On Tue, 31 Jan 2023 at 20:18, Dionna Amalie Glaze <dionnagl...@google.com> wrote: > > > > > efi: mem94: [Conventional| | |CC| | | | | | | | | | | ] > > range=[0x0000000100000000-0x000000023fffffff] (5120MB) > > > > This does not have the cache capabilities one would expect for system > > memory, UC|WC|WT|WB. > > > > After this change, the same entry becomes > > > > efi: mem94: [Conventional| | |CC| | | | | | | |WB|WT|WC|UC] > > range=[0x0000000100000000-0x000000023fffffff] (5120MB) > > > > This has all the expected attributes. > > > > This change is made given a request from Ard. The CC capability is not > applied to other system memory ranges that probably should also have > that capability, given that it's encrypted and accepted. I haven't > considered carefully where EFI_MEMORY_CPU_CRYPTO should be added to > conventional memory, given the acceptance happens before DXE > initializes. Perhaps > CoreConvertResourceDescriptorHobAttributesToCapabilities? This is more > of a question to Ard and Thomas. >
It's not clear to me whether the CC attribute applies to the host or the guest. From the guest PoV, there is really no distinction, whereas on the host, I could imagine that only CC capable memory can be used for handing out to VMs. The important thing for this conversion is that - the type changes to ConventionalMemory - EFI_MEMORY_WB gets set (along with the other ones set in the capability), as otherwise, Linux will disregard this memory and not use it at all. The EFI_MEMORY_CPU_CRYPTO flag is currently only referenced by Linux in code that prints the memory map for diagnostic purposes, and not used anywhere else. -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#99405): https://edk2.groups.io/g/devel/message/99405 Mute This Topic: https://groups.io/mt/96659595/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
