Date:   Thu, 2 Dec 2021 14:43:36 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     Tianyu Lan <ltykernel@gmail.com>
Cc:     kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com,
        wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        x86@kernel.org, hpa@zytor.com, jgross@suse.com,
        sstabellini@kernel.org, boris.ostrovsky@oracle.com,
        joro@8bytes.org, will@kernel.org, davem@davemloft.net,
        kuba@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com,
        arnd@arndb.de, hch@infradead.org, m.szyprowski@samsung.com,
        robin.murphy@arm.com, Tianyu.Lan@microsoft.com,
        thomas.lendacky@amd.com, xen-devel@lists.xenproject.org,
        michael.h.kelley@microsoft.com, iommu@lists.linux-foundation.org,
        linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
        netdev@vger.kernel.org, vkuznets@redhat.com, brijesh.singh@amd.com,
        konrad.wilk@oracle.com, hch@lst.de, parri.andrea@gmail.com,
        dave.hansen@intel.com
Subject: Re: [PATCH V3 3/5] hyperv/IOMMU: Enable swiotlb bounce buffer for
 Isolation VM
Message-ID: <20211202144336.z2sfs6kw5kdsfqgv@liuwe-devbox-debian-v2>
References: <20211201160257.1003912-1-ltykernel@gmail.com>
 <20211201160257.1003912-4-ltykernel@gmail.com>
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On Wed, Dec 01, 2021 at 11:02:54AM -0500, Tianyu Lan wrote:
[...]
> diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
> index 46df59aeaa06..30fd0600b008 100644
> --- a/arch/x86/xen/pci-swiotlb-xen.c
> +++ b/arch/x86/xen/pci-swiotlb-xen.c
> @@ -4,6 +4,7 @@
>  
>  #include <linux/dma-map-ops.h>
>  #include <linux/pci.h>
> +#include <linux/hyperv.h>
>  #include <xen/swiotlb-xen.h>
>  
>  #include <asm/xen/hypervisor.h>
> @@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void)
>  EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
>  
>  IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
> -		  NULL,
> +		  hyperv_swiotlb_detect,

It is not immediately obvious why this is needed just by reading the
code. Please consider copying some of the text in the commit message to
a comment here.

Thanks,
Wei.