Subject: Re: [PATCH v2 34/37] KVM: PPC: Book3S HV: add virtual mode handlers for HPT hcalls and page faults

From: Fabiano Rosas <[email-masked]>
Date: Wed, 03 Mar 2021 17:09:57 -0300

Nicholas Piggin <[email-masked]> writes:

> In order to support hash guests in the P9 path (which does not do real
> mode hcalls or page fault handling), these real-mode hash specific
> interrupts need to be implemented in virt mode.
>
> Signed-off-by: Nicholas Piggin <[email-masked]>
> ---
>  arch/powerpc/kvm/book3s_hv.c | 118 +++++++++++++++++++++++++++++++++--
>  1 file changed, 113 insertions(+), 5 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 9d2fa21201c1..1bbc46f2cfbf 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -935,6 +935,52 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
>  		return RESUME_HOST;
>
>  	switch (req) {
> +	case H_REMOVE:
> +		ret = kvmppc_h_remove(vcpu, kvmppc_get_gpr(vcpu, 4),
> +					kvmppc_get_gpr(vcpu, 5),
> +					kvmppc_get_gpr(vcpu, 6));
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +	case H_ENTER:
> +		ret = kvmppc_h_enter(vcpu, kvmppc_get_gpr(vcpu, 4),
> +					kvmppc_get_gpr(vcpu, 5),
> +					kvmppc_get_gpr(vcpu, 6),
> +					kvmppc_get_gpr(vcpu, 7));
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +	case H_READ:
> +		ret = kvmppc_h_read(vcpu, kvmppc_get_gpr(vcpu, 4),
> +					kvmppc_get_gpr(vcpu, 5));
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +	case H_CLEAR_MOD:
> +		ret = kvmppc_h_clear_mod(vcpu, kvmppc_get_gpr(vcpu, 4),
> +					kvmppc_get_gpr(vcpu, 5));
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +	case H_CLEAR_REF:
> +		ret = kvmppc_h_clear_ref(vcpu, kvmppc_get_gpr(vcpu, 4),
> +					kvmppc_get_gpr(vcpu, 5));
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +	case H_PROTECT:
> +		ret = kvmppc_h_protect(vcpu, kvmppc_get_gpr(vcpu, 4),
> +					kvmppc_get_gpr(vcpu, 5),
> +					kvmppc_get_gpr(vcpu, 6));
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +	case H_BULK_REMOVE:
> +		ret = kvmppc_h_bulk_remove(vcpu);
> +		if (ret == H_TOO_HARD)
> +			return RESUME_HOST;
> +		break;
> +

Some of these symbols need to be exported.

ERROR: modpost: "kvmppc_h_bulk_remove" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_h_clear_mod" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_xive_xics_hcall" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_h_remove" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "decrementers_next_tb" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_hpte_hv_fault" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_h_protect" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_h_enter" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_h_clear_ref" [arch/powerpc/kvm/kvm-hv.ko] undefined!
ERROR: modpost: "kvmppc_h_read" [arch/powerpc/kvm/kvm-hv.ko] undefined!

>  	case H_CEDE:
>  		break;
>  	case H_PROD:
> @@ -1134,6 +1180,7 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
>  	default:
>  		return RESUME_HOST;
>  	}
> +	WARN_ON_ONCE(ret == H_TOO_HARD);
>  	kvmppc_set_gpr(vcpu, 3, ret);
>  	vcpu->arch.hcall_needed = 0;
>  	return RESUME_GUEST;
> @@ -1420,19 +1467,80 @@ static int kvmppc_handle_exit_hv(struct kvm_vcpu *vcpu,
>  	 * host page has been paged out.  Any other HDSI/HISI interrupts
>  	 * have been handled already.
>  	 */
> -	case BOOK3S_INTERRUPT_H_DATA_STORAGE:
> -		r = RESUME_PAGE_FAULT;
> -		if (vcpu->arch.fault_dsisr == HDSISR_CANARY)
> +	case BOOK3S_INTERRUPT_H_DATA_STORAGE: {
> +		unsigned long vsid;
> +		long err;
> +
> +		if (vcpu->arch.fault_dsisr == HDSISR_CANARY) {
>  			r = RESUME_GUEST; /* Just retry if it's the canary */
> +			break;
> +		}
> +
> +		if (kvm_is_radix(vcpu->kvm)) {
> +			r = RESUME_PAGE_FAULT;
> +			break;
> +		}
> +
> +		if (!(vcpu->arch.fault_dsisr & (DSISR_NOHPTE | DSISR_PROTFAULT))) {
> +			kvmppc_core_queue_data_storage(vcpu, vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
> +			r = RESUME_GUEST;
> +			break;
> +		}
> +		if (!(vcpu->arch.shregs.msr & MSR_DR)) {
> +			vsid = vcpu->kvm->arch.vrma_slb_v;
> +		} else {
> +			vsid = vcpu->arch.fault_gpa;
> +		}
> +		err = kvmppc_hpte_hv_fault(vcpu, vcpu->arch.fault_dar,
> +				vsid, vcpu->arch.fault_dsisr, true);
> +		if (err == 0) {
> +			r = RESUME_GUEST;
> +		} else if (err == -1 || err == -2) {
> +			r = RESUME_PAGE_FAULT;
> +		} else {
> +			kvmppc_core_queue_data_storage(vcpu, vcpu->arch.fault_dar, err);
> +			r = RESUME_GUEST;
> +		}
>  		break;
> -	case BOOK3S_INTERRUPT_H_INST_STORAGE:
> +	}
> +	case BOOK3S_INTERRUPT_H_INST_STORAGE: {
> +		unsigned long vsid;
> +		long err;
> +
>  		vcpu->arch.fault_dar = kvmppc_get_pc(vcpu);
>  		vcpu->arch.fault_dsisr = vcpu->arch.shregs.msr &
>  			DSISR_SRR1_MATCH_64S;
>  		if (vcpu->arch.shregs.msr & HSRR1_HISI_WRITE)
>  			vcpu->arch.fault_dsisr |= DSISR_ISSTORE;
> -		r = RESUME_PAGE_FAULT;
> +		if (kvm_is_radix(vcpu->kvm)) {
> +			r = RESUME_PAGE_FAULT;
> +			break;
> +		}
> +
> +		if (!(vcpu->arch.fault_dsisr & SRR1_ISI_NOPT)) {
> +			/* XXX: clear DSISR_ISSTORE? */
> +			kvmppc_core_queue_inst_storage(vcpu, vcpu->arch.fault_dsisr);
> +			r = RESUME_GUEST;
> +			break;
> +		}
> +		if (!(vcpu->arch.shregs.msr & MSR_DR)) {
> +			vsid = vcpu->kvm->arch.vrma_slb_v;
> +		} else {
> +			vsid = vcpu->arch.fault_gpa;
> +		}
> +		err = kvmppc_hpte_hv_fault(vcpu, vcpu->arch.fault_dar,
> +				vsid, vcpu->arch.fault_dsisr, false);
> +		if (err == 0) {
> +			r = RESUME_GUEST;
> +		} else if (err == -1) {
> +			r = RESUME_PAGE_FAULT;
> +		} else {
> +			kvmppc_core_queue_inst_storage(vcpu, err);
> +			r = RESUME_GUEST;
> +		}
>  		break;
> +	}
> +
>  	/*
>  	 * This occurs if the guest executes an illegal instruction.
>  	 * If the guest debug is disabled, generate a program interrupt