The ID mapping routines on virtual platforms simply map the entire address space as device memory, and then punch some holes for regions that need to be mapped cacheable. On virtual platforms hosted on CPUs that support a large physical address range, this may result in a lot of overhead, i.e., 4 KB of page tables for each 512 GB of address space, which quickly adds up (i.e. 2 MB for the architectural maximum of 48 bits).
Since there may be a platform specific limit to the size of the (I)PA space that is not reflected by CPU id registers, restrict the range of the ID mapping to gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize bits, since we cannot manipulate mappings above that limit anwyay (because they are not covered by GCD). This allows the PCD to be set by platforms whose (I)PA space has a fixed limit. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> --- ArmVirtPkg/Library/ArmVirtPlatformLib/ArmVirtPlatformLib.inf | 1 + ArmVirtPkg/Library/ArmVirtPlatformLib/VirtMem.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/ArmVirtPkg/Library/ArmVirtPlatformLib/ArmVirtPlatformLib.inf b/ArmVirtPkg/Library/ArmVirtPlatformLib/ArmVirtPlatformLib.inf index 22ee3625c37a..3cb3fb1f3aea 100644 --- a/ArmVirtPkg/Library/ArmVirtPlatformLib/ArmVirtPlatformLib.inf +++ b/ArmVirtPkg/Library/ArmVirtPlatformLib/ArmVirtPlatformLib.inf @@ -61,3 +61,4 @@ [FixedPcd] gArmTokenSpaceGuid.PcdArmPrimaryCore gArmTokenSpaceGuid.PcdFdBaseAddress gArmTokenSpaceGuid.PcdFdSize + gEmbeddedTokenSpaceGuid.PcdPrePiCpuMemorySize diff --git a/ArmVirtPkg/Library/ArmVirtPlatformLib/VirtMem.c b/ArmVirtPkg/Library/ArmVirtPlatformLib/VirtMem.c index 530f7d608e0b..e5536ecd8e28 100644 --- a/ArmVirtPkg/Library/ArmVirtPlatformLib/VirtMem.c +++ b/ArmVirtPkg/Library/ArmVirtPlatformLib/VirtMem.c @@ -97,7 +97,9 @@ ArmPlatformGetVirtualMemoryMap ( // Peripheral space after DRAM VirtualMemoryTable[2].PhysicalBase = VirtualMemoryTable[0].Length + VirtualMemoryTable[1].Length; VirtualMemoryTable[2].VirtualBase = VirtualMemoryTable[2].PhysicalBase; - VirtualMemoryTable[2].Length = ArmGetPhysAddrTop () - VirtualMemoryTable[2].PhysicalBase; + VirtualMemoryTable[2].Length = MIN (1ULL << FixedPcdGet8 (PcdPrePiCpuMemorySize), + ArmGetPhysAddrTop ()) - + VirtualMemoryTable[2].PhysicalBase; VirtualMemoryTable[2].Attributes = ARM_MEMORY_REGION_ATTRIBUTE_DEVICE; // Remap the FD region as normal executable memory -- 1.9.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
