The name of EDKII_MEMORY_ACCEPT_PROTOCOL indicates it is only used in edk2. It's not going to be included in UEFI spec, at least in current stage. In our design of the protocol (EDKII_MEMORY_ACCEPT_PROTOCOL), it contains the function of EDKII_ACCEPT_MEMORY which is to accept the un-accepted memories based on the input address and size. We just want to make the protocol clear and straightforward.
> -----Original Message----- > From: Dionna Amalie Glaze <[email protected]> > Sent: Monday, October 10, 2022 11:51 PM > To: Ni, Ray <[email protected]> > Cc: Xu, Min M <[email protected]>; [email protected]; Gao, Liming > <[email protected]>; Gao, Zhichao <[email protected]>; Aktas, > Erdem <[email protected]>; Gerd Hoffmann <[email protected]>; > James Bottomley <[email protected]>; Yao, Jiewen > <[email protected]>; Tom Lendacky <[email protected]>; Gao, > Jiaqi <[email protected]>; Wang, Jian J <[email protected]>; Liu, > Zhiguang <[email protected]>; Kinney, Michael D > <[email protected]> > Subject: Re: [edk2-devel] 回复: [PATCH V4 00/10] Introduce Lazy-accept for > Tdx guest > > > > > Can OS call AcceptMemory protocol for those ranges that are not accepted? > > > > AcceptMemory is not specified to avoid accepting previously accepted > memory. As I understand it, AcceptMemory is purely a hardware abstraction > layer for CC technologies inside the UEFI implementation. > It additionally is not meant to modify address spaces. Address space > modification happens around it. Gao has a point though, that the two could > be combined. I'm not sure if it's particularly helpful to expose AcceptMemory > to the OS. Exposing it I think would necessitate changing its semantics to be > safer, e.g., > > Use the insight that AcceptMemory is only used to accept full or partial > regions of unaccepted memory spaces: > > /** > * Accepts memory in page granularity from the beginning of a pointed-to > memory descriptor, and changes > * the type of the affected memory range to EfiConventionalMemory. > * > * @param[This] This A pointer to this protocol instance > * @param[AddressInSpace] An address within the memory descriptor from > which to accept pages. > * @param[NumPages] The amount of EFI_PAGE_SIZE blocks of memory to > accept from the memory > * descriptor's beginning and convert into EfiConventionalMemory. If pages > remain in the memory descriptor > * after acceptance, the remaining memory will start at the initial memory > descriptor's > * start address + NumPages * EFI_PAGE_SIZE > * with type EfiUnacceptedMemory. > * The changes to the memory map affect only the memory descriptor > named by AddressInSpace. > * > * Returns EFI_INVALID_PARAMETER if AddressInSpace names to a memory > descriptor that is not > * EfiUnacceptedMemory, or if the named memory descriptor is not at least > NumPages in size. > */ > EFI_STATUS EFIAPI AcceptFromMemorySpaceBeginning ( > IN ProtocolType *This, > IN EFI_VIRTUAL_ADDRESS AddressInSpace, > IN UINTN NumPages > ); > > /** > * To be called by the OS loader to indicate that it supports and accepts > responsibility for EfiUnacceptedMemory. > * > * Without calling this function, ExitBootServices will accept all unaccepted > memory before returning. This > * behavior maintains safety for OSes that do not support unaccepted > memory or know of this protocol. > */ > VOID EFIAPI DisableAcceptAllOnExitBootServices (IN ProtocolType *This); > > I think this could be a fine protocol to expose to the OS loader since it > would > be safer written this way, albeit AcceptFromMemorySpaceBeginning is rather > redundant for the behavior that the OS would need to implement if it calls > the disable function. > > I'm not too pleased about the naming behavior, but I also don't really like > requiring the interface