Re: [PATCH v3] cxl/mce: Avoid alias page retirement for corrected errors
Alison Schofield <[email protected]>
| Newsgroups | org.kernel.vger.stable,org.kernel.vger.linux-cxl,org.kernel.vger.linux-edac,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
On Mon, Aug 24, 2026 at 07:19:57PM +0530, Shaikh Kamaluddin wrote:
> cxl_handle_mce() offlines the aliased page of an Extended Linear Cache
> (ELC) region for any MCE with a usable address in the region. This
> includes corrected errors, needlessly reducing usable memory.
>
> Skip ELC alias retirement when mce_is_correctable() identifies the
> reported error as corrected. Uncorrected errors with a usable address
> in the ELC region continue to retire the aliased page as before.
>
> mce_usable_address() already implements the per-vendor checks that
> determine whether the reported address is usable, so no separate
> memory-error classification is needed.
>
> On AMD, a corrected legacy bank 4 DRAM ECC error (XEC 8) reports a
> usable address and retired the aliased page before this change.
> Tested under QEMU with Intel Skylake-Server and AMD EPYC-Milan models.
>
> Fixes: 516e5bd0b6bf ("cxl: Add mce notifier to emit aliased address for extended linear cache")
> Signed-off-by: Shaikh Kamaluddin <[email protected]>
Reviewed-by: Alison Schofield <[email protected]>
To be complete, I'm not retesting since v2, so not offering my
testing tag here. I have confidence in your thorough testing!
-- Alison
> ---
> Changelog:
>
> v2 -> v3:
> - Drop the mce_is_memory_error() gate added in v2. On AMD it rejects
> every non-UMC bank type, so poison-consumption records reported from
> Load/Store or Data Fabric banks never reached mce_usable_address(),
> which would have accepted them via MCA_STATUS[Poison]. (Sashiko)
> - mce_usable_address() already implements the complete per-vendor
> address-usability logic, so no separate memory-error classification
> is needed.
> - Add AMD test coverage (QEMU/TCG, EPYC-Milan) alongside the existing
> Intel results.
>
> Link to v2: https://lore.kernel.org/linux-cxl/[email protected]/
>
> v1 -> v2:
> - Reworked commit message per review feedback
> - Dropped redundant comment from the code
>
> Link to v1: https://lore.kernel.org/linux-cxl/[email protected]/
>
> Reproduced under QEMU/vng. QEMU's cxl-type3 does not emulate the HMAT
> extended-linear address_mode bit, so ELC was forced locally for testing
> via a one-line debug hack in cxl_region_probe() (not part of this patch):
>
> if (!p->cache_size && p->res)
> p->cache_size = resource_size(p->res) / 2;
>
> Steps:
> 1. Boot with an Intel CPU model under TCG (KVM host-passthrough will
> otherwise leak the host's real vendor ID, and AMD/SMCA takes a
> different mce_usable_address() path, covered in the section below):
>
> vng -v -r ./arch/x86/boot/bzImage --disable-kvm --qemu-opts='-cpu Skylake-Server-v4,+mce,+mca -m 4G -machine q35,cxl=on -object memory-backend-ram,id=cxl-mem0,size=512M -device pxb-cxl,bus_nr=12,bus=pcie.0,id=cxl.0 -device cxl-rp,port=0,bus=cxl.0,id=root_port0,chassis=0,slot=0 -device cxl-type3,bus=root_port0,volatile-memdev=cxl-mem0,id=cxl-mem-device0 -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=512M'
>
> 2. modprobe mce-inject
> $ cxl list -M
> $ cxl list -D
> $ cxl create-region -m mem0 -d decoder0.0 -w 1 -g 256 -t ram
> $ dmesg | grep "DEBUG: forced cache_size"
> $ modprobe device_dax
> $ modprobe kmem
> $ ls /sys/bus/dax/devices/
> $ daxctl reconfigure-device dax0.0 --mode=system-ram
> $ lsmem
> RANGE SIZE STATE REMOVABLE BLOCK
> 0x0000000000000000-0x000000007fffffff 2G online yes 0-15
> 0x0000000100000000-0x000000017fffffff 2G online yes 32-47
> 0x0000000190000000-0x00000001afffffff 512M online yes 50-53
>
> Memory block size: 128M
> Total online memory: 4.5G
> Total offline memory: 0B
>
> 3. Load the injector if not loaded earlier and derive the two MCi_STATUS values.
