On 2025-10-28 13:46, Peter Maydell wrote:
On Sun, 29 Jun 2025 at 21:49, Bernhard Beschow <[email protected]> wrote:
Allows the imx8mp-evk machine to be run with KVM acceleration as a guest.
Signed-off-by: Bernhard Beschow <[email protected]>
---
docs/system/arm/imx8mp-evk.rst | 7 +++++++
hw/arm/fsl-imx8mp.c | 33 ++++++++++++++++++++++++++++-----
hw/arm/imx8mp-evk.c | 11 +++++++++++
hw/arm/Kconfig | 3 ++-
hw/arm/meson.build | 2 +-
5 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/docs/system/arm/imx8mp-evk.rst b/docs/system/arm/imx8mp-evk.rst
index b2f7d29ade..1399820163 100644
--- a/docs/system/arm/imx8mp-evk.rst
+++ b/docs/system/arm/imx8mp-evk.rst
@@ -60,3 +60,10 @@ Now that everything is prepared the machine can be started
as follows:
-dtb imx8mp-evk.dtb \
-append "root=/dev/mmcblk2p2" \
-drive file=sdcard.img,if=sd,bus=2,format=raw,id=mmcblk2
+
+
+KVM Virtualization
+------------------
+
+To enable hardware-assisted acceleration via KVM, append
+``-accel kvm -cpu host`` to the command line.
Coming back to this now we've resolved the "does this put
things inside our security-promises that we don't want"
question...
I think we should be a bit clearer in the documentation
about what tradeoffs the user is making here when they select
KVM. Specifically:
* we should note that this is intended only to improve
performance, and is not covered by QEMU's security policy
* we should say that you will not get a Cortex-A53, so any
guest code with tight dependencies on the host CPU type
might not work correctly
* we should say that the guest will only be able to run
at EL1, and (unlike TCG) there is no EL2 or EL3
diff --git a/hw/arm/fsl-imx8mp.c b/hw/arm/fsl-imx8mp.c
index 866f4d1d74..7e61392abb 100644
--- a/hw/arm/fsl-imx8mp.c
+++ b/hw/arm/fsl-imx8mp.c
@@ -12,11 +12,13 @@
#include "system/address-spaces.h"
#include "hw/arm/bsa.h"
#include "hw/arm/fsl-imx8mp.h"
-#include "hw/intc/arm_gicv3.h"
Why does this include get removed ?
#include "hw/misc/unimp.h"
#include "hw/boards.h"
+#include "system/kvm.h"
#include "system/system.h"
+#include "target/arm/cpu.h"
#include "target/arm/cpu-qom.h"
+#include "target/arm/kvm_arm.h"
#include "qapi/error.h"
#include "qobject/qlist.h"
diff --git a/hw/arm/meson.build b/hw/arm/meson.build
index d90be8f4c9..a4212a6ab2 100644
--- a/hw/arm/meson.build
+++ b/hw/arm/meson.build
@@ -59,7 +59,7 @@ arm_common_ss.add(when: 'CONFIG_MUSCA', if_true:
files('musca.c'))
arm_common_ss.add(when: 'CONFIG_ARMSSE', if_true: files('armsse.c'))
arm_common_ss.add(when: 'CONFIG_FSL_IMX7', if_true: files('fsl-imx7.c',
'mcimx7d-sabre.c'))
arm_common_ss.add(when: 'CONFIG_FSL_IMX8MP', if_true: files('fsl-imx8mp.c'))
-arm_common_ss.add(when: 'CONFIG_FSL_IMX8MP_EVK', if_true:
files('imx8mp-evk.c'))
+arm_ss.add(when: 'CONFIG_FSL_IMX8MP_EVK', if_true: files('imx8mp-evk.c'))
arm_common_ss.add(when: 'CONFIG_ARM_SMMUV3', if_true: files('smmuv3.c'))
arm_common_ss.add(when: 'CONFIG_FSL_IMX6UL', if_true: files('fsl-imx6ul.c',
'mcimx6ul-evk.c'))
arm_common_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_soc.c'))
Philippe, Pierrick: is it OK that this moves the
fsl-imx8p.c file from arm_common to arm_ss, or is there
a preferable way to do this from a single-binary point
of view?
Looking at original patch, this is needed because an ifdef CONFIG_KVM is
introduced.
static void imx8mp_evk_machine_init(MachineClass *mc)
{
+ static const char *const valid_cpu_types[] = {
+ ARM_CPU_TYPE_NAME("cortex-a53"),
+#ifdef CONFIG_KVM
+ ARM_CPU_TYPE_NAME("host"),
+#endif /* CONFIG_KVM */
+ NULL
+ };
+
This is not needed, and valid_cpu_types array can be dynamically
created, adding "host" only if kvm_enabled().
See this patch for reference:
https://lore.kernel.org/qemu-devel/[email protected]/
thanks
-- PMM
Pierrick
