[PATCH 1/2] KVM: arm64: Move __adjust_pc out of line

[Alexandru Elisei]

Hi Marc,

On 5/10/21 10:49 AM, Marc Zyngier wrote:
> In order to make it easy to call __adjust_pc() from the EL1 code
> (in the case of nVHE), rename it to __kvm_adjust_pc() and move
> it out of line.
>
> No expected functional change.

It does look to me like they're functionally identical. Minor comments below.

>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> Cc: stable at vger.kernel.org # 5.11
> ---
>  arch/arm64/include/asm/kvm_asm.h           |  2 ++
>  arch/arm64/kvm/hyp/exception.c             | 18 +++++++++++++++++-
>  arch/arm64/kvm/hyp/include/hyp/adjust_pc.h | 18 ------------------
>  arch/arm64/kvm/hyp/nvhe/switch.c           |  2 +-
>  arch/arm64/kvm/hyp/vhe/switch.c            |  2 +-
>  5 files changed, 21 insertions(+), 21 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index cf8df032b9c3..d5b11037401d 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -201,6 +201,8 @@ extern void __kvm_timer_set_cntvoff(u64 cntvoff);
>  
>  extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
>  
> +extern void __kvm_adjust_pc(struct kvm_vcpu *vcpu);

It looks pretty strange to have the file
arch/arm64/kvm/hyp/include/hyp/adjust_pc.h, but the function __kvm_adjust_pc() in
another header. I guess this was done because arch/arm64/kvm/arm.c will use the
function in the next patch. I was thinking that maybe renaming
adjust_pc.h->skip_instr.h would make more sense, what do you think? I can send a
patch on top of this series with the rename if you prefer.

> +
>  extern u64 __vgic_v3_get_gic_config(void);
>  extern u64 __vgic_v3_read_vmcr(void);
>  extern void __vgic_v3_write_vmcr(u32 vmcr);
> diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c
> index 73629094f903..0812a496725f 100644
> --- a/arch/arm64/kvm/hyp/exception.c
> +++ b/arch/arm64/kvm/hyp/exception.c
> @@ -296,7 +296,7 @@ static void enter_exception32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
>  	*vcpu_pc(vcpu) = vect_offset;
>  }
>  
> -void kvm_inject_exception(struct kvm_vcpu *vcpu)
> +static void kvm_inject_exception(struct kvm_vcpu *vcpu)
>  {
>  	if (vcpu_el1_is_32bit(vcpu)) {
>  		switch (vcpu->arch.flags & KVM_ARM64_EXCEPT_MASK) {
> @@ -329,3 +329,19 @@ void kvm_inject_exception(struct kvm_vcpu *vcpu)
>  		}
>  	}
>  }
> +
> +/*
> + * Adjust the guest PC on entry, depending on flags provided by EL1

This is also called by the VHE code running at EL2, but the comment is reworded in
the next patch, so it doesn't really matter, and keeping the diff a straight move
makes it easier to read.

> + * for the purpose of emulation (MMIO, sysreg) or exception injection.
> + */
> +void __kvm_adjust_pc(struct kvm_vcpu *vcpu)
> +{
> +	if (vcpu->arch.flags & KVM_ARM64_PENDING_EXCEPTION) {
> +		kvm_inject_exception(vcpu);
> +		vcpu->arch.flags &= ~(KVM_ARM64_PENDING_EXCEPTION |
> +				      KVM_ARM64_EXCEPT_MASK);
> +	} else 	if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
> +		kvm_skip_instr(vcpu);
> +		vcpu->arch.flags &= ~KVM_ARM64_INCREMENT_PC;
> +	}
> +}
> diff --git a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
> index 61716359035d..4fdfeabefeb4 100644
> --- a/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
> +++ b/arch/arm64/kvm/hyp/include/hyp/adjust_pc.h
> @@ -13,8 +13,6 @@
>  #include <asm/kvm_emulate.h>
>  #include <asm/kvm_host.h>
>  
> -void kvm_inject_exception(struct kvm_vcpu *vcpu);
> -
>  static inline void kvm_skip_instr(struct kvm_vcpu *vcpu)
>  {
>  	if (vcpu_mode_is_32bit(vcpu)) {
> @@ -43,22 +41,6 @@ static inline void __kvm_skip_instr(struct kvm_vcpu *vcpu)
>  	write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
>  }
>  
> -/*
> - * Adjust the guest PC on entry, depending on flags provided by EL1
> - * for the purpose of emulation (MMIO, sysreg) or exception injection.
> - */
> -static inline void __adjust_pc(struct kvm_vcpu *vcpu)
> -{
> -	if (vcpu->arch.flags & KVM_ARM64_PENDING_EXCEPTION) {
> -		kvm_inject_exception(vcpu);
> -		vcpu->arch.flags &= ~(KVM_ARM64_PENDING_EXCEPTION |
> -				      KVM_ARM64_EXCEPT_MASK);
> -	} else 	if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
> -		kvm_skip_instr(vcpu);
> -		vcpu->arch.flags &= ~KVM_ARM64_INCREMENT_PC;
> -	}
> -}
> -
>  /*
>   * Skip an instruction while host sysregs are live.
>   * Assumes host is always 64-bit.
> diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
> index e9f6ea704d07..b8ac123c3419 100644
> --- a/arch/arm64/kvm/hyp/nvhe/switch.c
> +++ b/arch/arm64/kvm/hyp/nvhe/switch.c
> @@ -201,7 +201,7 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
>  	 */
>  	__debug_save_host_buffers_nvhe(vcpu);
>  
> -	__adjust_pc(vcpu);
> +	__kvm_adjust_pc(vcpu);
>  
>  	/*
>  	 * We must restore the 32-bit state before the sysregs, thanks
> diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
> index 7b8f7db5c1ed..3eafed0431f5 100644
> --- a/arch/arm64/kvm/hyp/vhe/switch.c
> +++ b/arch/arm64/kvm/hyp/vhe/switch.c
> @@ -132,7 +132,7 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
>  	__load_guest_stage2(vcpu->arch.hw_mmu);
>  	__activate_traps(vcpu);
>  
> -	__adjust_pc(vcpu);
> +	__kvm_adjust_pc(vcpu);

With the function now moved to kvm_asm.h, the header include adjust_pc.h is not
needed. Same for the nvhe version of switch.c.

Thanks,

Alex

>  
>  	sysreg_restore_guest_state_vhe(guest_ctxt);
>  	__debug_switch_to_guest(vcpu);