We have to relocate based upon best practice. The mailbox must be in ACPI-NVS. And the ACPI-NVS should be in high memory.
The original mailbox location is in low memory. If we do not relocate to high memory, then the OS will see a hole in low memory. That is not preferred. Thank you Yao Jiewen > -----Original Message----- > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Gerd > Hoffmann > Sent: Wednesday, October 13, 2021 12:49 PM > To: devel@edk2.groups.io; Xu, Min M <min.m...@intel.com> > Cc: Ard Biesheuvel <ardb+tianoc...@kernel.org>; Justen, Jordan L > <jordan.l.jus...@intel.com>; Brijesh Singh <brijesh.si...@amd.com>; Erdem > Aktas <erdemak...@google.com>; James Bottomley <j...@linux.ibm.com>; > Yao, Jiewen <jiewen....@intel.com>; Tom Lendacky > <thomas.lenda...@amd.com> > Subject: Re: [edk2-devel] [PATCH V2 21/28] OvmfPkg: Update PlatformPei to > support TDX > > Hi, > > > 2. Relocate mailbox > > At the beginning of system boot, a 4K-aligned, 4K-size memory (Td > > mailbox) is pre-allocated by host VMM. BSP & APs do the page accept > > together in that memory region. > > After that TDVF is designed to relocate the mailbox to a 4K-aligned, > > 4K-size memory block which is allocated in the ACPI Nvs memory. APs > > are waken up and spin around the relocated mailbox waiting for > > further command. > > Why is the mailbox relocated? Are there any problems when simply > continuing to use the memfd page? > > The memfd page location is known to qemu, so when not relocating the > mailbox the MADT update could be done on the host side. > > take care, > Gerd > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#82073): https://edk2.groups.io/g/devel/message/82073 Mute This Topic: https://groups.io/mt/86085763/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
