From: Vlastimil Babka <vbabka@suse.cz>
To: Nicolas Boichat <drinkcat@chromium.org>,
Will Deacon <will.deacon@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
Joerg Roedel <joro@8bytes.org>, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>,
Mel Gorman <mgorman@techsingularity.net>,
Levin Alexander <Alexander.Levin@microsoft.com>,
Huaisheng Ye <yehs1@lenovo.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
linux-arm-kernel@lists.infradead.org,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Yong Wu <yong.wu@mediatek.com>,
Matthias Brugger <matthias.bgg@gmail.com>,
Tomasz Figa <tfiga@google.com>,
yingjoe.chen@mediatek.com, hch@infradead.org,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v4 3/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging
Date: Wed, 5 Dec 2018 15:43:52 +0100 [thread overview]
Message-ID: <cf005731-5f37-4aba-519f-7d7d4da04ec7@suse.cz> (raw)
In-Reply-To: <20181205054828.183476-4-drinkcat@chromium.org>
On 12/5/18 6:48 AM, Nicolas Boichat wrote:
> IOMMUs using ARMv7 short-descriptor format require page tables
> (level 1 and 2) to be allocated within the first 4GB of RAM, even
> on 64-bit systems.
>
> For level 1/2 pages, ensure GFP_DMA32 is used if CONFIG_ZONE_DMA32
> is defined (e.g. on arm64 platforms).
>
> For level 2 pages, allocate a slab cache in SLAB_CACHE_DMA32.
>
> Also, print an error when the physical address does not fit in
> 32-bit, to make debugging easier in the future.
>
> Fixes: ad67f5a6545f ("arm64: replace ZONE_DMA with ZONE_DMA32")
> Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
> ---
>
> Changes since v2:
> - Commit message
>
> (v3 used the page_frag approach)
>
> drivers/iommu/io-pgtable-arm-v7s.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
> index 445c3bde04800c..996f7b6d00b44a 100644
> --- a/drivers/iommu/io-pgtable-arm-v7s.c
> +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> @@ -161,6 +161,14 @@
>
> #define ARM_V7S_TCR_PD1 BIT(5)
>
> +#ifdef CONFIG_ZONE_DMA32
> +#define ARM_V7S_TABLE_GFP_DMA GFP_DMA32
> +#define ARM_V7S_TABLE_SLAB_CACHE SLAB_CACHE_DMA32
> +#else
> +#define ARM_V7S_TABLE_GFP_DMA GFP_DMA
> +#define ARM_V7S_TABLE_SLAB_CACHE SLAB_CACHE_DMA
> +#endif
> +
> typedef u32 arm_v7s_iopte;
>
> static bool selftest_running;
> @@ -198,13 +206,17 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp,
> void *table = NULL;
>
> if (lvl == 1)
> - table = (void *)__get_dma_pages(__GFP_ZERO, get_order(size));
> + table = (void *)__get_free_pages(
> + __GFP_ZERO | ARM_V7S_TABLE_GFP_DMA, get_order(size));
> else if (lvl == 2)
> - table = kmem_cache_zalloc(data->l2_tables, gfp | GFP_DMA);
> + table = kmem_cache_zalloc(data->l2_tables,
> + gfp | ARM_V7S_TABLE_GFP_DMA);
So as I've explained in 2/3, you don't need ARM_V7S_TABLE_GFP_DMA here
(and then you don't need to adjust the slab warnings).
> phys = virt_to_phys(table);
> - if (phys != (arm_v7s_iopte)phys)
> + if (phys != (arm_v7s_iopte)phys) {
> /* Doesn't fit in PTE */
> + dev_err(dev, "Page table does not fit in PTE: %pa", &phys);
> goto out_free;
> + }
> if (table && !(cfg->quirks & IO_PGTABLE_QUIRK_NO_DMA)) {
> dma = dma_map_single(dev, table, size, DMA_TO_DEVICE);
> if (dma_mapping_error(dev, dma))
> @@ -737,7 +749,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
> data->l2_tables = kmem_cache_create("io-pgtable_armv7s_l2",
> ARM_V7S_TABLE_SIZE(2),
> ARM_V7S_TABLE_SIZE(2),
> - SLAB_CACHE_DMA, NULL);
> + ARM_V7S_TABLE_SLAB_CACHE, NULL);
> if (!data->l2_tables)
> goto out_free_data;
>
>
prev parent reply other threads:[~2018-12-05 14:46 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-05 5:48 [PATCH v4 0/3] iommu/io-pgtable-arm-v7s: Use DMA32 zone for page tables Nicolas Boichat
2018-12-05 5:48 ` [PATCH v4 1/3] mm: slab/slub: Add check_slab_flags function to check for valid flags Nicolas Boichat
2018-12-05 13:34 ` Vlastimil Babka
2018-12-05 5:48 ` [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone Nicolas Boichat
2018-12-05 7:25 ` Wei Yang
2018-12-05 7:39 ` Nicolas Boichat
2018-12-05 9:18 ` Wei Yang
2018-12-05 12:18 ` Wei Yang
2018-12-06 0:41 ` Nicolas Boichat
2018-12-06 3:32 ` Wei Yang
2018-12-06 3:55 ` Nicolas Boichat
2018-12-06 6:29 ` Wei Yang
2018-12-05 9:55 ` Michal Hocko
2018-12-05 11:01 ` Nicolas Boichat
2018-12-05 11:37 ` Michal Hocko
2018-12-05 13:59 ` Vlastimil Babka
2018-12-06 3:49 ` Nicolas Boichat
2018-12-06 9:34 ` Vlastimil Babka
2018-12-06 10:09 ` Nicolas Boichat
2018-12-05 5:48 ` [PATCH v4 3/3] iommu/io-pgtable-arm-v7s: Request DMA32 memory, and improve debugging Nicolas Boichat
2018-12-05 13:54 ` Christoph Hellwig
2018-12-05 14:40 ` Robin Murphy
2018-12-05 14:43 ` Christoph Hellwig
2018-12-05 14:46 ` Will Deacon
2018-12-05 14:43 ` Vlastimil Babka [this message]
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