PING: [PATCH] KVM: arm64: Decode basic HYP fault information

[Pavel Fedin <p.fedin@samsung.com>]

PING

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia


> -----Original Message-----
> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On Behalf Of Pavel Fedin
> Sent: Tuesday, August 11, 2015 10:34 AM
> To: kvmarm@lists.cs.columbia.edu; kvm@vger.kernel.org
> Cc: 'Christoffer Dall'; 'Marc Zyngier'
> Subject: [PATCH] KVM: arm64: Decode basic HYP fault information
> 
> Print exception vector name, exception class and PC translated to EL1 virtual
> address. Significantly aids debugging HYP crashes without special means like
> JTAG.
> 
> Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
> ---
>  arch/arm64/kvm/handle_exit.c | 30 +++++++++++++++++++++++++++++
>  arch/arm64/kvm/hyp.S         | 46 +++++++++++++++++---------------------------
>  2 files changed, 48 insertions(+), 28 deletions(-)
> 
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 29b184a..4d70d64 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -136,3 +136,33 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
>  		return 0;
>  	}
>  }
> +
> +static const char *const hyp_faults[] = {
> +	"EL2t Synchronous",
> +	"EL2t IRQ",
> +	"EL2t FIQ",
> +	"EL2t Error",
> +	"EL2h Synchronous",
> +	"EL2h IRQ",
> +	"EL2h FIQ",
> +	"EL2h Error",
> +	"EL1 Synchronous",
> +	"EL1 IRQ",
> +	"EL1 FIQ",
> +	"EL1 Error"
> +};
> +
> +void kvm_hyp_panic(unsigned long vector, unsigned int spsr, unsigned long pc,
> +		   unsigned int esr, unsigned long far, unsigned long hpfar,
> +		   unsigned long par, struct kvm_vcpu *vcpu)
> +{
> +	pr_emerg("Unhandled HYP exception %s on VCPU %p\n",
> +		hyp_faults[vector], vcpu);
> +	pr_emerg("PC : %016lx SPSR : %08x         ESR: %08x\n", pc, spsr, esr);
> +	pr_emerg("FAR: %016lx HPFAR: %016lx PAR: %016lx\n", far, hpfar, par);
> +
> +	pr_emerg("Exception class: %02x Translated PC: %016lx\n",
> +		esr >> ESR_ELx_EC_SHIFT, pc - HYP_PAGE_OFFSET + PAGE_OFFSET);
> +
> +	panic("HYP panic");
> +}
> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> index c81eaaf..62785cd 100644
> --- a/arch/arm64/kvm/hyp.S
> +++ b/arch/arm64/kvm/hyp.S
> @@ -1060,13 +1060,11 @@ __kvm_hyp_panic:
>  	ldr	x2, [x0, #VCPU_HOST_CONTEXT]
>  	kern_hyp_va x2
> 
> +	mov	x0, lr
>  	bl __restore_sysregs
> +	mov	lr, x0
> 
> -1:	adr	x0, __hyp_panic_str
> -	adr	x1, 2f
> -	ldp	x2, x3, [x1]
> -	sub	x0, x0, x2
> -	add	x0, x0, x3
> +1:	mov	x0, lr
>  	mrs	x1, spsr_el2
>  	mrs	x2, elr_el2
>  	mrs	x3, esr_el2
> @@ -1078,20 +1076,11 @@ __kvm_hyp_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
> +	ldr	lr, =kvm_hyp_panic
>  	msr	elr_el2, lr
>  	eret
> -
> -	.align	3
> -2:	.quad	HYP_PAGE_OFFSET
> -	.quad	PAGE_OFFSET
>  ENDPROC(__kvm_hyp_panic)
> 
> -__hyp_panic_str:
> -	.ascii	"HYP panic:\nPS:%08x PC:%p ESR:%p\nFAR:%p HPFAR:%p PAR:%p\nVCPU:%p\n\0"
> -
> -	.align	2
> -
>  /*
>   * u64 kvm_call_hyp(void *hypfn, ...);
>   *
> @@ -1115,26 +1104,27 @@ ENTRY(kvm_call_hyp)
>  	ret
>  ENDPROC(kvm_call_hyp)
> 
> -.macro invalid_vector	label, target
> +.macro invalid_vector	label, N, target
>  	.align	2
>  \label:
> +	mov lr, #\N
>  	b \target
>  ENDPROC(\label)
>  .endm
> 
>  	/* None of these should ever happen */
> -	invalid_vector	el2t_sync_invalid, __kvm_hyp_panic
> -	invalid_vector	el2t_irq_invalid, __kvm_hyp_panic
> -	invalid_vector	el2t_fiq_invalid, __kvm_hyp_panic
> -	invalid_vector	el2t_error_invalid, __kvm_hyp_panic
> -	invalid_vector	el2h_sync_invalid, __kvm_hyp_panic
> -	invalid_vector	el2h_irq_invalid, __kvm_hyp_panic
> -	invalid_vector	el2h_fiq_invalid, __kvm_hyp_panic
> -	invalid_vector	el2h_error_invalid, __kvm_hyp_panic
> -	invalid_vector	el1_sync_invalid, __kvm_hyp_panic
> -	invalid_vector	el1_irq_invalid, __kvm_hyp_panic
> -	invalid_vector	el1_fiq_invalid, __kvm_hyp_panic
> -	invalid_vector	el1_error_invalid, __kvm_hyp_panic
> +	invalid_vector	el2t_sync_invalid, 0, __kvm_hyp_panic
> +	invalid_vector	el2t_irq_invalid, 1, __kvm_hyp_panic
> +	invalid_vector	el2t_fiq_invalid, 2, __kvm_hyp_panic
> +	invalid_vector	el2t_error_invalid, 3, __kvm_hyp_panic
> +	invalid_vector	el2h_sync_invalid, 4, __kvm_hyp_panic
> +	invalid_vector	el2h_irq_invalid, 5, __kvm_hyp_panic
> +	invalid_vector	el2h_fiq_invalid, 6, __kvm_hyp_panic
> +	invalid_vector	el2h_error_invalid, 7, __kvm_hyp_panic
> +	invalid_vector	el1_sync_invalid, 8, __kvm_hyp_panic
> +	invalid_vector	el1_irq_invalid, 9, __kvm_hyp_panic
> +	invalid_vector	el1_fiq_invalid, 10, __kvm_hyp_panic
> +	invalid_vector	el1_error_invalid, 11, __kvm_hyp_panic
> 
>  el1_sync:					// Guest trapped into EL2
>  	push	x0, x1
> --
> 2.4.4
> 
> 
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
> 
> 
> 
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