2012-10-11 02:14:54

by Ren Qiaowei

[permalink] [raw]
Subject: [PATCH v2] x86: add a new SMP bring up way for tboot case

tboot provides a better AP wakeup mechanism based on cpu MWAIT feature for
OS/VMM. With this mechanism, system will boot faster and will NOT require
VT to be enabled. But it requires that OS/VMM must have support it, otherwise
system can never boot up.

Once this mechanism is enabled, tboot will put APs waiting in MWAIT loops
before launching kernel. kernel can check the new flag field in v6 tboot
shared page for the hint. If the bit TB_FLAG_AP_WAKE_SUPPORT in flag field
is set, kernel BSP has to write the monitored memory (tboot->ap_wake_trigger)
to bring APs out of MWAIT loops. The sipi vector should be written in
tboot->ap_wake_addr before waking up APs.

Signed-off-by: Qiaowei Ren <[email protected]>
Signed-off-by: Xiaoyan Zhang <[email protected]>
Signed-off-by: Gang Wei <[email protected]>
---
arch/x86/kernel/smpboot.c | 21 +++++++++++----------
arch/x86/kernel/tboot.c | 17 +++++++++++++++++
include/linux/tboot.h | 17 +++++++++++++++++
3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index c80a33b..884c3e7 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -662,8 +662,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
/* start_ip had better be page-aligned! */
unsigned long start_ip = real_mode_header->trampoline_start;

- unsigned long boot_error = 0;
- int timeout;
+ int timeout, boot_error = 0;

/* Just in case we booted with a single CPU. */
alternatives_enable_smp();
@@ -710,14 +709,16 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
}
}

- /*
- * Kick the secondary CPU. Use the method in the APIC driver
- * if it's defined - or use an INIT boot APIC message otherwise:
- */
- if (apic->wakeup_secondary_cpu)
- boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
- else
- boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
+ if (!tboot_wake_up(apicid, start_ip)) {
+ /*
+ * Kick the secondary CPU. Use the method in the APIC driver
+ * if it's defined - or use an INIT boot APIC message otherwise:
+ */
+ if (apic->wakeup_secondary_cpu)
+ boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
+ else
+ boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
+ }

if (!boot_error) {
/*
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index f84fe00..e5e50b8 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -101,6 +101,8 @@ void __init tboot_probe(void)
pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
+ if (tboot->version >= 6)
+ pr_info("flags: 0x%08x\n", tboot->flags);
}

static pgd_t *tboot_pg_dir;
@@ -453,3 +455,18 @@ int tboot_force_iommu(void)

return 1;
}
+
+int tboot_wake_up(int apicid, unsigned long sipi_vec)
+{
+ if (!tboot_enabled())
+ return 0;
+
+ if ((tboot->version < 6) ||
+ !(tboot->flags & TB_FLAG_AP_WAKE_SUPPORT))
+ return 0;
+
+ tboot->ap_wake_addr = sipi_vec;
+ tboot->ap_wake_trigger = apicid;
+
+ return 1;
+}
diff --git a/include/linux/tboot.h b/include/linux/tboot.h
index c75128b..d65f7e9 100644
--- a/include/linux/tboot.h
+++ b/include/linux/tboot.h
@@ -124,8 +124,23 @@ struct tboot {

/* number of processors in wait-for-SIPI */
u32 num_in_wfs;
+
+ /*
+ * version 6+ fields:
+ */
+
+ u32 flags;
+
+ /* phys addr of kernel/VMM SIPI vector */
+ u64 ap_wake_addr;
+
+ /* kernel/VMM writes APIC ID to wake AP */
+ u32 ap_wake_trigger;
} __packed;

+/* kernel/VMM use INIT-SIPI-SIPI if clear, ap_wake_* if set */
+#define TB_FLAG_AP_WAKE_SUPPORT 0X00000001
+
/*
* UUID for tboot data struct to facilitate matching
* defined as {663C8DFF-E8B3-4b82-AABF-19EA4D057A08} by tboot, which is
@@ -146,6 +161,7 @@ extern void tboot_shutdown(u32 shutdown_type);
extern struct acpi_table_header *tboot_get_dmar_table(
struct acpi_table_header *dmar_tbl);
extern int tboot_force_iommu(void);
+extern int tboot_wake_up(int apicid, unsigned long sipi_vec);

#else

@@ -156,6 +172,7 @@ extern int tboot_force_iommu(void);
do { } while (0)
#define tboot_get_dmar_table(dmar_tbl) (dmar_tbl)
#define tboot_force_iommu() 0
+#define tboot_wake_up(apicid, sipi_vec) 0

#endif /* !CONFIG_INTEL_TXT */

--
1.7.9.5


2012-11-14 11:14:57

by Wei, Gang

[permalink] [raw]
Subject: RE: [PATCH v2] x86: add a new SMP bring up way for tboot case

Any comments on this patch?

