Messages in this thread | | | Date | Fri, 24 Sep 2021 10:26:03 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH 1/5] x86/mce/inject: Check if a bank is unpopulated before error simulation |
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On Wed, Sep 15, 2021 at 06:27:35PM -0500, Smita Koralahalli wrote: > The MCA_IPID register uniquely identifies a bank's type on Scalable MCA > (SMCA) systems. When an MCA bank is not populated, the MCA_IPID register > will read as zero and writes to it will be ignored. Check the value of > this register before trying to simulate the error. > > Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> > --- > arch/x86/kernel/cpu/mce/inject.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c > index 0bfc14041bbb..51ac575c4605 100644 > --- a/arch/x86/kernel/cpu/mce/inject.c > +++ b/arch/x86/kernel/cpu/mce/inject.c > @@ -577,6 +577,24 @@ static int inj_bank_set(void *data, u64 val) > } > > m->bank = val; > + > + /* Read IPID value to determine if a bank is unpopulated on the target > + * CPU. > + */
Kernel comments style format is:
/* * A sentence ending with a full-stop. * Another sentence. ... * More sentences. ... */
> + if (boot_cpu_has(X86_FEATURE_SMCA)) {
This whole thing belongs into inj_ipid_set() where you should verify whether the bank is set when you try to set the IPID for that bank.
> + > + /* Check for user provided IPID value. */ > + if (!m->ipid) { > + rdmsrl_on_cpu(m->extcpu, MSR_AMD64_SMCA_MCx_IPID(val), > + &m->ipid);
Oh well, one IPI per ipid write. We're doing injection so we can't be on a production machine so who cares about IPIs there.
> + if (!m->ipid) { > + pr_err("Error simulation not possible: Bank %llu unpopulated\n",
"Cannot set IPID for bank... - bank %d unpopulated\n"
Also, in all your text, use "injection" instead of "simulation" so that there's no confusion.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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