在 2019年01月29日 03:45, Kazuhito Hagio 写道:
> On 1/28/2019 9:24 AM, Lendacky, Thomas wrote:
>> On 1/27/19 11:46 PM, Lianbo Jiang wrote:
>>> For AMD machine with SME feature, if SME is enabled in the first
>>> kernel, the crashed kernel's page table(pgd/pud/pmd/pte) contains
>>> the memory encryption mask, so makedumpfile needs to remove the
>>> memory encryption mask to obtain the true physical address.
>>>
>>> Signed-off-by: Lianbo Jiang <lijiang@xxxxxxxxxx>
>>> ---
>>> Changes since v1:
>>> 1. Merge them into a patch.
>>> 2. The sme_mask is not an enum number, remove it.
>>> 3. Sanity check whether the sme_mask is in vmcoreinfo.
>>> 4. Deal with the huge pages case.
>>> 5. Cover the 5-level path.
>>>
>>> arch/x86_64.c | 30 +++++++++++++++++-------------
>>> makedumpfile.c | 4 ++++
>>> makedumpfile.h | 1 +
>>> 3 files changed, 22 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/arch/x86_64.c b/arch/x86_64.c
>>> index 537fb78..7b3ed10 100644
>>> --- a/arch/x86_64.c
>>> +++ b/arch/x86_64.c
>>> @@ -291,6 +291,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>>> unsigned long page_dir, pgd, pud_paddr, pud_pte, pmd_paddr, pmd_pte;
>>> unsigned long pte_paddr, pte;
>>> unsigned long p4d_paddr, p4d_pte;
>>> + unsigned long sme_me_mask = ~0UL;
>>>
>>> /*
>>> * Get PGD.
>>> @@ -302,6 +303,9 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>>> return NOT_PADDR;
>>> }
>>>
>>> + if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
>>> + sme_me_mask = ~(NUMBER(sme_mask));
>>
>> This is a bit confusing since this isn't the sme_me_mask any more, but the
>> complement. Might want to somehow rename this so that it doesn't cause any
>> confusion.
>>
>>> +
>>> if (check_5level_paging()) {
>>> page_dir += pgd5_index(vaddr) * sizeof(unsigned long);
>>> if (!readmem(PADDR, page_dir, &pgd, sizeof pgd)) {
>>> @@ -309,7 +313,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>>> return NOT_PADDR;
>>> }
>>> if (info->vaddr_for_vtop == vaddr)
>>> - MSG(" PGD : %16lx => %16lx\n", page_dir, pgd);
>>> + MSG(" PGD : %16lx => %16lx\n", page_dir, (pgd & sme_me_mask));
>>
>> No need to remove the mask here. You're just printing out the value of
>> the entry. It might be nice to know whether the encryption bit is set or
>> not - after all, ENTRY_MASK is still part of this value.
>
> Agreed.
>
>>
>>>
>>> if (!(pgd & _PAGE_PRESENT)) {
>>> ERRMSG("Can't get a valid pgd.\n");
>>> @@ -318,20 +322,20 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>>> /*
>>> * Get P4D.
>>> */
>>> - p4d_paddr = pgd & ENTRY_MASK;
>>> + p4d_paddr = pgd & ENTRY_MASK & sme_me_mask;
>>
>> This goes back to my original comment that you should just make a local
>> variable that is "ENTRY_MASK & ~(NUMBER(sme_mask))" since you are
>> performing this ANDing everywhere ENTRY_MASK is used - except then you
>> miss the one at the very end of this routine on the return statement.
>
> This was my idea I said to Lianbo before seeing your comment, but
> yes, including ENTRY_MASK in a local variable is better than that.
> Thanks for your good suggestion.
>
> As for the variable's name, I think that "entry_mask" is good enough,
> but any better name?
>
> unsigned long entry_mask = ENTRY_MASK;
>
> if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
> entry_mask &= ~(NUMBER(sme_mask));
> ...
