Messages in this thread | | | Subject | Re: [RFCv2 15/16] KVM: Unmap protected pages from direct mapping | From | Tom Lendacky <> | Date | Mon, 26 Oct 2020 14:55:20 -0500 |
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On 10/20/20 7:18 AM, David Hildenbrand wrote: > On 20.10.20 08:18, Kirill A. Shutemov wrote: >> If the protected memory feature enabled, unmap guest memory from >> kernel's direct mappings. > > Gah, ugly. I guess this also defeats compaction, swapping, ... oh gosh. > As if all of the encrypted VM implementations didn't bring us enough > ugliness already (SEV extensions also don't support reboots, but can at > least kexec() IIRC).
SEV does support reboot. SEV-ES using Qemu doesn't support reboot because of the way Qemu resets the vCPU state. If Qemu could relaunch the guest through the SEV APIs to reset the vCPU state, then a "reboot" would be possible.
SEV does support kexec, SEV-ES does not at the moment.
Thanks, Tom
> > Something similar is done with secretmem [1]. And people don't seem to > like fragmenting the direct mapping (including me). > > [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.kernel.org%2Fr%2F20200924132904.1391-1-rppt%40kernel.org&data=04%7C01%7Cthomas.lendacky%40amd.com%7Cb98a5033da37432131b508d874f25194%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637387931403890525%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=BzC%2FeIyOau7BORuUY%2BaiRzYZ%2BOAHANvBDcmV9hpkrts%3D&reserved=0 >
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