Messages in this thread | | | Date | Fri, 24 Jun 2022 15:34:42 -0700 | Subject | Re: [PATCH v5] x86/mce: Check for writes ignored in MCA_STATUS register | From | Smita Koralahalli <> |
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Hi Boris,
On 6/22/2022 10:29 AM, Borislav Petkov wrote: > On Fri, Jun 10, 2022 at 07:25:15PM +0000, Smita Koralahalli wrote: >> arch/x86/kernel/cpu/mce/inject.c | 50 +++++++++++++++++++++++++++++- >> arch/x86/kernel/cpu/mce/internal.h | 2 +- >> 2 files changed, 50 insertions(+), 2 deletions(-) > I've simplified, improved and removed some stuff. See if that still > works on that platform which ignores writes.
I tested out the patch. Its not behaving as expected. The module fails silently again. > + cpu = get_cpu(); > + > + for (bank = 0; bank < MAX_NR_BANKS; ++bank) { > + u64 status = MCI_STATUS_VAL, ipid; > + > + /* Check whether bank is populated */ > + rdmsrl(MSR_AMD64_SMCA_MCx_IPID(bank), ipid); > + if (!ipid) > + continue; > + > + toggle_hw_mce_inject(cpu, true); > + > + if (wrmsrl_safe(mca_msr_reg(bank, MCA_STATUS), status)) {
The wrmsrl_safe() doesn't throw an error here. I think we need to read back the written value and check for it whatsoever. What do you think?
Thanks, Smita > + hw_injection_possible = false; > + pr_warn("Platform does not allow *hardware* error injection." > + "Try using APEI EINJ instead.\n"); > + } > + > + toggle_hw_mce_inject(cpu, false); > + > + break; > + } > + > + put_cpu(); > +}
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