qemu-e2k/softmmu
Peter Maydell 5202861b20 semihosting: Allow optional use of semihosting from userspace
Currently our semihosting implementations generally prohibit use of
semihosting calls in system emulation from the guest userspace.  This
is a very long standing behaviour justified originally "to provide
some semblance of security" (since code with access to the
semihosting ABI can do things like read and write arbitrary files on
the host system).  However, it is sometimes useful to be able to run
trusted guest code which performs semihosting calls from guest
userspace, notably for test code.  Add a command line suboption to
the existing semihosting-config option group so that you can
explicitly opt in to semihosting from guest userspace with
 -semihosting-config userspace=on

(There is no equivalent option for the user-mode emulator, because
there by definition all code runs in userspace and has access to
semihosting already.)

This commit adds the infrastructure for the command line option and
adds a bool 'is_user' parameter to the function
semihosting_userspace_enabled() that target code can use to check
whether it should be permitting the semihosting call for userspace.
It mechanically makes all the callsites pass 'false', so they
continue checking "is semihosting enabled in general".  Subsequent
commits will make each target that implements semihosting honour the
userspace=on option by passing the correct value and removing
whatever "don't do this for userspace" checking they were doing by
hand.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220822141230.3658237-2-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-09-13 17:18:21 +01:00
..
arch_init.c
balloon.c
bootdevice.c machine: use QAPI struct for boot configuration 2022-05-12 12:29:43 +02:00
cpu-throttle.c
cpu-timers.c
cpus.c whpx: Added support for breakpoints and stepping 2022-04-06 14:31:55 +02:00
datadir.c meson: Prefix each element of firmware path 2022-07-13 16:58:57 +02:00
device_tree.c
dirtylimit.c softmmu/dirtylimit: Implement dirty page rate limit 2022-07-20 12:15:08 +01:00
dma-helpers.c
globals.c ui: Switch "-display sdl" to use the QAPI parser 2022-06-03 08:03:28 +02:00
icount.c replay: rewrite async event handling 2022-06-06 09:26:53 +02:00
ioport.c
main.c qapi: Add exit-failure PanicAction 2022-07-29 09:48:01 +01:00
memory_mapping.c
memory.c
meson.build softmmu/dirtylimit: Implement vCPU dirtyrate calculation periodically 2022-07-20 12:15:08 +01:00
physmem.c accel/tcg: Move qemu_ram_addr_from_host_nofail to physmem.c 2022-09-06 08:04:26 +01:00
qdev-monitor.c qdev: unplug blocker for devices 2022-06-15 14:50:41 +01:00
qemu-seccomp.c
qtest.c
rtc.c
runstate-action.c
runstate.c qapi: Add exit-failure PanicAction 2022-07-29 09:48:01 +01:00
timers-state.h
tpm.c
trace-events softmmu/dirtylimit: Implement virtual CPU throttle 2022-07-20 12:15:08 +01:00
trace.h
vl.c semihosting: Allow optional use of semihosting from userspace 2022-09-13 17:18:21 +01:00