Hi, Kazu
Thank you for the comment.
On Fri, Jul 29, 2022 at 5:19 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio...@nec.com>
wrote:
> On 2022/07/28 16:11, Lianbo Jiang wrote:
> > Kernel commit changes(see [1]/[2]) may cause the failure of crash-utility
> > with the following error:
> >
> > #./crash /home/vmlinux /home/vmcore
> > ...
> > For help, type "help".
> > Type "apropos word" to search for commands related to "word"...
> >
> > crash: seek error: physical address: 8000760a14000 type: "p4d page"
> >
> > Let's get the "NUMBER(sme_mask)" from vmcoreinfo, and try to remove
> > the C-bit from the page table entries, the intention is to get the
> > true physical address.
> >
> > Related kernel commits:
> > [1] aad983913d77 ("x86/mm/encrypt: Simplify sme_populate_pgd() and
> sme_populate_pgd_large()")
> > [2] e7d445ab26db ("x86/sme: Use #define USE_EARLY_PGTABLE_L5 in
> mem_encrypt_identity.c")
> >
> > Signed-off-by: Lianbo Jiang <liji...@redhat.com>
> > ---
> > Note: This issue also occurs in live debugging system.
> >
> > defs.h | 1 +
> > x86_64.c | 19 ++++++++++++++++---
> > 2 files changed, 17 insertions(+), 3 deletions(-)
> >
> > diff --git a/defs.h b/defs.h
> > index 9b1b69a4f421..9d6d8916284b 100644
> > --- a/defs.h
> > +++ b/defs.h
> > @@ -6198,6 +6198,7 @@ struct machine_specific {
> > ulong cpu_entry_area_end;
> > ulong page_offset_force;
> > char **exception_functions;
> > + ulong sme_mask;
> > };
> >
> > #define KSYMS_START (0x1)
> > diff --git a/x86_64.c b/x86_64.c
> > index cfafbcc4dabe..1dae39bcbb3c 100644
> > --- a/x86_64.c
> > +++ b/x86_64.c
> > @@ -208,6 +208,10 @@ x86_64_init(int when)
> > machdep->machspec->kernel_image_size =
> dtol(string, QUIET, NULL);
> > free(string);
> > }
> > + if ((string = pc->read_vmcoreinfo("NUMBER(sme_mask)"))) {
> > + machdep->machspec->sme_mask = dtol(string, QUIET,
> NULL);
> > + free(string);
> > + }
> > if (SADUMP_DUMPFILE() || QEMU_MEM_DUMP_NO_VMCOREINFO() ||
> > VMSS_DUMPFILE())
> > /* Need for calculation of kaslr_offset and
> phys_base */
> > @@ -940,6 +944,7 @@ x86_64_dump_machdep_table(ulong arg)
> > ms->kernel_image_size/MEGABYTES(1));
> > else
> > fprintf(fp, "(uninitialized)\n");
> > + fprintf(fp, " sme_mask: %lx\n", ms->sme_mask);
> > fprintf(fp, " physical_mask_shift: %ld\n",
> ms->physical_mask_shift);
> > fprintf(fp, " pgdir_shift: %ld\n", ms->pgdir_shift);
> > fprintf(fp, " GART_start: %lx\n", ms->GART_start);
> > @@ -1817,7 +1822,7 @@ x86_64_kpgd_offset(ulong kvaddr, int verbose, int
> IS_XEN)
> > if (IS_XEN)
> > fprintf(fp, "PAGE DIRECTORY: %lx [machine]\n",
> *pgd);
> > else
> > - fprintf(fp, "PAGE DIRECTORY: %lx\n", *pgd);
> > + fprintf(fp, "PAGE DIRECTORY: %lx\n", *pgd &
> ~machdep->machspec->sme_mask);
> > }
> >
> > return pgd;
> > @@ -1854,7 +1859,7 @@ x86_64_upgd_offset_legacy(struct task_context *tc,
> ulong uvaddr, int verbose, in
> > if (IS_XEN)
> > fprintf(fp, " PGD: %lx => %lx [machine]\n",
> (ulong)pud, pud_pte);
> > else
> > - fprintf(fp, " PGD: %lx => %lx\n", (ulong)pud,
> pud_pte);
> > + fprintf(fp, " PGD: %lx => %lx\n", (ulong)pud,
> pud_pte & ~machdep->machspec->sme_mask);
> > }
> >
> > return pud_pte;
> > @@ -1885,7 +1890,7 @@ x86_64_upgd_offset(struct task_context *tc, ulong
> uvaddr, int verbose, int IS_XE
> > if (IS_XEN)
> > fprintf(fp, " PGD: %lx => %lx [machine]\n",
> (ulong)pgd, pgd_pte);
> > else
> > - fprintf(fp, " PGD: %lx => %lx\n", (ulong)pgd,
> pgd_pte);
> > + fprintf(fp, " PGD: %lx => %lx\n", (ulong)pgd,
> pgd_pte & ~machdep->machspec->sme_mask);