> p4d_paddr = pgd & entry_mask;
>
Ok. Thanks.
> And, I found that the find_vmemmap_x86_64() function also uses the
> page table for the -e option and looks to be affected by SME.
> Lianbo, would you fix the function, too?
>
Yes, it's my pleasure. Thank you, Kazu.
I will fix this function in patch v3.
Regards,
Lianbo
> Thanks,
> Kazu
>
>>
>>> p4d_paddr += p4d_index(vaddr) * sizeof(unsigned long);
>>> if (!readmem(PADDR, p4d_paddr, &p4d_pte, sizeof p4d_pte)) {
>>> ERRMSG("Can't get p4d_pte (p4d_paddr:%lx).\n", p4d_paddr);
>>> return NOT_PADDR;
>>> }
>>> if (info->vaddr_for_vtop == vaddr)
>>> - MSG(" P4D : %16lx => %16lx\n", p4d_paddr, p4d_pte);
>>> + MSG(" P4D : %16lx => %16lx\n", p4d_paddr, (p4d_pte & sme_me_mask));
>>>
>>> if (!(p4d_pte & _PAGE_PRESENT)) {
>>> ERRMSG("Can't get a valid p4d_pte.\n");
>>> return NOT_PADDR;
>>> }
>>> - pud_paddr = p4d_pte & ENTRY_MASK;
>>> + pud_paddr = p4d_pte & ENTRY_MASK & sme_me_mask;
>>> }else {
>>> page_dir += pgd_index(vaddr) * sizeof(unsigned long);
>>> if (!readmem(PADDR, page_dir, &pgd, sizeof pgd)) {
>>> @@ -339,13 +343,13 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>>> return NOT_PADDR;
>>> }
>>> if (info->vaddr_for_vtop == vaddr)
>>> - MSG(" PGD : %16lx => %16lx\n", page_dir, pgd);
>>> + MSG(" PGD : %16lx => %16lx\n", page_dir, (pgd & sme_me_mask));
>>>
>>> if (!(pgd & _PAGE_PRESENT)) {
>>> ERRMSG("Can't get a valid pgd.\n");
>>> return NOT_PADDR;
>>> }
>>> - pud_paddr = pgd & ENTRY_MASK;
>>> + pud_paddr = pgd & ENTRY_MASK & sme_me_mask;
>>> }
>>>
>>> /*
>>> @@ -357,47 +361,47 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>>> return NOT_PADDR;
>>> }
>>> if (info->vaddr_for_vtop == vaddr)
>>> - MSG(" PUD : %16lx => %16lx\n", pud_paddr, pud_pte);
>>> + MSG(" PUD : %16lx => %16lx\n", pud_paddr, (pud_pte & sme_me_mask));
>>>
>>> if (!(pud_pte & _PAGE_PRESENT)) {
>>> ERRMSG("Can't get a valid pud_pte.\n");
>>> return NOT_PADDR;
>>> }
>>> if (pud_pte & _PAGE_PSE) /* 1GB pages */
>>> - return (pud_pte & ENTRY_MASK & PUD_MASK) +
>>> + return (pud_pte & ENTRY_MASK & PUD_MASK & sme_me_mask) +
>>> (vaddr & ~PUD_MASK);
>>>
>>> /*
>>> * Get PMD.
>>> */
>>> - pmd_paddr = pud_pte & ENTRY_MASK;
>>> + pmd_paddr = pud_pte & ENTRY_MASK & sme_me_mask;
>>> pmd_paddr += pmd_index(vaddr) * sizeof(unsigned long);
>>> if (!readmem(PADDR, pmd_paddr, &pmd_pte, sizeof pmd_pte)) {
>>> ERRMSG("Can't get pmd_pte (pmd_paddr:%lx).\n", pmd_paddr);
>>> return NOT_PADDR;
>>> }
>>> if (info->vaddr_for_vtop == vaddr)
>>> - MSG(" PMD : %16lx => %16lx\n", pmd_paddr, pmd_pte);
>>> + MSG(" PMD : %16lx => %16lx\n", pmd_paddr, (pmd_pte & sme_me_mask));
>>>
>>> if (!(pmd_pte & _PAGE_PRESENT)) {
>>> ERRMSG("Can't get a valid pmd_pte.\n");
>>> return NOT_PADDR;
>>> }
>>> if (pmd_pte & _PAGE_PSE) /* 2MB pages */
>>> - return (pmd_pte & ENTRY_MASK & PMD_MASK) +
>>> + return (pmd_pte & ENTRY_MASK & PMD_MASK & sme_me_mask) +
>>> (vaddr & ~PMD_MASK);
>>>
>>> /*
>>> * Get PTE.
