forked from Minki/linux
b827760053
With this patch we provide the functionality to initialize the Xen-SWIOTLB late in the bootup cycle - specifically for Xen PCI-frontend. We still will work if the user had supplied 'iommu=soft' on the Linux command line. Note: We cannot depend on after_bootmem to automatically determine whether this is early or not. This is because when PCI IOMMUs are initialized it is after after_bootmem but before a lot of "other" subsystems are initialized. CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> [v1: Fix smatch warnings] [v2: Added check for xen_swiotlb] [v3: Rebased with new xen-swiotlb changes] [v4: squashed xen/swiotlb: Depending on after_bootmem is not correct in] Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
/* Glue code to lib/swiotlb-xen.c */
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#include <linux/dma-mapping.h>
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#include <linux/pci.h>
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#include <xen/swiotlb-xen.h>
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#include <asm/xen/hypervisor.h>
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#include <xen/xen.h>
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#include <asm/iommu_table.h>
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#ifdef CONFIG_X86_64
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#include <asm/iommu.h>
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#include <asm/dma.h>
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#endif
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#include <linux/export.h>
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int xen_swiotlb __read_mostly;
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static struct dma_map_ops xen_swiotlb_dma_ops = {
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.mapping_error = xen_swiotlb_dma_mapping_error,
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.alloc = xen_swiotlb_alloc_coherent,
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.free = xen_swiotlb_free_coherent,
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.sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
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.sync_single_for_device = xen_swiotlb_sync_single_for_device,
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.sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
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.sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
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.map_sg = xen_swiotlb_map_sg_attrs,
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.unmap_sg = xen_swiotlb_unmap_sg_attrs,
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.map_page = xen_swiotlb_map_page,
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.unmap_page = xen_swiotlb_unmap_page,
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.dma_supported = xen_swiotlb_dma_supported,
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};
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/*
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* pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
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*
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* This returns non-zero if we are forced to use xen_swiotlb (by the boot
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* option).
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*/
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int __init pci_xen_swiotlb_detect(void)
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{
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if (!xen_pv_domain())
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return 0;
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/* If running as PV guest, either iommu=soft, or swiotlb=force will
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* activate this IOMMU. If running as PV privileged, activate it
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* irregardless.
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*/
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if ((xen_initial_domain() || swiotlb || swiotlb_force))
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xen_swiotlb = 1;
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/* If we are running under Xen, we MUST disable the native SWIOTLB.
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* Don't worry about swiotlb_force flag activating the native, as
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* the 'swiotlb' flag is the only one turning it on. */
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swiotlb = 0;
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#ifdef CONFIG_X86_64
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/* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu == 0
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* (so no iommu=X command line over-writes).
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* Considering that PV guests do not want the *native SWIOTLB* but
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* only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
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*/
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if (max_pfn > MAX_DMA32_PFN)
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no_iommu = 1;
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#endif
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return xen_swiotlb;
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}
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void __init pci_xen_swiotlb_init(void)
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{
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if (xen_swiotlb) {
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xen_swiotlb_init(1, true /* early */);
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dma_ops = &xen_swiotlb_dma_ops;
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/* Make sure ACS will be enabled */
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pci_request_acs();
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}
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}
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int pci_xen_swiotlb_init_late(void)
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{
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int rc;
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if (xen_swiotlb)
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return 0;
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rc = xen_swiotlb_init(1, false /* late */);
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if (rc)
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return rc;
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dma_ops = &xen_swiotlb_dma_ops;
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/* Make sure ACS will be enabled */
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pci_request_acs();
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return 0;
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}
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EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
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IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
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0,
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pci_xen_swiotlb_init,
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0);
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