[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 3/4] iommu: introduce iommu_groups
On Mon, Jul 15, 2019 at 01:37:09PM +0100, Paul Durrant wrote: > Some devices may share a single PCIe initiator id, e.g. if they are actually > legacy PCI devices behind a bridge, and hence DMA from such devices will > be subject to the same address translation in the IOMMU. Hence these devices > should be treated as a unit for the purposes of assignment. There are also > other reasons why multiple devices should be treated as a unit, e.g. those > subject to a shared RMRR or those downstream of a bridge that does not > support ACS. > > This patch introduces a new struct iommu_group to act as a container for > devices that should be treated as a unit, and builds a list of them as > PCI devices are scanned. The iommu_ops already implement a method, > get_device_group_id(), that is seemingly intended to return the initiator > id for a given SBDF so use this as the mechanism for group assignment in > the first instance. Assignment based on shared RMRR or lack of ACS will be > dealt with in subsequent patches, as will modifications to the device > assignment code. > > Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx> LGTM, just two comments below. > --- > Cc: Jan Beulich <jbeulich@xxxxxxxx> > Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx> > Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> > Cc: Julien Grall <julien.grall@xxxxxxx> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx> > Cc: Tim Deegan <tim@xxxxxxx> > Cc: Wei Liu <wl@xxxxxxx> > > v2: > - Move code into new drivers/passthrough/groups.c > - Drop the group index. > - Handle failure to get group id. > - Drop the group devs list. > --- > xen/drivers/passthrough/Makefile | 1 + > xen/drivers/passthrough/groups.c | 91 > +++++++++++++++++++++++++++++++++++++ > xen/drivers/passthrough/x86/iommu.c | 8 +++- > xen/include/xen/iommu.h | 7 +++ > xen/include/xen/pci.h | 2 + > 5 files changed, 108 insertions(+), 1 deletion(-) > create mode 100644 xen/drivers/passthrough/groups.c > > diff --git a/xen/drivers/passthrough/Makefile > b/xen/drivers/passthrough/Makefile > index d50ab188c8..8a77110179 100644 > --- a/xen/drivers/passthrough/Makefile > +++ b/xen/drivers/passthrough/Makefile > @@ -4,6 +4,7 @@ subdir-$(CONFIG_X86) += x86 > subdir-$(CONFIG_ARM) += arm > > obj-y += iommu.o > +obj-$(CONFIG_HAS_PCI) += groups.o > obj-$(CONFIG_HAS_PCI) += pci.o > obj-$(CONFIG_HAS_DEVICE_TREE) += device_tree.o > > diff --git a/xen/drivers/passthrough/groups.c > b/xen/drivers/passthrough/groups.c > new file mode 100644 > index 0000000000..1a2f461c87 > --- /dev/null > +++ b/xen/drivers/passthrough/groups.c > @@ -0,0 +1,91 @@ > +/* > + * Copyright (c) 2019 Citrix Systems Inc. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <xen/iommu.h> > +#include <xen/radix-tree.h> > + > +struct iommu_group { > + unsigned int id; > +}; > + > +static struct radix_tree_root iommu_groups; > + > +void __init iommu_groups_init(void) > +{ > + radix_tree_init(&iommu_groups); > +} > + > +static struct iommu_group *alloc_iommu_group(unsigned int id) > +{ > + struct iommu_group *grp = xzalloc(struct iommu_group); > + > + if ( !grp ) > + return NULL; > + > + grp->id = id; > + > + if ( radix_tree_insert(&iommu_groups, id, grp) ) > + { > + xfree(grp); > + grp = NULL; > + } > + > + return grp; > +} > + > +static struct iommu_group *get_iommu_group(unsigned int id) > +{ > + struct iommu_group *grp = radix_tree_lookup(&iommu_groups, id); > + > + if ( !grp ) > + grp = alloc_iommu_group(id); > + > + return grp; > +} > + > +int iommu_group_assign(struct pci_dev *pdev, void *arg) I'm not sure I see the point of the arg parameter, AFAICT it's completely unused. > +{ > + const struct iommu_ops *ops = iommu_get_ops(); > + unsigned int id; > + struct iommu_group *grp; > + > + if ( !ops->get_device_group_id ) > + return 0; > + > + id = ops->get_device_group_id(pdev->seg, pdev->bus, pdev->devfn); I think I would prefer id to be of signed type here, then when you pass it to get_iommu_group it's already made unsigned. Thanks, Roger. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/mailman/listinfo/xen-devel
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