Messages in this thread | | | Date | Fri, 10 Dec 2021 22:01:16 +0800 | Subject | Re: [PATCH V6 3/5] hyper-v: Enable swiotlb bounce buffer for Isolation VM | From | Tianyu Lan <> |
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On 12/10/2021 9:25 PM, Tianyu Lan wrote: >>> @@ -319,8 +320,16 @@ static void __init ms_hyperv_init_platform(void) >>> pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B >>> 0x%x\n", >>> ms_hyperv.isolation_config_a, >>> ms_hyperv.isolation_config_b); >>> >>> - if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) >>> + if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) { >>> static_branch_enable(&isolation_type_snp); >>> + swiotlb_unencrypted_base = ms_hyperv.shared_gpa_boundary; >>> + } >>> + >>> + /* >>> + * Enable swiotlb force mode in Isolation VM to >>> + * use swiotlb bounce buffer for dma transaction. >>> + */ >>> + swiotlb_force = SWIOTLB_FORCE; >> I'm good with this approach that directly updates the swiotlb settings >> here >> >> rather than in IOMMU initialization code. It's a lot more >> straightforward. >> >> However, there's an issue if building for X86_32 without PAE, in that the >> swiotlb module may not be built, resulting in compile and link >> errors. The >> swiotlb.h file needs to be updated to provide a stub function for >> swiotlb_update_mem_attributes(). swiotlb_unencrypted_base probably >> needs wrapper functions to get/set it, which can be stubs when >> CONFIG_SWIOTLB is not set. swiotlb_force is a bit of a mess in that >> it already >> has a stub definition that assumes it will only be read, and not set. >> A bit of >> thinking will be needed to sort that out. > > It's ok to fix the issue via selecting swiotlb when CONFIG_HYPERV is > set? > Sorry. ignore the previous statement. These codes doesn't depend on CONFIG_HYPERV.
How about making these code under #ifdef CONFIG_X86_64 or CONFIG_SWIOTLB?
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