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    Subject[PATCH v6 2/6] iommu: Allow .iotlb_sync_map to fail and handle s390's -ENOMEM return
    Date
    On s390 when using a paging hypervisor, .iotlb_sync_map is used to sync
    mappings by letting the hypervisor inspect the synced IOVA range and
    updating a shadow table. This however means that .iotlb_sync_map can
    fail as the hypervisor may run out of resources while doing the sync.
    This can be due to the hypervisor being unable to pin guest pages, due
    to a limit on mapped addresses such as vfio_iommu_type1.dma_entry_limit
    or lack of other resources. Either way such a failure to sync a mapping
    should result in a DMA_MAPPING_ERROR.

    Now especially when running with batched IOTLB flushes for unmap it may
    be that some IOVAs have already been invalidated but not yet synced via
    .iotlb_sync_map. Thus if the hypervisor indicates running out of
    resources, first do a global flush allowing the hypervisor to free
    resources associated with these mappings as well a retry creating the
    new mappings and only if that also fails report this error to callers.

    Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
    Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
    Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
    ---
    v3 -> v4:
    - Adapted signature of .iommu_tlb_sync mapo for sun50i IOMMU driver added in
    v6.2-rc1 (kernel test robot)

    drivers/iommu/amd/iommu.c | 5 +++--
    drivers/iommu/apple-dart.c | 5 +++--
    drivers/iommu/intel/iommu.c | 5 +++--
    drivers/iommu/iommu.c | 20 ++++++++++++++++----
    drivers/iommu/msm_iommu.c | 5 +++--
    drivers/iommu/mtk_iommu.c | 5 +++--
    drivers/iommu/s390-iommu.c | 29 ++++++++++++++++++++++++-----
    drivers/iommu/sprd-iommu.c | 5 +++--
    drivers/iommu/sun50i-iommu.c | 4 +++-
    drivers/iommu/tegra-gart.c | 5 +++--
    include/linux/iommu.h | 4 ++--
    11 files changed, 66 insertions(+), 26 deletions(-)

    diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
    index cbeaab55c0db..3df7d20e0e52 100644
    --- a/drivers/iommu/amd/iommu.c
    +++ b/drivers/iommu/amd/iommu.c
    @@ -2180,14 +2180,15 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
    return ret;
    }

    -static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom,
    - unsigned long iova, size_t size)
    +static int amd_iommu_iotlb_sync_map(struct iommu_domain *dom,
    + unsigned long iova, size_t size)
    {
    struct protection_domain *domain = to_pdomain(dom);
    struct io_pgtable_ops *ops = &domain->iop.iop.ops;

    if (ops->map_pages)
    domain_flush_np_cache(domain, iova, size);
    + return 0;
    }

    static int amd_iommu_map_pages(struct iommu_domain *dom, unsigned long iova,
    diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
    index 4f4a323be0d0..4a76f4d95459 100644
    --- a/drivers/iommu/apple-dart.c
    +++ b/drivers/iommu/apple-dart.c
    @@ -344,10 +344,11 @@ static void apple_dart_iotlb_sync(struct iommu_domain *domain,
    apple_dart_domain_flush_tlb(to_dart_domain(domain));
    }

    -static void apple_dart_iotlb_sync_map(struct iommu_domain *domain,
    - unsigned long iova, size_t size)
    +static int apple_dart_iotlb_sync_map(struct iommu_domain *domain,
    + unsigned long iova, size_t size)
    {
    apple_dart_domain_flush_tlb(to_dart_domain(domain));
    + return 0;
    }

    static phys_addr_t apple_dart_iova_to_phys(struct iommu_domain *domain,
    diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
    index 59df7e42fd53..3b36a544c8fa 100644
    --- a/drivers/iommu/intel/iommu.c
    +++ b/drivers/iommu/intel/iommu.c
    @@ -4725,8 +4725,8 @@ static bool risky_device(struct pci_dev *pdev)
    return false;
    }

