Comment 14 for bug 1821595

Hi. I didnt build Qemu but I downloaded the last version 5.1.0 from https://qemu.weilnetz.de/w64/ and the error "Failed to emulate MMIO access with EmulatorReturnStatus: 2" happens when I use -drive if=pflash or -pflash with -accel whpx.

"qemu-system-x86_64.exe -pflash d:\macWIN\OVMF_CODE.fd -accel whpx
Windows Hypervisor Platform accelerator is operational
qemu-system-x86_64.exe: WHPX: Failed to emulate MMIO access with EmulatorReturnStatus: 2
qemu-system-x86_64.exe: WHPX: Failed to exec a virtual processor"

If I remove pflash and change to -bios "ovmf" the machine works.
qemu-system-x86_64.exe -bios d:\macWIN\OVMF_CODE.fd -accel whpx

If I maintain pflash but remove -accel whpx the machine works too.
qemu-system-x86_64.exe -pflash d:\macWIN\OVMF_CODE.fd