From: Alexey Kardashevskiy <aik@ozlabs•ru>
To: David Gibson <david@gibson•dropbear.id.au>
Cc: Alex Williamson <alex.williamson@redhat•com>,
linuxppc-dev@lists•ozlabs.org, linux-kernel@vger•kernel.org,
Paul Mackerras <paulus@samba•org>
Subject: Re: [PATCH kernel v8 15/31] powerpc/iommu: Fix IOMMU ownership control functions
Date: Mon, 20 Apr 2015 16:34:24 +1000 [thread overview]
Message-ID: <55349DF0.6090301@ozlabs.ru> (raw)
In-Reply-To: <20150420024638.GE10218@voom>
On 04/20/2015 12:46 PM, David Gibson wrote:
> On Fri, Apr 17, 2015 at 08:16:13PM +1000, Alexey Kardashevskiy wrote:
>> On 04/16/2015 04:10 PM, David Gibson wrote:
>>> On Fri, Apr 10, 2015 at 04:30:57PM +1000, Alexey Kardashevskiy wrote:
>>>> This adds missing locks in iommu_take_ownership()/
>>>> iommu_release_ownership().
>>>>
>>>> This marks all pages busy in iommu_table::it_map in order to catch
>>>> errors if there is an attempt to use this table while ownership over it
>>>> is taken.
>>>>
>>>> This only clears TCE content if there is no page marked busy in it_map.
>>>> Clearing must be done outside of the table locks as iommu_clear_tce()
>>>> called from iommu_clear_tces_and_put_pages() does this.
>>>>
>>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs•ru>
>>>> ---
>>>> Changes:
>>>> v5:
>>>> * do not store bit#0 value, it has to be set for zero-based table
>>>> anyway
>>>> * removed test_and_clear_bit
>>>> ---
>>>> arch/powerpc/kernel/iommu.c | 26 ++++++++++++++++++++++----
>>>> 1 file changed, 22 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
>>>> index 7d6089b..068fe4ff 100644
>>>> --- a/arch/powerpc/kernel/iommu.c
>>>> +++ b/arch/powerpc/kernel/iommu.c
>>>> @@ -1052,17 +1052,28 @@ EXPORT_SYMBOL_GPL(iommu_tce_build);
>>>>
>>>> static int iommu_table_take_ownership(struct iommu_table *tbl)
>>>> {
>>>> - unsigned long sz = (tbl->it_size + 7) >> 3;
>>>> + unsigned long flags, i, sz = (tbl->it_size + 7) >> 3;
>>>> + int ret = 0;
>>>> +
>>>> + spin_lock_irqsave(&tbl->large_pool.lock, flags);
>>>> + for (i = 0; i < tbl->nr_pools; i++)
>>>> + spin_lock(&tbl->pools[i].lock);
>>>>
>>>> if (tbl->it_offset == 0)
>>>> clear_bit(0, tbl->it_map);
>>>>
>>>> if (!bitmap_empty(tbl->it_map, tbl->it_size)) {
>>>> pr_err("iommu_tce: it_map is not empty");
>>>> - return -EBUSY;
>>>> + ret = -EBUSY;
>>>> + if (tbl->it_offset == 0)
>>>> + set_bit(0, tbl->it_map);
>>>
>>> This really needs a comment. Why on earth are you changing the it_map
>>> on a failure case?
>>
>>
>> Does this explain?
>>
>> /*
>> * The platform code reserves zero address in iommu_init_table().
>> * As we cleared busy bit for page @0 before using bitmap_empty(),
>> * we are restoring it now.
>> */
>
> Only partly. What's it reserved for, and why do you know it was
> always set on entry?
Because it is only handled in this file and I can see it in the code. Or I
did not understand the question here...
