Subject: [PATCH v3 14/41] KVM: arm64: Introduce VHE-specific kvm_vcpu_run

From: [email-masked] (Julien Grall)
Date: Fri, 9 Feb 2018 17:34:05 +0000

Hi Christoffer,

On 01/12/2018 12:07 PM, Christoffer Dall wrote:
> So far this is just a copy of the legacy non-VHE switch function, but we
> will start reworking these functions in separate directions to work on
> VHE and non-VHE in the most optimal way in later patches.
> 
> Reviewed-by: Marc Zyngier <[email-masked]>
> Signed-off-by: Christoffer Dall <[email-masked]>
> ---
>   arch/arm/include/asm/kvm_asm.h   |  5 +++-
>   arch/arm/kvm/hyp/switch.c        |  2 +-
>   arch/arm64/include/asm/kvm_asm.h |  4 ++-
>   arch/arm64/kvm/hyp/switch.c      | 58 +++++++++++++++++++++++++++++++++++++++-
>   virt/kvm/arm/arm.c               |  5 +++-
>   5 files changed, 69 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
> index 36dd2962a42d..4ac717276543 100644
> --- a/arch/arm/include/asm/kvm_asm.h
> +++ b/arch/arm/include/asm/kvm_asm.h
> @@ -70,7 +70,10 @@ extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
>   
>   extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
>   
> -extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
> +/* no VHE on 32-bit :( */
> +static inline int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu) { return 0; }

Should we return an error or add a BUG() to catch potential use of this 
function?

> +
> +extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
>   
>   extern void __init_stage2_translation(void);
>   
> diff --git a/arch/arm/kvm/hyp/switch.c b/arch/arm/kvm/hyp/switch.c
> index c3b9799e2e13..7b2bd25e3b10 100644
> --- a/arch/arm/kvm/hyp/switch.c
> +++ b/arch/arm/kvm/hyp/switch.c
> @@ -153,7 +153,7 @@ static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
>   	return true;
>   }
>   
> -int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
> +int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
>   {
>   	struct kvm_cpu_context *host_ctxt;
>   	struct kvm_cpu_context *guest_ctxt;
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 6c7599b5cb40..fb91e728207b 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -58,7 +58,9 @@ extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu);
>   
>   extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high);
>   
> -extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
> +extern int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu);
> +
> +extern int __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu);
>   
>   extern u64 __vgic_v3_get_ich_vtr_el2(void);
>   extern u64 __vgic_v3_read_vmcr(void);
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index 55ca2e3d42eb..accfe9a016f9 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -338,7 +338,63 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
>   	return false;
>   }
>   
> -int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
> +/* Switch to the guest for VHE systems running in EL2 */
> +int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_cpu_context *host_ctxt;
> +	struct kvm_cpu_context *guest_ctxt;
> +	u64 exit_code;
> +
> +	vcpu = kern_hyp_va(vcpu);
> +
> +	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
> +	host_ctxt->__hyp_running_vcpu = vcpu;
> +	guest_ctxt = &vcpu->arch.ctxt;
> +
> +	__sysreg_save_host_state(host_ctxt);
> +
> +	__activate_traps(vcpu);
> +	__activate_vm(vcpu);
> +
> +	__vgic_restore_state(vcpu);
> +	__timer_enable_traps(vcpu);
> +
> +	/*
> +	 * We must restore the 32-bit state before the sysregs, thanks
> +	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
> +	 */
> +	__sysreg32_restore_state(vcpu);
> +	__sysreg_restore_guest_state(guest_ctxt);
> +	__debug_switch_to_guest(vcpu);
> +
> +	do {
> +		/* Jump in the fire! */
> +		exit_code = __guest_enter(vcpu, host_ctxt);
> +
> +		/* And we're baaack! */
> +	} while (fixup_guest_exit(vcpu, &exit_code));
> +
> +	__sysreg_save_guest_state(guest_ctxt);
> +	__sysreg32_save_state(vcpu);
> +	__timer_disable_traps(vcpu);
> +	__vgic_save_state(vcpu);
> +
> +	__deactivate_traps(vcpu);
> +	__deactivate_vm(vcpu);
> +
> +	__sysreg_restore_host_state(host_ctxt);
> +
> +	/*
> +	 * This must come after restoring the host sysregs, since a non-VHE
> +	 * system may enable SPE here and make use of the TTBRs.
> +	 */
> +	__debug_switch_to_host(vcpu);
> +
> +	return exit_code;
> +}
> +
> +/* Switch to the guest for legacy non-VHE systems */
> +int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
>   {
>   	struct kvm_cpu_context *host_ctxt;
>   	struct kvm_cpu_context *guest_ctxt;
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 5b1487bd91e8..6bce8f9c55db 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -733,7 +733,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
>   		trace_kvm_entry(*vcpu_pc(vcpu));
>   		guest_enter_irqoff();
>   
> -		ret = kvm_call_hyp(__kvm_vcpu_run, vcpu);
> +		if (has_vhe())
> +			ret = kvm_vcpu_run_vhe(vcpu);
> +		else
> +			ret = kvm_call_hyp(__kvm_vcpu_run_nvhe, vcpu);
>   
>   		vcpu->mode = OUTSIDE_GUEST_MODE;
>   		vcpu->stat.exits++;
> 

Cheers,

-- 
Julien Grall