Re: [PATCH 16/19] KVM: PPC: Book3S HV: add get/set accessors for the EQ configuration

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jan 07, 2019 at 07:43:28PM +0100, Cédric Le Goater wrote:
> These are used to capture the XIVE END table of the KVM device. It
> relies on an OPAL call to retrieve from the XIVE IC the EQ toggle bit
> and index which are updated by the HW when events are enqueued in the
> guest RAM.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  arch/powerpc/include/uapi/asm/kvm.h   |  21 ++++
>  arch/powerpc/kvm/book3s_xive_native.c | 166 ++++++++++++++++++++++++++
>  2 files changed, 187 insertions(+)
> 
> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
> index faf024f39858..95302558ce10 100644
> --- a/arch/powerpc/include/uapi/asm/kvm.h
> +++ b/arch/powerpc/include/uapi/asm/kvm.h
> @@ -684,6 +684,7 @@ struct kvm_ppc_cpu_char {
>  #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 */
> +#define KVM_DEV_XIVE_GRP_EQ		5	/* 64-bit eq attributes */
>  
>  /* Layout of 64-bit XIVE source attribute values */
>  #define KVM_XIVE_LEVEL_SENSITIVE	(1ULL << 0)
> @@ -699,4 +700,24 @@ struct kvm_ppc_cpu_char {
>  #define KVM_XIVE_EAS_EISN_SHIFT		33
>  #define KVM_XIVE_EAS_EISN_MASK		0xfffffffe00000000ULL
>  
> +/* Layout of 64-bit eq attribute */
> +#define KVM_XIVE_EQ_PRIORITY_SHIFT	0
> +#define KVM_XIVE_EQ_PRIORITY_MASK	0x7
> +#define KVM_XIVE_EQ_SERVER_SHIFT	3
> +#define KVM_XIVE_EQ_SERVER_MASK		0xfffffff8ULL
> +
> +/* Layout of 64-bit eq attribute values */
> +struct kvm_ppc_xive_eq {
> +	__u32 flags;
> +	__u32 qsize;
> +	__u64 qpage;
> +	__u32 qtoggle;
> +	__u32 qindex;

Should we pad this in case a) we discover some fields in the EQ that
we thought weren't relevant to the guest actually are or b) future
XIVE extensions add something we need to migrate.

