I am trying some bare metal program on cortex-M4 processor. So I try to find a QEMU virtual platform that can work with cortex-M4.
My QEMU:
QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.30)
Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers
Below command shows the cortex-M4 is one of the available CPUs for the virt platform. Btw, I chose virt because it seems to have a flexible cpu configuration.
xxx@box01:~/dev$ qemu-system-arm -machine virt -cpu help
Available CPUs:
arm1026
arm1136
arm1136-r2
arm1176
arm11mpcore
arm926
arm946
cortex-a15 <==== supported
cortex-a7 <==== supported
cortex-a8
cortex-a9
cortex-m0
cortex-m3
cortex-m33
cortex-m4 <==== listed but unsupported
cortex-r5
cortex-r5f
max <==== supported
pxa250
pxa255
pxa260
pxa261
pxa262
pxa270-a0
pxa270-a1
pxa270
pxa270-b0
pxa270-b1
pxa270-c0
pxa270-c5
sa1100
sa1110
ti925t
But when I try to run below combination of virt + cortex-M4, it says unsupported.
xxx@box01:~/dev$ qemu-system-arm -M virt -cpu cortex-m4 -kernel build/kernel.elf
qemu-system-arm: mach-virt: CPU type cortex-m4-arm-cpu not supported
Why?
(I also tried a few other CPUs, seems only a few are supported.)
I cannot query CPU directly.
xxx@box01:~/dev$ qemu-system-arm -cpu help
qemu-system-arm: No machine specified, and there is no default
Use -machine help to list supported machines
But when I query cpu with another machine using -M option, I got exactly the same list of available CPUs.
Then I randomly picked one machine netduino2, it can work with cortex-M4. But I don't know if it is REALLY OK to do so based on the above query experience...
xxx@box01:~/dev$ qemu-system-arm -M netduino2 -cpu cortex-m4 -kernel build/kernel.elf
The page for the netduino2 list several machines. But with qemu-arm-system -M help I can only see the netduino2. I guess it is because my QEMU is not the latest. So I try to install the latest version from the latest source.
I am using Ubuntu 20.04.6 LTS. Below are my steps:
sudo apt install flex bison
pip3 install standard-imghdr
# install QEMU (due to the glib mismatch on my ubuntu version, I cannot build the latest 10.0.0)
wget https://download.qemu.org/qemu-8.2.10.tar.xz
tar -xvf qemu-8.2.10.tar.xz
cd qemu-8.2.10
./configure
make
sudo make install
The old QEMU 4.2.1 supports below machines:
xxx@box01:~/dev$ /usr/bin/qemu-system-arm --version
QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.30)
Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers
xxx@box01:~/dev$ qemu-system-arm -M help
Supported machines are:
akita Sharp SL-C1000 (Akita) PDA (PXA270)
ast2500-evb Aspeed AST2500 EVB (ARM1176)
ast2600-evb Aspeed AST2600 EVB (Cortex A7)
borzoi Sharp SL-C3100 (Borzoi) PDA (PXA270)
canon-a1100 Canon PowerShot A1100 IS
cheetah Palm Tungsten|E aka. Cheetah PDA (OMAP310)
collie Sharp SL-5500 (Collie) PDA (SA-1110)
