qemu arm: fix boot with -M virt,highmem=off

README.adoc

@@ -2436,18 +2436,6 @@ Bibliography:
 
 === arm
 
-QEMU 3.0.0-rc3 and 3.0.0-rc4 boot failing: http://lists.nongnu.org/archive/html/qemu-discuss/2018-08/msg00030.html
-
-....
-<4>[    0.723878] VFS: Cannot open root device "vda" or unknown-block(0,0): error -6
-<4>[    0.724096] Please append a correct "root=" boot option; here are the available partitions:
-<4>[    0.724585] 1f00          131072 mtdblock0
-<4>[    0.724632]  (driver?)
-<0>[    0.724998] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
-....
-
-Workaround for now by going back to QEMU v2.12.0 with <<qemu-build-variants>>.
-
 ==== Run arm executable in aarch64
 
 TODO Can you run arm executables in the aarch64 guest? https://stackoverflow.com/questions/22460589/armv8-running-legacy-32-bit-applications-on-64-bit-os/51466709#51466709
@@ -9468,7 +9456,7 @@ However, for many types of crashes, it is trivial to bisect down to the offendin
 
 For example, when updating from QEMU `v2.12.0` to `v3.0.0-rc3`, the Linux kernel boot started to panic for `arm`.
 
-We then bisected it as explained at: https://stackoverflow.com/questions/4713088/how-to-use-git-bisect with the link:qemu-bisect-boot[] script:
+We then bisected it as explained at: https://stackoverflow.com/questions/4713088/how-to-use-git-bisect/22592593#22592593 with the link:qemu-bisect-boot[] script:
 
 ....
 cd qemu

run

@@ -350,9 +350,11 @@ ${qemu_common}\
       else
         cpu=cortex-a57
       fi
+      # highmem=off needed since v3.0.0 due to:
+      # http://lists.nongnu.org/archive/html/qemu-discuss/2018-08/msg00034.html
       cmd="\
 ${qemu_common}\
--M virt \\
+-M virt,highmem=off \\
 -append '${root} ${extra_append}' \\
 -cpu "$cpu" \\
 ${virtio_gpu_pci}\