QEMU on x64

[Christopher Caulfield]

Hi QEMU community,

This is Christopher from the debugging experiences team at Microsoft focused on kernel debugging. I am reaching out with a few questions about QEMU on x64.

1. Is it possible for the QEMU-x86-64 GDB Server to send the full set of x64 system registers (whether they are included in a separated system xml file or as part of the core registers xml file)?
• e.g. System registers missing from i386-64bit.xml file
  
  DWORD64 IDTBase;
  DWORD64 IDTLimit;
  DWORD64 GDTBase;
  DWORD64 GDTLimit;
  DWORD SelLDT;
  SEG64_DESC_INFO SegLDT;
  DWORD SelTSS;
  SEG64_DESC_INFO SegTSS;
  
2. How can I access x64 MSR registers by using the QEMU-x86-64 GDB server?
• #define MSR_EFER 0xc0000080 // extended function enable register
  #define MSR_STAR 0xc0000081 // system call selectors
  #define MSR_LSTAR 0xc0000082 // system call 64-bit entry
  #define MSR_CSTAR 0xc0000083 // system call 32-bit entry
3. Going off of #2 - can you access it via reading GDB memory command? if not - is there any plan to support reading/writing to MSRs via QEMU-x86-64 GDB server?
   

Thank you for taking time to answer our questions! :)

-Christopher

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