Messages in this thread | | | Subject | Re: [PATCH 0/5] x86: Impplement support for unaccepted memory | From | Dave Hansen <> | Date | Tue, 10 Aug 2021 07:08:58 -0700 |
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On 8/9/21 11:26 PM, Kirill A. Shutemov wrote: > UEFI Specification version 2.9 introduces concept of memory acceptance: > Some Virtual Machine platforms, such as Intel TDX or AMD SEV-SNP, > requiring memory to be accepted before it can be used by the guest. > Accepting happens via a protocol specific for the Virtrual Machine > platform. > > Accepting memory is costly and it makes VMM allocate memory for the > accepted guest physical address range. We don't want to accept all memory > upfront.
This could use a bit more explanation. Any VM is likely to *eventually* touch all its memory, so it's not like a VMM has a long-term advantage by delaying this.
So, it must have to do with resource use at boot. Is this to help boot times?
I had expected this series, but I also expected it to be connected to CONFIG_DEFERRED_STRUCT_PAGE_INIT somehow. Could you explain a bit how this problem is different and demands a totally orthogonal solution?
For instance, what prevents us from declaring: "Memory is accepted at the time that its 'struct page' is initialized" ? Then, we use all the infrastructure we already have for DEFERRED_STRUCT_PAGE_INIT.
This series isn't too onerous, but I do want to make sure that we're not reinventing the wheel.
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