freebsd-dev/sys/x86
Roger Pau Monné b6d85a5f51 stand/multiboot: adjust the protocol between loader and kernel
There's a currently ad-hoc protocol to hand off the FreeBSD kernel
payload between the loader and the kernel itself when Xen is in the
middle of the picture. Such protocol wasn't very resilient to changes
to the loader itself, because it relied on moving metadata around to
package it using a certain layout. This has proven to be fragile, so
replace it with a more robust version.

The new protocol requires using a xen_header structure that will be
used to pass data between the FreeBSD loader and the FreeBSD kernel
when booting in dom0 mode. At the moment the only data conveyed is the
offset of the start of the module metadata relative to the start of the
module itself.

This is a slightly disruptive change since it also requires a change
to the kernel which is contained in this patch. In order to update
with this change the kernel must be updated before updating the
loader, as described in the handbook. Note this is only required when
booting a FreeBSD/Xen dom0. This change doesn't affect the normal
FreeBSD boot protocol.

This fixes booting FreeBSD/Xen in dom0 mode after
3630506b9d.

Sponsored by:		Citrix Systems R&D
MFC after:		3 days
Reviewed by:		tsoome
Differential Revision:	https://reviews.freebsd.org/D28411
2021-01-29 15:23:26 +01:00
..
acpica x86: clean up empty lines in .c and .h files 2020-09-01 21:23:59 +00:00
bios Explicit CTLFLAG_DYN not needed 2020-10-04 19:37:15 +00:00
conf Use envvar rather than nonstandard hint. lines 2020-09-23 19:18:53 +00:00
cpufreq hwpstate_intel: don't unconditionally print the error message 2020-11-29 01:43:04 +00:00
include stand/multiboot: adjust the protocol between loader and kernel 2021-01-29 15:23:26 +01:00
iommu dmar: reserve memory windows of PCIe root port 2020-12-09 18:43:58 +00:00
isa timer_restore is now unused, remove it 2020-10-08 20:56:11 +00:00
linux linux(4): Deduplicate unimpl/dummy syscall handlers 2020-11-05 19:30:31 +00:00
pci x86: clean up empty lines in .c and .h files 2020-09-01 21:23:59 +00:00
x86 x86: switch kernel TSC timecounter to RDTSCP on AMD Zen CPUs 2021-01-21 14:55:31 +02:00
xen stand/multiboot: adjust the protocol between loader and kernel 2021-01-29 15:23:26 +01:00