Re: [PATCH v2 08/16] KVM: PPC: Book3S HV: XIVE: add a control to sync the sources

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

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On Fri, Feb 22, 2019 at 12:28:32PM +0100, Cédric Le Goater wrote:
> This control will be used by the H_INT_SYNC hcall from QEMU.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  arch/powerpc/include/uapi/asm/kvm.h        |  1 +
>  arch/powerpc/kvm/book3s_xive_native.c      | 34 ++++++++++++++++++++++
>  Documentation/virtual/kvm/devices/xive.txt |  9 ++++++
>  3 files changed, 44 insertions(+)
> 
> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
> index 7ae8cb22af7d..289c504b7c1d 100644
> --- a/arch/powerpc/include/uapi/asm/kvm.h
> +++ b/arch/powerpc/include/uapi/asm/kvm.h
> @@ -681,6 +681,7 @@ struct kvm_ppc_cpu_char {
>  #define KVM_DEV_XIVE_GRP_SOURCE		2	/* 64-bit source attributes */
>  #define KVM_DEV_XIVE_GRP_SOURCE_CONFIG	3	/* 64-bit source attributes */
>  #define KVM_DEV_XIVE_GRP_EQ_CONFIG	4	/* 64-bit eq attributes */
> +#define KVM_DEV_XIVE_GRP_SOURCE_SYNC	5       /* 64-bit source attributes */
>  
>  /* Layout of 64-bit XIVE source attribute values */
>  #define KVM_XIVE_LEVEL_SENSITIVE	(1ULL << 0)
> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
> index bb3e121c918a..dd2a9d411fe7 100644
> --- a/arch/powerpc/kvm/book3s_xive_native.c
> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> @@ -341,6 +341,36 @@ static int kvmppc_xive_native_set_source_config(struct kvmppc_xive *xive,
>  						       priority, eisn);
>  }
>  
> +static int kvmppc_xive_native_sync_source(struct kvmppc_xive *xive,
> +					  long irq, u64 addr)
> +{
> +	struct kvmppc_xive_src_block *sb;
> +	struct kvmppc_xive_irq_state *state;
> +	struct xive_irq_data *xd;
> +	u32 hw_num;
> +	u16 src;
> +
> +	pr_devel("%s irq=0x%lx", __func__, irq);
> +
> +	sb = kvmppc_xive_find_source(xive, irq, &src);
> +	if (!sb)
> +		return -ENOENT;
> +
> +	state = &sb->irq_state[src];
> +
> +	if (!state->valid)

Is testing this before you take the lock safe?

> +		return -EINVAL;
> +
> +	arch_spin_lock(&sb->lock);
> +
> +	kvmppc_xive_select_irq(state, &hw_num, &xd);
> +	xive_native_sync_source(hw_num);
> +
> +	arch_spin_unlock(&sb->lock);
> +
> +	return 0;
> +}
> +
>  static int xive_native_validate_queue_size(u32 qsize)
>  {
>  	switch (qsize) {
> @@ -631,6 +661,9 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>  	case KVM_DEV_XIVE_GRP_EQ_CONFIG:
>  		return kvmppc_xive_native_set_queue_config(xive, attr->attr,
>  							   attr->addr);
> +	case KVM_DEV_XIVE_GRP_SOURCE_SYNC:
> +		return kvmppc_xive_native_sync_source(xive, attr->attr,
> +						      attr->addr);
>  	}
>  	return -ENXIO;
>  }
> @@ -660,6 +693,7 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
>  		break;
>  	case KVM_DEV_XIVE_GRP_SOURCE:
>  	case KVM_DEV_XIVE_GRP_SOURCE_CONFIG:
> +	case KVM_DEV_XIVE_GRP_SOURCE_SYNC:
>  		if (attr->attr >= KVMPPC_XIVE_FIRST_IRQ &&
>  		    attr->attr < KVMPPC_XIVE_NR_IRQS)
>  			return 0;
> diff --git a/Documentation/virtual/kvm/devices/xive.txt b/Documentation/virtual/kvm/devices/xive.txt
> index f1d007f485a9..267634eae9e0 100644
> --- a/Documentation/virtual/kvm/devices/xive.txt
> +++ b/Documentation/virtual/kvm/devices/xive.txt
> @@ -86,3 +86,12 @@ the legacy interrupt mode, referred as XICS (POWER7/8).
>      -EFAULT: Invalid user pointer for attr->addr.
>      -ENOMEM: Invalid queue address
>      -EIO:    Configuration of the underlying HW failed
> +
> +  5. KVM_DEV_XIVE_GRP_SOURCE_SYNC (write only)
> +  Synchronize the source to flush event notification
> +  Attributes:
> +    Interrupt source number  (64-bit)
> +  Errors:
> +    -ENOENT: Unknown source number
> +    -EINVAL: Not initialized source number, invalid priority or
> +             invalid CPU number.

-- 
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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