[v12,13/19] x86/reboot: Secure Launch SEXIT support on reboot paths

Commit Message

Ross Philipson Dec. 19, 2024, 7:42 p.m. UTC

If the MLE kernel is being powered off, rebooted or halted,
then SEXIT must be called. Note that the SEXIT GETSEC leaf
can only be called after a machine_shutdown() has been done on
these paths. The machine_shutdown() is not called on a few paths
like when poweroff action does not have a poweroff callback (into
ACPI code) or when an emergency reset is done. In these cases,
just the TXT registers are finalized but SEXIT is skipped.

Signed-off-by: Ross Philipson <[e-mail]>
---
 arch/x86/kernel/reboot.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

Patch

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 615922838c51..c02463d8d1e9 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -13,6 +13,7 @@ 
 #include <linux/objtool.h>
 #include <linux/pgtable.h>
 #include <linux/kexec.h>
+#include <linux/slaunch.h>
 #include <acpi/reboot.h>
 #include <asm/io.h>
 #include <asm/apic.h>
@@ -778,6 +779,7 @@  static void native_machine_restart(char *__unused)
 
 	if (!reboot_force)
 		machine_shutdown();
+	slaunch_finalize(!reboot_force);
 	__machine_emergency_restart(0);
 }
 
@@ -788,6 +790,9 @@  static void native_machine_halt(void)
 
 	tboot_shutdown(TB_SHUTDOWN_HALT);
 
+	/* SEXIT done after machine_shutdown() to meet TXT requirements */
+	slaunch_finalize(1);
+
 	stop_this_cpu(NULL);
 }
 
@@ -796,8 +801,12 @@  static void native_machine_power_off(void)
 	if (kernel_can_power_off()) {
 		if (!reboot_force)
 			machine_shutdown();
+		slaunch_finalize(!reboot_force);
 		do_kernel_power_off();
+	} else {
+		slaunch_finalize(0);
 	}
+
 	/* A fallback in case there is no PM info available */
 	tboot_shutdown(TB_SHUTDOWN_HALT);
 }
@@ -825,6 +834,7 @@  void machine_shutdown(void)
 
 void machine_emergency_restart(void)
 {
+	slaunch_finalize(0);
 	__machine_emergency_restart(1);
 }