[PATCH v2 3/6] arm/arm64: KVM: Reset the HCR on each vcpu when resetting the vcpu

[Marc Zyngier]

On 03/12/14 21:18, Christoffer Dall wrote:
> When userspace resets the vcpu using KVM_ARM_VCPU_INIT, we should also
> reset the HCR, because we now modify the HCR dynamically to
> enable/disable trapping of guest accesses to the VM registers.
> 
> This is crucial for reboot of VMs working since otherwise we will not be
> doing the necessary cache maintenance operations when faulting in pages
> with the guest MMU off.
> 
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
> ---
>  arch/arm/include/asm/kvm_emulate.h   | 5 +++++
>  arch/arm/kvm/arm.c                   | 2 ++
>  arch/arm/kvm/guest.c                 | 1 -
>  arch/arm64/include/asm/kvm_emulate.h | 5 +++++
>  arch/arm64/kvm/guest.c               | 1 -
>  5 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
> index b9db269..66ce176 100644
> --- a/arch/arm/include/asm/kvm_emulate.h
> +++ b/arch/arm/include/asm/kvm_emulate.h
> @@ -33,6 +33,11 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu);
>  void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  
> +static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
> +{
> +	vcpu->arch.hcr = HCR_GUEST_MASK;
> +}
> +
>  static inline bool vcpu_mode_is_32bit(struct kvm_vcpu *vcpu)
>  {
>  	return 1;
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index edc1964..24c9ca4 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -658,6 +658,8 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
>  	if (ret)
>  		return ret;
>  
> +	vcpu_reset_hcr(vcpu);
> +
>  	/*
>  	 * Handle the "start in power-off" case by marking the VCPU as paused.
>  	 */
> diff --git a/arch/arm/kvm/guest.c b/arch/arm/kvm/guest.c
> index cc0b787..8c97208 100644
> --- a/arch/arm/kvm/guest.c
> +++ b/arch/arm/kvm/guest.c
> @@ -38,7 +38,6 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
>  
>  int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
>  {
> -	vcpu->arch.hcr = HCR_GUEST_MASK;
>  	return 0;
>  }
>  
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 5674a55..8127e45 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -38,6 +38,11 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu);
>  void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
>  
> +static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu)
> +{
> +	vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
> +}
> +
>  static inline unsigned long *vcpu_pc(const struct kvm_vcpu *vcpu)
>  {
>  	return (unsigned long *)&vcpu_gp_regs(vcpu)->regs.pc;
> diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
> index 7679469..84d5959 100644
> --- a/arch/arm64/kvm/guest.c
> +++ b/arch/arm64/kvm/guest.c
> @@ -38,7 +38,6 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
>  
>  int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
>  {
> -	vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
>  	return 0;
>  }
>  
> 

Acked-by: Marc Zyngier <marc.zyngier at arm.com>

	M.
-- 
Jazz is not dead. It just smells funny...