From: David Gibson <david@gibson.dropbear.id.au>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org,
Alex Williamson <alex.williamson@redhat.com>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH kernel v9 26/32] powerpc/iommu: Add userspace view of TCE table
Date: Fri, 1 May 2015 14:23:19 +1000 [thread overview]
Message-ID: <20150501042319.GM24886@voom.redhat.com> (raw)
In-Reply-To: <5542FA8D.2060400@ozlabs.ru>
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On Fri, May 01, 2015 at 02:01:17PM +1000, Alexey Kardashevskiy wrote:
> On 04/29/2015 04:31 PM, David Gibson wrote:
> >On Sat, Apr 25, 2015 at 10:14:50PM +1000, Alexey Kardashevskiy wrote:
> >>In order to support memory pre-registration, we need a way to track
> >>the use of every registered memory region and only allow unregistration
> >>if a region is not in use anymore. So we need a way to tell from what
> >>region the just cleared TCE was from.
> >>
> >>This adds a userspace view of the TCE table into iommu_table struct.
> >>It contains userspace address, one per TCE entry. The table is only
> >>allocated when the ownership over an IOMMU group is taken which means
> >>it is only used from outside of the powernv code (such as VFIO).
> >>
> >>Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> >>---
> >>Changes:
> >>v9:
> >>* fixed code flow in error cases added in v8
> >>
> >>v8:
> >>* added ENOMEM on failed vzalloc()
> >>---
> >> arch/powerpc/include/asm/iommu.h | 6 ++++++
> >> arch/powerpc/kernel/iommu.c | 18 ++++++++++++++++++
> >> arch/powerpc/platforms/powernv/pci-ioda.c | 22 ++++++++++++++++++++--
> >> 3 files changed, 44 insertions(+), 2 deletions(-)
> >>
> >>diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h
> >>index 7694546..1472de3 100644
> >>--- a/arch/powerpc/include/asm/iommu.h
> >>+++ b/arch/powerpc/include/asm/iommu.h
> >>@@ -111,9 +111,15 @@ struct iommu_table {
> >> unsigned long *it_map; /* A simple allocation bitmap for now */
> >> unsigned long it_page_shift;/* table iommu page size */
> >> struct iommu_table_group *it_table_group;
> >>+ unsigned long *it_userspace; /* userspace view of the table */
> >
> >A single unsigned long doesn't seem like enough.
>
> Why single? This is an array.
As in single per page.
> > How do you know
> >which process's address space this address refers to?
>
> It is a current task. Multiple userspaces cannot use the same container/tables.
Where is that enforced?
More to the point, that's a VFIO constraint, but it's here affecting
the design of a structure owned by the platform code.
[snip]
> >> static void pnv_pci_ioda_setup_opal_tce_kill(struct pnv_phb *phb,
> >>@@ -2062,12 +2071,21 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group,
> >> int nid = pe->phb->hose->node;
> >> __u64 bus_offset = num ? pe->tce_bypass_base : 0;
> >> long ret;
> >>+ unsigned long *uas, uas_cb = sizeof(*uas) * (window_size >> page_shift);
> >>+
> >>+ uas = vzalloc(uas_cb);
> >>+ if (!uas)
> >>+ return -ENOMEM;
> >
> >I don't see why this is allocated both here as well as in
> >take_ownership.
>
> Where else? The only alternative is vfio_iommu_spapr_tce but I really do not
> want to touch iommu_table fields there.
Well to put it another way, why isn't take_ownership calling create
itself (or at least a common helper).
Clearly the it_userspace table needs to have lifetime which matches
the TCE table itself, so there should be a single function that marks
the beginning of that joint lifetime.
> >Isn't this function used for core-kernel users of the
> >iommu as well, in which case it shouldn't need the it_userspace.
>
>
> No. This is an iommu_table_group_ops callback which calls what the platform
> code calls (pnv_pci_create_table()) plus allocates this it_userspace thing.
> The callback is only called from VFIO.
Ok.
