[PATCH 2/2] KVM: PPC: Book3E: Emulate MCSRR0/1 SPR and rfmci instruction

[Alexander Graf]

On 03.07.2013, at 15:30, Mihai Caraman wrote:

> Some guests are making use of return from machine check instruction
> to do crazy things even though the 64-bit kernel doesn't handle yet
> this interrupt. Emulate MCSRR0/1 SPR and rfmci instruction accordingly.
> 
> Signed-off-by: Mihai Caraman <mihai.caraman at freescale.com>
> ---
> arch/powerpc/include/asm/kvm_host.h |    1 +
> arch/powerpc/kvm/booke_emulate.c    |   25 +++++++++++++++++++++++++
> arch/powerpc/kvm/timing.c           |    1 +
> 3 files changed, 27 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
> index af326cd..0466789 100644
> --- a/arch/powerpc/include/asm/kvm_host.h
> +++ b/arch/powerpc/include/asm/kvm_host.h
> @@ -148,6 +148,7 @@ enum kvm_exit_types {
> 	EMULATED_TLBWE_EXITS,
> 	EMULATED_RFI_EXITS,
> 	EMULATED_RFCI_EXITS,
> +	EMULATED_RFMCI_EXITS,

I would quite frankly prefer to see us abandon the whole exit timing framework in the kernel and instead use trace points. Then we don't have to maintain all of this randomly exercised code.

FWIW I think in this case however, treating RFMCI the same as RFI or random "instruction emulation" shouldn't hurt. This whole table is only about timing measurements. If you want to know for real what's going on, use trace points.

Otherwise looks good.


Alex

> 	DEC_EXITS,
> 	EXT_INTR_EXITS,
> 	HALT_WAKEUP,
> diff --git a/arch/powerpc/kvm/booke_emulate.c b/arch/powerpc/kvm/booke_emulate.c
> index 27a4b28..aaff1b7 100644
> --- a/arch/powerpc/kvm/booke_emulate.c
> +++ b/arch/powerpc/kvm/booke_emulate.c
> @@ -23,6 +23,7 @@
> 
> #include "booke.h"
> 
> +#define OP_19_XOP_RFMCI   38
> #define OP_19_XOP_RFI     50
> #define OP_19_XOP_RFCI    51
> 
> @@ -43,6 +44,12 @@ static void kvmppc_emul_rfci(struct kvm_vcpu *vcpu)
> 	kvmppc_set_msr(vcpu, vcpu->arch.csrr1);
> }
> 
> +static void kvmppc_emul_rfmci(struct kvm_vcpu *vcpu)
> +{
> +	vcpu->arch.pc = vcpu->arch.mcsrr0;
> +	kvmppc_set_msr(vcpu, vcpu->arch.mcsrr1);
> +}
> +
> int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
>                             unsigned int inst, int *advance)
> {
> @@ -65,6 +72,12 @@ int kvmppc_booke_emulate_op(struct kvm_run *run, struct kvm_vcpu *vcpu,
> 			*advance = 0;
> 			break;
> 
> +		case OP_19_XOP_RFMCI:
> +			kvmppc_emul_rfmci(vcpu);
> +			kvmppc_set_exit_type(vcpu, EMULATED_RFMCI_EXITS);
> +			*advance = 0;
> +			break;
> +
> 		default:
> 			emulated = EMULATE_FAIL;
> 			break;
> @@ -138,6 +151,12 @@ int kvmppc_booke_emulate_mtspr(struct kvm_vcpu *vcpu, int sprn, ulong spr_val)
> 	case SPRN_DBCR1:
> 		vcpu->arch.dbg_reg.dbcr1 = spr_val;
> 		break;
> +	case SPRN_MCSRR0:
> +		vcpu->arch.mcsrr0 = spr_val;
> +		break;
> +	case SPRN_MCSRR1:
> +		vcpu->arch.mcsrr1 = spr_val;
> +		break;
> 	case SPRN_DBSR:
> 		vcpu->arch.dbsr &= ~spr_val;
> 		break;
> @@ -284,6 +303,12 @@ int kvmppc_booke_emulate_mfspr(struct kvm_vcpu *vcpu, int sprn, ulong *spr_val)
> 	case SPRN_DBCR1:
> 		*spr_val = vcpu->arch.dbg_reg.dbcr1;
> 		break;
> +	case SPRN_MCSRR0:
> +		*spr_val = vcpu->arch.mcsrr0;
> +		break;
> +	case SPRN_MCSRR1:
> +		*spr_val = vcpu->arch.mcsrr1;
> +		break;
> 	case SPRN_DBSR:
> 		*spr_val = vcpu->arch.dbsr;
> 		break;
> diff --git a/arch/powerpc/kvm/timing.c b/arch/powerpc/kvm/timing.c
> index c392d26..670f63d 100644
> --- a/arch/powerpc/kvm/timing.c
> +++ b/arch/powerpc/kvm/timing.c
> @@ -129,6 +129,7 @@ static const char *kvm_exit_names[__NUMBER_OF_KVM_EXIT_TYPES] = {
> 	[EMULATED_TLBSX_EXITS] =    "EMUL_TLBSX",
> 	[EMULATED_TLBWE_EXITS] =    "EMUL_TLBWE",
> 	[EMULATED_RFI_EXITS] =      "EMUL_RFI",
> +	[EMULATED_RFMCI_EXITS] =    "EMUL_RFMCI",
> 	[DEC_EXITS] =               "DEC",
> 	[EXT_INTR_EXITS] =          "EXTINT",
> 	[HALT_WAKEUP] =             "HALT",
> -- 
> 1.7.3.4
> 
> 
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