On 1/23/2019 5:16 PM, Kazuhito Hagio wrote:
> 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)
> ...
Considering hugepage and the code, it might be better to add
a local variable for the mask value to __vtop4_x86_64() function
and mask it without condition, for example
unsigned long sme_mask = ~0UL;
if (NUMBER(sme_mask) != NOT_FOUND_NUMBER)
sme_mask = ~(NUMBER(sme_mask));
...
pud_paddr = pgd & ENTRY_MASK & sme_mask;
to avoid adding lots of 'if' statements.
Thanks,
Kazu
>
> 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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