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

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

[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.

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 <joseph.cihula@intel.com>
Signed-off-by: Shane Wang <shane.wang@intel.com>

---

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
--- linus-2.6.git-0629/arch/x86/kernel/smpboot.c	2009-06-29 21:57:17.000000000 -0700
+++ linus-2.6.git-0629-txt/arch/x86/kernel/smpboot.c	2009-06-30 16:09:10.000000000 -0700
@@ -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();
 }
 
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
--- linus-2.6.git-0629/drivers/acpi/acpica/hwsleep.c	2009-06-29 21:57:18.000000000 -0700
+++ linus-2.6.git-0629-txt/drivers/acpi/acpica/hwsleep.c	2009-06-30 16:07:51.000000000 -0700
@@ -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);
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
--- linus-2.6.git-0629/kernel/cpu.c	2009-06-29 21:57:26.000000000 -0700
+++ linus-2.6.git-0629-txt/kernel/cpu.c	2009-06-30 16:01:58.000000000 -0700
@@ -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 */

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

[Pavel Machek]

On Tue 2009-06-30 19:31:07, Joseph Cihula wrote:
> 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.

> Signed-off-by: Joseph Cihula <joseph.cihula@intel.com>
> Signed-off-by: Shane Wang <shane.wang@intel.com>

NAK.
								Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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

[Rafael J. Wysocki]

On Wednesday 01 July 2009, Joseph Cihula wrote:
> 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.

> 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

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

[Andi Kleen]

On Fri, Jul 03, 2009 at 01:15:23AM +0200, Rafael J. Wysocki wrote:
> Is there any documentation describing how ACPI sleeps states are supposed to
> work with the TXT hardware?

2.4.8.4 in http://download.intel.com/technology/security/downloads/315168.pdf

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

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

[Rafael J. Wysocki]

On Friday 03 July 2009, Andi Kleen wrote:
> On Fri, Jul 03, 2009 at 01:15:23AM +0200, Rafael J. Wysocki wrote:
> > Is there any documentation describing how ACPI sleeps states are supposed to
> > work with the TXT hardware?
> 
> 2.4.8.4 in http://download.intel.com/technology/security/downloads/315168.pdf

Thanks!

Best,
Rafael