connex Gumstix Connex (PXA255)
cubieboard cubietech cubieboard (Cortex-A8)
emcraft-sf2 SmartFusion2 SOM kit from Emcraft (M2S010)
highbank Calxeda Highbank (ECX-1000)
imx25-pdk ARM i.MX25 PDK board (ARM926)
integratorcp ARM Integrator/CP (ARM926EJ-S)
kzm ARM KZM Emulation Baseboard (ARM1136)
lm3s6965evb Stellaris LM3S6965EVB
lm3s811evb Stellaris LM3S811EVB
mainstone Mainstone II (PXA27x)
mcimx6ul-evk Freescale i.MX6UL Evaluation Kit (Cortex A7)
mcimx7d-sabre Freescale i.MX7 DUAL SABRE (Cortex A7)
microbit BBC micro:bit
midway Calxeda Midway (ECX-2000)
mps2-an385 ARM MPS2 with AN385 FPGA image for Cortex-M3
mps2-an505 ARM MPS2 with AN505 FPGA image for Cortex-M33
mps2-an511 ARM MPS2 with AN511 DesignStart FPGA image for Cortex-M3
mps2-an521 ARM MPS2 with AN521 FPGA image for dual Cortex-M33
musca-a ARM Musca-A board (dual Cortex-M33)
musca-b1 ARM Musca-B1 board (dual Cortex-M33)
musicpal Marvell 88w8618 / MusicPal (ARM926EJ-S)
n800 Nokia N800 tablet aka. RX-34 (OMAP2420)
n810 Nokia N810 tablet aka. RX-44 (OMAP2420)
netduino2 Netduino 2 Machine
none empty machine
nuri Samsung NURI board (Exynos4210)
palmetto-bmc OpenPOWER Palmetto BMC (ARM926EJ-S)
raspi2 Raspberry Pi 2
realview-eb ARM RealView Emulation Baseboard (ARM926EJ-S)
realview-eb-mpcore ARM RealView Emulation Baseboard (ARM11MPCore)
realview-pb-a8 ARM RealView Platform Baseboard for Cortex-A8
realview-pbx-a9 ARM RealView Platform Baseboard Explore for Cortex-A9
romulus-bmc OpenPOWER Romulus BMC (ARM1176)
sabrelite Freescale i.MX6 Quad SABRE Lite Board (Cortex A9)
smdkc210 Samsung SMDKC210 board (Exynos4210)
spitz Sharp SL-C3000 (Spitz) PDA (PXA270)
swift-bmc OpenPOWER Swift BMC (ARM1176)
sx1 Siemens SX1 (OMAP310) V2
sx1-v1 Siemens SX1 (OMAP310) V1
terrier Sharp SL-C3200 (Terrier) PDA (PXA270)
tosa Sharp SL-6000 (Tosa) PDA (PXA255)
verdex Gumstix Verdex (PXA270)
versatileab ARM Versatile/AB (ARM926EJ-S)
versatilepb ARM Versatile/PB (ARM926EJ-S)
vexpress-a15 ARM Versatile Express for Cortex-A15
vexpress-a9 ARM Versatile Express for Cortex-A9
virt-2.10 QEMU 2.10 ARM Virtual Machine
virt-2.11 QEMU 2.11 ARM Virtual Machine
virt-2.12 QEMU 2.12 ARM Virtual Machine
virt-2.6 QEMU 2.6 ARM Virtual Machine
virt-2.7 QEMU 2.7 ARM Virtual Machine
virt-2.8 QEMU 2.8 ARM Virtual Machine
virt-2.9 QEMU 2.9 ARM Virtual Machine
virt-3.0 QEMU 3.0 ARM Virtual Machine
virt-3.1 QEMU 3.1 ARM Virtual Machine
virt-4.0 QEMU 4.0 ARM Virtual Machine
virt-4.1 QEMU 4.1 ARM Virtual Machine
virt QEMU 4.2 ARM Virtual Machine (alias of virt-4.2)
virt-4.2 QEMU 4.2 ARM Virtual Machine
witherspoon-bmc OpenPOWER Witherspoon BMC (ARM1176)
xilinx-zynq-a9 Xilinx Zynq Platform Baseboard for Cortex-A9
z2 Zipit Z2 (PXA27x)
The newly built QEMU 8.2.10 provides much more machines, which include the netduinoplus2 with Cortex-M4.