> > }
> >
> > return pgd_pte;
> > @@ -1903,9 +1908,11 @@ x86_64_p4d_offset(ulong pgd_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > ulong p4d_pte;
> >
> > p4d_paddr = pgd_pte & PHYSICAL_PAGE_MASK;
> > + p4d_paddr &= ~machdep->machspec->sme_mask;
> > FILL_P4D(p4d_paddr, PHYSADDR, PAGESIZE());
> > p4d = ((ulong *)p4d_paddr) + p4d_index(vaddr);
> > p4d_pte = ULONG(machdep->machspec->p4d + PAGEOFFSET(p4d));
> > + p4d_pte &= ~machdep->machspec->sme_mask;
> > if (verbose) {
> > if (IS_XEN)
> > fprintf(fp, " P4D: %lx => %lx [machine]\n",
> (ulong)p4d, p4d_pte);
> > @@ -1928,6 +1935,7 @@ x86_64_pud_offset(ulong pgd_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > ulong pud_pte;
> >
> > pud_paddr = pgd_pte & PHYSICAL_PAGE_MASK;
> > + pud_paddr &= ~machdep->machspec->sme_mask;
> >
> > if (IS_XEN) {
> > pud_paddr = xen_m2p(pud_paddr);
> > @@ -1938,6 +1946,7 @@ x86_64_pud_offset(ulong pgd_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > FILL_PUD(pud_paddr, PHYSADDR, PAGESIZE());
> > pud = ((ulong *)pud_paddr) + pud_index(vaddr);
> > pud_pte = ULONG(machdep->pud + PAGEOFFSET(pud));
> > + pud_pte &= ~machdep->machspec->sme_mask;
>
> Taking this for example, the pud_pte is masked here..
>
>
Good questions. This was based on two considerations:
[1] ensure to display the printing information as below:
...
P4D: 761c01a70 => 761c02067
PUD: 761c02b28 => 16bea5063
^^^^^^^^^^
Otherwise, it will display the address of PUD with the C-bit.
Or Remove the C-bit when printing information?
+ fprintf(fp, " PUD: %lx => %lx\n", (ulong)pud, pud_pte &
~machdep->machspec->sme_mask);
[2] consider the cases of using hugepage.
-On this machine, it supports 1G and 2M hugepage according to the
vmcore.
> > if (verbose) {
> > if (IS_XEN)
> > fprintf(fp, " PUD: %lx => %lx [machine]\n",
> (ulong)pud, pud_pte);
> > @@ -1960,6 +1969,7 @@ x86_64_pmd_offset(ulong pud_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > ulong pmd_pte;
> >
> > pmd_paddr = pud_pte & PHYSICAL_PAGE_MASK;
> > + pmd_paddr &= ~machdep->machspec->sme_mask;
>
> and also here the pud_pte is masked again. Is this needed?
>
>
They are needed, otherwise some crash commands may not work well, for
example:
...
kmem: seek error: kernel virtual address: ffedfea0c627ec28 type: "page
inuse"
...
Thanks.
Lianbo
Thanks,
> Kazu
>
> >
> > if (IS_XEN) {
> > pmd_paddr = xen_m2p(pmd_paddr);
> > @@ -1970,6 +1980,7 @@ x86_64_pmd_offset(ulong pud_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > FILL_PMD(pmd_paddr, PHYSADDR, PAGESIZE());
> > pmd = ((ulong *)pmd_paddr) + pmd_index(vaddr);
> > pmd_pte = ULONG(machdep->pmd + PAGEOFFSET(pmd));
> > + pmd_pte &= ~machdep->machspec->sme_mask;
> > if (verbose) {
> > if (IS_XEN)
> > fprintf(fp, " PMD: %lx => %lx [machine]\n",
> (ulong)pmd, pmd_pte);
> > @@ -1991,6 +2002,7 @@ x86_64_pte_offset(ulong pmd_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > ulong pte;
> >
> > pte_paddr = pmd_pte & PHYSICAL_PAGE_MASK;
> > + pte_paddr &= ~machdep->machspec->sme_mask;
> >
> > if (IS_XEN) {
> > pte_paddr = xen_m2p(pte_paddr);
> > @@ -2001,6 +2013,7 @@ x86_64_pte_offset(ulong pmd_pte, ulong vaddr, int
> verbose, int IS_XEN)
> > FILL_PTBL(pte_paddr, PHYSADDR, PAGESIZE());
> > ptep = ((ulong *)pte_paddr) + pte_index(vaddr);
> > pte = ULONG(machdep->ptbl + PAGEOFFSET(ptep));
> > + pte &= ~machdep->machspec->sme_mask;
> > if (verbose) {
> > if (IS_XEN)
> > fprintf(fp, " PTE: %lx => %lx [machine]\n",
> (ulong)ptep, pte);
--
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