@@ -43599,11 +43599,20 @@ Invoking guix system
overwritten. This behavior mirrors that of @command{guix package}
(@pxref{Invoking guix package}).
-It also adds a bootloader menu entry for the new OS configuration,
+It adds a bootloader menu entry for the new OS configuration,
---unless @option{--no-bootloader} is passed. For GRUB, it moves
entries for older configurations to a submenu, allowing you to choose
an older system generation at boot time should you need it.
+@cindex kexec, for fast reboots
+@cindex rebooting @i{via} Linux kexec
+On Linux, @command{guix system reconfigure} also loads the new system
+for fast reboot @i{via} kexec: running @command{reboot --kexec} will
+boot the new system by directly executing its kernel, thus bypassing the
+BIOS initialization phase and bootloader (@pxref{Invoking reboot,,,
+shepherd, The GNU Shepherd Manual}). You can avoid this behavior by
+passing the @option{--no-kexec} option.
+
@cindex provenance tracking, of the operating system
Upon completion, the new system is deployed under
@file{/run/current-system}. This directory contains @dfn{provenance
@@ -1,6 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.org>
-;;; Copyright © 2020-2023 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2020-2024 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2024 Ricardo <rekado@elephly.net>
;;;
;;; This file is part of GNU Guix.
@@ -552,6 +552,13 @@ (define (deploy-managed-host machine)
(inferior-exception-arguments
c)))
os)
+ (load-system-for-kexec (eval/error-handling c
+ (warning (G_ "\
+failed to load system of '~a' for kexec reboot:~%~{~s ~}~%")
+ host
+ (inferior-exception-arguments
+ c)))
+ os)
(install-bootloader (eval/error-handling c
(raise (formatted-message
(G_ "\
@@ -1,5 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.org>
+;;; Copyright © 2024 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -18,9 +19,12 @@
(define-module (gnu tests reconfigure)
#:use-module (gnu bootloader)
+ #:use-module (gnu services)
+ #:use-module (gnu services base)
#:use-module (gnu services shepherd)
#:use-module (gnu system)
#:use-module (gnu system accounts)
+ #:use-module (gnu system file-systems)
#:use-module (gnu system shadow)
#:use-module (gnu system vm)
#:use-module (gnu tests)
@@ -31,6 +35,7 @@ (define-module (gnu tests reconfigure)
#:use-module (guix store)
#:export (%test-switch-to-system
%test-upgrade-services
+ %test-upgrade-kexec
%test-install-bootloader))
;;; Commentary:
@@ -178,6 +183,73 @@ (define* (run-upgrade-services-test)
(disable (upgrade-services-program '() '() '(dummy) '())))
(test enable disable))))
+(define (run-kexec-test)
+ "Run a test aiming to reboot via Linux kexec into a new system."
+ (define os
+ (marionette-operating-system
+ (operating-system
+ (inherit %simple-os)
+ (services (modify-services %base-services
+ (syslog-service-type
+ config => (syslog-configuration
+ (inherit config)
+ (config-file
+ (plain-file
+ "syslog.conf"
+ "*.* /dev/console\n")))))))
+ #:imported-modules '((gnu services herd)
+ (guix combinators))))
+
+ (define new-os
+ (marionette-operating-system
+ (virtualized-operating-system ;run as with "guix system vm"
+ (operating-system
+ (inherit %simple-os)
+ (host-name "the-new-os")
+ (kernel-arguments '("console=ttyS0"))) ;be verbose
+ #:volatile? #t) ;mount root read-only
+ #:imported-modules '((gnu services herd)
+ (guix combinators))))
+
+ (define vm (virtual-machine os))
+
+ (define test
+ (with-imported-modules '((gnu build marionette))
+ #~(begin
+ (use-modules (gnu build marionette)
+ (srfi srfi-64))
+
+ (define marionette
+ (make-marionette (list #$vm)))
+
+ (test-runner-current (system-test-runner #$output))
+ (test-begin "kexec")
+
+ (test-equal "host name"
+ #$(operating-system-host-name os)
+ (marionette-eval '(gethostname) marionette))
+
+ (test-assert "kexec-loading-program"
+ (marionette-eval
+ '(primitive-load #$(kexec-loading-program new-os))
+ marionette))
+
+ (test-assert "reboot/kexec"
+ (marionette-eval
+ '(begin
+ (use-modules (gnu services herd))
+ (with-shepherd-action 'root ('kexec) result
+ (pk 'reboot-kexec result)))
+ marionette))
+
+ (test-equal "host name of new OS"
+ #$(operating-system-host-name new-os)
+ (marionette-eval '(gethostname) marionette))
+
+ (test-end))))
+
+ (gexp->derivation "kexec-test" test))
+
(define* (run-install-bootloader-test)
"Run a test of an OS running INSTALL-BOOTLOADER-PROGRAM, which installs a
bootloader's configuration file."
@@ -268,6 +340,12 @@ (define %test-upgrade-services
loading new services.")
(value (run-upgrade-services-test))))
+(define %test-upgrade-kexec
+ (system-test
+ (name "upgrade-kexec")
+ (description "Load a system and reboot into it via Linux kexec.")
+ (value (run-kexec-test))))
+
(define %test-install-bootloader
(system-test
(name "install-bootloader")
@@ -798,6 +798,7 @@ (define* (perform-action action image
save-provenance?
skip-safety-checks?
install-bootloader?
+ load-for-kexec?
dry-run? derivations-only?
use-substitutes? target
full-boot?
@@ -900,7 +901,13 @@ (define* (perform-action action image
To complete the upgrade, run 'herd restart SERVICE' to stop,
upgrade, and restart each service that was not automatically restarted.\n")))
(return (format #t (G_ "\
-Run 'herd status' to view the list of services on your system.\n"))))))
+Run 'herd status' to view the list of services on your system.\n"))))
+ (mwhen load-for-kexec?
+ (mlet %store-monad ((kexec? (load-system-for-kexec local-eval
+ os)))
+ (mwhen kexec?
+ (return (info (G_ "system loaded for fast reboot \
+ with 'reboot --kexec'~%"))))))))
((init)
(newline)
(format #t (G_ "initializing operating system under '~a'...~%")
@@ -1025,6 +1032,8 @@ (define (show-help)
--image-size=SIZE for 'image', produce an image of SIZE"))
(display (G_ "
--no-bootloader for 'init', do not install a bootloader"))
+ (display (G_ "
+ --no-kexec for 'reconfigure', do not load system for kexec reboot"))
(display (G_ "
--volatile for 'image', make the root file system volatile"))
(display (G_ "
@@ -1127,6 +1136,9 @@ (define %options
(option '("no-bootloader" "no-grub") #f #f
(lambda (opt name arg result)
(alist-cons 'install-bootloader? #f result)))
+ (option '("no-kexec") #f #f
+ (lambda (opt name arg result)
+ (alist-cons 'load-for-kexec? #f result)))
(option '("volatile") #f #f
(lambda (opt name arg result)
(alist-cons 'volatile-image-root? #t result)))
@@ -1198,6 +1210,7 @@ (define %default-options
(image-type . mbr-hybrid-raw)
(image-size . guess)
(install-bootloader? . #t)
+ (load-for-kexec? . #t)
(label . #f)
(volatile-image-root? . #f)
(volatile-vm-root? . #t)
@@ -1275,6 +1288,7 @@ (define (process-action action args opts)
(leave (G_ "no configuration specified~%")))))))
(dry? (assoc-ref opts 'dry-run?))
(bootloader? (assoc-ref opts 'install-bootloader?))
+ (kexec? (assoc-ref opts 'load-for-kexec?))
(label (assoc-ref opts 'label))
(image-type (lookup-image-type-by-name
(assoc-ref opts 'image-type)))
@@ -1360,6 +1374,7 @@ (define (process-action action args opts)
(_ #f))
opts)
#:install-bootloader? bootloader?
+ #:load-for-kexec? kexec?
#:target target-file
#:gc-root (assoc-ref opts 'gc-root)))))
#:target target
@@ -31,6 +31,7 @@ (define-module (guix scripts system reconfigure)
#:use-module (gnu services herd)
#:use-module (gnu services shepherd)
#:use-module (gnu system)
+ #:autoload (gnu system file-systems) (file-system-device)
#:use-module (guix gexp)
#:use-module (guix modules)
#:use-module (guix monads)
@@ -52,6 +53,9 @@ (define-module (guix scripts system reconfigure)
upgrade-services-program
upgrade-shepherd-services
+ kexec-loading-program
+ load-system-for-kexec
+
install-bootloader-program
install-bootloader
@@ -176,6 +180,27 @@ (define (upgrade-services-program service-files to-start to-unload to-restart)
(for-each unload-service '#$to-unload)
(for-each start-service '#$to-start)))))
+(define (kexec-loading-program os)
+ "Return a program that calls 'kexec_file_load' to allow rebooting into OS
+via 'kexec'."
+ (let ((root-device (file-system-device
+ (operating-system-root-file-system os))))
+ (program-file
+ "kexec-load-system.scm"
+ (with-imported-modules '((guix build syscalls))
+ #~(begin
+ (use-modules (guix build syscalls))
+
+ (let ((kernel (open-fdes #$(operating-system-kernel-file os)
+ O_RDONLY))
+ (initrd (open-fdes #$(operating-system-initrd-file os)
+ O_RDONLY)))
+ (kexec-load-file kernel initrd
+ (string-join
+ (list #$@(operating-system-kernel-arguments
+ os root-device)))
+ KEXEC_FILE_DEBUG)))))))
+
(define* (upgrade-shepherd-services eval os)
"Using EVAL, a monadic procedure taking a single G-Expression as an argument,
upgrade the Shepherd (PID 1) by unloading obsolete services and loading new
@@ -205,6 +230,12 @@ (define* (upgrade-shepherd-services eval os)
to-unload
to-restart)))))))
+(define (load-system-for-kexec eval os)
+ "Load OS so that it can be rebooted into via kexec, if supported. Return
+true on success."
+ (eval #~(and (string-contains %host-type "-linux")
+ (primitive-load #$(kexec-loading-program os)))))
+
;;;
;;; Bootloader configuration.