Re: [Xen-devel] [PATCH 1/6] domain: introduce XEN_DOMCTL_CDF_iommu

From: Jan Beulich <jbeulich@suse.com>
To: Paul Durrant <paul.durrant@citrix.com>
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
	"Wei Liu" <wl@xen.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"George Dunlap" <George.Dunlap@eu.citrix.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	TimDeegan <tim@xen.org>, "Julien Grall" <julien.grall@arm.com>,
	"Anthony PERARD" <anthony.perard@citrix.com>,
	xen-devel@lists.xenproject.org,
	"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 1/6] domain: introduce XEN_DOMCTL_CDF_iommu
Date: Wed, 7 Aug 2019 11:21:34 +0200	[thread overview]
Message-ID: <25891f16-43ae-96c5-1016-672668a5b759@suse.com> (raw)
In-Reply-To: <20190730134419.2739-2-paul.durrant@citrix.com>

On 30.07.2019 15:44, Paul Durrant wrote:
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -673,8 +673,7 @@ int arch_domain_create(struct domain *d,
>   
>       ASSERT(config != NULL);
>   
> -    /* p2m_init relies on some value initialized by the IOMMU subsystem */
> -    if ( (rc = iommu_domain_init(d)) != 0 )
> +    if ( is_iommu_enabled(d) && (rc = iommu_domain_init(d)) != 0 )
>           goto fail;

Instead of this and ...

> --- a/xen/arch/x86/domain.c
> +++ b/xen/arch/x86/domain.c
> @@ -604,7 +604,7 @@ int arch_domain_create(struct domain *d,
>       if ( (rc = init_domain_irq_mapping(d)) != 0 )
>           goto fail;
>   
> -    if ( (rc = iommu_domain_init(d)) != 0 )
> +    if ( is_iommu_enabled(d) && (rc = iommu_domain_init(d)) != 0 )
>           goto fail;

... this (and any further copies in future ports), wouldn't it
be better to centrally do this in iommu_domain_init() itself?

> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -301,7 +301,8 @@ static int sanitise_domain_config(struct xen_domctl_createdomain *config)
>                              XEN_DOMCTL_CDF_hap |
>                              XEN_DOMCTL_CDF_s3_integrity |
>                              XEN_DOMCTL_CDF_oos_off |
> -                           XEN_DOMCTL_CDF_xs_domain) )
> +                           XEN_DOMCTL_CDF_xs_domain |
> +                           XEN_DOMCTL_CDF_iommu) )
>       {
>           dprintk(XENLOG_INFO, "Unknown CDF flags %#x\n", config->flags);
>           return -EINVAL;

Also refuse XEN_DOMCTL_CDF_iommu when !iommu_enabled?

> --- a/xen/include/xen/sched.h
> +++ b/xen/include/xen/sched.h
> @@ -981,6 +981,11 @@ static inline bool is_xenstore_domain(const struct domain *d)
>       return d->options & XEN_DOMCTL_CDF_xs_domain;
>   }
>   
> +static inline bool is_iommu_enabled(const struct domain *d)
> +{
> +    return d->options & XEN_DOMCTL_CDF_iommu;
> +}

Perhaps wrap in evaluate_nospec()?

Jan

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