>
> # modprobe mce-inject
>
> MCi_STATUS bit layout used here (arch/x86/include/asm/mce.h):
> bit 63 VAL - record valid
> bit 61 UC - uncorrected (0 = corrected error under test)
> bit 60 EN - error reporting enabled
> bit 59 MISCV - MCi_MISC valid
> bit 58 ADDRV - MCi_ADDR valid
> bits[15:0] MCACOD - retained from the v2 test setup so the Intel
> and AMD runs differ only in CPU model; not
> consulted by this path.
>
> python3 -c "
> VAL, UC, EN, MISCV, ADDRV = 1<<63, 1<<61, 1<<60, 1<<59, 1<<58
> MCACOD_MEM = 1<<7
> ce = VAL | EN | MISCV | ADDRV | MCACOD_MEM
> uc = ce | UC
> print(f'CE status = {hex(ce)}')
> print(f'UC status = {hex(uc)}')"
> # CE status = 0x9c00000000000080
> # UC status = 0xbc00000000000080
>
> MCi_MISC: address-mode field, bits[8:6], must be 2 (physical):
>
> python3 -c "print(hex(2 << 6))"
> # misc = 0x80
>
> 4. # cd /sys/kernel/debug/mce-inject
> # echo sw > flags
> # echo 0x9C00000000000080 > status
> # echo 0x80 > misc
> # echo 0x190010000 > addr
> # echo 9 > bank
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00000000000080 addr=0x190010000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> cxl_mce_debug: spa=0x190010000 contains=1
> cxl_mce_debug: spa_alias=0x1a0010000 pfn=0x1a0010 pfn_valid=1
> cxl_region region0: Offlining aliased SPA address0: 0x1a0010000
> Memory failure: 0x1a0010: recovery action for free buddy page: Recovered
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00000000000080
> mce: [Hardware Error]: TSC a605ccda40 ADDR 190010000 MISC 80
> mce: [Hardware Error]: PROCESSOR 0:50654 TIME 1786375908 SOCKET 0 APIC 0 microcode 1
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 4 kB
> ---------------------------------------
>
> CE without this patch:
> cxl_region region0: Offlining aliased SPA address0: 0x1a0010000
> Memory failure: 0x1a0010: recovery action for free buddy page: Recovered
> HardwareCorrupted: 4 kB
> -------------------------------------
>
> CE with this patch:
> (no "Offlining aliased SPA" message logged)
> HardwareCorrupted: 0 kB
>
> # cd /sys/kernel/debug/mce-inject
> # echo sw > flags
> # echo 0x9C00000000000080 > status
> # echo 0x80 > misc
> # echo 0x190010000 > addr
> # echo 9 > bank
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00000000000080 addr=0x190010000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00000000000080
> mce: [Hardware Error]: TSC 2eeae32fe0 ADDR 190010000 MISC 80
> mce: [Hardware Error]: PROCESSOR 0:50654 TIME 1786377156 SOCKET 0 APIC 0 microcode 1
> clocksource: Watchdog remote CPU 11 read timed out
>
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> --------------------------------------
>
> For UC, same steps only status bit information will change :
>
> # cd /sys/kernel/debug/mce-inject
> # echo sw > flags
> # echo 0xbc00000000000080 > status
> # echo 0x80 > misc
> # echo 0x190010000 > addr
> # echo 9 > bank
> # dmesg | grep cxl_mce_debug
> # grep HardwareCorrupted /proc/meminfo
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0xbc00000000000080 addr=0x190010000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> cxl_mce_debug: spa=0x190010000 contains=1
> cxl_mce_debug: spa_alias=0x1a0010000 pfn=0x1a0010 pfn_valid=1
> cxl_region region0: Offlining aliased SPA address0: 0x1a0010000
> Memory failure: 0x1a0010: recovery action for free buddy page: Recovered
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: bc00000000000080
> mce: [Hardware Error]: TSC e9dd2869e0 ADDR 190010000 MISC 80
> mce: [Hardware Error]: PROCESSOR 0:50654 TIME 1786377750 SOCKET 0 APIC 0 microcode 1
>
> Patched, UC: alias still offlined, confirming uncorrected handling is unchanged by this patch.