>>> */
>>> - pte_paddr = pmd_pte & ENTRY_MASK;
>>> + pte_paddr = pmd_pte & ENTRY_MASK & sme_me_mask;
>>> pte_paddr += pte_index(vaddr) * sizeof(unsigned long);
>>> if (!readmem(PADDR, pte_paddr, &pte, sizeof pte)) {
>>> ERRMSG("Can't get pte (pte_paddr:%lx).\n", pte_paddr);
>>> return NOT_PADDR;
>>> }
>>> if (info->vaddr_for_vtop == vaddr)
>>> - MSG(" PTE : %16lx => %16lx\n", pte_paddr, pte);
>>> + MSG(" PTE : %16lx => %16lx\n", pte_paddr, (pte & sme_me_mask));
>>>
>>> if (!(pte & _PAGE_PRESENT)) {
>>> ERRMSG("Can't get a valid pte.\n");
>>
>> Just after here is where I think an "& sme_me_mask" is missing...
>>
>> Thanks,
>> Tom
>>
>>> diff --git a/makedumpfile.c b/makedumpfile.c
>>> index 8923538..2237eb8 100644
>>> --- a/makedumpfile.c
>>> +++ b/makedumpfile.c
>>> @@ -977,6 +977,8 @@ next_page:
>>> read_size = MIN(info->page_size - PAGEOFFSET(paddr), size);
>>>
>>> pgaddr = PAGEBASE(paddr);
>>> + if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
>>> + pgaddr = pgaddr & ~(NUMBER(sme_mask));
>>> pgbuf = cache_search(pgaddr, read_size);
>>> if (!pgbuf) {
>>> ++cache_miss;
>>> @@ -2276,6 +2278,7 @@ write_vmcoreinfo_data(void)
>>> WRITE_NUMBER("NR_FREE_PAGES", NR_FREE_PAGES);
>>> WRITE_NUMBER("N_ONLINE", N_ONLINE);
>>> WRITE_NUMBER("pgtable_l5_enabled", pgtable_l5_enabled);
>>> + WRITE_NUMBER("sme_mask", sme_mask);
>>>
>>> WRITE_NUMBER("PG_lru", PG_lru);
>>> WRITE_NUMBER("PG_private", PG_private);
>>> @@ -2672,6 +2675,7 @@ read_vmcoreinfo(void)
>>> READ_NUMBER("NR_FREE_PAGES", NR_FREE_PAGES);
>>> READ_NUMBER("N_ONLINE", N_ONLINE);
>>> READ_NUMBER("pgtable_l5_enabled", pgtable_l5_enabled);
>>> + READ_NUMBER("sme_mask", sme_mask);
>>>
>>> READ_NUMBER("PG_lru", PG_lru);
>>> READ_NUMBER("PG_private", PG_private);
>>> diff --git a/makedumpfile.h b/makedumpfile.h
>>> index 73813ed..e97b2e7 100644
>>> --- a/makedumpfile.h
>>> +++ b/makedumpfile.h
>>> @@ -1912,6 +1912,7 @@ struct number_table {
>>> long NR_FREE_PAGES;
>>> long N_ONLINE;
>>> long pgtable_l5_enabled;
>>> + long sme_mask;
>>>
>>> /*
>>> * Page flags
>>>
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