On 1/22/2019 3:03 AM, 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>
> ---
> arch/x86_64.c | 3 +++
> makedumpfile.c | 1 +
> 2 files changed, 4 insertions(+)
>
> diff --git a/arch/x86_64.c b/arch/x86_64.c
> index 537fb78..7651d36 100644
> --- a/arch/x86_64.c
> +++ b/arch/x86_64.c
> @@ -346,6 +346,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
> return NOT_PADDR;
> }
> pud_paddr = pgd & ENTRY_MASK;
> + pud_paddr = pud_paddr & ~(NUMBER(sme_mask));
> }
>
> /*
> @@ -371,6 +372,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
> * Get PMD.
> */
> pmd_paddr = pud_pte & ENTRY_MASK;
> + pmd_paddr = pmd_paddr & ~(NUMBER(sme_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);
> @@ -391,6 +393,7 @@ __vtop4_x86_64(unsigned long vaddr, unsigned long pagetable)
> * Get PTE.
> */
> pte_paddr = pmd_pte & ENTRY_MASK;
> + pte_paddr = pte_paddr & ~(NUMBER(sme_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);
> diff --git a/makedumpfile.c b/makedumpfile.c
> index a03aaa1..81c7bb4 100644
> --- a/makedumpfile.c
> +++ b/makedumpfile.c
> @@ -977,6 +977,7 @@ next_page:
> read_size = MIN(info->page_size - PAGEOFFSET(paddr), size);
>
> pgaddr = PAGEBASE(paddr);
> + pgaddr = pgaddr & ~(NUMBER(sme_mask));
Since NUMBER(sme_mask) is initialized with -1 (NOT_FOUND_NUMBER),
if the sme_mask is not in vmcoreinfo, ~(NUMBER(sme_mask)) will be 0.
So the four lines added above need
if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
...
and, what I'm wondering is whether it doesn't need to take hugepages
into account such as this
392 if (pmd_pte & _PAGE_PSE) /* 2MB pages */
393 return (pmd_pte & ENTRY_MASK & PMD_MASK) +
394 (vaddr & ~PMD_MASK);
"arch/x86_64.c"
Thanks,
Kazu
> pgbuf = cache_search(pgaddr, read_size);
> if (!pgbuf) {
> ++cache_miss;
> --
> 2.17.1
>
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