Commit f9781bb1 authored by Jane Chu's avatar Jane Chu Committed by Borislav Petkov
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x86/mce: Retrieve poison range from hardware 



When memory poison consumption machine checks fire, MCE notifier
handlers like nfit_handle_mce() record the impacted physical address
range which is reported by the hardware in the MCi_MISC MSR. The error
information includes data about blast radius, i.e. how many cachelines
did the hardware determine are impacted. A recent change

  7917f9cd ("acpi/nfit: rely on mce->misc to determine poison granularity")

updated nfit_handle_mce() to stop hard coding the blast radius value of
1 cacheline, and instead rely on the blast radius reported in 'struct
mce' which can be up to 4K (64 cachelines).

It turns out that apei_mce_report_mem_error() had a similar problem in
that it hard coded a blast radius of 4K rather than reading the blast
radius from the error information. Fix apei_mce_report_mem_error() to
convey the proper poison granularity.

Signed-off-by: default avatarJane Chu <jane.chu@oracle.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Reviewed-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/7ed50fd8-521e-cade-77b1-738b8bfb8502@oracle.com
Link: https://lore.kernel.org/r/20220826233851.1319100-1-jane.chu@oracle.com
parent d25c6948

arch/x86/kernel/cpu/mce/apei.c

+12 −1
Original line number Diff line number Diff line
@@ -29,15 +29,26 @@ 
void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)

{

	struct mce m;

	int lsb;



	if (!(mem_err->validation_bits & CPER_MEM_VALID_PA))

		return;



	/*

	 * Even if the ->validation_bits are set for address mask,

	 * to be extra safe, check and reject an error radius '0',

	 * and fall back to the default page size.

	 */

	if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK)

		lsb = find_first_bit((void *)&mem_err->physical_addr_mask, PAGE_SHIFT);

	else

		lsb = PAGE_SHIFT;



	mce_setup(&m);

	m.bank = -1;

	/* Fake a memory read error with unknown channel */

	m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | MCI_STATUS_MISCV | 0x9f;

	m.misc = (MCI_MISC_ADDR_PHYS << 6) | PAGE_SHIFT;

	m.misc = (MCI_MISC_ADDR_PHYS << 6) | lsb;



	if (severity >= GHES_SEV_RECOVERABLE)

		m.status |= MCI_STATUS_UC;