CVE-2024-26761

Summary

In the Linux kernel, the following vulnerability has been resolved:

cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS window

The Linux CXL subsystem is built on the assumption that HPA == SPA. That is, the host physical address (HPA) the HDM decoder registers are programmed with are system physical addresses (SPA).

During HDM decoder setup, the DVSEC CXL range registers (cxl-3.1, 8.1.3.8) are checked if the memory is enabled and the CXL range is in a HPA window that is described in a CFMWS structure of the CXL host bridge (cxl-3.1, 9.18.1.3).

Now, if the HPA is not an SPA, the CXL range does not match a CFMWS window and the CXL memory range will be disabled then. The HDM decoder stops working which causes system memory being disabled and further a system hang during HDM decoder initialization, typically when a CXL enabled kernel boots.

Prevent a system hang and do not disable the HDM decoder if the decoder's CXL range is not found in a CFMWS window.

Note the change only fixes a hardware hang, but does not implement HPA/SPA translation. Support for this can be added in a follow on patch series.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux34e37b4c432cd0f1842b352fde4b8878b4166888 < 031217128990d7f0ab8c46db1afb3cf1e075fd29affected
LinuxLinux34e37b4c432cd0f1842b352fde4b8878b4166888 < 2cc1a530ab31c65b52daf3cb5d0883c8b614ea69affected
LinuxLinux34e37b4c432cd0f1842b352fde4b8878b4166888 < 3a3181a71935774bda2398451256d7441426420baffected
LinuxLinux34e37b4c432cd0f1842b352fde4b8878b4166888 < 0cab687205986491302cd2e440ef1d253031c221affected
LinuxLinux5.19affected
LinuxLinux0 < 5.19unaffected
LinuxLinux6.1.80 <= 6.1.*unaffected
LinuxLinux6.6.19 <= 6.6.*unaffected
LinuxLinux6.7.7 <= 6.7.*unaffected
LinuxLinux6.8 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References