x86/bugs: Add "unknown" reporting for MMIO Stale Data

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commit 7df548840c upstream.

Older Intel CPUs that are not in the affected processor list for MMIO
Stale Data vulnerabilities currently report "Not affected" in sysfs,
which may not be correct. Vulnerability status for these older CPUs is
unknown.

Add known-not-affected CPUs to the whitelist. Report "unknown"
mitigation status for CPUs that are not in blacklist, whitelist and also
don't enumerate MSR ARCH_CAPABILITIES bits that reflect hardware
immunity to MMIO Stale Data vulnerabilities.

Mitigation is not deployed when the status is unknown.

  [ bp: Massage, fixup. ]

Fixes: 8d50cdf8b8 ("x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data")
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Suggested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/a932c154772f2121794a5f2eded1a11013114711.1657846269.git.pawan.kumar.gupta@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Pawan Gupta 2022-08-03 14:41:32 -07:00 • committed by Greg Kroah-Hartman

parent 0666703c4b

commit 9d0a21053c

4 changed files with 56 additions and 19 deletions

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14

Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst

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5

arch/x86/include/asm/cpufeatures.h

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14

arch/x86/kernel/cpu/bugs.c

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42

arch/x86/kernel/cpu/common.c

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