> +};
> +
> +#define KVM_XIVE_EQ_FLAG_ENABLED	0x00000001
> +#define KVM_XIVE_EQ_FLAG_ALWAYS_NOTIFY	0x00000002
> +#define KVM_XIVE_EQ_FLAG_ESCALATE	0x00000004
> +
> +
>  #endif /* __LINUX_KVM_POWERPC_H */
> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
> index 0468b605baa7..f4eb71eafc57 100644
> --- a/arch/powerpc/kvm/book3s_xive_native.c
> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> @@ -607,6 +607,164 @@ static int kvmppc_xive_native_get_eas(struct kvmppc_xive *xive, long irq,
>  	return 0;
>  }
>  
> +static int kvmppc_xive_native_set_queue(struct kvmppc_xive *xive, long eq_idx,
> +				      u64 addr)
> +{
> +	struct kvm *kvm = xive->kvm;
> +	struct kvm_vcpu *vcpu;
> +	struct kvmppc_xive_vcpu *xc;
> +	void __user *ubufp = (u64 __user *) addr;
> +	u32 server;
> +	u8 priority;
> +	struct kvm_ppc_xive_eq kvm_eq;
> +	int rc;
> +	__be32 *qaddr = 0;
> +	struct page *page;
> +	struct xive_q *q;
> +
> +	/*
> +	 * Demangle priority/server tuple from the EQ index
> +	 */
> +	priority = (eq_idx & KVM_XIVE_EQ_PRIORITY_MASK) >>
> +		KVM_XIVE_EQ_PRIORITY_SHIFT;
> +	server = (eq_idx & KVM_XIVE_EQ_SERVER_MASK) >>
> +		KVM_XIVE_EQ_SERVER_SHIFT;
> +
> +	if (copy_from_user(&kvm_eq, ubufp, sizeof(kvm_eq)))
> +		return -EFAULT;
> +
> +	vcpu = kvmppc_xive_find_server(kvm, server);
> +	if (!vcpu) {
> +		pr_err("Can't find server %d\n", server);
> +		return -ENOENT;
> +	}
> +	xc = vcpu->arch.xive_vcpu;
> +
> +	if (priority != xive_prio_from_guest(priority)) {
> +		pr_err("Trying to restore invalid queue %d for VCPU %d\n",
> +		       priority, server);
> +		return -EINVAL;
> +	}
> +	q = &xc->queues[priority];
> +
> +	pr_devel("%s VCPU %d priority %d fl:%x sz:%d addr:%llx g:%d idx:%d\n",
> +		 __func__, server, priority, kvm_eq.flags,
> +		 kvm_eq.qsize, kvm_eq.qpage, kvm_eq.qtoggle, kvm_eq.qindex);
> +
> +	rc = xive_native_validate_queue_size(kvm_eq.qsize);
> +	if (rc || !kvm_eq.qsize) {
> +		pr_err("invalid queue size %d\n", kvm_eq.qsize);
> +		return rc;
> +	}
> +
> +	page = gfn_to_page(kvm, gpa_to_gfn(kvm_eq.qpage));
> +	if (is_error_page(page)) {
> +		pr_warn("Couldn't get guest page for %llx!\n", kvm_eq.qpage);
> +		return -ENOMEM;
> +	}
> +	qaddr = page_to_virt(page) + (kvm_eq.qpage & ~PAGE_MASK);
> +
> +	/* Backup queue page guest address for migration */
> +	q->guest_qpage = kvm_eq.qpage;
> +	q->guest_qsize = kvm_eq.qsize;
> +
> +	rc = xive_native_configure_queue(xc->vp_id, q, priority,
> +					 (__be32 *) qaddr, kvm_eq.qsize, true);
> +	if (rc) {
> +		pr_err("Failed to configure queue %d for VCPU %d: %d\n",
> +		       priority, xc->server_num, rc);
> +		put_page(page);
> +		return rc;
> +	}
> +
> +	rc = xive_native_set_queue_state(xc->vp_id, priority, kvm_eq.qtoggle,
> +					 kvm_eq.qindex);
> +	if (rc)
> +		goto error;
> +
> +	rc = kvmppc_xive_attach_escalation(vcpu, priority);
> +error:
> +	if (rc)
> +		xive_native_cleanup_queue(vcpu, priority);
> +	return rc;
> +}
> +
> +static int kvmppc_xive_native_get_queue(struct kvmppc_xive *xive, long eq_idx,
> +				      u64 addr)
> +{
> +	struct kvm *kvm = xive->kvm;
> +	struct kvm_vcpu *vcpu;
> +	struct kvmppc_xive_vcpu *xc;
> +	struct xive_q *q;
> +	void __user *ubufp = (u64 __user *) addr;
> +	u32 server;
> +	u8 priority;
> +	struct kvm_ppc_xive_eq kvm_eq;
> +	u64 qpage;
> +	u64 qsize;
> +	u64 qeoi_page;
> +	u32 escalate_irq;
> +	u64 qflags;
> +	int rc;
> +
> +	/*
> +	 * Demangle priority/server tuple from the EQ index
> +	 */
> +	priority = (eq_idx & KVM_XIVE_EQ_PRIORITY_MASK) >>
> +		KVM_XIVE_EQ_PRIORITY_SHIFT;
> +	server = (eq_idx & KVM_XIVE_EQ_SERVER_MASK) >>
> +		KVM_XIVE_EQ_SERVER_SHIFT;
> +
> +	vcpu = kvmppc_xive_find_server(kvm, server);
> +	if (!vcpu) {
> +		pr_err("Can't find server %d\n", server);
> +		return -ENOENT;
> +	}
> +	xc = vcpu->arch.xive_vcpu;
> +
> +	if (priority != xive_prio_from_guest(priority)) {
> +		pr_err("invalid priority for queue %d for VCPU %d\n",
> +		       priority, server);
> +		return -EINVAL;
> +	}
> +	q = &xc->queues[priority];
> +
> +	memset(&kvm_eq, 0, sizeof(kvm_eq));
> +
> +	if (!q->qpage)
> +		return 0;
> +
> +	rc = xive_native_get_queue_info(xc->vp_id, priority, &qpage, &qsize,
> +					&qeoi_page, &escalate_irq, &qflags);
> +	if (rc)
> +		return rc;
> +
> +	kvm_eq.flags = 0;
> +	if (qflags & OPAL_XIVE_EQ_ENABLED)
> +		kvm_eq.flags |= KVM_XIVE_EQ_FLAG_ENABLED;
> +	if (qflags & OPAL_XIVE_EQ_ALWAYS_NOTIFY)
> +		kvm_eq.flags |= KVM_XIVE_EQ_FLAG_ALWAYS_NOTIFY;
> +	if (qflags & OPAL_XIVE_EQ_ESCALATE)
> +		kvm_eq.flags |= KVM_XIVE_EQ_FLAG_ESCALATE;
> +
> +	kvm_eq.qsize = q->guest_qsize;
> +	kvm_eq.qpage = q->guest_qpage;
> +
> +	rc = xive_native_get_queue_state(xc->vp_id, priority, &kvm_eq.qtoggle,
> +					 &kvm_eq.qindex);
> +	if (rc)
> +		return rc;
> +
> +	pr_devel("%s VCPU %d priority %d fl:%x sz:%d addr:%llx g:%d idx:%d\n",
> +		 __func__, server, priority, kvm_eq.flags,
> +		 kvm_eq.qsize, kvm_eq.qpage, kvm_eq.qtoggle, kvm_eq.qindex);
> +
> +	if (copy_to_user(ubufp, &kvm_eq, sizeof(kvm_eq)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>  static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>  				       struct kvm_device_attr *attr)
>  {
> @@ -628,6 +786,9 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>  		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);
> +	case KVM_DEV_XIVE_GRP_EQ:
> +		return kvmppc_xive_native_set_queue(xive, attr->attr,
> +						    attr->addr);
>  	}
>  	return -ENXIO;
>  }
> @@ -650,6 +811,9 @@ static int kvmppc_xive_native_get_attr(struct kvm_device *dev,
>  		break;
>  	case KVM_DEV_XIVE_GRP_EAS:
>  		return kvmppc_xive_native_get_eas(xive, attr->attr, attr->addr);
> +	case KVM_DEV_XIVE_GRP_EQ:
> +		return kvmppc_xive_native_get_queue(xive, attr->attr,
> +						    attr->addr);
>  	}
>  	return -ENXIO;
>  }
> @@ -674,6 +838,8 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
>  		    attr->attr < KVMPPC_XIVE_NR_IRQS)
>  			return 0;
>  		break;
> +	case KVM_DEV_XIVE_GRP_EQ:
> +		return 0;
>  	}
>  	return -ENXIO;
>  }

-- 
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

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