Messages in this thread | | | Date | Tue, 14 Dec 2021 12:36:56 +0800 | From | Tianyu Lan <> | Subject | Re: [PATCH V7 1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM |
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On 12/14/2021 12:45 AM, Dave Hansen wrote: > On 12/12/21 11:14 PM, Tianyu Lan wrote: >> In Isolation VM with AMD SEV, bounce buffer needs to be accessed via >> extra address space which is above shared_gpa_boundary (E.G 39 bit >> address line) reported by Hyper-V CPUID ISOLATION_CONFIG. The access >> physical address will be original physical address + shared_gpa_boundary. >> The shared_gpa_boundary in the AMD SEV SNP spec is called virtual top of >> memory(vTOM). Memory addresses below vTOM are automatically treated as >> private while memory above vTOM is treated as shared. > > This seems to be independently reintroducing some of the SEV > infrastructure. Is it really OK that this doesn't interact at all with > any existing SEV code? > > For instance, do we need a new 'swiotlb_unencrypted_base', or should > this just be using sme_me_mask somehow?
Hi Dave: Thanks for your review. Hyper-V provides a para-virtualized confidential computing solution based on the AMD SEV function and not expose sev&sme capabilities to guest. So sme_me_mask is unset in the Hyper-V Isolation VM. swiotlb_unencrypted_base is more general solution to handle such case of different address space for encrypted and decrypted memory and other platform also may reuse it.
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