Re: [PATCH] arch/x86: Don't try to poke disabled/non-existent APIC

[Prarit Bhargava]

On 10/21/2016 10:18 PM, ville.syrj...@linux.intel.com wrote:
> From: Ville Syrjälä 
> 
> Apparently trying to poke a disabled or non-existent APIC
> leads to a box that doesn't even boot. Let's not do that.
> 
> No real clue if this is the right fix, but at least my
> P3 machine boots again.
> 
> Cc: sta...@vger.kernel.org
> Cc: Ingo Molnar 
> Cc: "H. Peter Anvin" 
> Cc: x...@kernel.org
> Cc: Prarit Bhargava 
> Cc: Peter Zijlstra 
> Cc: Len Brown 
> Cc: Borislav Petkov 
> Cc: Andi Kleen 
> Cc: Jiri Olsa 
> Cc: Juergen Gross 
> Cc: dyo...@redhat.com
> Cc: Eric Biederman 
> Cc: ke...@lists.infradead.org
> Cc: Thomas Gleixner 
> Fixes: 2a51fe083eba ("arch/x86: Handle non enumerated CPU after physical 
> hotplug")
> Signed-off-by: Ville Syrjälä 
> ---
>  arch/x86/kernel/smpboot.c | 16 +---
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 951f093a96fe..42f5eb7b4f6c 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1409,15 +1409,17 @@ __init void prefill_possible_map(void)
>  
>   /* No boot processor was found in mptable or ACPI MADT */
>   if (!num_processors) {
> - int apicid = boot_cpu_physical_apicid;
> - int cpu = hard_smp_processor_id();
> + if (boot_cpu_has(X86_FEATURE_APIC)) {


It looks okay to gate on X86_FEATURE_APIC, but not sure if it should be

 cpu_has(_data(0), X86_FEATURE_APIC)

since smp_store_boot_cpu_info() was already called.

tglx?

P.




> + int apicid = boot_cpu_physical_apicid;
> + int cpu = hard_smp_processor_id();
>  
> - pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
> + pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
>  
> - /* Make sure boot cpu is enumerated */
> - if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
> - apic->apic_id_valid(apicid))
> - generic_processor_info(apicid, boot_cpu_apic_version);
> + /* Make sure boot cpu is enumerated */
> + if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
> + apic->apic_id_valid(apicid))
> + generic_processor_info(apicid, 
> boot_cpu_apic_version);
> + }
>  
>   if (!num_processors)
>   num_processors = 1;
> 

Re: [PATCH] arch/x86: Don't try to poke disabled/non-existent APIC

[Prarit Bhargava]

On 10/21/2016 10:18 PM, ville.syrj...@linux.intel.com wrote:
> From: Ville Syrjälä 
> 
> Apparently trying to poke a disabled or non-existent APIC
> leads to a box that doesn't even boot. Let's not do that.
> 
> No real clue if this is the right fix, but at least my
> P3 machine boots again.
> 
> Cc: sta...@vger.kernel.org
> Cc: Ingo Molnar 
> Cc: "H. Peter Anvin" 
> Cc: x...@kernel.org
> Cc: Prarit Bhargava 
> Cc: Peter Zijlstra 
> Cc: Len Brown 
> Cc: Borislav Petkov 
> Cc: Andi Kleen 
> Cc: Jiri Olsa 
> Cc: Juergen Gross 
> Cc: dyo...@redhat.com
> Cc: Eric Biederman 
> Cc: ke...@lists.infradead.org
> Cc: Thomas Gleixner 
> Fixes: 2a51fe083eba ("arch/x86: Handle non enumerated CPU after physical 
> hotplug")
> Signed-off-by: Ville Syrjälä 
> ---
>  arch/x86/kernel/smpboot.c | 16 +---
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 951f093a96fe..42f5eb7b4f6c 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1409,15 +1409,17 @@ __init void prefill_possible_map(void)
>  
>   /* No boot processor was found in mptable or ACPI MADT */
>   if (!num_processors) {
> - int apicid = boot_cpu_physical_apicid;
> - int cpu = hard_smp_processor_id();
> + if (boot_cpu_has(X86_FEATURE_APIC)) {


It looks okay to gate on X86_FEATURE_APIC, but not sure if it should be

 cpu_has(_data(0), X86_FEATURE_APIC)

since smp_store_boot_cpu_info() was already called.

tglx?

P.




