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 <lijiang@xxxxxxxxxx>
>> ---
>> 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 ]
>> + * 0000_0000_0000_0000_1000_0000_0000_0000_0000_0000_..._0000
>> + * 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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