On 25/10/2023 7:26 pm, David Woodhouse wrote: > On Wed, 2023-10-25 at 13:20 -0500, Eric Blake wrote: >> On Wed, Oct 25, 2023 at 03:50:42PM +0100, David Woodhouse wrote: >>> + >>> +Booting Xen PV guests >>> +--------------------- >>> + >>> +Booting PV guest kernels is possible by using the Xen PV shim (a version >>> of Xen >>> +itself, designed to run inside a Xen HVM guest and provide memory >>> management >>> +services for one guest alone). >>> + >>> +The Xen binary is provided as the ``-kernel`` and the guest kernel itself >>> (or >>> +PV Grub image) as the ``-initrd`` image, which actually just means the >>> first >>> +multiboot "module". For example: >>> + >>> +.. parsed-literal:: >>> + >>> + |qemu_system| --accel kvm,xen-version=0x40011,kernel-irqchip=split \\ >>> + -chardev stdio,id=char0 -device xen-console,chardev=char0 \\ >>> + -display none -m 1G -kernel xen -initrd bzImage \\ >>> + -append "pv-shim console=xen,pv -- console=hvc0 root=/dev/xvda1" \\ >>> + -drive file=${GUEST_IMAGE},if=xen >> Is the space between -- and console= intentionsl? > Yes, that one is correct. The -- is how you separate Xen's command line > (on the left) from the guest kernel command line (on the right).
To expand on this a bit. Multiboot1 supports multiple modules but only a single command line. As one of the modules passed to Xen is the dom0 kernel, we need some way to pass it's command line, hence the " -- ". Multiboot2 and PVH support a command line per module, which is the preferred way to pass the commandlines, given a choice. ~Andrew