Re: [PATCH 2/2 v2] kdump, vmcoreinfo: Export the value of sme mask to vmcoreinfo

2018-12-09 Thread lijiang 
在 2018年12月05日 18:24, Dave Young 写道:
> On 12/02/18 at 11:08am, Lianbo Jiang wrote:
>> For AMD machine with SME feature, makedumpfile tools need to know
>> whether the crash kernel was encrypted or not. If SME is enabled
>> in the first kernel, the crash kernel's page table(pgd/pud/pmd/pte)
>> contains the memory encryption mask, so need to remove the sme mask
>> to obtain the true physical address.
>>
>> Signed-off-by: Lianbo Jiang 
>> ---
>>  arch/x86/kernel/machine_kexec_64.c | 14 ++
>>  1 file changed, 14 insertions(+)
>>
>> diff --git a/arch/x86/kernel/machine_kexec_64.c 
>> b/arch/x86/kernel/machine_kexec_64.c
>> index 4c8acdfdc5a7..1860fe24117d 100644
>> --- a/arch/x86/kernel/machine_kexec_64.c
>> +++ b/arch/x86/kernel/machine_kexec_64.c
>> @@ -352,10 +352,24 @@ void machine_kexec(struct kimage *image)
>>  
>>  void arch_crash_save_vmcoreinfo(void)
>>  {
>> +u64 sme_mask = sme_me_mask;
>> +
>>  VMCOREINFO_NUMBER(phys_base);
>>  VMCOREINFO_SYMBOL(init_top_pgt);
>>  vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
>>  pgtable_l5_enabled());
>> +/*
>> + * Currently, the local variable 'sme_mask' stores the value of
>> + * sme_me_mask(bit 47), and also write the value of sme_mask to
>> + * the vmcoreinfo.
>> + * If need, the bit(sme_mask) might be redefined in the future,
>> + * but the 'bit63' will be reserved.
>> + * For example:
>> + * [ misc  ][ enc bit  ][ other misc SME info   ]
>> + * ____1000______..._
>> + * 63   59   55   51   47   43   39   35   31   27   ... 3
>> + */
>> +VMCOREINFO_NUMBER(sme_mask);
> 
> #define VMCOREINFO_NUMBER(name) \
> vmcoreinfo_append_str("NUMBER(%s)=%ld\n", #name, (long)name)
> 
> VMCOREINFO_NUMBER is defined as above, so it looks questionable to add
> more users of that for different data types although it may work in real
> world.
> 

Thank you, Dave.
For the sme_mask, the bit47 is set '1', and the VMCOREINFO_NUMBER is a signed
64 bit number(x86_64), it is big enough to the sme_mask.


> A new macro like below may be better, may need to choose a better name
> though:
> _VMCOREINFO_NUMBER(name, format, type)
> so you can pass the format specifier and data types explictly
> 

That should be a good suggestion. But for now, maybe it is not time for 
improving it.
Because it is still big enough.

Thanks.
Lianbo

> 
>>  
>>  #ifdef CONFIG_NUMA
>>  VMCOREINFO_SYMBOL(node_data);
>> -- 
>> 2.17.1
>>
> 
> Thanks
> Dave
> 

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Re: [PATCH 2/2 v2] kdump, vmcoreinfo: Export the value of sme mask to vmcoreinfo

2018-12-05 Thread Dave Young 
On 12/02/18 at 11:08am, Lianbo Jiang wrote:
> For AMD machine with SME feature, makedumpfile tools need to know
> whether the crash kernel was encrypted or not. If SME is enabled
> in the first kernel, the crash kernel's page table(pgd/pud/pmd/pte)
> contains the memory encryption mask, so need to remove the sme mask
> to obtain the true physical address.
> 
> Signed-off-by: Lianbo Jiang 
> ---
>  arch/x86/kernel/machine_kexec_64.c | 14 ++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/arch/x86/kernel/machine_kexec_64.c 
> b/arch/x86/kernel/machine_kexec_64.c
> index 4c8acdfdc5a7..1860fe24117d 100644
> --- a/arch/x86/kernel/machine_kexec_64.c
> +++ b/arch/x86/kernel/machine_kexec_64.c
> @@ -352,10 +352,24 @@ void machine_kexec(struct kimage *image)
>  
>  void arch_crash_save_vmcoreinfo(void)
>  {
> + u64 sme_mask = sme_me_mask;
> +
>   VMCOREINFO_NUMBER(phys_base);
>   VMCOREINFO_SYMBOL(init_top_pgt);
>   vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
>   pgtable_l5_enabled());
> + /*
> +  * Currently, the local variable 'sme_mask' stores the value of
> +  * sme_me_mask(bit 47), and also write the value of sme_mask to
> +  * the vmcoreinfo.
> +  * If need, the bit(sme_mask) might be redefined in the future,
> +  * but the 'bit63' will be reserved.
> +  * For example:
> +  * [ misc  ][ enc bit  ][ other misc SME info   ]
> +  * ____1000______..._
> +  * 63   59   55   51   47   43   39   35   31   27   ... 3
> +  */
> + VMCOREINFO_NUMBER(sme_mask);

#define VMCOREINFO_NUMBER(name) \
vmcoreinfo_append_str("NUMBER(%s)=%ld\n", #name, (long)name)

VMCOREINFO_NUMBER is defined as above, so it looks questionable to add
more users of that for different data types although it may work in real
world.

A new macro like below may be better, may need to choose a better name
though:
_VMCOREINFO_NUMBER(name, format, type)
so you can pass the format specifier and data types explictly


>  
>  #ifdef CONFIG_NUMA
>   VMCOREINFO_SYMBOL(node_data);
> -- 
> 2.17.1
> 

Thanks
Dave

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[PATCH 2/2 v2] kdump, vmcoreinfo: Export the value of sme mask to vmcoreinfo

2018-12-01 Thread Lianbo Jiang 
For AMD machine with SME feature, makedumpfile tools need to know
whether the crash kernel was encrypted or not. If SME is enabled
in the first kernel, the crash kernel's page table(pgd/pud/pmd/pte)
contains the memory encryption mask, so need to remove the sme mask
to obtain the true physical address.

Signed-off-by: Lianbo Jiang 
---
 arch/x86/kernel/machine_kexec_64.c | 14 ++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/kernel/machine_kexec_64.c 
b/arch/x86/kernel/machine_kexec_64.c
index 4c8acdfdc5a7..1860fe24117d 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -352,10 +352,24 @@ void machine_kexec(struct kimage *image)
 
 void arch_crash_save_vmcoreinfo(void)
 {
+   u64 sme_mask = sme_me_mask;
+
VMCOREINFO_NUMBER(phys_base);
VMCOREINFO_SYMBOL(init_top_pgt);
vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
pgtable_l5_enabled());
+   /*
+* Currently, the local variable 'sme_mask' stores the value of
+* sme_me_mask(bit 47), and also write the value of sme_mask to
+* the vmcoreinfo.
+* If need, the bit(sme_mask) might be redefined in the future,
+* but the 'bit63' will be reserved.
+* For example:
+* [ misc  ][ enc bit  ][ other misc SME info   ]
+* ____1000______..._
+* 63   59   55   51   47   43   39   35   31   27   ... 3
+*/
+   VMCOREINFO_NUMBER(sme_mask);
 
 #ifdef CONFIG_NUMA
VMCOREINFO_SYMBOL(node_data);
-- 
2.17.1


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