Re: [PATCH kernel 2/4] KVM: PPC: Inform the userspace about TCE update failures

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

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On Thu, Aug 30, 2018 at 01:16:45PM +1000, Alexey Kardashevskiy wrote:
> We return H_TOO_HARD from TCE update handlers when we think that
> the next handler (realmode -> virtual mode -> user mode) has a chance to
> handle the request; H_HARDWARE/H_CLOSED otherwise.
> 
> This changes the handlers to return H_TOO_HARD on every error giving
> the userspace an opportunity to handle any request or at least log
> them all.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  arch/powerpc/kvm/book3s_64_vio.c    | 8 ++++----
>  arch/powerpc/kvm/book3s_64_vio_hv.c | 6 +++---
>  2 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
> index 0fef22b..3e8ac98 100644
> --- a/arch/powerpc/kvm/book3s_64_vio.c
> +++ b/arch/powerpc/kvm/book3s_64_vio.c
> @@ -401,7 +401,7 @@ static long kvmppc_tce_iommu_do_unmap(struct kvm *kvm,
>  	long ret;
>  
>  	if (WARN_ON_ONCE(iommu_tce_xchg(tbl, entry, &hpa, &dir)))
> -		return H_HARDWARE;
> +		return H_TOO_HARD;
>  
>  	if (dir == DMA_NONE)
>  		return H_SUCCESS;
> @@ -449,15 +449,15 @@ long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
>  		return H_TOO_HARD;
>  
>  	if (WARN_ON_ONCE(mm_iommu_ua_to_hpa(mem, ua, tbl->it_page_shift, &hpa)))
> -		return H_HARDWARE;
> +		return H_TOO_HARD;
>  
>  	if (mm_iommu_mapped_inc(mem))
> -		return H_CLOSED;
> +		return H_TOO_HARD;
>  
>  	ret = iommu_tce_xchg(tbl, entry, &hpa, &dir);
>  	if (WARN_ON_ONCE(ret)) {
>  		mm_iommu_mapped_dec(mem);
> -		return H_HARDWARE;
> +		return H_TOO_HARD;
>  	}
>  
>  	if (dir != DMA_NONE)
> diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
> index 7ab6f3f..9584d9b 100644
> --- a/arch/powerpc/kvm/book3s_64_vio_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
> @@ -277,10 +277,10 @@ static long kvmppc_rm_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
>  
>  	if (WARN_ON_ONCE_RM(mm_iommu_ua_to_hpa_rm(mem, ua, tbl->it_page_shift,
>  			&hpa)))
> -		return H_HARDWARE;
> +		return H_TOO_HARD;
>  
>  	if (WARN_ON_ONCE_RM(mm_iommu_mapped_inc(mem)))
> -		return H_CLOSED;
> +		return H_TOO_HARD;
>  
>  	ret = iommu_tce_xchg_rm(tbl, entry, &hpa, &dir);
>  	if (ret) {
> @@ -478,7 +478,7 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
>  
>  		rmap = (void *) vmalloc_to_phys(rmap);
>  		if (WARN_ON_ONCE_RM(!rmap))
> -			return H_HARDWARE;
> +			return H_TOO_HARD;
>  
>  		/*
>  		 * Synchronize with the MMU notifier callbacks in

-- 
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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