> cxl_region region0: Offlining aliased SPA address0: 0x1a0010000
> Memory failure: 0x1a0010: recovery action for free buddy page: Recovered
> HardwareCorrupted: 4 kB
> -----------------------------------------------------------------------
>
> AMD Platform Testing:
> ---------------------
>
> Note the vendor difference: on Intel, MISCV with MCi_MISC[8:6]=2 makes
> any ADDRV record usable, so a plain CE is address-usable. On AMD an
> address is usable only via poison, legacy bank-4 DRAM ECC, or PADDRV --
> hence the differing usable= values for the same status word below.
>
>
> vendor_id : AuthenticAMD
> model name : AMD EPYC-Milan Processor
>
> -------------------------------------
> Mainline Kernel Without this patch:
> -------------------------------------
>
> vng -v -r ./arch/x86/boot/bzImage --disable-kvm --qemu-opts='-cpu EPYC-Milan -m 4G -machine q35,cxl=on -object memory-backend-ram,id=cxl-mem0,size=512M -device pxb-cxl,bus_nr=12,bus=pcie.0,id=cxl.0 -device cxl-rp,port=0,bus=cxl.0,id=root_port0,chassis=0,slot=0 -device cxl-type3,bus=root_port0,volatile-memdev=cxl-mem0,id=cxl-mem-device0 -M cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.size=512M'
>
> # cxl list -M
> # cxl list -D
> # cxl create-region -m mem0 -d decoder0.0 -w 1 -g 256 -t ram
> # dmesg | grep "DEBUG: forced cache_size"
> # modprobe device_dax
> # modprobe kmem
> # daxctl reconfigure-device dax0.0 --mode=system-ram
>
> # lsmem
> RANGE SIZE STATE REMOVABLE BLOCK
> 0x0000000000000000-0x000000007fffffff 2G online yes 0-15
> 0x0000000100000000-0x000000017fffffff 2G online yes 32-47
> 0x0000000190000000-0x00000001afffffff 512M online yes 50-53
>
> Memory block size: 128M
> Total online memory: 4.5G
> Total offline memory: 0B
> Load Injector
> # modprobe mce-inject
> --------------------------------------------------------------------------------
>
> case1:
>
> label status addr bank note
>
> [LEGACY_B4_CE] 0x9c00000000080000 0x190070000 4 "case 3: bank4 XEC8 corrected+usable "[Before Patch]
> ---------------------------------------------------------------------------------------------------------------------
>
> # cd /sys/kernel/debug/mce-inject
> # echo sw > flags
> # echo 0x9c00000000080000 > status
> # echo 0x80 > misc
> # echo 0x190070000 > addr
> # echo 4 > bank
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00000000080000 addr=0x190070000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> cxl_mce_debug: spa=0x190070000 contains=1
> cxl_mce_debug: spa_alias=0x1a0070000 pfn=0x1a0070 pfn_valid=1
> cxl_region region0: Offlining aliased SPA address0: 0x1a0070000
> Memory failure: 0x1a0070: recovery action for free buddy page: Recovered
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 4: 9c00000000080000
> mce: [Hardware Error]: TSC cbdf882d20 ADDR 190070000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787479138 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 4 kB
> --------------------------------------------------------------------------------------------
>
> case2:
> label status addr bank note
>
> [POISON] 0x9c00080000000080 0x190040000 9 "case 2: poison only (UC=0) - divergence to note"[Before Patch]
> -----------------------------------------------------------------------------------------------------------------------
>
> # echo sw > flags
> # echo 0x9c00080000000080 > status
> # echo 0x80 > misc
> # echo 0x190040000 > addr
> # echo 9 > bank
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00080000000080 addr=0x190040000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> cxl_mce_debug: spa=0x190040000 contains=1
> cxl_mce_debug: spa_alias=0x1a0040000 pfn=0x1a0040 pfn_valid=1
> cxl_region region0: Offlining aliased SPA address0: 0x1a0040000
> Memory failure: 0x1a0040: recovery action for free buddy page: Recovered
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00080000000080
> mce: [Hardware Error]: TSC 17153949200 ADDR 190040000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787479277 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 8 kB (cumulative added previous 4kb + 4kb this test)
> -----------------------------------------------
>
> AMD Platform Testing with applied patch:
> ------------------------------------------
>
> # cxl list -D
> # cxl create-region -m mem0 -d decoder0.0 -w 1 -g 256 -t ram
> # dmesg | grep "DEBUG: forced cache_size"
