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 <[email protected]>
---
 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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