在 2019年01月28日 22:24, Lendacky, Thomas 写道:
> 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.
>
Thanks for your comment.
I will change the sme_me_mask to entry_mask in patch v3.
>> +
>> 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.
>
Ok, i will remove it in patch v3.
>>
>> 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.
>
Ok, i will improve them in patch v3.
>> 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...
>
Ok. Thank you for pointing out my mistake. I will improve them in patch v3.
Regards,
Lianbo
> 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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