[gnome-build-meta.wiki] Update Bootable images in virtual machines - note that `-cpu host` is required

[Sam Thursfield <sthursfield src gnome org>]

commit 534f73e7195b36ad57ebfb654de1c988ee606559
Author: Sam Thursfield <sam afuera me uk>
Date:   Wed Aug 11 12:37:40 2021 +0000

    Update Bootable images in virtual machines - note that `-cpu host` is required

 Bootable-images-in-virtual-machines.md | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/Bootable-images-in-virtual-machines.md b/Bootable-images-in-virtual-machines.md
index 8f4e04f..1d16aa0 100644
--- a/Bootable-images-in-virtual-machines.md
+++ b/Bootable-images-in-virtual-machines.md
@@ -70,7 +70,7 @@ Then, run with QEMU:
 
 ```
 qemu-system-x86_64 \
-  -enable-kvm -m 4G -smp 4 -machine q35,accel=kvm \
+  -enable-kvm -m 4G -smp 4 -machine q35,accel=kvm -cpu host \
   -drive if=pflash,format=raw,unit=0,file=/usr/share/OVMF/OVMF_CODE.fd,readonly=on \
   -drive if=pflash,format=raw,unit=1,file=OVMF_VARS.fd \
   -display gtk,gl=on -vga virtio \
@@ -101,7 +101,7 @@ Then run with QEMU:
 
 ```
 qemu-system-x86_64 \
-  -enable-kvm -m 4G -smp 4 -machine q35,accel=kvm \
+  -enable-kvm -m 4G -smp 4 -machine q35,accel=kvm -cpu host \
   -drive if=pflash,format=raw,unit=0,file=/usr/share/OVMF/OVMF_CODE.fd,readonly=on \
   -drive if=pflash,format=raw,unit=1,file=OVMF_VARS.fd \
   -display gtk,gl=on -vga virtio \
@@ -116,7 +116,7 @@ After installation re-launch QEMU, but remove the last drive (CD-ROM).
 
 ```
 qemu-system-x86_64 \
-  -enable-kvm -m 4G -smp 4 -machine q35,accel=kvm \
+  -enable-kvm -m 4G -smp 4 -machine q35,accel=kvm -cpu host \
   -drive if=pflash,format=raw,unit=0,file=/usr/share/OVMF/OVMF_CODE.fd,readonly=on \
   -drive if=pflash,format=raw,unit=1,file=OVMF_VARS.fd \
   -display gtk,gl=on -vga virtio \
@@ -162,6 +162,8 @@ qemu-img create -f qcow2 disk.qcow2 64G
 
 For x86_64 with KVM: `-enable-kvm -machine q35,accel=kvm`
 
+Use same CPU architecture as host: `-cpu host`  (the default can be a basic one that doesn't support all 
instructions modern compilers use, leading to SIGILL crashes)
+
 UEFI boot:
 
 ```