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    Subject[PATCH 5.13 678/800] iommu/amd: Tidy up DMA ops init
    Date
    From: Robin Murphy <robin.murphy@arm.com>

    [ Upstream commit be227f8e99a663d097536e9f9bc935fb26bdbc41 ]

    Now that DMA ops are part of the core API via iommu-dma, fold the
    vestigial remains of the IOMMU_DMA_OPS init state into the IOMMU API
    phase, and clean up a few other leftovers. This should also close the
    race window wherein bus_set_iommu() effectively makes the DMA ops state
    visible before its nominal initialisation - it seems this was previously
    fairly benign, but since commit a250c23f15c2 ("iommu: remove
    DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE") it can now lead to the strict flush
    queue policy inadvertently being picked for default domains allocated
    during that window, with a corresponding unexpected perfomance impact.

    Reported-by: Jussi Maki <joamaki@gmail.com>
    Tested-by: Jussi Maki <joamaki@gmail.com>
    Signed-off-by: Robin Murphy <robin.murphy@arm.com>
    Fixes: a250c23f15c2 ("iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE")
    Link: https://lore.kernel.org/r/665db61e23ff8d54ac5eb391bef520b3a803fcb9.1622727974.git.robin.murphy@arm.com
    Signed-off-by: Joerg Roedel <jroedel@suse.de>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/iommu/amd/amd_iommu.h | 2 --
    drivers/iommu/amd/init.c | 5 -----
    drivers/iommu/amd/iommu.c | 31 +++++++++++++------------------
    3 files changed, 13 insertions(+), 25 deletions(-)

    diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
    index 55dd38d814d9..416815a525d6 100644
    --- a/drivers/iommu/amd/amd_iommu.h
    +++ b/drivers/iommu/amd/amd_iommu.h
    @@ -11,8 +11,6 @@

    #include "amd_iommu_types.h"

    -extern int amd_iommu_init_dma_ops(void);
    -extern int amd_iommu_init_passthrough(void);
    extern irqreturn_t amd_iommu_int_thread(int irq, void *data);
    extern irqreturn_t amd_iommu_int_handler(int irq, void *data);
    extern void amd_iommu_apply_erratum_63(u16 devid);
    diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
    index 1ded8a69c246..5ff7e5364ef4 100644
    --- a/drivers/iommu/amd/init.c
    +++ b/drivers/iommu/amd/init.c
    @@ -231,7 +231,6 @@ enum iommu_init_state {
    IOMMU_ENABLED,
    IOMMU_PCI_INIT,
    IOMMU_INTERRUPTS_EN,
    - IOMMU_DMA_OPS,
    IOMMU_INITIALIZED,
    IOMMU_NOT_FOUND,
    IOMMU_INIT_ERROR,
    @@ -2895,10 +2894,6 @@ static int __init state_next(void)
    init_state = ret ? IOMMU_INIT_ERROR : IOMMU_INTERRUPTS_EN;
    break;
    case IOMMU_INTERRUPTS_EN:
    - ret = amd_iommu_init_dma_ops();
    - init_state = ret ? IOMMU_INIT_ERROR : IOMMU_DMA_OPS;
    - break;
    - case IOMMU_DMA_OPS:
    init_state = IOMMU_INITIALIZED;
    break;
    case IOMMU_INITIALIZED:
    diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
    index 3ac42bbdefc6..c46dde88a132 100644
    --- a/drivers/iommu/amd/iommu.c
    +++ b/drivers/iommu/amd/iommu.c
    @@ -30,7 +30,6 @@
    #include <linux/msi.h>
    #include <linux/irqdomain.h>
    #include <linux/percpu.h>
    -#include <linux/iova.h>
    #include <linux/io-pgtable.h>
    #include <asm/irq_remapping.h>
    #include <asm/io_apic.h>
    @@ -1773,13 +1772,22 @@ void amd_iommu_domain_update(struct protection_domain *domain)
    amd_iommu_domain_flush_complete(domain);
    }

    +static void __init amd_iommu_init_dma_ops(void)
    +{
    + swiotlb = (iommu_default_passthrough() || sme_me_mask) ? 1 : 0;
    +
    + if (amd_iommu_unmap_flush)
    + pr_info("IO/TLB flush on unmap enabled\n");
    + else
    + pr_info("Lazy IO/TLB flushing enabled\n");
    + iommu_set_dma_strict(amd_iommu_unmap_flush);
    +}
    +
    int __init amd_iommu_init_api(void)
    {
    - int ret, err = 0;
    + int err = 0;

    - ret = iova_cache_get();
    - if (ret)
    - return ret;
    + amd_iommu_init_dma_ops();

    err = bus_set_iommu(&pci_bus_type, &amd_iommu_ops);
    if (err)
    @@ -1796,19 +1804,6 @@ int __init amd_iommu_init_api(void)
    return 0;
    }

    -int __init amd_iommu_init_dma_ops(void)
    -{
    - swiotlb = (iommu_default_passthrough() || sme_me_mask) ? 1 : 0;
    -
    - if (amd_iommu_unmap_flush)
    - pr_info("IO/TLB flush on unmap enabled\n");
    - else
    - pr_info("Lazy IO/TLB flushing enabled\n");
    - iommu_set_dma_strict(amd_iommu_unmap_flush);
    - return 0;
    -
    -}
    -
    /*****************************************************************************
    *
    * The following functions belong to the exported interface of AMD IOMMU
    --
    2.30.2


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