[Crash-utility] [PATCH 3/5] Use XEN_MACHINE_ADDR command flag instead of overriding readmem

The intention is to switch off physical-to-machine address translation temporarily. Overriding readmem works, but only for a single file format. Using the flag is a better solution, because it does not add a dependency on a single file format. Unsetting the flag (rather than restoring it) is safe, because these functions are not called if XEN_MACHINE_ADDR is set in pc->curcmd_flags. Signed-off-by: Petr Tesarik <ptesarik(a)suse.com&gt; --- ia64.c | 22 ++++++++++------------ x86.c | 15 +++++++-------- x86_64.c | 15 +++++++-------- xen_dom0.c | 12 ++++++++++-- 4 files changed, 34 insertions(+), 30 deletions(-) diff --git a/ia64.c b/ia64.c index 60fcf20..2e1d15f 100644 --- a/ia64.c +++ b/ia64.c @@ -3983,13 +3983,12 @@ static int ia64_xen_kdump_p2m_create(struct xen_kdump_data *xkd) { /* - * Temporarily read physical (machine) addresses from vmcore by - * going directly to read_netdump() instead of via read_kdump(). + * Temporarily read physical (machine) addresses from vmcore. */ - pc->readmem = read_netdump; + pc->curcmd_flags |= XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) { - fprintf(fp, "readmem (temporary): read_netdump()\n"); + fprintf(fp, "readmem (temporary): force XEN_MACHINE_ADDR\n"); fprintf(fp, "ia64_xen_kdump_p2m_create: p2m_mfn: %lx\n", xkd->p2m_mfn); } @@ -4002,9 +4001,9 @@ ia64_xen_kdump_p2m_create(struct xen_kdump_data *xkd) xkd->p2m_frames = PAGESIZE()/sizeof(ulong); - pc->readmem = read_kdump; + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (restore): read_kdump()\n"); + fprintf(fp, "readmem (restore): p2m translation\n"); return TRUE; } @@ -4017,12 +4016,11 @@ ia64_xen_kdump_p2m(struct xen_kdump_data *xkd, physaddr_t pseudo) physaddr_t paddr; /* - * Temporarily read physical (machine) addresses from vmcore by - * going directly to read_netdump() instead of via read_kdump(). + * Temporarily read physical (machine) addresses from vmcore. */ - pc->readmem = read_netdump; + pc->curcmd_flags |= XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (temporary): read_netdump()\n"); + fprintf(fp, "readmem (temporary): force XEN_MACHINE_ADDR\n"); xkd->accesses += 2; @@ -4074,9 +4072,9 @@ ia64_xen_kdump_p2m(struct xen_kdump_data *xkd, physaddr_t pseudo) paddr = (paddr & _PFN_MASK) | PAGEOFFSET(pseudo); out: - pc->readmem = read_kdump; + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (restore): read_kdump()\n"); + fprintf(fp, "readmem (restore): p2m translation\n"); return paddr; } diff --git a/x86.c b/x86.c index f5a0275..54ce7a5 100644 --- a/x86.c +++ b/x86.c @@ -4541,12 +4541,11 @@ x86_xen_kdump_p2m_create(struct xen_kdump_data *xkd) int mfns[MAX_X86_FRAMES] = { 0 }; /* - * Temporarily read physical (machine) addresses from vmcore by - * going directly to read_netdump() instead of via read_kdump(). + * Temporarily read physical (machine) addresses from vmcore. */ - pc->readmem = read_netdump; + pc->curcmd_flags |= XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (temporary): read_netdump()\n"); + fprintf(fp, "readmem (temporary): force XEN_MACHINE_ADDR\n"); if (xkd->flags & KDUMP_CR3) goto use_cr3; @@ -4623,9 +4622,9 @@ x86_xen_kdump_p2m_create(struct xen_kdump_data *xkd) fprintf(fp, "\n"); } - pc->readmem = read_kdump; + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (restore): read_kdump()\n"); + fprintf(fp, "readmem (restore): p2m translation\n"); return TRUE; @@ -4714,9 +4713,9 @@ use_cr3: machdep->last_ptbl_read = 0; machdep->last_pmd_read = 0; machdep->last_pgd_read = 0; - pc->readmem = read_kdump; + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (restore): read_kdump()\n"); + fprintf(fp, "readmem (restore): p2m translation\n"); return TRUE; } diff --git a/x86_64.c b/x86_64.c index 975354d..ff6fdd5 100644 --- a/x86_64.c +++ b/x86_64.c @@ -5748,12 +5748,11 @@ x86_64_xen_kdump_p2m_create(struct xen_kdump_data *xkd) struct syment *sp; /* - * Temporarily read physical (machine) addresses from vmcore by - * going directly to read_netdump() instead of via read_kdump(). + * Temporarily read physical (machine) addresses from vmcore. */ - pc->readmem = read_netdump; + pc->curcmd_flags |= XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (temporary): read_netdump()\n"); + fprintf(fp, "readmem (temporary): force XEN_MACHINE_ADDR\n"); if (xkd->flags & KDUMP_CR3) goto use_cr3; @@ -5813,9 +5812,9 @@ x86_64_xen_kdump_p2m_create(struct xen_kdump_data *xkd) fprintf(fp, "\n"); } - pc->readmem = read_kdump; + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (restore): read_kdump()\n"); + fprintf(fp, "readmem (restore): p2m translation\n"); return TRUE; @@ -5882,9 +5881,9 @@ use_cr3: machdep->last_pgd_read = 0; machdep->last_ptbl_read = 0; machdep->last_pmd_read = 0; - pc->readmem = read_kdump; + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; if (CRASHDEBUG(1)) - fprintf(fp, "readmem (restore): read_kdump()\n"); + fprintf(fp, "readmem (restore): p2m translation\n"); return TRUE; } diff --git a/xen_dom0.c b/xen_dom0.c index 826a90b..7c9c76e 100644 --- a/xen_dom0.c +++ b/xen_dom0.c @@ -206,12 +206,20 @@ xen_kdump_p2m(physaddr_t pseudo) if (mfn_frame == xkd->last_mfn_read) xkd->cache_hits++; else { + int res; + if (CRASHDEBUG(8)) fprintf(fp, "xen_kdump_p2m: paddr/pfn: %llx/%lx: " "read mfn_frame: %llx\n", (ulonglong)pseudo, pfn, PTOB(mfn_frame)); - if (read_netdump(0, xkd->page, PAGESIZE(), 0, - (physaddr_t)PTOB(mfn_frame)) != PAGESIZE()) + + pc->curcmd_flags |= XEN_MACHINE_ADDR; + res = readmem((physaddr_t)PTOB(mfn_frame), PHYSADDR, + xkd->page, PAGESIZE(), + "xen_kdump_p2m mfn frame", RETURN_ON_ERROR); + pc->curcmd_flags &= ~XEN_MACHINE_ADDR; + + if (!res) return P2M_FAILURE; } -- 2.1.4