--
Alexey
next prev parent reply other threads:[~2015-04-20 6:34 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-10 6:30 [PATCH kernel v8 00/31] powerpc/iommu/vfio: Enable Dynamic DMA windows Alexey Kardashevskiy
2015-04-10 6:30 ` [PATCH kernel v8 01/31] vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver Alexey Kardashevskiy
2015-04-15 3:56 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 02/31] vfio: powerpc/spapr: Do cleanup when releasing the group Alexey Kardashevskiy
2015-04-15 4:00 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 03/31] vfio: powerpc/spapr: Check that IOMMU page is fully contained by system page Alexey Kardashevskiy
2015-04-15 4:03 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 04/31] vfio: powerpc/spapr: Use it_page_size Alexey Kardashevskiy
2015-04-10 6:30 ` [PATCH kernel v8 05/31] vfio: powerpc/spapr: Move locked_vm accounting to helpers Alexey Kardashevskiy
2015-04-15 4:09 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 06/31] vfio: powerpc/spapr: Disable DMA mappings on disabled container Alexey Kardashevskiy
2015-04-15 7:05 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 07/31] vfio: powerpc/spapr: Moving pinning/unpinning to helpers Alexey Kardashevskiy
2015-04-15 7:10 ` David Gibson
2015-04-15 12:09 ` Alexey Kardashevskiy
2015-04-10 6:30 ` [PATCH kernel v8 08/31] vfio: powerpc/spapr: Rework groups attaching Alexey Kardashevskiy
2015-04-15 7:14 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 09/31] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE Alexey Kardashevskiy
2015-04-15 7:17 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 10/31] powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table Alexey Kardashevskiy
2015-04-15 7:23 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 11/31] powerpc/iommu: Introduce iommu_table_alloc() helper Alexey Kardashevskiy
2015-04-16 5:31 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 12/31] powerpc/spapr: vfio: Switch from iommu_table to new iommu_table_group Alexey Kardashevskiy
2015-04-16 5:55 ` David Gibson
2015-04-16 15:48 ` Alexey Kardashevskiy
2015-04-20 2:36 ` David Gibson
2015-04-17 9:46 ` Alexey Kardashevskiy
2015-04-20 2:37 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 13/31] vfio: powerpc/spapr: powerpc/iommu: Rework IOMMU ownership control Alexey Kardashevskiy
2015-04-16 6:00 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 14/31] vfio: powerpc/spapr: powerpc/powernv/ioda2: " Alexey Kardashevskiy
2015-04-16 6:07 ` David Gibson
2015-04-17 10:09 ` Alexey Kardashevskiy
2015-04-20 2:44 ` David Gibson
2015-04-20 6:55 ` Alexey Kardashevskiy
2015-04-21 9:43 ` David Gibson
2015-04-21 11:47 ` Alexey Kardashevskiy
2015-04-22 5:22 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 15/31] powerpc/iommu: Fix IOMMU ownership control functions Alexey Kardashevskiy
2015-04-10 21:28 ` Alex Williamson
2015-04-16 6:10 ` David Gibson
2015-04-17 10:16 ` Alexey Kardashevskiy
2015-04-20 2:46 ` David Gibson
2015-04-20 6:34 ` Alexey Kardashevskiy [this message]
2015-04-21 7:12 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 16/31] powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free() Alexey Kardashevskiy
2015-04-16 6:17 ` David Gibson
2015-04-10 6:30 ` [PATCH kernel v8 17/31] powerpc/iommu/powernv: Release replaced TCE Alexey Kardashevskiy
2015-04-16 6:26 ` David Gibson
2015-04-17 10:37 ` Alexey Kardashevskiy
2015-04-20 2:50 ` David Gibson
2015-04-10 6:31 ` [PATCH kernel v8 18/31] powerpc/powernv/ioda2: Rework iommu_table creation Alexey Kardashevskiy
2015-04-16 6:29 ` David Gibson
2015-04-10 6:31 ` [PATCH kernel v8 19/31] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_create_table/pnc_pci_free_table Alexey Kardashevskiy
2015-04-16 6:42 ` David Gibson
2015-04-10 6:31 ` [PATCH kernel v8 20/31] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window Alexey Kardashevskiy
2015-04-16 6:43 ` David Gibson
2015-04-10 6:31 ` [PATCH kernel v8 21/31] powerpc/iommu: Split iommu_free_table into 2 helpers Alexey Kardashevskiy
2015-04-16 6:46 ` David Gibson
2015-04-16 16:29 ` Alexey Kardashevskiy
2015-04-20 2:51 ` David Gibson
2015-04-10 6:31 ` [PATCH kernel v8 22/31] powerpc/powernv: Implement multilevel TCE tables Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 23/31] powerpc/powernv: Change prototypes to receive iommu Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 24/31] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 25/31] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework ownership Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 26/31] powerpc/iommu: Add userspace view of TCE table Alexey Kardashevskiy
2015-04-10 21:31 ` Alex Williamson
2015-04-10 6:31 ` [PATCH kernel v8 27/31] powerpc/iommu/ioda2: Add get_table_size() to calculate the size of fiture table Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 28/31] powerpc/mmu: Add userspace-to-physical addresses translation cache Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 29/31] vfio: powerpc/spapr: Register memory and define IOMMU v2 Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 30/31] vfio: powerpc/spapr: Support multiple groups in one container if possible Alexey Kardashevskiy
2015-04-10 6:31 ` [PATCH kernel v8 31/31] vfio: powerpc/spapr: Support Dynamic DMA windows Alexey Kardashevskiy
2015-04-10 22:13 ` [PATCH kernel v8 00/31] powerpc/iommu/vfio: Enable " Alex Williamson
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