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988f0e24bb
Its pretty easy:
1). We only check to see if we need Xen SWIOTLB for PV guests.
2). If swiotlb=force or iommu=soft is set, then Xen SWIOTLB will
be enabled.
3). If it is an initial domain, then Xen SWIOTLB will be enabled.
4). Native SWIOTLB must be disabled for PV guests.
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
69 lines
1.8 KiB
C
69 lines
1.8 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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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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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);
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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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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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