mirror of
https://github.com/FEX-Emu/FEX.git
synced 2026-10-06 14:00:16 +02:00
Ryan Houdek
4cf48ca9bb
Exposes the host architecture through this CPUID function. Only exposes the architectures we support. Not burning 16-bits on using ELF machine definitions here. Uses 4 bits still for future expansion.
41 lines
1.2 KiB
Markdown
41 lines
1.2 KiB
Markdown
# FEXCore custom CPUID functions
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## 4000_0000h - Hypervisor information function
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* Follows VMWare and Microsoft's hypervisor information proposal
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* https://lwn.net/Articles/301888/
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* https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/feature-discovery
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* EAX - The maximum input value for the hypervisor CPUID information
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* 4000_0001h
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* EBX - Hypervisor vendor ID signature
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* 'FEXI' - 4958_4546h
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* ECX - Hypervisor vendor ID signature
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* 'FEXI' - 4958_4546h
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* EDX - Hypervisor vendor ID signature
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* 'EMU\0' - 0055_4d45h
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* memcpy ebx:ecx:edx in to a 12 byte string to get 'FEXIFEXIEMU\0' for determining running under FEX
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## 4000_0001h - Hypervisor config function
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### Sub-Leaf 0: ECX == 0
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* EAX:
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* Bits EAX[3:0] - Host architecture
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* 0 - Unknown architecture
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* 1 - x86_64
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* 2 - AArch64
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* 3-15: **Reserved**
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* EBX - **Reserved** - Read as zero
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* ECX - **Reserved** - Read as zero
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* EDX - **Reserved** - Read as zero
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### Sub-Leaf 0000_0001 - FFFF_FFFF: **Reserved**
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## 4000_0002h - 4000_000Fh
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* **Reserved range**
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* Returns zero until implemented
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## 4000_0010h - 4FFF_FFFFh
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* **Undefined**
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* FEX-Emu will return zero until implemented
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