On 12/9/22 10:55, David Woodhouse wrote:
- m->default_machine_opts = "accel=xen,suppress-vmdesc=on";
+ if (xen_enabled())
+ m->default_machine_opts = "accel=xen,suppress-vmdesc=on";
+ else
+ m->default_machine_opts = "accel=kvm,xen-version=0x30001";
Please do not modify pc_xen_hvm_init().
"-M xenfv" should be the same as "-M pc-i440fx-...,suppress-vmdesc=on
-accel xen -device xen-platform". It must work *without* "-accel xen",
while here you're basically requiring it. For now, please make
KVM-emulated Xen use "-M pc -device xen-platform". We can figure out
"-M xenfv" later.
You can instead have:
- a check in xen_init() that checks that xen_mode is XEN_ATTACH. If
not, fail.
- an extra enum value for xen_mode, XEN_DISABLED, which is the default
instead of XEN_EMULATE;
- an accelerator property "-accel kvm,xen-version=...", added in
kvm_accel_class_init() instead of the machine property. The property,
when set to a nonzero value, flips xen_mode from XEN_DISABLED to
XEN_EMULATE.
The Xen overlay device can be created using the mc->kvm_type function
(which you can set in DEFINE_PC_MACHINE); at that point, xen_mode has
switched from XEN_DISABLED to XEN_EMULATE. Those xen_enabled() checks
that apply to KVM then become xen_mode != XEN_DISABLED, as long as they
run during mc->kvm_type or afterwards.
The platform device can be created either in mc->kvm_type or manually
(not sure if it makes sense to have a "XenVMMXenVMM" CPUID + emulated
hypercalls but no platform device---would it still use pvclock for
example?).
Paolo