to only accept the start address of any particular > memory descriptor. That's a matter of taste though. The implementation of > the memory descriptor search would not be much more complicated than a > couple inequality checks instead of a single equality check. > > I don't think it's worth the effort in this interface to allow an arbitrary > range > that could split a single memory descriptor into at most three instead of at > most two, since it is logic I don't think would be readily exercised. Given > that > we're talking about calling this function given knowledge of the MemoryMap, > and that the MemoryMap should be condensed to not have separate > memory descriptors that could be coalesced, I think the limitation that > NumPages fits within the single descriptor is reasonable. > > All this being said, what's the value of combining the protocols? One fewer > header and guid? I honestly don't know since I haven't been around long > enough to understand how these kinds of things evolve and create possible > warts. > > If it's just two two things though, I think a header and guid are worth > avoiding confusion by exposing AcceptMemory unnecessarily. > > > > -----Original Message----- > > > From: Xu, Min M <[email protected]> > > > Sent: Monday, October 10, 2022 11:08 AM > > > To: [email protected]; Dionna Amalie Glaze > > > <[email protected]>; Gao, Liming <[email protected]> > > > Cc: Gao, Zhichao <[email protected]>; Ni, Ray > > > <[email protected]>; Aktas, Erdem <[email protected]>; 'Gerd > Hoffmann' > > > <[email protected]>; 'James Bottomley' <[email protected]>; Yao, > > > Jiewen <[email protected]>; 'Tom Lendacky' > > > <[email protected]>; Gao, Jiaqi <[email protected]>; Wang, > > > Jian J <[email protected]>; Liu, Zhiguang > > > <[email protected]>; Kinney, Michael D > > > <[email protected]>; Xu, Min M <[email protected]> > > > Subject: RE: [edk2-devel] 回复: [PATCH V4 00/10] Introduce Lazy-accept > > > for Tdx guest > > > > > > On October 10, 2022 10:28 AM, Gao Liming wrote: > > > > > > > > Min: > > > > I have no comments for new unaccepted resource type and > > > > unaccepted > > > gcd > > > > type. In fact, they are mapping to UEFI EfiUnacceptedMemoryType. > > > > > > > > For new protocol EfiMemoryAcceptProtocol, I see another patch > > > > serial > > > > https://edk2.groups.io/g/devel/message/94763 base on it to > > > > introduce ACCEPT_ALL_UNACCEPTED_MEMORY_PROTOCOL. Can these > two > > > protocols > > > > be combined into one? > > > > > > > EfiMemoryAcceptProtocol looks like this: > > > typedef > > > EFI_STATUS > > > (EFIAPI *EDKII_ACCEPT_MEMORY)( > > > IN EDKII_MEMORY_ACCEPT_PROTOCOL *This, > > > IN EFI_PHYSICAL_ADDRESS StartAddress, > > > IN UINTN Size > > > ); > > > This protocol is called to accept the memory based on the input > > > start address and size. > > > > > > While ACCEPT_ALL_UNACCEPTED_MEMORY_PROTOCOL looks like below: > > > typedef > > > EFI_STATUS > > > (EFIAPI *BZ3987_DISABLE_ACCEPT_ALL_UNACCEPTED_MEMORY)( > > > IN BZ3987_ACCEPT_ALL_UNACCEPTED_MEMORY_PROTOCOL *This ); > > > According to its description > > > (https://edk2.groups.io/g/devel/message/94768) > > > this protocol is used to disable the behavior of accepting all > > > unaccepted memory. And it is designed to be called by the OS loader, not > EDK2 itself. > > > > > > I am afraid these 2 protocols cannot be combined into one. > > > > > > Dionna what's your thought? > > > > > > Thanks > > > Min > > > > -- > -Dionna Glaze, PhD (she/her) -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#95050): https://edk2.groups.io/g/devel/message/95050 Mute This Topic: https://groups.io/mt/94229046/21656 Group Owner: [email protected] Unsubscribe: https://edk2.groups.io/g/devel/unsub [[email protected]] -=-=-=-=-=-=-=-=-=-=-=-
