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| author | Robin Murphy <robin.murphy@arm.com> | 2021-03-05 16:32:34 +0000 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2021-03-18 10:55:23 +0100 |
| commit | 3542dcb15cef66c0b9e6c3b33168eb657e0d9520 (patch) | |
| tree | e8484ba2f056cd6ee5b1d042af44834136cb97cb /drivers/iommu/dma-iommu.c | |
| parent | b9abb19fa5fd2d8a4be61c6cd4b2a48aa1a17f9c (diff) | |
| download | linux-3542dcb15cef66c0b9e6c3b33168eb657e0d9520.tar.bz2 | |
iommu/dma: Resurrect the "forcedac" option
In converting intel-iommu over to the common IOMMU DMA ops, it quietly
lost the functionality of its "forcedac" option. Since this is a handy
thing both for testing and for performance optimisation on certain
platforms, reimplement it under the common IOMMU parameter namespace.
For the sake of fixing the inadvertent breakage of the Intel-specific
parameter, remove the dmar_forcedac remnants and hook it up as an alias
while documenting the transition to the new common parameter.
Fixes: c588072bba6b ("iommu/vt-d: Convert intel iommu driver to the iommu ops")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/7eece8e0ea7bfbe2cd0e30789e0d46df573af9b0.1614961776.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/dma-iommu.c')
| -rw-r--r-- | drivers/iommu/dma-iommu.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index af765c813cc8..fdd095e1fa52 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -52,6 +52,17 @@ struct iommu_dma_cookie { }; static DEFINE_STATIC_KEY_FALSE(iommu_deferred_attach_enabled); +bool iommu_dma_forcedac __read_mostly; + +static int __init iommu_dma_forcedac_setup(char *str) +{ + int ret = kstrtobool(str, &iommu_dma_forcedac); + + if (!ret && iommu_dma_forcedac) + pr_info("Forcing DAC for PCI devices\n"); + return ret; +} +early_param("iommu.forcedac", iommu_dma_forcedac_setup); void iommu_dma_free_cpu_cached_iovas(unsigned int cpu, struct iommu_domain *domain) @@ -444,7 +455,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain, dma_limit = min(dma_limit, (u64)domain->geometry.aperture_end); /* Try to get PCI devices a SAC address */ - if (dma_limit > DMA_BIT_MASK(32) && dev_is_pci(dev)) + if (dma_limit > DMA_BIT_MASK(32) && !iommu_dma_forcedac && dev_is_pci(dev)) iova = alloc_iova_fast(iovad, iova_len, DMA_BIT_MASK(32) >> shift, false); |