Re: [Crash-utility] [PATCH] x86_64: Fix for AMD SME issue

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 <lijiang(a)redhat.com&gt; > --- > 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..

> 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?

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);