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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Wei Liu <wei.liu@kernel.org>,
        Linux on Hyper-V List <linux-hyperv@vger.kernel.org>
Cc:     virtualization@lists.linux-foundation.org,
        Linux Kernel List <linux-kernel@vger.kernel.org>,
        Michael Kelley <mikelley@microsoft.com>,
        Vineeth Pillai <viremana@linux.microsoft.com>,
        Sunil Muthuswamy <sunilmut@microsoft.com>,
        Nuno Das Neves <nunodasneves@linux.microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Joerg Roedel <jroedel@suse.de>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Joerg Roedel <joro@8bytes.org>,
        "open list:IOMMU DRIVERS" <iommu@lists.linux-foundation.org>
Subject: Re: [PATCH v2 04/17] iommu/hyperv: don't setup IRQ remapping when
 running as root
In-Reply-To: <20201105165814.29233-5-wei.liu@kernel.org>
References: <20201105165814.29233-1-wei.liu@kernel.org>
 <20201105165814.29233-5-wei.liu@kernel.org>
Date:   Thu, 12 Nov 2020 16:27:14 +0100
Message-ID: <87ft5ey4rx.fsf@vitty.brq.redhat.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Wei Liu <wei.liu@kernel.org> writes:

> The IOMMU code needs more work. We're sure for now the IRQ remapping
> hooks are not applicable when Linux is the root.

Super-nitpick: I would suggest we always say 'root partition' as 'root'
has a 'slightly different' meaning in Linux and this commit message may
sound confusing to an unprepared reader.

>
> Signed-off-by: Wei Liu <wei.liu@kernel.org>
> Acked-by: Joerg Roedel <jroedel@suse.de>
> ---
>  drivers/iommu/hyperv-iommu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/hyperv-iommu.c b/drivers/iommu/hyperv-iommu.c
> index e09e2d734c57..8d3ce3add57d 100644
> --- a/drivers/iommu/hyperv-iommu.c
> +++ b/drivers/iommu/hyperv-iommu.c
> @@ -20,6 +20,7 @@
>  #include <asm/io_apic.h>
>  #include <asm/irq_remapping.h>
>  #include <asm/hypervisor.h>
> +#include <asm/mshyperv.h>
>  
>  #include "irq_remapping.h"
>  
> @@ -143,7 +144,7 @@ static int __init hyperv_prepare_irq_remapping(void)
>  	int i;
>  
>  	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) ||
> -	    !x2apic_supported())
> +	    !x2apic_supported() || hv_root_partition)
>  		return -ENODEV;
>  
>  	fn = irq_domain_alloc_named_id_fwnode("HYPERV-IR", 0);

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

-- 
Vitaly