On 21 March 2018 at 19:07, Girish Pathak <girish.pat...@arm.com> wrote: > > >> -----Original Message----- >> From: Ard Biesheuvel [mailto:ard.biesheu...@linaro.org] >> Sent: 21 March 2018 03:38 >> To: Girish Pathak <girish.pat...@arm.com> >> Cc: edk2-devel@lists.01.org; Leif Lindholm <leif.lindh...@linaro.org>; >> Matteo Carlini <matteo.carl...@arm.com>; Stephanie Hughes-Fitt >> <stephanie.hughes-f...@arm.com>; nd <n...@arm.com>; Arvind Chauhan >> <arvind.chau...@arm.com>; Daniil Egranov <daniil.egra...@arm.com>; >> Thomas Abraham <thomas.abra...@arm.com> >> Subject: Re: [PATCH edk2-platforms v3 12/17] ARM/VExpressPkg: Allocate >> framebuffer using EfiRuntimeServicesData >> >> On 21 March 2018 at 00:18, Girish Pathak <girish.pat...@arm.com> wrote: >> > As per the UEFI specification(2.7) section 12.9, the GOP framebuffer >> > memory can be accessed in the pre-boot and the post boot phase (by OS) >> > Therefore the memory type EfiBootServicesData is incorrect for the >> > framebuffer memory allocation. Change EfiBootServicesData with >> > EfiRuntimeServicesData flag so that allocated memory can be access by >> > the OS in the post boot phase. >> > >> >> EfiRuntimeServicesData is intended for allocations that the EFI runtime >> services need to access themselves at runtime, and will hence be virtually >> remapped by SetVirtualAddressMap(). >> >> This does not apply to the framebuffer. Even if it may be used at OS runtime, >> the firmware itself will never access it, so EfiRuntimeServicesData is not >> appropriate >> >> Please use EfiReservedMemory instead. > > Specification (UEFI Spec 2_7_A Sept 6.pdf) describes EfiReservedMemoryType as > Not usable before and after ExitBootServices, See Table 28 & 29 > Hence EfiReservedMemoryType is not suitable in this case. Agree? >
It is not usable as ordinary memory, given that you turn it into 'special' memory (with side effects) by turning it into a framebuffer. So EfiReservedMemory is perfectly appropriate here. _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
