Messages in this thread | | | Subject | Re: [RFC PATCH V3 09/11] HV/IOMMU: Enable swiotlb bounce buffer for Isolation VM | From | Tianyu Lan <> | Date | Wed, 2 Jun 2021 23:01:36 +0800 |
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Hi Boris: Thanks for your review.
On 6/2/2021 9:16 AM, Boris Ostrovsky wrote: > > On 5/30/21 11:06 AM, Tianyu Lan wrote: >> @@ -91,6 +92,6 @@ int pci_xen_swiotlb_init_late(void) >> EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late); >> >> IOMMU_INIT_FINISH(2, >> - NULL, >> + hyperv_swiotlb_detect, >> pci_xen_swiotlb_init, >> NULL); > > > Could you explain this change?
Hyper-V allocates its own swiotlb bounce buffer and the default swiotlb buffer should not be allocated. swiotlb_init() in pci_swiotlb_init() is to allocate default swiotlb buffer. To achieve this, put hyperv_swiotlb_detect() as the first entry in the iommu_table_entry list. The detect loop in the pci_iommu_alloc() will exit once hyperv_swiotlb_detect() is called in Hyper-V VM and other iommu_table_entry callback will not be called.
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