On Tue, Aug 11, 2015 at 10:34:07AM +0300, Pavel Fedin wrote:
> Print exception vector name, exception class and PC translated to EL1 virtual
> address. Significantly aids debugging HYP crashes without special means like
> JTAG.
my overall concern with this patch is that it adds complexity to an
already really bad situation, and potentially increases the likelihood
of not seeing any debug info at all.
do you encounter this kind of panic a lot? I haven't experienced a
great need for more hyp debugging help lately...
>
> Signed-off-by: Pavel Fedin <p.fedin@xxxxxxxxxxx>
> ---
> 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
why can you get rid of this?
> 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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