xxx@box01:~/dev$ /usr/local/bin/qemu-system-arm --version
QEMU emulator version 8.2.10
Copyright (c) 2003-2023 Fabrice Bellard and the QEMU Project developers
xxx@box01:~/dev$ qemu-system-arm -M help
Supported machines are:
akita Sharp SL-C1000 (Akita) PDA (PXA270)
ast1030-evb Aspeed AST1030 MiniBMC (Cortex-M4)
ast2500-evb Aspeed AST2500 EVB (ARM1176)
ast2600-evb Aspeed AST2600 EVB (Cortex-A7)
bletchley-bmc Facebook Bletchley BMC (Cortex-A7)
borzoi Sharp SL-C3100 (Borzoi) PDA (PXA270)
bpim2u Bananapi M2U (Cortex-A7)
canon-a1100 Canon PowerShot A1100 IS (ARM946)
cheetah Palm Tungsten|E aka. Cheetah PDA (OMAP310)
collie Sharp SL-5500 (Collie) PDA (SA-1110)
connex Gumstix Connex (PXA255)
cubieboard cubietech cubieboard (Cortex-A8)
emcraft-sf2 SmartFusion2 SOM kit from Emcraft (M2S010)
fby35-bmc Facebook fby35 BMC (Cortex-A7)
fby35 Meta Platforms fby35
fp5280g2-bmc Inspur FP5280G2 BMC (ARM1176)
fuji-bmc Facebook Fuji BMC (Cortex-A7)
g220a-bmc Bytedance G220A BMC (ARM1176)
highbank Calxeda Highbank (ECX-1000)
imx25-pdk ARM i.MX25 PDK board (ARM926)
integratorcp ARM Integrator/CP (ARM926EJ-S)
kudo-bmc Kudo BMC (Cortex-A9)
kzm ARM KZM Emulation Baseboard (ARM1136)
lm3s6965evb Stellaris LM3S6965EVB (Cortex-M3)
lm3s811evb Stellaris LM3S811EVB (Cortex-M3)
mainstone Mainstone II (PXA27x)
mcimx6ul-evk Freescale i.MX6UL Evaluation Kit (Cortex-A7)
mcimx7d-sabre Freescale i.MX7 DUAL SABRE (Cortex-A7)
microbit BBC micro:bit (Cortex-M0)
midway Calxeda Midway (ECX-2000)
mori-bmc Mori BMC (Cortex-A9)
mps2-an385 ARM MPS2 with AN385 FPGA image for Cortex-M3
mps2-an386 ARM MPS2 with AN386 FPGA image for Cortex-M4
mps2-an500 ARM MPS2 with AN500 FPGA image for Cortex-M7
mps2-an505 ARM MPS2 with AN505 FPGA image for Cortex-M33
mps2-an511 ARM MPS2 with AN511 DesignStart FPGA image for Cortex-M3
mps2-an521 ARM MPS2 with AN521 FPGA image for dual Cortex-M33
mps3-an524 ARM MPS3 with AN524 FPGA image for dual Cortex-M33
mps3-an547 ARM MPS3 with AN547 FPGA image for Cortex-M55
musca-a ARM Musca-A board (dual Cortex-M33)
musca-b1 ARM Musca-B1 board (dual Cortex-M33)
musicpal Marvell 88w8618 / MusicPal (ARM926EJ-S)
n800 Nokia N800 tablet aka. RX-34 (OMAP2420)
n810 Nokia N810 tablet aka. RX-44 (OMAP2420)
netduino2 Netduino 2 Machine (Cortex-M3)
netduinoplus2 Netduino Plus 2 Machine (Cortex-M4)
none empty machine
npcm750-evb Nuvoton NPCM750 Evaluation Board (Cortex-A9)
nuri Samsung NURI board (Exynos4210)
olimex-stm32-h405 Olimex STM32-H405 (Cortex-M4)
orangepi-pc Orange Pi PC (Cortex-A7)
palmetto-bmc OpenPOWER Palmetto BMC (ARM926EJ-S)
qcom-dc-scm-v1-bmc Qualcomm DC-SCM V1 BMC (Cortex A7)
qcom-firework-bmc Qualcomm DC-SCM V1/Firework BMC (Cortex A7)
quanta-gbs-bmc Quanta GBS (Cortex-A9)
quanta-gsj Quanta GSJ (Cortex-A9)
quanta-q71l-bmc Quanta-Q71l BMC (ARM926EJ-S)
rainier-bmc IBM Rainier BMC (Cortex-A7)
