[PATCH 15/21] arm64: KVM: Add panic handling
Marc Zyngier
marc.zyngier at arm.com
Mon Nov 16 06:26:40 PST 2015
On 16/11/15 14:16, Mark Rutland wrote:
>> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
>> index 06d3e20..cdc2a96 100644
>> --- a/arch/arm64/kvm/hyp/switch.c
>> +++ b/arch/arm64/kvm/hyp/switch.c
>> @@ -140,3 +140,38 @@ int __hyp_text __guest_run(struct kvm_vcpu *vcpu)
>>
>> return exit_code;
>> }
>> +
>> +static const char *__hyp_panic_string = "HYP panic:\nPS:%08x PC:%p ESR:%p\nFAR:%p HPFAR:%p PAR:%p\nVCPU:%p\n";
>
> I assume that if [1] goes in we'll update this to match.
Definitely.
>> +
>> +void __hyp_text __noreturn __hyp_panic(void)
>> +{
>> + 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);
>> +
>> + write_sysreg(host_ctxt->gp_regs.sp_el1, sp_el1);
>
> __sysreg_restore_state restores the host sp_el1, no?
Better safe than sorry! ;-) Looks like a leftover from some ancient
version... I'll fix that.
>> + }
>> +
>> + /* Call panic for real */
>> + while (1) {
>> + unsigned long str_va = (unsigned long)__hyp_panic_string;
>> +
>> + str_va -= HYP_PAGE_OFFSET;
>> + str_va += PAGE_OFFSET;
>> + __hyp_do_panic(str_va,
>> + spsr, elr,
>> + read_sysreg(esr_el2), read_sysreg(far_el2),
>> + read_sysreg(hpfar_el2), par,
>> + read_sysreg(tpidr_el2));
>> + }
>> +}
>
> I think the while (1) here is confusing.
>
> Can we not jsut declare str_va at the start of the function and get rid
> of the loop?
The while(1) is to prevent GCC from screaming (it otherwise believes
that the function actually returns, despite the __noreturn attribute).
Or were you thinking of something else?
M.
--
Jazz is not dead. It just smells funny...
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