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Subject: Re: [PATCH 1/5] x86/mce/inject: Check if a bank is unpopulated before
 error simulation
To:     Borislav Petkov <bp@alien8.de>
Cc:     Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>,
        x86@kernel.org, linux-edac@vger.kernel.org,
        linux-kernel@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
        "H . Peter Anvin" <hpa@zytor.com>, yazen.ghannam@amd.com
References: <20210915232739.6367-1-Smita.KoralahalliChannabasappa@amd.com>
 <20210915232739.6367-2-Smita.KoralahalliChannabasappa@amd.com>
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From:   Smita Koralahalli Channabasappa <skoralah@amd.com>
Message-ID: <7e790ba1-0b31-690c-7bd3-d8361109cef5@amd.com>
Date:   Mon, 27 Sep 2021 16:56:17 -0500
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On 9/27/21 3:15 PM, Borislav Petkov wrote:

> On Mon, Sep 27, 2021 at 02:51:56PM -0500, Smita Koralahalli Channabasappa wrote:
>> Can you please elaborate on this? I'm not sure if I understood this
>> right. Should I read the ipid file to verify that the user has input
>> proper ipid? If ipid file reads zero then do rdmsrl_on_cpu?
> No, on a write to the ipid file you should do that checking and write if
> the bank is populated or fail the write otherwise. And you should put
> all that code in inj_bank_set() - that's why I say "on a write to the
> ipid file".
>
> And instead of boot_cpu_has() you should use cpu_feature_enabled().
>
> Makes sense?

Yes, this makes sense to me now. But you meant to say inj_ipid_set()
instead of inj_bank_set()..?

Something like this:

-MCE_INJECT_SET(ipid)

+static int inj_ipid_set(void *data, u64 val)
+{
+	struct mce *m = (struct mce*)data;

+	if cpu_feature_enabled(X86_FEATURE_SMCA)) {

+		rdmsrl_on_cpu(..
		..
		..
+	m->ipid = val;
+	..
+}

Thanks,