    -static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
    - unsigned long iova, size_t size)
    +static int intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
    + unsigned long iova, size_t size)
    {
    struct dmar_domain *dmar_domain = to_dmar_domain(domain);
    unsigned long pages = aligned_nrpages(iova, size);
    @@ -4736,6 +4736,7 @@ static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,

    xa_for_each(&dmar_domain->iommu_array, i, info)
    __mapping_notify_one(info->iommu, dmar_domain, pfn, pages);
    + return 0;
    }

    static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
    diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
    index 5f6a85aea501..5565e510f7d2 100644
    --- a/drivers/iommu/iommu.c
    +++ b/drivers/iommu/iommu.c
    @@ -2367,8 +2367,17 @@ static int _iommu_map(struct iommu_domain *domain, unsigned long iova,
    int ret;

    ret = __iommu_map(domain, iova, paddr, size, prot, gfp);
    - if (ret == 0 && ops->iotlb_sync_map)
    - ops->iotlb_sync_map(domain, iova, size);
    + if (ret == 0 && ops->iotlb_sync_map) {
    + ret = ops->iotlb_sync_map(domain, iova, size);
    + if (ret)
    + goto out_err;
    + }
    +
    + return ret;
    +
    +out_err:
    + /* undo mappings already done */
    + iommu_unmap(domain, iova, size);

    return ret;
    }
    @@ -2516,8 +2525,11 @@ static ssize_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
    sg = sg_next(sg);
    }

    - if (ops->iotlb_sync_map)
    - ops->iotlb_sync_map(domain, iova, mapped);
    + if (ops->iotlb_sync_map) {
    + ret = ops->iotlb_sync_map(domain, iova, mapped);
    + if (ret)
    + goto out_err;
    + }
    return mapped;

    out_err:
    diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
    index c60624910872..62fc52765554 100644
    --- a/drivers/iommu/msm_iommu.c
    +++ b/drivers/iommu/msm_iommu.c
    @@ -486,12 +486,13 @@ static int msm_iommu_map(struct iommu_domain *domain, unsigned long iova,
    return ret;
    }

    -static void msm_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
    - size_t size)
    +static int msm_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
    + size_t size)
    {
    struct msm_priv *priv = to_msm_priv(domain);

    __flush_iotlb_range(iova, size, SZ_4K, false, priv);
    + return 0;
    }

    static size_t msm_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
    diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
    index 2badd6acfb23..76d413aef1ef 100644
    --- a/drivers/iommu/mtk_iommu.c
    +++ b/drivers/iommu/mtk_iommu.c
    @@ -758,12 +758,13 @@ static void mtk_iommu_iotlb_sync(struct iommu_domain *domain,
    mtk_iommu_tlb_flush_range_sync(gather->start, length, dom->bank);
    }

    -static void mtk_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
    - size_t size)
    +static int mtk_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
    + size_t size)
    {
    struct mtk_iommu_domain *dom = to_mtk_domain(domain);

    mtk_iommu_tlb_flush_range_sync(iova, size, dom->bank);
    + return 0;
    }

    static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
    diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
    index ed33c6cce083..4dfa557270f4 100644
    --- a/drivers/iommu/s390-iommu.c
    +++ b/drivers/iommu/s390-iommu.c
    @@ -210,6 +210,14 @@ static void s390_iommu_release_device(struct device *dev)
    __s390_iommu_detach_device(zdev);
    }

    +
    +static int zpci_refresh_all(struct zpci_dev *zdev)
    +{
    + return zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
    + zdev->end_dma - zdev->start_dma + 1);
    +
    +}
    +
    static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
    {
    struct s390_domain *s390_domain = to_s390_domain(domain);
    @@ -217,8 +225,7 @@ static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)

    rcu_read_lock();
    list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
    - zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
    - zdev->end_dma - zdev->start_dma + 1);
    + zpci_refresh_all(zdev);
    }
    rcu_read_unlock();
    }
    @@ -242,20 +249,32 @@ static void s390_iommu_iotlb_sync(struct iommu_domain *domain,
    rcu_read_unlock();
    }

