On 10/1/21 12:35 PM, Stefan Hajnoczi wrote:

QEMU's TCG threads execute translated code. There are events that
require interrupting these threads. Today a check is performed at the
start of every translated block. Most of the time the check is false and
it's a waste of CPU.

User interrupts can eliminate the need for checks by interrupting TCG
threads when events occur.

We used to use interrupts, and stopped because we need to wait until the guest is in a 
stable state.  The guest is always in a stable state at the beginning of each TB.

See 378df4b2375.


r~