raspi0 Raspberry Pi Zero (revision 1.2)
raspi1ap Raspberry Pi A+ (revision 1.1)
raspi2b Raspberry Pi 2B (revision 1.1)
realview-eb ARM RealView Emulation Baseboard (ARM926EJ-S)
realview-eb-mpcore ARM RealView Emulation Baseboard (ARM11MPCore)
realview-pb-a8 ARM RealView Platform Baseboard for Cortex-A8
realview-pbx-a9 ARM RealView Platform Baseboard Explore for Cortex-A9
romulus-bmc OpenPOWER Romulus BMC (ARM1176)
sabrelite Freescale i.MX6 Quad SABRE Lite Board (Cortex-A9)
smdkc210 Samsung SMDKC210 board (Exynos4210)
sonorapass-bmc OCP SonoraPass BMC (ARM1176)
spitz Sharp SL-C3000 (Spitz) PDA (PXA270)
stm32vldiscovery ST STM32VLDISCOVERY (Cortex-M3)
supermicro-x11spi-bmc Supermicro X11 SPI BMC (ARM1176)
supermicrox11-bmc Supermicro X11 BMC (ARM926EJ-S)
sx1 Siemens SX1 (OMAP310) V2
sx1-v1 Siemens SX1 (OMAP310) V1
tacoma-bmc OpenPOWER Tacoma BMC (Cortex-A7)
terrier Sharp SL-C3200 (Terrier) PDA (PXA270)
tiogapass-bmc Facebook Tiogapass BMC (ARM1176)
tosa Sharp SL-6000 (Tosa) PDA (PXA255)
verdex Gumstix Verdex Pro XL6P COMs (PXA270)
versatileab ARM Versatile/AB (ARM926EJ-S)
versatilepb ARM Versatile/PB (ARM926EJ-S)
vexpress-a15 ARM Versatile Express for Cortex-A15
vexpress-a9 ARM Versatile Express for Cortex-A9
virt-2.10 QEMU 2.10 ARM Virtual Machine
virt-2.11 QEMU 2.11 ARM Virtual Machine
virt-2.12 QEMU 2.12 ARM Virtual Machine
virt-2.6 QEMU 2.6 ARM Virtual Machine
virt-2.7 QEMU 2.7 ARM Virtual Machine
virt-2.8 QEMU 2.8 ARM Virtual Machine
virt-2.9 QEMU 2.9 ARM Virtual Machine
virt-3.0 QEMU 3.0 ARM Virtual Machine
virt-3.1 QEMU 3.1 ARM Virtual Machine
virt-4.0 QEMU 4.0 ARM Virtual Machine
virt-4.1 QEMU 4.1 ARM Virtual Machine
virt-4.2 QEMU 4.2 ARM Virtual Machine
virt-5.0 QEMU 5.0 ARM Virtual Machine
virt-5.1 QEMU 5.1 ARM Virtual Machine
virt-5.2 QEMU 5.2 ARM Virtual Machine
virt-6.0 QEMU 6.0 ARM Virtual Machine
virt-6.1 QEMU 6.1 ARM Virtual Machine
virt-6.2 QEMU 6.2 ARM Virtual Machine
virt-7.0 QEMU 7.0 ARM Virtual Machine
virt-7.1 QEMU 7.1 ARM Virtual Machine
virt-7.2 QEMU 7.2 ARM Virtual Machine
virt-8.0 QEMU 8.0 ARM Virtual Machine
virt-8.1 QEMU 8.1 ARM Virtual Machine
virt QEMU 8.2 ARM Virtual Machine (alias of virt-8.2)
virt-8.2 QEMU 8.2 ARM Virtual Machine
witherspoon-bmc OpenPOWER Witherspoon BMC (ARM1176)
xilinx-zynq-a9 Xilinx Zynq Platform Baseboard for Cortex-A9
yosemitev2-bmc Facebook YosemiteV2 BMC (ARM1176)
z2 Zipit Z2 (PXA27x)
The virt documentation page you linked has a list of supported CPUs, and Cortex-M4 isn't among them. The corresponding page for netduino shows Cortex-M4 as supported. So presumably those pages are your source for which CPUs are supported for each board (or if all else fails, the QEMU source code).
I agree the behavior of -cpu help is a bit confusing. You could open an issue to suggest it be enhanced.