Re: [PATCH v12 23/31] LoongArch: KVM: Implement handle gspr exception

[bibo, mao]

Reviewed-by: Bibo, Mao <maobibo@xxxxxxxxxxx>


在 2023/5/30 09:52, Tianrui Zhao 写道:
> Implement kvm handle gspr exception interface, including emulate the
> reading and writing of cpucfg, csr, iocsr resource.
> 
> Signed-off-by: Tianrui Zhao <zhaotianrui@xxxxxxxxxxx>
> ---
>  arch/loongarch/kvm/exit.c | 115 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 115 insertions(+)
> 
> diff --git a/arch/loongarch/kvm/exit.c b/arch/loongarch/kvm/exit.c
> index 3fdb42939a05..26283a9d3c6d 100644
> --- a/arch/loongarch/kvm/exit.c
> +++ b/arch/loongarch/kvm/exit.c
> @@ -208,3 +208,118 @@ int _kvm_emu_idle(struct kvm_vcpu *vcpu)
>  
>  	return EMULATE_DONE;
>  }
> +
> +static int _kvm_trap_handle_gspr(struct kvm_vcpu *vcpu)
> +{
> +	enum emulation_result er = EMULATE_DONE;
> +	struct kvm_run *run = vcpu->run;
> +	larch_inst inst;
> +	unsigned long curr_pc;
> +	int rd, rj;
> +	unsigned int index;
> +
> +	/*
> +	 *  Fetch the instruction.
> +	 */
> +	inst.word = vcpu->arch.badi;
> +	curr_pc = vcpu->arch.pc;
> +	update_pc(&vcpu->arch);
> +
> +	trace_kvm_exit_gspr(vcpu, inst.word);
> +	er = EMULATE_FAIL;
> +	switch (((inst.word >> 24) & 0xff)) {
> +	case 0x0:
> +		/* cpucfg GSPR */
> +		if (inst.reg2_format.opcode == 0x1B) {
> +			rd = inst.reg2_format.rd;
> +			rj = inst.reg2_format.rj;
> +			++vcpu->stat.cpucfg_exits;
> +			index = vcpu->arch.gprs[rj];
> +
> +			vcpu->arch.gprs[rd] = read_cpucfg(index);
> +			/* Nested KVM is not supported */
> +			if (index == 2)
> +				vcpu->arch.gprs[rd] &= ~CPUCFG2_LVZP;
> +			if (index == 6)
> +				vcpu->arch.gprs[rd] &= ~CPUCFG6_PMP;
> +			er = EMULATE_DONE;
> +		}
> +		break;
> +	case 0x4:
> +		/* csr GSPR */
> +		er = _kvm_handle_csr(vcpu, inst);
> +		break;
> +	case 0x6:
> +		/* iocsr,cache,idle GSPR */
> +		switch (((inst.word >> 22) & 0x3ff)) {
> +		case 0x18:
> +			/* cache GSPR */
> +			er = EMULATE_DONE;
> +			trace_kvm_exit_cache(vcpu, KVM_TRACE_EXIT_CACHE);
> +			break;
> +		case 0x19:
> +			/* iocsr/idle GSPR */
> +			switch (((inst.word >> 15) & 0x1ffff)) {
> +			case 0xc90:
> +				/* iocsr GSPR */
> +				er = _kvm_emu_iocsr(inst, run, vcpu);
> +				break;
> +			case 0xc91:
> +				/* idle GSPR */
> +				er = _kvm_emu_idle(vcpu);
> +				break;
> +			default:
> +				er = EMULATE_FAIL;
> +				break;
> +			}
> +			break;
> +		default:
> +			er = EMULATE_FAIL;
> +			break;
> +		}
> +		break;
> +	default:
> +		er = EMULATE_FAIL;
> +		break;
> +	}
> +
> +	/* Rollback PC only if emulation was unsuccessful */
> +	if (er == EMULATE_FAIL) {
> +		kvm_err("[%#lx]%s: unsupported gspr instruction 0x%08x\n",
> +			curr_pc, __func__, inst.word);
> +
> +		kvm_arch_vcpu_dump_regs(vcpu);
> +		vcpu->arch.pc = curr_pc;
> +	}
> +	return er;
> +}
> +
> +/*
> + * Execute cpucfg instruction will tirggerGSPR,
> + * Also the access to unimplemented csrs 0x15
> + * 0x16, 0x50~0x53, 0x80, 0x81, 0x90~0x95, 0x98
> + * 0xc0~0xff, 0x100~0x109, 0x500~0x502,
> + * cache_op, idle_op iocsr ops the same
> + */
> +static int _kvm_handle_gspr(struct kvm_vcpu *vcpu)
> +{
> +	enum emulation_result er = EMULATE_DONE;
> +	int ret = RESUME_GUEST;
> +
> +	er = _kvm_trap_handle_gspr(vcpu);
> +
> +	if (er == EMULATE_DONE) {
> +		ret = RESUME_GUEST;
> +	} else if (er == EMULATE_DO_MMIO) {
> +		vcpu->run->exit_reason = KVM_EXIT_MMIO;
> +		ret = RESUME_HOST;
> +	} else if (er == EMULATE_DO_IOCSR) {
> +		vcpu->run->exit_reason = KVM_EXIT_LOONGARCH_IOCSR;
> +		ret = RESUME_HOST;
> +	} else {
> +		kvm_err("%s internal error\n", __func__);
> +		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
> +		ret = RESUME_HOST;
> +	}
> +	return ret;
> +}