Re: [PATCH 3/3] KVM: PPC: Book3S HV: Add H_SET_MODE hcall handling

[Alexander Graf <agraf@suse.de>]

On 26.05.14 14:17, Paul Mackerras wrote:
> From: Michael Neuling <mikey@neuling.org>
>
> This adds support for the H_SET_MODE hcall.  This hcall is a
> multiplexer that has several functions, some of which are called
> rarely, and some which are potentially called very frequently.
> Here we add support for the functions that set the debug registers
> CIABR (Completed Instruction Address Breakpoint Register) and
> DAWR/DAWRX (Data Address Watchpoint Register and eXtension),
> since they could be updated by the guest as often as every context
> switch.
>
> This also adds a kvmppc_power8_compatible() function to test to see
> if a guest is compatible with POWER8 or not.  The CIABR and DAWR/X
> only exist on POWER8.
>
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> Signed-off-by: Paul Mackerras <paulus@samba.org>
> ---
>   arch/powerpc/include/asm/hvcall.h |  6 +++++
>   arch/powerpc/kvm/book3s_hv.c      | 51 ++++++++++++++++++++++++++++++++++++++-
>   2 files changed, 56 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
> index 5dbbb29..85bc8c0 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -279,6 +279,12 @@
>   #define H_GET_24X7_DATA		0xF07C
>   #define H_GET_PERF_COUNTER_INFO	0xF080
>   
> +/* Values for 2nd argument to H_SET_MODE */
> +#define H_SET_MODE_RESOURCE_SET_CIABR		1
> +#define H_SET_MODE_RESOURCE_SET_DAWR		2
> +#define H_SET_MODE_RESOURCE_ADDR_TRANS_MODE	3
> +#define H_SET_MODE_RESOURCE_LE			4
> +
>   #ifndef __ASSEMBLY__
>   
>   /**
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 1f91130..53e2b63 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -557,6 +557,47 @@ static void kvmppc_create_dtl_entry(struct kvm_vcpu *vcpu,
>   	vcpu->arch.dtl.dirty = true;
>   }
>   
> +static bool kvmppc_power8_compatible(struct kvm_vcpu *vcpu)
> +{
> +	if (vcpu->arch.vcore->arch_compat >= PVR_ARCH_207)
> +		return true;
> +	if ((!vcpu->arch.vcore->arch_compat) &&
> +	    cpu_has_feature(CPU_FTR_ARCH_207S))
> +		return true;
> +	return false;
> +}
> +
> +static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags,
> +			     unsigned long resource, unsigned long value1,
> +			     unsigned long value2)
> +{
> +	switch (resource) {
> +	case H_SET_MODE_RESOURCE_SET_CIABR:
> +		if (!kvmppc_power8_compatible(vcpu))
> +			return H_P2;
> +		if (value2)
> +			return H_P4;
> +		if (mflags)
> +			return H_UNSUPPORTED_FLAG_START;
> +		if ((value1 & 0x3) == 0x3)

What is this?

Alex

> +			return H_P3;
> +		vcpu->arch.ciabr  = value1;
> +		return H_SUCCESS;
> +	case H_SET_MODE_RESOURCE_SET_DAWR:
> +		if (!kvmppc_power8_compatible(vcpu))
> +			return H_P2;
> +		if (mflags)
> +			return H_UNSUPPORTED_FLAG_START;
> +		if (value2 & DABRX_HYP)
> +			return H_P4;
> +		vcpu->arch.dawr  = value1;
> +		vcpu->arch.dawrx = value2;
> +		return H_SUCCESS;
> +	default:
> +		return H_TOO_HARD;
> +	}
> +}
> +
>   int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
>   {
>   	unsigned long req = kvmppc_get_gpr(vcpu, 3);
> @@ -626,7 +667,14 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
>   
>   		/* Send the error out to userspace via KVM_RUN */
>   		return rc;
> -
> +	case H_SET_MODE:
> +		ret = kvmppc_h_set_mode(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_XIRR:
>   	case H_CPPR:
>   	case H_EOI:
> @@ -652,6 +700,7 @@ static int kvmppc_hcall_impl_hv(struct kvm *kvm, unsigned long cmd)
>   	case H_PROD:
>   	case H_CONFER:
>   	case H_REGISTER_VPA:
> +	case H_SET_MODE:
>   #ifdef CONFIG_KVM_XICS
>   	case H_XIRR:
>   	case H_CPPR: