Subject: Re: [PATCH 15/19] KVM: PPC: Book3S HV: add get/set accessors for the source configuration

From: David Gibson <[email-masked]>
Date: Mon, 4 Feb 2019 16:21:49 +1100

On Mon, Jan 07, 2019 at 07:43:27PM +0100, Cédric Le Goater wrote:
> Theses are use to capure the XIVE EAS table of the KVM device, the
> configuration of the source targets.
> 
> Signed-off-by: Cédric Le Goater <[email-masked]>
> ---
>  arch/powerpc/include/uapi/asm/kvm.h   | 11 ++++
>  arch/powerpc/kvm/book3s_xive_native.c | 87 +++++++++++++++++++++++++++
>  2 files changed, 98 insertions(+)
> 
> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
> index 1a8740629acf..faf024f39858 100644
> --- a/arch/powerpc/include/uapi/asm/kvm.h
> +++ b/arch/powerpc/include/uapi/asm/kvm.h
> @@ -683,9 +683,20 @@ struct kvm_ppc_cpu_char {
>  #define   KVM_DEV_XIVE_SAVE_EQ_PAGES	4
>  #define KVM_DEV_XIVE_GRP_SOURCES	2	/* 64-bit source attributes */
>  #define KVM_DEV_XIVE_GRP_SYNC		3	/* 64-bit source attributes */
> +#define KVM_DEV_XIVE_GRP_EAS		4	/* 64-bit eas attributes */
>  
>  /* Layout of 64-bit XIVE source attribute values */
>  #define KVM_XIVE_LEVEL_SENSITIVE	(1ULL << 0)
>  #define KVM_XIVE_LEVEL_ASSERTED		(1ULL << 1)
>  
> +/* Layout of 64-bit eas attribute values */
> +#define KVM_XIVE_EAS_PRIORITY_SHIFT	0
> +#define KVM_XIVE_EAS_PRIORITY_MASK	0x7
> +#define KVM_XIVE_EAS_SERVER_SHIFT	3
> +#define KVM_XIVE_EAS_SERVER_MASK	0xfffffff8ULL
> +#define KVM_XIVE_EAS_MASK_SHIFT		32
> +#define KVM_XIVE_EAS_MASK_MASK		0x100000000ULL
> +#define KVM_XIVE_EAS_EISN_SHIFT		33
> +#define KVM_XIVE_EAS_EISN_MASK		0xfffffffe00000000ULL
> +
>  #endif /* __LINUX_KVM_POWERPC_H */
> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
> index f2de1bcf3b35..0468b605baa7 100644
> --- a/arch/powerpc/kvm/book3s_xive_native.c
> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> @@ -525,6 +525,88 @@ static int kvmppc_xive_native_sync(struct kvmppc_xive *xive, long irq, u64 addr)
>  	return 0;
>  }
>  
> +static int kvmppc_xive_native_set_eas(struct kvmppc_xive *xive, long irq,
> +				      u64 addr)

I'd prefer to avoid the name "EAS" here.  IIUC these aren't "raw" EAS
values, but rather essentially the "source config" in the terminology
of the PAPR hcalls.  Which, yes, is basically implemented by setting
the EAS, but since it's the PAPR architected state that we need to
preserve across migration, I'd prefer to stick as close as we can to
the PAPR terminology.

> +{
> +	struct kvmppc_xive_src_block *sb;
> +	struct kvmppc_xive_irq_state *state;
> +	u64 __user *ubufp = (u64 __user *) addr;
> +	u16 src;
> +	u64 kvm_eas;
> +	u32 server;
> +	u8 priority;
> +	u32 eisn;
> +
> +	sb = kvmppc_xive_find_source(xive, irq, &src);
> +	if (!sb)
> +		return -ENOENT;
> +
> +	state = &sb->irq_state[src];
> +
> +	if (!state->valid)
> +		return -EINVAL;
> +
> +	if (get_user(kvm_eas, ubufp))
> +		return -EFAULT;
> +
> +	pr_devel("%s irq=0x%lx eas=%016llx\n", __func__, irq, kvm_eas);
> +
> +	priority = (kvm_eas & KVM_XIVE_EAS_PRIORITY_MASK) >>
> +		KVM_XIVE_EAS_PRIORITY_SHIFT;
> +	server = (kvm_eas & KVM_XIVE_EAS_SERVER_MASK) >>
> +		KVM_XIVE_EAS_SERVER_SHIFT;
> +	eisn = (kvm_eas & KVM_XIVE_EAS_EISN_MASK) >> KVM_XIVE_EAS_EISN_SHIFT;
> +
> +	if (priority != xive_prio_from_guest(priority)) {
> +		pr_err("invalid priority for queue %d for VCPU %d\n",
> +		       priority, server);
> +		return -EINVAL;
> +	}
> +
> +	return kvmppc_xive_native_set_source_config(xive, sb, state, server,
> +						    priority, eisn);
> +}
> +
> +static int kvmppc_xive_native_get_eas(struct kvmppc_xive *xive, long irq,
> +				      u64 addr)
> +{
> +	struct kvmppc_xive_src_block *sb;
> +	struct kvmppc_xive_irq_state *state;
> +	u64 __user *ubufp = (u64 __user *) addr;
> +	u16 src;
> +	u64 kvm_eas;
> +
> +	sb = kvmppc_xive_find_source(xive, irq, &src);
> +	if (!sb)
> +		return -ENOENT;
> +
> +	state = &sb->irq_state[src];
> +
> +	if (!state->valid)
> +		return -EINVAL;
> +
> +	arch_spin_lock(&sb->lock);
> +
> +	if (state->act_priority == MASKED)
> +		kvm_eas = KVM_XIVE_EAS_MASK_MASK;
> +	else {
> +		kvm_eas = (state->act_priority << KVM_XIVE_EAS_PRIORITY_SHIFT) &
> +			KVM_XIVE_EAS_PRIORITY_MASK;
> +		kvm_eas |= (state->act_server << KVM_XIVE_EAS_SERVER_SHIFT) &
> +			KVM_XIVE_EAS_SERVER_MASK;
> +		kvm_eas |= ((u64) state->eisn << KVM_XIVE_EAS_EISN_SHIFT) &
> +			KVM_XIVE_EAS_EISN_MASK;
> +	}
> +	arch_spin_unlock(&sb->lock);
> +
> +	pr_devel("%s irq=0x%lx eas=%016llx\n", __func__, irq, kvm_eas);
> +
> +	if (put_user(kvm_eas, ubufp))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>  static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>  				       struct kvm_device_attr *attr)
>  {
> @@ -544,6 +626,8 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>  						     attr->addr);
>  	case KVM_DEV_XIVE_GRP_SYNC:
>  		return kvmppc_xive_native_sync(xive, attr->attr, attr->addr);
> +	case KVM_DEV_XIVE_GRP_EAS:
> +		return kvmppc_xive_native_set_eas(xive, attr->attr, attr->addr);
>  	}
>  	return -ENXIO;
>  }
> @@ -564,6 +648,8 @@ static int kvmppc_xive_native_get_attr(struct kvm_device *dev,
>  			return kvmppc_xive_native_get_vc_base(xive, attr->addr);
>  		}
>  		break;
> +	case KVM_DEV_XIVE_GRP_EAS:
> +		return kvmppc_xive_native_get_eas(xive, attr->attr, attr->addr);
>  	}
>  	return -ENXIO;
>  }
> @@ -583,6 +669,7 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
>  		break;
>  	case KVM_DEV_XIVE_GRP_SOURCES:
>  	case KVM_DEV_XIVE_GRP_SYNC:
> +	case KVM_DEV_XIVE_GRP_EAS:
>  		if (attr->attr >= KVMPPC_XIVE_FIRST_IRQ &&
>  		    attr->attr < KVMPPC_XIVE_NR_IRQS)
>  			return 0;

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson