| Message ID | 20230504145023.835096-12-ross.philipson@oracle.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | x86: Trenchboot secure dynamic launch Linux kernel support | expand |
On Thu, May 04, 2023 at 02:50:20PM +0000, Ross Philipson wrote: > 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. What are the consequences of SEXIT not being called, and why is it ok to skip it in these circumstances?
On 5/12/23 07:40, Matthew Garrett wrote: > On Thu, May 04, 2023 at 02:50:20PM +0000, Ross Philipson wrote: >> 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. > > What are the consequences of SEXIT not being called, and why is it ok to > skip it in these circumstances? Well the system is resetting so there are no real consequences. The problem on those two paths is that the APs have not been halted with a machine_shutdown() and that is a precondition to issuing GETSEC[SEXIT]. Only the BSP should be active and SEXIT must be done on it. Thanks Ross
On 5/15/23 14:16, Ross Philipson wrote: > On 5/12/23 07:40, Matthew Garrett wrote: >> On Thu, May 04, 2023 at 02:50:20PM +0000, Ross Philipson wrote: >>> 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. >> >> What are the consequences of SEXIT not being called, and why is it ok to >> skip it in these circumstances? > > Well the system is resetting so there are no real consequences. The > problem on those two paths is that the APs have not been halted with a > machine_shutdown() and that is a precondition to issuing GETSEC[SEXIT]. > Only the BSP should be active and SEXIT must be done on it. To expand on this just a bit further. On all paths we were able to identify, the SECRETS bit is cleared, memconfig is unlocked, and the private registers are all closed. This makes the system as safe as possible to go through a power event and be able to come back up on the other side. The clean way is to always go through an SEXIT before a power event, but as Ross highlighted this can only be done after the APs have been halted. v/r, dps
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 3adbe97..732c81b 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -12,6 +12,7 @@ #include <linux/delay.h> #include <linux/objtool.h> #include <linux/pgtable.h> +#include <linux/slaunch.h> #include <acpi/reboot.h> #include <asm/io.h> #include <asm/apic.h> @@ -720,6 +721,7 @@ static void native_machine_restart(char *__unused) if (!reboot_force) machine_shutdown(); + slaunch_finalize(!reboot_force); __machine_emergency_restart(0); } @@ -730,6 +732,9 @@ 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); } @@ -738,8 +743,12 @@ 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); } @@ -767,6 +776,7 @@ void machine_shutdown(void) void machine_emergency_restart(void) { + slaunch_finalize(0); __machine_emergency_restart(1); }
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 <ross.philipson@oracle.com> --- arch/x86/kernel/reboot.c | 10 ++++++++++ 1 file changed, 10 insertions(+)