> # modprobe device_dax
> # modprobe kmem
> # daxctl reconfigure-device dax0.0 --mode=system-ram
> # lsmem
> # modprobe mce-inject
> ----------------------------------------------------
>
> case1:
> label status addr bank note
>
> [ CE] 0x9c00000000000080 0x190010000 9 "case 1: corrected, no usable addr"
> ----------------------------------------------------------------------------------------
>
> # cd /sys/kernel/debug/mce-inject
> # echo sw > flags
> # echo 0x9c00000000000080 > status
> # echo 0x80 > misc
> # echo 0x190010000 > addr
> # echo 9 > bank
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00000000000080 addr=0x190010000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=0
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00000000000080
> mce: [Hardware Error]: TSC 8e59f2f3bc0 ADDR 190010000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787454918 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> -------------------------------------------------------------------------
>
> case2:
> label status addr bank note
> [ UC ] 0xbc00000000000080 0x190020000 9 "case 1: uncorrected, no poison -> unusable"
> -------------------------------------------------------------------------------------------------
>
> cd /sys/kernel/debug/mce-inject
> echo sw > flags
> echo 0xbc00000000000080 > status
> echo 0x80 > misc
> echo 0x190020000 > addr
> echo 9 > bank
> Result:
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0xbc00000000000080 addr=0x190020000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=0
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: bc00000000000080
> mce: [Hardware Error]: TSC 134d6de13240 ADDR 190020000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787460569 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> -------------------------------------------------------------------
>
> case3:
> label status addr bank note
>
> [ POISON ] 0x9c00080000000080 0x190040000 9 "case 2: poison only (UC=0) - divergence to note"
> ------------------------------------------------------------------------------------------------------------
>
> # cd /sys/kernel/debug/mce-inject
> # echo sw > flags
> # echo 0x9c00080000000080 > status
> # echo 0x80 > misc
> # echo 0x190040000 > addr
> # echo 9 > bank
> Result:
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00080000000080 addr=0x190040000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00080000000080
> mce: [Hardware Error]: TSC 14e29da617c0 ADDR 190040000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787463321 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> ------------------------------------------
>
> case4:
> label status addr bank note
>
> [ DEFERRED ] 0x9c00100000000080 0x190020000 9 "case 1: deferred, no poison -> unusable"
> ------------------------------------------------------------------------------------------------
>
> # echo sw > flags
> # echo 0x9c00100000000080 > status
> # echo 0x80 > misc
> #echo 0x190020000 > addr
> #echo 9 > bank
> Result:
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00100000000080 addr=0x190020000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=0
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00100000000080
> mce: [Hardware Error]: TSC 9a2d801ff40 ADDR 190020000
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787456818 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> -----------------------------------------------
>
> case5:
> label status addr bank note
>
> [ DEF_POISON ] 0x9c00180000000080 0x190060000 9 "case 2: deferred+poison - MUST be handled"
> --------------------------------------------------------------------------------------------------------
>
> # echo sw > flags
> # echo 0x9c00180000000080 > status
> # echo 0x80 > misc
> # echo 0x190060000 > addr
> # echo 9 > bank
> Result:
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00180000000080 addr=0x190060000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> cxl_mce_debug: spa=0x190060000 contains=1
> cxl_mce_debug: spa_alias=0x1a0060000 pfn=0x1a0060 pfn_valid=1
> cxl_region region0: Offlining aliased SPA address0: 0x1a0060000
> Memory failure: 0x1a0060: recovery action for free buddy page: Recovered
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: 9c00180000000080