As touched on above it seems more like this should be owned by VFIO
code than the platform code.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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next prev parent reply other threads:[~2015-05-01 4:53 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-25 12:14 [PATCH kernel v9 00/32] powerpc/iommu/vfio: Enable Dynamic DMA windows Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 01/32] powerpc/iommu: Split iommu_free_table into 2 helpers Alexey Kardashevskiy
2015-04-29 2:03 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 02/32] Revert "powerpc/powernv: Allocate struct pnv_ioda_pe iommu_table dynamically" Alexey Kardashevskiy
2015-04-27 21:05 ` Alex Williamson
2015-04-29 2:05 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 03/32] vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 04/32] vfio: powerpc/spapr: Check that IOMMU page is fully contained by system page Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 05/32] vfio: powerpc/spapr: Use it_page_size Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 06/32] vfio: powerpc/spapr: Move locked_vm accounting to helpers Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 07/32] vfio: powerpc/spapr: Disable DMA mappings on disabled container Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 08/32] vfio: powerpc/spapr: Moving pinning/unpinning to helpers Alexey Kardashevskiy
2015-04-29 2:14 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 09/32] vfio: powerpc/spapr: Rework groups attaching Alexey Kardashevskiy
2015-04-29 2:16 ` David Gibson
2015-04-30 2:29 ` Alexey Kardashevskiy
2015-04-30 4:05 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 10/32] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 11/32] powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 12/32] powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group Alexey Kardashevskiy
2015-04-29 2:49 ` David Gibson
2015-04-30 2:30 ` Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 13/32] vfio: powerpc/spapr/iommu/powernv/ioda2: Rework IOMMU ownership control Alexey Kardashevskiy
2015-04-29 3:02 ` David Gibson
2015-04-29 9:19 ` Alexey Kardashevskiy
2015-04-30 4:08 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 14/32] powerpc/iommu: Fix IOMMU ownership control functions Alexey Kardashevskiy
2015-04-29 3:08 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 15/32] powerpc/powernv/ioda/ioda2: Rework TCE invalidation in tce_build()/tce_free() Alexey Kardashevskiy
2015-04-29 3:18 ` David Gibson
2015-04-30 2:58 ` Alexey Kardashevskiy
2015-04-30 4:16 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 16/32] powerpc/powernv/ioda: Move TCE kill register address to PE Alexey Kardashevskiy
2015-04-27 21:05 ` Alex Williamson
2015-04-29 3:25 ` David Gibson
2015-04-29 9:00 ` Alexey Kardashevskiy
2015-04-30 4:18 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 17/32] powerpc/powernv: Implement accessor to TCE entry Alexey Kardashevskiy
2015-04-29 4:04 ` David Gibson
2015-04-29 9:02 ` Alexey Kardashevskiy
2015-04-30 0:13 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 18/32] powerpc/iommu/powernv: Release replaced TCE Alexey Kardashevskiy
2015-04-29 4:18 ` David Gibson
2015-04-29 9:51 ` Alexey Kardashevskiy
2015-04-30 4:21 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 19/32] powerpc/powernv/ioda2: Rework iommu_table creation Alexey Kardashevskiy
2015-04-29 4:27 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 20/32] powerpc/powernv/ioda2: Introduce pnv_pci_create_table/pnv_pci_free_table Alexey Kardashevskiy
2015-04-29 4:39 ` David Gibson
2015-04-29 9:12 ` Alexey Kardashevskiy
2015-04-30 4:24 ` David Gibson
2015-05-01 10:13 ` Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 21/32] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window Alexey Kardashevskiy
2015-04-29 4:45 ` David Gibson
2015-04-29 9:26 ` Alexey Kardashevskiy
2015-04-30 4:32 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 22/32] powerpc/powernv: Implement multilevel TCE tables Alexey Kardashevskiy
2015-04-29 5:04 ` David Gibson
2015-05-01 9:48 ` Alexey Kardashevskiy
2015-05-05 12:05 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 23/32] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks Alexey Kardashevskiy
2015-04-29 5:30 ` David Gibson
2015-04-29 9:44 ` Alexey Kardashevskiy
2015-04-30 4:37 ` David Gibson
2015-04-30 9:56 ` Alexey Kardashevskiy
2015-05-01 3:36 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 24/32] powerpc/powernv/ioda2: Use new helpers to do proper cleanup on PE release Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 25/32] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework ownership Alexey Kardashevskiy
2015-04-29 5:39 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 26/32] powerpc/iommu: Add userspace view of TCE table Alexey Kardashevskiy
2015-04-29 6:31 ` David Gibson
2015-05-01 4:01 ` Alexey Kardashevskiy
2015-05-01 4:23 ` David Gibson [this message]
2015-05-01 7:12 ` Alexey Kardashevskiy
2015-05-05 12:02 ` David Gibson
2015-05-11 2:11 ` Alexey Kardashevskiy
2015-05-11 4:52 ` Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 27/32] powerpc/iommu/ioda2: Add get_table_size() to calculate the size of future table Alexey Kardashevskiy
2015-04-29 6:40 ` David Gibson
2015-05-01 4:10 ` Alexey Kardashevskiy
2015-05-01 5:12 ` David Gibson
2015-05-01 6:53 ` Alexey Kardashevskiy
2015-05-05 11:58 ` David Gibson
2015-05-11 2:24 ` Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 28/32] powerpc/mmu: Add userspace-to-physical addresses translation cache Alexey Kardashevskiy
2015-04-29 7:01 ` David Gibson
2015-05-01 11:26 ` Alexey Kardashevskiy
2015-05-05 12:12 ` David Gibson
2015-04-30 6:34 ` David Gibson
2015-04-30 8:25 ` Paul Mackerras
2015-05-01 3:39 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 29/32] vfio: powerpc/spapr: Register memory and define IOMMU v2 Alexey Kardashevskiy
2015-04-30 6:55 ` David Gibson
2015-05-01 4:35 ` Alexey Kardashevskiy
2015-05-01 5:23 ` David Gibson
2015-05-01 6:27 ` Alexey Kardashevskiy
2015-05-05 11:53 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 30/32] vfio: powerpc/spapr: Use 32bit DMA window properties from table_group Alexey Kardashevskiy
2015-04-27 22:18 ` Alex Williamson
2015-04-30 6:58 ` David Gibson
2015-04-25 12:14 ` [PATCH kernel v9 31/32] vfio: powerpc/spapr: Support multiple groups in one container if possible Alexey Kardashevskiy
2015-04-30 7:22 ` David Gibson
2015-04-30 9:33 ` Alexey Kardashevskiy
2015-05-01 0:46 ` Benjamin Herrenschmidt
2015-05-01 4:44 ` David Gibson
2015-05-01 4:33 ` David Gibson
2015-05-01 6:05 ` Alexey Kardashevskiy
2015-05-05 11:50 ` David Gibson
2015-05-11 2:26 ` Alexey Kardashevskiy
2015-04-25 12:14 ` [PATCH kernel v9 32/32] vfio: powerpc/spapr: Support Dynamic DMA windows Alexey Kardashevskiy
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