Re: [PATCH v2 15/21] arm64: KVM: Add panic handling

[Christoffer Dall <christoffer.dall@linaro.org>]

On Fri, Nov 27, 2015 at 06:50:09PM +0000, Marc Zyngier wrote:
> Add the panic handler, together with the small bits of assembly
> code to call the kernel's panic implementation.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/kvm/hyp/hyp-entry.S | 11 ++++++++++-
>  arch/arm64/kvm/hyp/hyp.h       |  1 +
>  arch/arm64/kvm/hyp/switch.c    | 30 ++++++++++++++++++++++++++++++
>  3 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
> index 8334407..39d6935 100644
> --- a/arch/arm64/kvm/hyp/hyp-entry.S
> +++ b/arch/arm64/kvm/hyp/hyp-entry.S
> @@ -150,7 +150,16 @@ el1_irq:
>  	mov	x1, #ARM_EXCEPTION_IRQ
>  	b	__guest_exit
>  
> -.macro invalid_vector	label, target = __kvm_hyp_panic
> +ENTRY(__hyp_do_panic)
> +	mov	lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
> +		      PSR_MODE_EL1h)
> +	msr	spsr_el2, lr
> +	ldr	lr, =panic
> +	msr	elr_el2, lr
> +	eret
> +ENDPROC(__hyp_do_panic)
> +
> +.macro invalid_vector	label, target = __hyp_panic
>  	.align	2
>  \label:
>  	b \target
> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h
> index 18365dd..87f16fa 100644
> --- a/arch/arm64/kvm/hyp/hyp.h
> +++ b/arch/arm64/kvm/hyp/hyp.h
> @@ -74,6 +74,7 @@ static inline bool __fpsimd_enabled(void)
>  }
>  
>  u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt);
> +void __noreturn __hyp_do_panic(unsigned long, ...);
>  
>  #endif /* __ARM64_KVM_HYP_H__ */
>  
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index 8affc19..7b81089 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -140,3 +140,33 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
>  
>  	return exit_code;
>  }
> +
> +static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";
> +
> +void __hyp_text __noreturn __hyp_panic(void)
> +{
> +	unsigned long str_va = (unsigned long)__hyp_panic_string;
> +	u64 spsr = read_sysreg(spsr_el2);
> +	u64 elr = read_sysreg(elr_el2);
> +	u64 par = read_sysreg(par_el1);
> +
> +	if (read_sysreg(vttbr_el2)) {
> +		struct kvm_vcpu *vcpu;
> +		struct kvm_cpu_context *host_ctxt;
> +
> +		vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
> +		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
> +		__deactivate_traps(vcpu);
> +		__deactivate_vm(vcpu);
> +		__sysreg_restore_state(host_ctxt);
> +	}
> +
> +	/* Call panic for real */
> +	__hyp_do_panic(str_va - HYP_PAGE_OFFSET + PAGE_OFFSET,

is the first parameter hyp_kern_va(str_va) ?  If so, can you add that
define instead?

> +		       spsr,  elr,
> +		       read_sysreg(esr_el2),   read_sysreg(far_el2),
> +		       read_sysreg(hpfar_el2), par,
> +		       (void *)read_sysreg(tpidr_el2));
> +
> +	unreachable();
> +}
> -- 
> 2.1.4
> 

Otherwise:

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>