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x86/microcode/intel: Writeback and invalidate caches before updating microcode

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commit 91df9fdf51492aec9fed6b4cbd33160886740f47 upstream.

Updating microcode is less error prone when caches have been flushed and
depending on what exactly the microcode is updating. For example, some
of the issues around certain Broadwell parts can be addressed by doing a
full cache flush.

[ Borislav: Massage it and use native_wbinvd() in both cases. ]

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Link: http://lkml.kernel.org/r/1519352533-15992-3-git-send-email-ashok.raj@intel.com
Link: https://lkml.kernel.org/r/20180228102846.13447-4-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ashok Raj 2018-02-28 11:28:42 +01:00 committed by Greg Kroah-Hartman
parent 170f8ec16c
commit 1707112c82
1 changed files with 12 additions and 0 deletions
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12
arch/x86/kernel/cpu/microcode/intel.c
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@ -600,6 +600,12 @@ static int apply_microcode_early(struct ucode_cpu_info *uci, bool early)
return UCODE_OK;
}
/*
* Writeback and invalidate caches before updating microcode to avoid
* internal issues depending on what the microcode is updating.
*/
native_wbinvd();
/* write microcode via MSR 0x79 */
native_wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
@ -816,6 +822,12 @@ static enum ucode_state apply_microcode_intel(int cpu)
return UCODE_OK;
}
/*
* Writeback and invalidate caches before updating microcode to avoid
* internal issues depending on what the microcode is updating.
*/
native_wbinvd();
/* write microcode via MSR 0x79 */
wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);