Re: [PATCH v2 08/50] target/i386: Assert IOPL is 0 for user-only

2021-05-18 Thread Paolo Bonzini
On 14/05/21 17:13, Richard Henderson wrote: On real hardware, the linux kernel has the iopl(2) syscall which can set IOPL to 3, to allow e.g. the xserver to briefly disable interrupts while programming the graphics card. However, QEMU cannot and does not implement this syscall, so the IOPL is ne

[PATCH v2 08/50] target/i386: Assert IOPL is 0 for user-only

2021-05-14 Thread Richard Henderson
On real hardware, the linux kernel has the iopl(2) syscall which can set IOPL to 3, to allow e.g. the xserver to briefly disable interrupts while programming the graphics card. However, QEMU cannot and does not implement this syscall, so the IOPL is never changed from 0. Which means that all of t