linux-kernel - Re: [PATCH 3/6] KVM: PPC: Book3S HV nestedv2: Keep nested guest DEXCR in sync

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Date: Tue, 04 Jun 2024 15:46:06 +1000
From: "Nicholas Piggin" <npiggin@...il.com>
To: "Shivaprasad G Bhat" <sbhat@...ux.ibm.com>, <kvm@...r.kernel.org>,
 <linux-doc@...r.kernel.org>, <linuxppc-dev@...ts.ozlabs.org>
Cc: <pbonzini@...hat.com>, <naveen.n.rao@...ux.ibm.com>,
 <christophe.leroy@...roup.eu>, <corbet@....net>, <mpe@...erman.id.au>,
 <namhyung@...nel.org>, <pbonzini@...hat.com>, <jniethe5@...il.com>,
 <atrajeev@...ux.vnet.ibm.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/6] KVM: PPC: Book3S HV nestedv2: Keep nested guest
 DEXCR in sync

On Mon Jun 3, 2024 at 9:14 PM AEST, Shivaprasad G Bhat wrote:
> The nestedv2 APIs has the guest state element defined for DEXCR
> for the save-restore with L0. However, its ignored in the code.
>
> The patch takes care of this for the DEXCR GSID.
>
> Signed-off-by: Shivaprasad G Bhat <sbhat@...ux.ibm.com>
> ---
>  arch/powerpc/include/asm/kvm_host.h   |    1 +
>  arch/powerpc/kvm/book3s_hv.h          |    1 +
>  arch/powerpc/kvm/book3s_hv_nestedv2.c |    6 ++++++
>  3 files changed, 8 insertions(+)
>
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index 8abac532146e..1e2fdcbecffd 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -599,6 +599,7 @@ struct kvm_vcpu_arch {
>  	ulong dawrx0;
>  	ulong dawr1;
>  	ulong dawrx1;
> +	ulong dexcr;
>  	ulong ciabr;
>  	ulong cfar;
>  	ulong ppr;

Actually I would reorder the patches so you introduce the KVM reg
first, and put this hunk there.

The nested v2 bits look okay. For them,

Reviewed-by: Nicholas Piggin <npiggin@...il.com>

> diff --git a/arch/powerpc/kvm/book3s_hv.h b/arch/powerpc/kvm/book3s_hv.h
> index 47b2c815641e..7b0fd282fe95 100644
> --- a/arch/powerpc/kvm/book3s_hv.h
> +++ b/arch/powerpc/kvm/book3s_hv.h
> @@ -116,6 +116,7 @@ KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(dawr0, 64, KVMPPC_GSID_DAWR0)
>  KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(dawr1, 64, KVMPPC_GSID_DAWR1)
>  KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(dawrx0, 64, KVMPPC_GSID_DAWRX0)
>  KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(dawrx1, 64, KVMPPC_GSID_DAWRX1)
> +KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(dexcr, 64, KVMPPC_GSID_DEXCR)
>  KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(ciabr, 64, KVMPPC_GSID_CIABR)
>  KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(wort, 64, KVMPPC_GSID_WORT)
>  KVMPPC_BOOK3S_HV_VCPU_ACCESSOR(ppr, 64, KVMPPC_GSID_PPR)
> diff --git a/arch/powerpc/kvm/book3s_hv_nestedv2.c b/arch/powerpc/kvm/book3s_hv_nestedv2.c
> index 1091f7a83b25..d207a6d936ff 100644
> --- a/arch/powerpc/kvm/book3s_hv_nestedv2.c
> +++ b/arch/powerpc/kvm/book3s_hv_nestedv2.c
> @@ -193,6 +193,9 @@ static int gs_msg_ops_vcpu_fill_info(struct kvmppc_gs_buff *gsb,
>  		case KVMPPC_GSID_DAWRX1:
>  			rc = kvmppc_gse_put_u32(gsb, iden, vcpu->arch.dawrx1);
>  			break;
> +		case KVMPPC_GSID_DEXCR:
> +			rc = kvmppc_gse_put_u64(gsb, iden, vcpu->arch.dexcr);
> +			break;
>  		case KVMPPC_GSID_CIABR:
>  			rc = kvmppc_gse_put_u64(gsb, iden, vcpu->arch.ciabr);
>  			break;
> @@ -441,6 +444,9 @@ static int gs_msg_ops_vcpu_refresh_info(struct kvmppc_gs_msg *gsm,
>  		case KVMPPC_GSID_DAWRX1:
>  			vcpu->arch.dawrx1 = kvmppc_gse_get_u32(gse);
>  			break;
> +		case KVMPPC_GSID_DEXCR:
> +			vcpu->arch.dexcr = kvmppc_gse_get_u64(gse);
> +			break;
>  		case KVMPPC_GSID_CIABR:
>  			vcpu->arch.ciabr = kvmppc_gse_get_u64(gse);
>  			break;