    -static void s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
    +static int s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
    unsigned long iova, size_t size)
    {
    struct s390_domain *s390_domain = to_s390_domain(domain);
    struct zpci_dev *zdev;
    + int ret = 0;

    rcu_read_lock();
    list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
    if (!zdev->tlb_refresh)
    continue;
    - zpci_refresh_trans((u64)zdev->fh << 32,
    - iova, size);
    + ret = zpci_refresh_trans((u64)zdev->fh << 32,
    + iova, size);
    + /*
    + * let the hypervisor discover invalidated entries
    + * allowing it to free IOVAs and unpin pages
    + */
    + if (ret == -ENOMEM) {
    + ret = zpci_refresh_all(zdev);
    + if (ret)
    + break;
    + }
    }
    rcu_read_unlock();
    +
    + return ret;
    }

    static int s390_iommu_validate_trans(struct s390_domain *s390_domain,
    diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
    index 219bfa11f7f4..9e590829992c 100644
    --- a/drivers/iommu/sprd-iommu.c
    +++ b/drivers/iommu/sprd-iommu.c
    @@ -330,8 +330,8 @@ static size_t sprd_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
    return size;
    }

    -static void sprd_iommu_sync_map(struct iommu_domain *domain,
    - unsigned long iova, size_t size)
    +static int sprd_iommu_sync_map(struct iommu_domain *domain,
    + unsigned long iova, size_t size)
    {
    struct sprd_iommu_domain *dom = to_sprd_domain(domain);
    unsigned int reg;
    @@ -343,6 +343,7 @@ static void sprd_iommu_sync_map(struct iommu_domain *domain,

    /* clear IOMMU TLB buffer after page table updated */
    sprd_iommu_write(dom->sdev, reg, 0xffffffff);
    + return 0;
    }

    static void sprd_iommu_sync(struct iommu_domain *domain,
    diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
    index 5b585eace3d4..9d2ff7a95624 100644
    --- a/drivers/iommu/sun50i-iommu.c
    +++ b/drivers/iommu/sun50i-iommu.c
    @@ -402,7 +402,7 @@ static void sun50i_iommu_flush_iotlb_all(struct iommu_domain *domain)
    spin_unlock_irqrestore(&iommu->iommu_lock, flags);
    }

    -static void sun50i_iommu_iotlb_sync_map(struct iommu_domain *domain,
    +static int sun50i_iommu_iotlb_sync_map(struct iommu_domain *domain,
    unsigned long iova, size_t size)
    {
    struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
    @@ -412,6 +412,8 @@ static void sun50i_iommu_iotlb_sync_map(struct iommu_domain *domain,
    spin_lock_irqsave(&iommu->iommu_lock, flags);
    sun50i_iommu_zap_range(iommu, iova, size);
    spin_unlock_irqrestore(&iommu->iommu_lock, flags);
    +
    + return 0;
    }

    static void sun50i_iommu_iotlb_sync(struct iommu_domain *domain,
    diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
    index ed53279d1106..a59966290e46 100644
    --- a/drivers/iommu/tegra-gart.c
    +++ b/drivers/iommu/tegra-gart.c
    @@ -252,10 +252,11 @@ static int gart_iommu_of_xlate(struct device *dev,
    return 0;
    }

    -static void gart_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
    - size_t size)
    +static int gart_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
    + size_t size)
    {
    FLUSH_GART_REGS(gart_handle);
    + return 0;
    }

    static void gart_iommu_sync(struct iommu_domain *domain,
    diff --git a/include/linux/iommu.h b/include/linux/iommu.h
    index 46e1347bfa22..e7f76599f09e 100644
    --- a/include/linux/iommu.h
    +++ b/include/linux/iommu.h
    @@ -332,8 +332,8 @@ struct iommu_domain_ops {
    struct iommu_iotlb_gather *iotlb_gather);

    void (*flush_iotlb_all)(struct iommu_domain *domain);
    - void (*iotlb_sync_map)(struct iommu_domain *domain, unsigned long iova,
    - size_t size);
    + int (*iotlb_sync_map)(struct iommu_domain *domain, unsigned long iova,
    + size_t size);
    void (*iotlb_sync)(struct iommu_domain *domain,
    struct iommu_iotlb_gather *iotlb_gather);

    --
    2.37.2
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