On Thu, 24 Jun 2021 at 18:09, Steven Raasch <sraa...@gmail.com> wrote: > NOTE: I do not yet understand how gdb interacts with the virtual machine. I > have experience with GDB, but only at a linux app-debug level. I don't grok > how gdb on a linux host works with QEMU running a windows guest. > My *assumption* is that the VM continues to run while an app is being > debugged with GDB can be stopped, stepped, etc. If this is the case, I would > expect that the VM's sense of time will continue to move forward while the > app is paused. This would be an issue for my time-sensitive app.
No, that's not how it works. A gdb connected to QEMU's gdbstub is a bit like a hardware JTAG debugger connected to a real CPU, if that helps. When gdb gets control the entire VM is stopped; stepping steps one instruction of whatever the VM is doing. gdb and the gdbstub have no understanding of individual processes running inside the guest OS -- single stepping will happily step through the app, into interrupt handlers, across the OS context switching and into other processes, etc. -- PMM