Jimmy

Ren, Qiaowei wrote on?2012-10-11:
> tboot provides a better AP wakeup mechanism based on cpu MWAIT feature
> for OS/VMM. With this mechanism, system will boot faster and will NOT
> require VT to be enabled. But it requires that OS/VMM must have support
> it, otherwise system can never boot up.
>
> Once this mechanism is enabled, tboot will put APs waiting in MWAIT
> loops before launching kernel. kernel can check the new flag field in v6
> tboot shared page for the hint. If the bit TB_FLAG_AP_WAKE_SUPPORT in
> flag field is set, kernel BSP has to write the monitored memory
> (tboot->ap_wake_trigger) to bring APs out of MWAIT loops. The sipi
> vector should be written in tboot->ap_wake_addr before waking up APs.
>
> Signed-off-by: Qiaowei Ren <[email protected]>
> Signed-off-by: Xiaoyan Zhang <[email protected]>
> Signed-off-by: Gang Wei <[email protected]>
> ---
> arch/x86/kernel/smpboot.c | 21 +++++++++++----------
> arch/x86/kernel/tboot.c | 17 +++++++++++++++++
> include/linux/tboot.h | 17 +++++++++++++++++
> 3 files changed, 45 insertions(+), 10 deletions(-)
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index c80a33b..884c3e7 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -662,8 +662,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu,
> struct task_struct *idle)
> /* start_ip had better be page-aligned! */
> unsigned long start_ip = real_mode_header->trampoline_start;
> - unsigned long boot_error = 0;
> - int timeout;
> + int timeout, boot_error = 0;
>
> /* Just in case we booted with a single CPU. */
> alternatives_enable_smp();
> @@ -710,14 +709,16 @@ static int __cpuinit do_boot_cpu(int apicid, int
cpu,
> struct task_struct *idle)
> }
> }
> - /* - * Kick the secondary CPU. Use the method in the APIC driver
- *
> if it's defined - or use an INIT boot APIC message otherwise: - */
- if
> (apic->wakeup_secondary_cpu) - boot_error =
> apic->wakeup_secondary_cpu(apicid, start_ip); - else -
boot_error =
> wakeup_secondary_cpu_via_init(apicid, start_ip); + if
> (!tboot_wake_up(apicid, start_ip)) { + /* + *
Kick the secondary CPU.
> Use the method in the APIC driver + * if it's defined - or use
an INIT
> boot APIC message otherwise: + */ + if
(apic->wakeup_secondary_cpu)
> + boot_error = apic->wakeup_secondary_cpu(apicid,
start_ip); + else
> + boot_error = wakeup_secondary_cpu_via_init(apicid,
start_ip); + }
>
> if (!boot_error) {
> /*
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
> index f84fe00..e5e50b8 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -101,6 +101,8 @@ void __init tboot_probe(void)
> pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
> pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
> pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
> + if (tboot->version >= 6)
> + pr_info("flags: 0x%08x\n", tboot->flags);
> }
>
> static pgd_t *tboot_pg_dir;
> @@ -453,3 +455,18 @@ int tboot_force_iommu(void)
>
> return 1;
> }
> +
> +int tboot_wake_up(int apicid, unsigned long sipi_vec)
> +{
> + if (!tboot_enabled())
> + return 0;
> +
> + if ((tboot->version < 6) ||
> + !(tboot->flags & TB_FLAG_AP_WAKE_SUPPORT))
> + return 0;
> +
> + tboot->ap_wake_addr = sipi_vec;
> + tboot->ap_wake_trigger = apicid;
> +
> + return 1;
> +}
> diff --git a/include/linux/tboot.h b/include/linux/tboot.h
> index c75128b..d65f7e9 100644
> --- a/include/linux/tboot.h
> +++ b/include/linux/tboot.h
> @@ -124,8 +124,23 @@ struct tboot {
>
> /* number of processors in wait-for-SIPI */
> u32 num_in_wfs;
> +
> + /*
> + * version 6+ fields:
> + */
> +
> + u32 flags;
> +
> + /* phys addr of kernel/VMM SIPI vector */
> + u64 ap_wake_addr;
> +
> + /* kernel/VMM writes APIC ID to wake AP */
> + u32 ap_wake_trigger;
> } __packed;
> +/* kernel/VMM use INIT-SIPI-SIPI if clear, ap_wake_* if set */
> +#define TB_FLAG_AP_WAKE_SUPPORT 0X00000001
> +
> /*
> * UUID for tboot data struct to facilitate matching
> * defined as {663C8DFF-E8B3-4b82-AABF-19EA4D057A08} by tboot, which is
> @@ -146,6 +161,7 @@ extern void tboot_shutdown(u32 shutdown_type);
> extern struct acpi_table_header *tboot_get_dmar_table(
> struct acpi_table_header *dmar_tbl);
> extern int tboot_force_iommu(void);
> +extern int tboot_wake_up(int apicid, unsigned long sipi_vec);
>
> #else
> @@ -156,6 +172,7 @@ extern int tboot_force_iommu(void);
> do { } while (0)
> #define tboot_get_dmar_table(dmar_tbl) (dmar_tbl)
> #define tboot_force_iommu() 0
> +#define tboot_wake_up(apicid, sipi_vec) 0
>
> #endif /* !CONFIG_INTEL_TXT */


