Linux Virtualization - Jan 2021 - [PATCH v5 04/16] iommu/hyperv: don't setup IRQ remapping when running as root

From: Wei Liu <wei.liu at kernel.org> Sent: Wednesday, January 20, 2021
4:01 AM
> 
> The IOMMU code needs more work. We're sure for now the IRQ remapping
> hooks are not applicable when Linux is the root partition.
> 
> Signed-off-by: Wei Liu <wei.liu at kernel.org>
> Acked-by: Joerg Roedel <jroedel at suse.de>
> Reviewed-by: Vitaly Kuznetsov <vkuznets at redhat.com>
> ---
>  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 1d21a0b5f724..b7db6024e65c 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"
> 
> @@ -122,7 +123,7 @@ static int __init hyperv_prepare_irq_remapping(void)
> 
>  	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) ||
>  	    x86_init.hyper.msi_ext_dest_id() ||
> -	    !x2apic_supported())
> +	    !x2apic_supported() || hv_root_partition)
>  		return -ENODEV;
> 
>  	fn = irq_domain_alloc_named_id_fwnode("HYPERV-IR", 0);
> --
> 2.20.1
Reviewed-by: Michael Kelley <mikelley at microsoft.com>