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    SubjectRe: [PATCH 14/34] AMD IOMMU: clue initialization code together
    On Wed, Jul 09, 2008 at 06:55:12PM -0700, Andrew Morton wrote:
    > On Thu, 26 Jun 2008 21:27:50 +0200 Joerg Roedel <joerg.roedel@amd.com> wrote:
    >
    > > This patch puts the AMD IOMMU ACPI table parsing and hardware initialization
    > > functions together to the main intialization routine.
    > >
    > > index 555fcc9..c792ddc 100644
    > > --- a/arch/x86/kernel/amd_iommu_init.c
    > > +++ b/arch/x86/kernel/amd_iommu_init.c
    > > @@ -643,3 +643,129 @@ static int __init init_memory_definitions(struct acpi_table_header *table)
    > > return 0;
    > > }
    > >
    > > +int __init amd_iommu_init(void)
    > > +{
    > > + int i, ret = 0;
    > > +
    > > +
    > > + if (amd_iommu_disable) {
    > > + printk(KERN_INFO "AMD IOMMU disabled by kernel command line\n");
    > > + return 0;
    > > + }
    > > +
    > > + /*
    > > + * First parse ACPI tables to find the largest Bus/Dev/Func
    > > + * we need to handle. Upon this information the shared data
    > > + * structures for the IOMMUs in the system will be allocated
    > > + */
    > > + if (acpi_table_parse("IVRS", find_last_devid_acpi) != 0)
    > > + return -ENODEV;
    > > +
    > > + dev_table_size = TBL_SIZE(DEV_TABLE_ENTRY_SIZE);
    > > + alias_table_size = TBL_SIZE(ALIAS_TABLE_ENTRY_SIZE);
    > > + rlookup_table_size = TBL_SIZE(RLOOKUP_TABLE_ENTRY_SIZE);
    > > +
    > > + ret = -ENOMEM;
    > > +
    > > + /* Device table - directly used by all IOMMUs */
    > > + amd_iommu_dev_table = (void *)__get_free_pages(GFP_KERNEL,
    > > + get_order(dev_table_size));
    >
    > Is there a reason for using __get_free_pages() in this manner everywhere?
    > kmalloc() or kzalloc() are unsuitable?

    Yes. The device table has to be page aligned and has a maximum size of
    2 MB.

    > > + if (amd_iommu_dev_table == NULL)
    > > + goto out;
    > > +
    > > + /*
    > > + * Alias table - map PCI Bus/Dev/Func to Bus/Dev/Func the
    > > + * IOMMU see for that device
    > > + */
    > > + amd_iommu_alias_table = (void *)__get_free_pages(GFP_KERNEL,
    > > + get_order(alias_table_size));

    Hmm, maybe this table will fit into a kmalloc allocation. Its maximum
    size is 128 kb.

    > > + if (amd_iommu_alias_table == NULL)
    > > + goto free;
    > > +
    > > + /* IOMMU rlookup table - find the IOMMU for a specific device */
    > > + amd_iommu_rlookup_table = (void *)__get_free_pages(GFP_KERNEL,
    > > + get_order(rlookup_table_size));
    > > + if (amd_iommu_rlookup_table == NULL)
    > > + goto free;
    > > +
    > > + /*
    > > + * Protection Domain table - maps devices to protection domains
    > > + * This table has the same size as the rlookup_table
    > > + */
    > > + amd_iommu_pd_table = (void *)__get_free_pages(GFP_KERNEL,
    > > + get_order(rlookup_table_size));

    The rlookup and the pd table have a maximum size of 1 MB.

    > > + if (amd_iommu_pd_table == NULL)
    > > + goto free;
    > > +
    > > + amd_iommu_pd_alloc_bitmap = (void *)__get_free_pages(GFP_KERNEL,
    > > + get_order(MAX_DOMAIN_ID/8));
    > > + if (amd_iommu_pd_alloc_bitmap == NULL)
    > > + goto free;
    > > +
    > > + /*
    > > + * memory is allocated now; initialize the device table with all zeroes
    > > + * and let all alias entries point to itself
    > > + */
    > > + memset(amd_iommu_dev_table, 0, dev_table_size);
    > > + for (i = 0; i < amd_iommu_last_bdf; ++i)
    > > + amd_iommu_alias_table[i] = i;
    > > +
    > > + memset(amd_iommu_pd_table, 0, rlookup_table_size);
    > > + memset(amd_iommu_pd_alloc_bitmap, 0, MAX_DOMAIN_ID / 8);
    >
    > Use of __GFP_ZERO in here would relieve us of a lot of memsets.
    >
    > > + /*
    > > + * never allocate domain 0 because its used as the non-allocated and
    > > + * error value placeholder
    > > + */
    > > + amd_iommu_pd_alloc_bitmap[0] = 1;
    > > +
    > > + /*
    > > + * now the data structures are allocated and basically initialized
    > > + * start the real acpi table scan
    > > + */
    > > + ret = -ENODEV;
    > > + if (acpi_table_parse("IVRS", init_iommu_all) != 0)
    > > + goto free;
    > > +
    > > + if (acpi_table_parse("IVRS", init_memory_definitions) != 0)
    > > + goto free;
    > > +
    > > + printk(KERN_INFO "AMD IOMMU: aperture size is %d MB\n",
    > > + (1 << (amd_iommu_aperture_order-20)));
    > > +
    > > + printk(KERN_INFO "AMD IOMMU: device isolation ");
    > > + if (amd_iommu_isolate)
    > > + printk("enabled\n");
    > > + else
    > > + printk("disabled\n");
    > > +
    > > +out:
    > > + return ret;
    > > +
    > > +free:
    > > + if (amd_iommu_pd_alloc_bitmap)
    > > + free_pages((unsigned long)amd_iommu_pd_alloc_bitmap, 1);
    > > +
    > > + if (amd_iommu_pd_table)
    > > + free_pages((unsigned long)amd_iommu_pd_table,
    > > + get_order(rlookup_table_size));
    > > +
    > > + if (amd_iommu_rlookup_table)
    > > + free_pages((unsigned long)amd_iommu_rlookup_table,
    > > + get_order(rlookup_table_size));
    > > +
    > > + if (amd_iommu_alias_table)
    > > + free_pages((unsigned long)amd_iommu_alias_table,
    > > + get_order(alias_table_size));
    > > +
    > > + if (amd_iommu_dev_table)
    > > + free_pages((unsigned long)amd_iommu_dev_table,
    > > + get_order(dev_table_size));
    >
    > free_pages(0) is legal, so all these tests are unneeded, I expect.
    >
    > This remains true if you decide to switch to kzalloc().

    Thanks for that hint. I will remove the checks.

    > > + free_iommu_all();
    > > +
    > > + free_unity_maps();
    > > +
    > > + goto out;
    > > +}
    >
    >

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