Attachments:
smime.p7s (8.38 kB)

2013-03-20 02:14:45

by Ren Qiaowei

[permalink] [raw]
Subject: RE: [PATCH v2] x86: add a new SMP bring up way for tboot case

Any comments on this patch?

Thanks,
Qiaowei

-----Original Message-----
From: Ren, Qiaowei
Sent: Thursday, October 11, 2012 6:11 PM
To: Thomas Gleixner; Ingo Molnar; H. Peter Anvin; [email protected]
Cc: Maliszewski, Richard L; [email protected]; [email protected]; Ren, Qiaowei; Xiaoyan Zhang; Wei, Gang
Subject: [PATCH v2] x86: add a new SMP bring up way for tboot case

tboot provides a better AP wakeup mechanism based on cpu MWAIT feature for OS/VMM. With this mechanism, system will boot faster and will NOT require VT to be enabled. But it requires that OS/VMM must have support it, otherwise system can never boot up.

Once this mechanism is enabled, tboot will put APs waiting in MWAIT loops before launching kernel. kernel can check the new flag field in v6 tboot shared page for the hint. If the bit TB_FLAG_AP_WAKE_SUPPORT in flag field is set, kernel BSP has to write the monitored memory (tboot->ap_wake_trigger) to bring APs out of MWAIT loops. The sipi vector should be written in
tboot->ap_wake_addr before waking up APs.

Signed-off-by: Qiaowei Ren <[email protected]>
Signed-off-by: Xiaoyan Zhang <[email protected]>
Signed-off-by: Gang Wei <[email protected]>
---
arch/x86/kernel/smpboot.c | 21 +++++++++++----------
arch/x86/kernel/tboot.c | 17 +++++++++++++++++
include/linux/tboot.h | 17 +++++++++++++++++
3 files changed, 45 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index c80a33b..884c3e7 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -662,8 +662,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
/* start_ip had better be page-aligned! */
unsigned long start_ip = real_mode_header->trampoline_start;

- unsigned long boot_error = 0;
- int timeout;
+ int timeout, boot_error = 0;

/* Just in case we booted with a single CPU. */
alternatives_enable_smp();
@@ -710,14 +709,16 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
}
}

- /*
- * Kick the secondary CPU. Use the method in the APIC driver
- * if it's defined - or use an INIT boot APIC message otherwise:
- */
- if (apic->wakeup_secondary_cpu)
- boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
- else
- boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
+ if (!tboot_wake_up(apicid, start_ip)) {
+ /*
+ * Kick the secondary CPU. Use the method in the APIC driver
+ * if it's defined - or use an INIT boot APIC message otherwise:
+ */
+ if (apic->wakeup_secondary_cpu)
+ boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
+ else
+ boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
+ }

if (!boot_error) {
/*
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c index f84fe00..e5e50b8 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -101,6 +101,8 @@ void __init tboot_probe(void)
pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
+ if (tboot->version >= 6)
+ pr_info("flags: 0x%08x\n", tboot->flags);
}

static pgd_t *tboot_pg_dir;
@@ -453,3 +455,18 @@ int tboot_force_iommu(void)

return 1;
}
+
+int tboot_wake_up(int apicid, unsigned long sipi_vec) {
+ if (!tboot_enabled())
+ return 0;
+
+ if ((tboot->version < 6) ||
+ !(tboot->flags & TB_FLAG_AP_WAKE_SUPPORT))
+ return 0;
+
+ tboot->ap_wake_addr = sipi_vec;
+ tboot->ap_wake_trigger = apicid;
+
+ return 1;
+}
diff --git a/include/linux/tboot.h b/include/linux/tboot.h index c75128b..d65f7e9 100644
--- a/include/linux/tboot.h
+++ b/include/linux/tboot.h
@@ -124,8 +124,23 @@ struct tboot {

