Messages in this thread | | | Subject | Re: [PATCH v7 09/45] x86/sev: Save the negotiated GHCB version | From | Brijesh Singh <> | Date | Tue, 7 Dec 2021 10:58:32 -0600 |
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On 12/7/21 7:17 AM, Borislav Petkov wrote: > On Tue, Dec 07, 2021 at 08:51:53PM +0800, Tianyu Lan wrote: >> Hi Brijesh: > > Do me a favor please and learn not to top-post on a public mailing list. > Also, take the time to read Documentation/process/ before you send > upstream patches and how to work with the community in general. > >> We find this patch breaks AMD SEV support in the Hyper-V Isolation >> VM. Hyper-V code also uses sev_es_ghcb_hv_call() to read or write msr >> value. The sev_es_check_cpu_features() isn't called in the Hyper-V >> code and so the ghcb_version is always 0. > > If hyperv is going to expose hypervisor features, then it better report > GHCB v2. If not, then I guess < 2 or 1 or so, depending on how this is > defined. > >> Could you add a new parameter ghcb_version for sev_es_ghcb_hv_call() >> and then caller may input ghcb_version? > > No, your hypervisor needs to adhere to the spec and report proper ghcb > version. We won't be doing any accomodate-hyperv hacks. >
Agreed, the HyperV support need to negotiate the GHCB version before making those HC. In the current patch, the sev_es_negotiate_protocol() will save the ghcb_version in global variable and the saved value is used during the HC. Just make sure that initial HyperV support is adhering to the specification.
thanks
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