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intel_txt: Intel(R) TXT Sx shutdown support

RFC PATCH NAK Joseph Cihula 4 participants 5 messages Jul 1, 2009 – Jul 4, 2009

Subsystems (4)
x86 ACPI ACPI component architecture (acpica) CPU hotplug
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Joseph Cihula

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#0 lore raw

RFC PATCH v6 3/4 intel_txt: Intel(R) TXT Sx shutdown support

Support for graceful handling of sleep states (S3/S4/S5) after an Intel(R) TXT launch.

Without this patch, attempting to place the system in one of the ACPI sleep states (S3/S4/S5) will cause the TXT hardware to treat this as an attack and will cause a system reset, with memory locked. Not only may the subsequent memory scrub take some time, but the platform will be unable to enter the requested power state.

This patch calls back into the tboot so that it may properly and securely clean up system state and clear the secrets-in-memory flag, after which it will place the system into the requested sleep state using ACPI information passed by the kernel.

 arch/x86/kernel/smpboot.c     |    2 ++
 drivers/acpi/acpica/hwsleep.c |    3 +++
 kernel/cpu.c                  |    7 ++++++-
 3 files changed, 11 insertions(+), 1 deletion(-)
Signed-off-by Joseph Cihula <[email protected]>
Signed-off-by Shane Wang <[email protected]>

---

arch/x86/kernel/smpboot.c +2 -0
diff -uprN -X linus-2.6.git-0629/Documentation/dontdiff linus-2.6.git-0629/arch/x86/kernel/smpboot.c linus-2.6.git-0629-txt/arch/x86/kernel/smpboot.c
@@ -62,6 +62,7 @@
 #include <asm/vmi.h>
 #include <asm/apic.h>
 #include <asm/setup.h>
+#include <asm/tboot.h>
 #include <asm/uv/uv.h>
 #include <linux/mc146818rtc.h>
 

@@ -1317,6 +1318,7 @@ void play_dead_common(void)
 void native_play_dead(void)
 {
 	play_dead_common();
+	tboot_shutdown(TB_SHUTDOWN_WFS);
 	wbinvd_halt();
 }
drivers/acpi/acpica/hwsleep.c +3 -0
diff -uprN -X linus-2.6.git-0629/Documentation/dontdiff linus-2.6.git-0629/drivers/acpi/acpica/hwsleep.c linus-2.6.git-0629-txt/drivers/acpi/acpica/hwsleep.c
@@ -45,6 +45,7 @@
 #include <acpi/acpi.h>
 #include "accommon.h"
 #include "actables.h"
+#include <asm/tboot.h>
 
 #define _COMPONENT          ACPI_HARDWARE
 ACPI_MODULE_NAME("hwsleep")

@@ -342,6 +343,8 @@ acpi_status asmlinkage acpi_enter_sleep_
 
 	ACPI_FLUSH_CPU_CACHE();
 
+	tboot_sleep(sleep_state, pm1a_control, pm1b_control);
+
 	/* Write #2: Write both SLP_TYP + SLP_EN */
 
 	status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
kernel/cpu.c +6 -1
diff -uprN -X linus-2.6.git-0629/Documentation/dontdiff linus-2.6.git-0629/kernel/cpu.c linus-2.6.git-0629-txt/kernel/cpu.c
@@ -14,6 +14,7 @@
 #include <linux/kthread.h>
 #include <linux/stop_machine.h>
 #include <linux/mutex.h>
+#include <asm/tboot.h>
 
 #ifdef CONFIG_SMP
 /* Serializes the updates to cpu_online_mask, cpu_present_mask */

@@ -376,7 +377,7 @@ static cpumask_var_t frozen_cpus;
 
 int disable_nonboot_cpus(void)
 {
-	int cpu, first_cpu, error;
+	int cpu, first_cpu, error, num_cpus = 0;
 
 	error = stop_machine_create();
 	if (error)

@@ -391,6 +392,7 @@ int disable_nonboot_cpus(void)
 	for_each_online_cpu(cpu) {
 		if (cpu == first_cpu)
 			continue;
+		num_cpus++;
 		error = _cpu_down(cpu, 1);
 		if (!error) {
 			cpumask_set_cpu(cpu, frozen_cpus);

@@ -401,6 +403,9 @@ int disable_nonboot_cpus(void)
 			break;
 		}
 	}
+	/* ensure all CPUs have gone into wait-for-SIPI */
+	error |= tboot_wait_for_aps(num_cpus);
+
 	if (!error) {
 		BUG_ON(num_online_cpus() > 1);
 		/* Make sure the CPUs won't be enabled by someone else */
NAK
#1 lore raw
Quoted 7 lines · Joseph Cihula

Support for graceful handling of sleep states (S3/S4/S5) after an Intel(R) TXT launch.

Without this patch, attempting to place the system in one of the ACPI sleep states (S3/S4/S5) will cause the TXT hardware to treat this as an attack and will cause a system reset, with memory locked. Not only may the subsequent memory scrub take some time, but the platform will be unable to enter the requested power state.

I believe I asked for Documentation how s3 works with txt before. As a suspend maintainer, I believe I deserve to know. Now you are resubmitting the patch without ccing me and without that explanation.

Quoted 2 lines
Signed-off-by Joseph Cihula <[email protected]>
Signed-off-by Shane Wang <[email protected]>

NAK.
Pavel

Signature · 2 lines
(english) http://www.livejournal.com/~pavelmachek
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#2 lore raw
In reply to Joseph Cihula
Quoted 4 lines · Joseph Cihula

Support for graceful handling of sleep states (S3/S4/S5) after an Intel(R) TXT launch.

Without this patch, attempting to place the system in one of the ACPI sleep states (S3/S4/S5)

To be precise, S5 is not a sleep state.

Quoted 8 lines

will cause the TXT hardware to treat this as an attack and
will cause a system reset, with memory locked. Not only may the subsequent memory scrub take some time, but the platform will be unable to enter the requested power state.

This patch calls back into the tboot so that it may properly and securely clean up system state and clear the secrets-in-memory flag, after which it will place the system into the requested sleep state using ACPI information passed by the kernel.

Is there any documentation describing how ACPI sleeps states are supposed to work with the TXT hardware?

Rafael