> + int apicid = boot_cpu_physical_apicid;
> + int cpu = hard_smp_processor_id();
>  
> - pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
> + pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
>  
> - /* Make sure boot cpu is enumerated */
> - if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
> - apic->apic_id_valid(apicid))
> - generic_processor_info(apicid, boot_cpu_apic_version);
> + /* Make sure boot cpu is enumerated */
> + if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
> + apic->apic_id_valid(apicid))
> + generic_processor_info(apicid, 
> boot_cpu_apic_version);
> + }
>  
>   if (!num_processors)
>   num_processors = 1;
> 

[PATCH] arch/x86: Don't try to poke disabled/non-existent APIC

[ville . syrjala]

From: Ville Syrjälä 

Apparently trying to poke a disabled or non-existent APIC
leads to a box that doesn't even boot. Let's not do that.

No real clue if this is the right fix, but at least my
P3 machine boots again.

Cc: sta...@vger.kernel.org
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: x...@kernel.org
Cc: Prarit Bhargava 
Cc: Peter Zijlstra 
Cc: Len Brown 
Cc: Borislav Petkov 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Juergen Gross 
Cc: dyo...@redhat.com
Cc: Eric Biederman 
Cc: ke...@lists.infradead.org
Cc: Thomas Gleixner 
Fixes: 2a51fe083eba ("arch/x86: Handle non enumerated CPU after physical 
hotplug")
Signed-off-by: Ville Syrjälä 
---
 arch/x86/kernel/smpboot.c | 16 +---
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 951f093a96fe..42f5eb7b4f6c 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1409,15 +1409,17 @@ __init void prefill_possible_map(void)
 
/* No boot processor was found in mptable or ACPI MADT */
if (!num_processors) {
-   int apicid = boot_cpu_physical_apicid;
-   int cpu = hard_smp_processor_id();
+   if (boot_cpu_has(X86_FEATURE_APIC)) {
+   int apicid = boot_cpu_physical_apicid;
+   int cpu = hard_smp_processor_id();
 
-   pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
+   pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
 
-   /* Make sure boot cpu is enumerated */
-   if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
-   apic->apic_id_valid(apicid))
-   generic_processor_info(apicid, boot_cpu_apic_version);
+   /* Make sure boot cpu is enumerated */
+   if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
+   apic->apic_id_valid(apicid))
+   generic_processor_info(apicid, 
boot_cpu_apic_version);
+   }
 
if (!num_processors)
num_processors = 1;
-- 
2.7.4

[PATCH] arch/x86: Don't try to poke disabled/non-existent APIC

[ville . syrjala]

From: Ville Syrjälä 

Apparently trying to poke a disabled or non-existent APIC
leads to a box that doesn't even boot. Let's not do that.

No real clue if this is the right fix, but at least my
P3 machine boots again.

Cc: sta...@vger.kernel.org
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: x...@kernel.org
Cc: Prarit Bhargava 
Cc: Peter Zijlstra 
Cc: Len Brown 
Cc: Borislav Petkov 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Juergen Gross 
Cc: dyo...@redhat.com
Cc: Eric Biederman 
Cc: ke...@lists.infradead.org
Cc: Thomas Gleixner 
Fixes: 2a51fe083eba ("arch/x86: Handle non enumerated CPU after physical 
hotplug")
Signed-off-by: Ville Syrjälä 
---
 arch/x86/kernel/smpboot.c | 16 +---
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 951f093a96fe..42f5eb7b4f6c 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1409,15 +1409,17 @@ __init void prefill_possible_map(void)
 
/* No boot processor was found in mptable or ACPI MADT */
if (!num_processors) {
-   int apicid = boot_cpu_physical_apicid;
-   int cpu = hard_smp_processor_id();
+   if (boot_cpu_has(X86_FEATURE_APIC)) {
+   int apicid = boot_cpu_physical_apicid;
+   int cpu = hard_smp_processor_id();
 
-   pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
+   pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
 
-   /* Make sure boot cpu is enumerated */
-   if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
-   apic->apic_id_valid(apicid))
-   generic_processor_info(apicid, boot_cpu_apic_version);
+   /* Make sure boot cpu is enumerated */
+   if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
+   apic->apic_id_valid(apicid))
+   generic_processor_info(apicid, 
boot_cpu_apic_version);
+   }
 
if (!num_processors)
num_processors = 1;
-- 
2.7.4