CVE-2024-26761

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.