在 2019年02月05日 01:12, Kazuhito Hagio 写道:
>> [PATCH v3] Remove the memory encryption mask to obtain the true physical address
>
> I forgot to comment on the subject and the commit log..
> I'll change this to
>
> x86_64: Add support for AMD Secure Memory Encryption
>
> On 1/29/2019 9:48 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.
>
> I added a few official words from some documents:
> ---
> On AMD machine with Secure Memory Encryption (SME) feature, if SME is
> enabled, page tables contain a specific attribute bit (C-bit) in their
> entries to indicate whether a page is encrypted or unencrypted.
>
> So get NUMBER(sme_mask) from vmcoreinfo, which stores the value of
> the C-bit position, and drop it to obtain the true physical address.
> ---
>
> If these are OK, I'll modify them when merging, so you don't need
> to repost.
>
It's fine to me. Thank you, Kazu.
Regards,
Lianbo
> And, I'm thinking to merge this after the kernel patch gets merged
> into the mainline.
>
> Thanks for your work.
> Kazu
>
>>
>> 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.
>>
>> Changes since v2:
>> 1. Change the sme_me_mask to entry_mask.
>> 2. No need to remove the mask when makedumpfile prints out the
>> value of the entry.
>> 3. Remove the sme mask from the pte at the end of the __vtop4_x86_64().
>> 4. Also need to remove the sme mask from page table entry in
>> find_vmemmap_x86_64()
>>
>> arch/x86_64.c | 30 +++++++++++++++++++-----------
>> makedumpfile.c | 4 ++++
>> makedumpfile.h | 1 +
>> 3 files changed, 24 insertions(+), 11 deletions(-)
>>
>> diff --git a/arch/x86_64.c b/arch/x86_64.c
>> index 537fb78..9977466 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 entry_mask = ENTRY_MASK;
>>
>> /*
>> * 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)
>> + entry_mask &= ~(NUMBER(sme_mask));
>> +
>> if (check_5level_paging()) {
>> page_dir += pgd5_index(vaddr) * sizeof(unsigned long);
>> if (!readmem(PADDR, page_dir, &pgd, sizeof pgd)) {
>> @@ -318,7 +322,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>> /*
>> * Get P4D.
>> */
>> - p4d_paddr = pgd & ENTRY_MASK;
>> + p4d_paddr = pgd & entry_mask;
>> 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);
>> @@ -331,7 +335,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>> ERRMSG("Can't get a valid p4d_pte.\n");
>> return NOT_PADDR;
>> }
>> - pud_paddr = p4d_pte & ENTRY_MASK;
>> + pud_paddr = p4d_pte & entry_mask;
>> }else {
>> page_dir += pgd_index(vaddr) * sizeof(unsigned long);
>> if (!readmem(PADDR, page_dir, &pgd, sizeof pgd)) {
>> @@ -345,7 +349,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>> ERRMSG("Can't get a valid pgd.\n");
>> return NOT_PADDR;
>> }
>> - pud_paddr = pgd & ENTRY_MASK;
>> + pud_paddr = pgd & entry_mask;
>> }
>>
>> /*
>> @@ -364,13 +368,13 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>> return NOT_PADDR;
>> }
>> if (pud_pte & _PAGE_PSE) /* 1GB pages */
>> - return (pud_pte & ENTRY_MASK & PUD_MASK) +
>> + return (pud_pte & entry_mask & PUD_MASK) +
>> (vaddr & ~PUD_MASK);
>>
>> /*
>> * Get PMD.
>> */
>> - pmd_paddr = pud_pte & ENTRY_MASK;
>> + pmd_paddr = pud_pte & entry_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);
>> @@ -384,13 +388,13 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>> return NOT_PADDR;
>> }
>> if (pmd_pte & _PAGE_PSE) /* 2MB pages */
>> - return (pmd_pte & ENTRY_MASK & PMD_MASK) +
>> + return (pmd_pte & entry_mask & PMD_MASK) +
>> (vaddr & ~PMD_MASK);
>>
>> /*
>> * Get PTE.
>> */
>> - pte_paddr = pmd_pte & ENTRY_MASK;
>> + pte_paddr = pmd_pte & entry_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);
>> @@ -403,7 +407,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
>> ERRMSG("Can't get a valid pte.\n");
>> return NOT_PADDR;
>> }
>> - return (pte & ENTRY_MASK) + PAGEOFFSET(vaddr);
>> + return (pte & entry_mask) + PAGEOFFSET(vaddr);
>> }
>>
>> unsigned long long
>> @@ -636,6 +640,7 @@ find_vmemmap_x86_64()
>> unsigned long pmd, tpfn;
>> unsigned long pvaddr = 0;
>> unsigned long data_addr = 0, last_data_addr = 0, start_data_addr = 0;
>> + unsigned long pmask = PMASK;
>> /*
>> * data_addr is the paddr of the page holding the page structs.
>> * We keep lists of contiguous pages and the pfn's that their
>> @@ -656,6 +661,9 @@ find_vmemmap_x86_64()
>> return FAILED;
>> }
>>
>> + if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
>> + pmask &= ~(NUMBER(sme_mask));
>> +
>> pagestructsize = size_table.page;
>> hugepagesize = PTRS_PER_PMD * info->page_size;
>> vaddr_base = info->vmemmap_start;
>> @@ -686,7 +694,7 @@ find_vmemmap_x86_64()
>> }
>>
>> /* mask the pgd entry for the address of the pud page */
>> - pud_addr &= PMASK;
>> + pud_addr &= pmask;
>> if (pud_addr == 0)
>> continue;
>> /* read the entire pud page */
>> @@ -699,7 +707,7 @@ find_vmemmap_x86_64()
>> /* pudp points to an entry in the pud page */
>> for (pudp = (unsigned long *)pud_page, pudindex = 0;
>> pudindex < PTRS_PER_PUD; pudindex++, pudp++) {
>> - pmd_addr = *pudp & PMASK;
>> + pmd_addr = *pudp & pmask;
>> /* read the entire pmd page */
>> if (pmd_addr == 0)
>> continue;
>> @@ -741,7 +749,7 @@ find_vmemmap_x86_64()
>> * - we discontiguous page is a string of valids
>> */
>> if (pmd) {
>> - data_addr = (pmd & PMASK);
>> + data_addr = (pmd & pmask);
>> if (start_range) {
>> /* first-time kludge */
>> start_data_addr = data_addr;
>> 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
>> --
>> 2.17.1
>>
>
>
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