[OE-core] [PATCH] runqemu: Add workaround for APIC hang on pre 4.15 kernels on qemux86

[Richard Purdie]

On pre 4.15 host kernels, an APIC window emulation bug can cause qemu
to hang. On 64 bit we can use the x2apic, for 32 bit, we just have to
disable the other timer sources and rely on kvm-clock.

[YOCTO #12301]

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
 scripts/runqemu | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/scripts/runqemu b/scripts/runqemu
index f2b4b3c..d998494 100755
--- a/scripts/runqemu
+++ b/scripts/runqemu
@@ -510,6 +510,11 @@ class BaseConfig(object):
 
         if os.access(dev_kvm, os.W_OK|os.R_OK):
             self.qemu_opt_script += ' -enable-kvm'
+            if self.get('MACHINE') == "qemux86":
+                # Workaround for broken APIC window on pre 4.15 host kernels which causes boot hangs
+                # See YOCTO #12301
+                # On 64 bit we use x2apic
+                self.kernel_cmdline_script += " clocksource=kvm-clock hpet=disable noapic nolapic"
         else:
             logger.error("You have no read or write permission on /dev/kvm.")
             logger.error("Please change the ownership of this file as described at:")
-- 
2.7.4