linux-kernel - Re: [PATCH] kdump, vmcoreinfo: Export sme_me

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Message-ID: <053CC83A-9A95-4C12-9627-AABD1427DA9C@alien8.de>
Date:   Fri, 26 Oct 2018 10:43:21 +0100
From:   Boris Petkov <bp@...en8.de>
To:     Lianbo Jiang <lijiang@...hat.com>, linux-kernel@...r.kernel.org
CC:     kexec@...ts.infradead.org, tglx@...utronix.de, mingo@...hat.com,
        x86@...nel.org, bhe@...hat.com, dyoung@...hat.com
Subject: Re: [PATCH] kdump, vmcoreinfo: Export sme_me_mask value to vmcoreinfo

On October 26, 2018 10:36:30 AM GMT+01:00, Lianbo Jiang <lijiang@...hat.com> wrote:
>For AMD machine with SME feature, makedumpfile tools need to know
>whether the crash kernel was encrypted or not. 

Why?

> So it is necessary
>to write the sme_me_mask to vmcoreinfo.
>
>Signed-off-by: Lianbo Jiang <lijiang@...hat.com>
>---
> arch/x86/kernel/machine_kexec_64.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/arch/x86/kernel/machine_kexec_64.c
>b/arch/x86/kernel/machine_kexec_64.c
>index 4c8acdfdc5a7..dcfdb64d1097 100644
>--- a/arch/x86/kernel/machine_kexec_64.c
>+++ b/arch/x86/kernel/machine_kexec_64.c
>@@ -357,6 +357,8 @@ void arch_crash_save_vmcoreinfo(void)
> 	vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
> 			pgtable_l5_enabled());
> 
>+	VMCOREINFO_NUMBER(sme_me_mask);

No we're not going to expose a kernel-internal mask to userspace. 

If at all needed, add functions to kexec which figure out whether we are encrypted or not and export that result as a kexec variable.


-- 
Sent from a small device: formatting sux and brevity is inevitable.