[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [XEN PATCH v3] xen/arm: introduce dummy iommu node for dom0
> -----Original Message----- > From: Xen-devel <xen-devel-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of > Rahul Singh > Sent: 2022年1月14日 16:22 > To: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx> > Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>; Stefano Stabellini > <sstabellini@xxxxxxxxxx>; Julien Grall <julien@xxxxxxx>; Oleksandr > Tyshchenko <olekstysh@xxxxxxxxx>; Andrii Anisov > <Andrii_Anisov@xxxxxxxx> > Subject: Re: [XEN PATCH v3] xen/arm: introduce dummy iommu node for > dom0 > > Hi, > > > On 11 Jan 2022, at 11:26 am, Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx> > wrote: > > > > Currently no IOMMU properties are exposed to dom0, thus kernel by > default > > assumes no protection and enables swiotlb-xen, which leads to costly and > > unnecessary buffers bouncing. > > > > To let kernel know which device is behing IOMMU and hence needs no [Jiamei Xie] behing? Typo Best wishes Jiamei Xie > swiotlb > > services we introduce dummy xen-iommu node in FDT and link protected > device > > nodes to it, using here device tree iommu bindings. > > > > Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx> > > Reviewed-by: Rahul Singh <rahul.singh@xxxxxxx> > > Regards, > Rahul > > --- > > Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx> > > Cc: Julien Grall <julien@xxxxxxx> > > Cc: Oleksandr Tyshchenko <olekstysh@xxxxxxxxx> > > Cc: Andrii Anisov <Andrii_Anisov@xxxxxxxx> > > > > > > Changelog: > > > > v3: rebased over staging & remove redundand phandle_iommu attribute, > discussion: > > https://lists.xenproject.org/archives/html/xen-devel/2021- > 12/msg01753.html > > > > v2: re-use common iommu dt bindings to let guests know which devices > are protected: > > https://lists.xenproject.org/archives/html/xen-devel/2021- > 10/msg00073.html > > > > xen/arch/arm/domain_build.c | 42 > +++++++++++++++++++++++++++ > > xen/include/public/device_tree_defs.h | 1 + > > 2 files changed, 43 insertions(+) > > > > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c > > index 6931c022a2..b82ba72fac 100644 > > --- a/xen/arch/arm/domain_build.c > > +++ b/xen/arch/arm/domain_build.c > > @@ -845,6 +845,12 @@ static int __init write_properties(struct domain *d, > struct kernel_info *kinfo, > > } > > } > > > > + if ( iommu_node && is_iommu_enabled(d) && > dt_device_is_protected(node) ) > > + { > > + res = fdt_property_cell(kinfo->fdt, "iommus", > GUEST_PHANDLE_IOMMU); > > + if ( res ) > > + return res; > > + } > > return 0; > > } > > > > @@ -1479,6 +1485,38 @@ static int __init make_cpus_node(const struct > domain *d, void *fdt) > > return res; > > } > > > > +static int __init make_iommu_node(const struct domain *d, > > + const struct kernel_info *kinfo) > > +{ > > + const char compat[] = "xen,iommu-el2-v1"; > > + int res; > > + > > + if ( !is_iommu_enabled(d) ) > > + return 0; > > + > > + dt_dprintk("Create iommu node\n"); > > + > > + res = fdt_begin_node(kinfo->fdt, "xen-iommu"); > > + if ( res ) > > + return res; > > + > > + res = fdt_property(kinfo->fdt, "compatible", compat, sizeof(compat)); > > + if ( res ) > > + return res; > > + > > + res = fdt_property_cell(kinfo->fdt, "#iommu-cells", 0); > > + if ( res ) > > + return res; > > + > > + res = fdt_property_cell(kinfo->fdt, "phandle", > GUEST_PHANDLE_IOMMU); > > + > > + res = fdt_end_node(kinfo->fdt); > > + if ( res ) > > + return res; > > + > > + return res; > > +} > > + > > static int __init make_gic_node(const struct domain *d, void *fdt, > > const struct dt_device_node *node) > > { > > @@ -2127,6 +2165,10 @@ static int __init handle_node(struct domain *d, > struct kernel_info *kinfo, > > if ( res ) > > return res; > > > > + res = make_iommu_node(d, kinfo); > > + if ( res ) > > + return res; > > + > > res = make_memory_node(d, kinfo->fdt, addrcells, sizecells, &kinfo- > >mem); > > if ( res ) > > return res; > > diff --git a/xen/include/public/device_tree_defs.h > b/xen/include/public/device_tree_defs.h > > index 209d43de3f..df58944bd0 100644 > > --- a/xen/include/public/device_tree_defs.h > > +++ b/xen/include/public/device_tree_defs.h > > @@ -7,6 +7,7 @@ > > * onwards. Reserve a high value for the GIC phandle. > > */ > > #define GUEST_PHANDLE_GIC (65000) > > +#define GUEST_PHANDLE_IOMMU (GUEST_PHANDLE_GIC + 1) > > > > #define GUEST_ROOT_ADDRESS_CELLS 2 > > #define GUEST_ROOT_SIZE_CELLS 2 > > -- > > 2.25.1 > > > > >
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