
> @@ -1136,6 +1136,11 @@ ENTRY(kvm_call_hyp)
> ret
> ENDPROC(kvm_call_hyp)
>
> +ENTRY(kvm_call_reset)
> + hvc #HVC_RESET
> + ret
> +ENDPROC(kvm_call_reset)
> +
> .macro invalid_vector label, target
> .align 2
> \label:
> @@ -1179,10 +1184,10 @@ el1_sync: // Guest trapped into EL2
> cmp x18, #HVC_GET_VECTORS
> b.ne 1f
> mrs x0, vbar_el2
> - b 2f
> -
> -1: /* Default to HVC_CALL_HYP. */
It seems you are deleting this comment and also
removing the logic that makes HVC_CALL_HYP the default.
> + b 3f
>
> +1: cmp x18, #HVC_CALL_HYP
> + b.ne 2f
> push lr, xzr
>
> /*
> @@ -1196,7 +1201,23 @@ el1_sync: // Guest trapped into EL2
> blr lr
>
> pop lr, xzr
> -2: eret
> + b 3f
> +
> + /*
> + * shuffle the parameters and jump into trampline code.
> + */
> +2: cmp x18, #HVC_RESET
> + b.ne 3f
> +
> + mov x18, x0
> + mov x0, x1
> + mov x1, x2
> + mov x2, x3
> + mov x3, x4
> + br x18
> + /* not reach here */
> +
> +3: eret
We don't need to change labels for each new hcall, I
think just this is OK:
cmp x18, #HVC_GET_VECTORS
b.ne 1f
mrs x0, vbar_el2
b 2f
+1: cmp x18, #HVC_RESET
+ b.ne 1f
+ br x3 // No return
1: /* Default to HVC_CALL_HYP. */
...
-Geoff
