From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH] bus/pci: forbid VA as IOVA mode if IOMMU
 address width too small
Date: Mon, 8 Jan 2018 07:38:41 -0800
Message-ID: <20180108073841.43c15072@xeon-e3>
References: <20180108135127.25869-1-maxime.coquelin@redhat.com>
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 santosh.shukla@caviumnetworks.com, anatoly.burakov@intel.com,
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To: Maxime Coquelin <maxime.coquelin@redhat.com>
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On Mon,  8 Jan 2018 14:51:27 +0100
Maxime Coquelin <maxime.coquelin@redhat.com> wrote:

> +static inline bool
> +pci_one_device_iommu_support_va(struct rte_pci_device *dev)
> +{
> +#if defined(RTE_ARCH_PPC_64)
> +	return false;
> +#elif defined(RTE_ARCH_X86)
> +

The cleaner way to handle this kind of ifdef is:

#ifdef RTE_ARCH_X86
static bool
pci_one_device_iommu_support_va(struct rte_pci_device *dev)
{
....
}
#elif defined(RTE_ARCH_PPC_64) 
static inline bool
pci_one_device_iommu_support_va(struct rte_pci_device *dev)
{
	return false;
}
#endif

What about AMD64?
Do all ARM processors have IOMMU, I think not.