Messages in this thread | | | Date | Mon, 7 Jan 2013 14:29:54 -0500 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH v7u1 26/31] x86: Don't enable swiotlb if there is not enough ram for it |
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> Also, since IOMMU drivers can no longer assume swiotlb is allocated > enough_mem_for_swiotlb() check fails, AMD IOMMU or another other iommu > driver can't simply rely on changing swiotlb=1 and assuming the buffer > is there. > > As Konrad suggested, a hook is needed, however, I think the logic to > ensure switolb buffer belongs in swiotlb modules. How about changing > pci_swiolb_late_init() logic to ensure swioltb late init is done > instead of leaving it up to AMD IOMMU driver or some other driver.
Perhaps by having the 'swiotlb' be more than just on/off? It could carry different flags, such as:
EARLY_BOOTMEM_ON (if pci_swiotlb_detect_4gb or pci_swiotlb_detect_override sets it) EARLY_BOOTMEM_OFF this would replace 'swiotlb=0' FORCE replaces 'swiotlb_force' LATE_INIT_ON this new option where pci_swiotlb_late_init() would call the late init.
That would require some tweaking also in the IA64 code, but seems like a step in the right direction. And we can get rid of that 'swiotlb_force' parameter.
Actually, that would also allow us to get rid of the pci_swiotlb_detect_override and the setup_io_tlb_npages function could now just set swiotlb |= SWIOTLB_FORCE;
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