/* number of processors in wait-for-SIPI */
u32 num_in_wfs;
+
+ /*
+ * version 6+ fields:
+ */
+
+ u32 flags;
+
+ /* phys addr of kernel/VMM SIPI vector */
+ u64 ap_wake_addr;
+
+ /* kernel/VMM writes APIC ID to wake AP */
+ u32 ap_wake_trigger;
} __packed;

+/* kernel/VMM use INIT-SIPI-SIPI if clear, ap_wake_* if set */ #define
+TB_FLAG_AP_WAKE_SUPPORT 0X00000001
+
/*
* UUID for tboot data struct to facilitate matching
* defined as {663C8DFF-E8B3-4b82-AABF-19EA4D057A08} by tboot, which is @@ -146,6 +161,7 @@ extern void tboot_shutdown(u32 shutdown_type); extern struct acpi_table_header *tboot_get_dmar_table(
struct acpi_table_header *dmar_tbl); extern int tboot_force_iommu(void);
+extern int tboot_wake_up(int apicid, unsigned long sipi_vec);

#else

@@ -156,6 +172,7 @@ extern int tboot_force_iommu(void);
do { } while (0)
#define tboot_get_dmar_table(dmar_tbl) (dmar_tbl)
#define tboot_force_iommu() 0
+#define tboot_wake_up(apicid, sipi_vec) 0

#endif /* !CONFIG_INTEL_TXT */

--
1.7.9.5

2013-03-20 03:05:03

by H. Peter Anvin

[permalink] [raw]
Subject: Re: [PATCH v2] x86: add a new SMP bring up way for tboot case

On 03/19/2013 07:14 PM, Ren, Qiaowei wrote:
> Any comments on this patch?
>
> Thanks,
> Qiaowei

The biggest question is probably if we can use an existing hook of some
sort.

Overriding the apic method is probably not the right way to go, though.
tglx, do you have any opinions here?

Furthermore, this really is not nice:

> +int tboot_wake_up(int apicid, unsigned long sipi_vec) {
> + if (!tboot_enabled())
> + return 0;
> +
> + if ((tboot->version < 6) ||
> + !(tboot->flags & TB_FLAG_AP_WAKE_SUPPORT))
> + return 0;
> +
> + tboot->ap_wake_addr = sipi_vec;
> + tboot->ap_wake_trigger = apicid;
> +
> + return 1;
> +}

Not only don't you set boot_error for the code above it, but there is
absolutely no indication how that does its job (are those active
operations? If so they should use writel()), nor does it include any
kind of synchronization.

-hpa

2013-04-11 07:16:43

by Ren Qiaowei

[permalink] [raw]
Subject: RE: [PATCH v2] x86: add a new SMP bring up way for tboot case

> -----Original Message-----
> From: H. Peter Anvin [mailto:[email protected]]
> Sent: Wednesday, March 20, 2013 11:02 AM
> To: Ren, Qiaowei
> Cc: Thomas Gleixner; Ingo Molnar; [email protected]; Maliszewski, Richard L;
> [email protected]; [email protected]; Xiaoyan
> Zhang; Wei, Gang
> Subject: Re: [PATCH v2] x86: add a new SMP bring up way for tboot case
>
> On 03/19/2013 07:14 PM, Ren, Qiaowei wrote:
> > Any comments on this patch?
> >
> > Thanks,
> > Qiaowei
>
> The biggest question is probably if we can use an existing hook of some sort.
>
> Overriding the apic method is probably not the right way to go, though.
> tglx, do you have any opinions here?
>

If we can't use an existing hook, could you please give me any suggestion about other opinions here?

> Furthermore, this really is not nice:
>
> > +int tboot_wake_up(int apicid, unsigned long sipi_vec) {
> > + if (!tboot_enabled())
> > + return 0;
> > +
> > + if ((tboot->version < 6) ||
> > + !(tboot->flags & TB_FLAG_AP_WAKE_SUPPORT))
> > + return 0;
> > +
> > + tboot->ap_wake_addr = sipi_vec;
> > + tboot->ap_wake_trigger = apicid;
> > +
> > + return 1;
> > +}
>
> Not only don't you set boot_error for the code above it, but there is absolutely
> no indication how that does its job (are those active operations? If so they
> should use writel()), nor does it include any kind of synchronization.
>

Ok. I should add some comments to explain how that does its job.
But I guess boot_error don't have to be set inside this function.

Thanks,
Qiaowei