> mce: [Hardware Error]: TSC a60fd45ae60 ADDR 190060000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787457072 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 4 kB
> -----------------------------------
>
> case6:
> label status addr bank note
>
> [UC_POISON] 0xbc00080000000080 0x190050000 9 "case 2: poison consumption - MUST be handled"
> --------------------------------------------------------------------------------------------------------
>
> # echo sw > flags
> # echo 0xbc00080000000080 > status
> # echo 0x80 > misc
> # echo 0x190050000 > addr
> # echo 9 > bank
>
> Resul:
>
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0xbc00080000000080 addr=0x190050000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> cxl_mce_debug: spa=0x190050000 contains=1
> cxl_mce_debug: spa_alias=0x1a0050000 pfn=0x1a0050 pfn_valid=1
> cxl_region region0: Offlining aliased SPA address0: 0x1a0050000
> Memory failure: 0x1a0050: recovery action for free buddy page: Recovered
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 9: bc00080000000080
> mce: [Hardware Error]: TSC f03abeed540 ADDR 190050000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787457328 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 4 kB
> -------------------------------------------------------------------------------------
>
> case7:
> label status addr bank note
>
> [B4_NONMEM_POISON] 0x9c00080000000080 0x190080000 4 "case 3 override: bank4 non-mem, poison ignored"
> -------------------------------------------------------------------------------------------------------------------
>
> # echo sw > flags
> # echo 0x9c00080000000080 > status
> # echo 0x80 > misc
> # echo 0x190080000 > addr
> # echo 4 > bank
>
> Result:
>
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00080000000080 addr=0x190080000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=0
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 4: 9c00080000000080
> mce: [Hardware Error]: TSC 21c66cecf80 ADDR 190080000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787454082 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> --------------------------------------------------------------------------------------------
>
> case8:
> label status addr bank note
>
> [LEGACY_B4_CE] 0x9c00000000080000 0x190070000 4 "case 3: bank4 XEC8 corrected+usable - THE FIX"
> -------------------------------------------------------------------------------------------------------------------
>
> echo sw > flags
> echo 0x9c00000000080000 > status
> echo 0x80 > misc
> echo 0x190070000 > addr
> echo 4 > bank
>
> result:
> -------
>
> mce: [Hardware Error]: Machine check events logged
> cxl_mce_debug: entered status=0x9c00000000080000 addr=0x190070000 cache_size=0x10000000 res=[mem 0x190000000-0x1afffffff flags 0x200] usable=1
> mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 4: 9c00000000080000
> mce: [Hardware Error]: TSC 3610305ed80 ADDR 190070000 MISC 80
> mce: [Hardware Error]: PROCESSOR 2:a00f11 TIME 1787454482 SOCKET 0 APIC 0 microcode 1000065
> # grep HardwareCorrupted /proc/meminfo
> HardwareCorrupted: 0 kB
> -------------------------------------------
>
> Note: an AMD record with MCI_STATUS_POISON set but UC and Deferred
> clear is filtered by this patch where it previously was not. Per AMD64
> APM 24593 Rev 3.45, when UC is clear the error class is determined
> solely by the Deferred bit, and Poison qualifies an uncorrected error
> rather than establishing one. Real poison is therefore always reported
> with Deferred set (not yet consumed) or UC set (consumed via #MC), and
> both of those cases still retire the alias. Poison with UC and Deferred
> both clear is not a valid encoding and appears only under software
> injection.
>
> drivers/cxl/core/mce.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/core/mce.c b/drivers/cxl/core/mce.c
> index 65fed913b221..3ac6802e750d 100644
> --- a/drivers/cxl/core/mce.c
> +++ b/drivers/cxl/core/mce.c
> @@ -18,7 +18,13 @@ static int cxl_handle_mce(struct notifier_block *nb, unsigned long val,
> u64 spa, spa_alias;
> unsigned long pfn;
>
> - if (!mce || !mce_usable_address(mce))
> + if (!mce)
> + return NOTIFY_DONE;
> +
> + if (mce_is_correctable(mce))
> + return NOTIFY_DONE;
> +
> + if (!mce_usable_address(mce))
> return NOTIFY_DONE;
>
> spa = mce->addr & MCI_ADDR_PHYSADDR;
>
> base-commit: 7098e9cd98a05c0c5de2fae0c2465f9d966fdd07
> --
> 2.43.0
>