In the Linux kernel, the following vulnerability has been resolved:
powerpc/pseries/iommu: IOMMU incorrectly marks MMIO range in DDW
Power Hypervisor can possibily allocate MMIO window intersecting with Dynamic DMA Window (DDW) range, which is over 32-bit addressing.
These MMIO pages needs to be marked as reserved so that IOMMU doesn't map DMA buffers in this range.
The current code is not marking these pages correctly which is resulting in LPAR to OOPS while booting. The stack is at below
BUG: Unable to handle kernel data access on read at 0xc00800005cd40000 Faulting instruction address: 0xc00000000005cdac Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: af_packet rfkill ibmveth(X) lpfc(+) nvmet_fc nvmet nvme_keyring crct10dif_vpmsum nvme_fc nvme_fabrics nvme_core be2net(+) nvme_auth rtc_generic nfsd auth_rpcgss nfs_acl lockd grace sunrpc fuse configfs ip_tables x_tables xfs libcrc32c dm_service_time ibmvfc(X) scsi_transport_fc vmx_crypto gf128mul crc32c_vpmsum dm_mirror dm_region_hash dm_log dm_multipath dm_mod sd_mod scsi_dh_emc scsi_dh_rdac scsi_dh_alua t10_pi crc64_rocksoft_generic crc64_rocksoft sg crc64 scsi_mod Supported: Yes, External CPU: 8 PID: 241 Comm: kworker/8:1 Kdump: loaded Not tainted 6.4.0-150600.23.14-default #1 SLE15-SP6 b44ee71c81261b9e4bab5e0cde1f2ed891d5359b Hardware name: IBM,9080-M9S POWER9 (raw) 0x4e2103 0xf000005 of:IBM,FW950.B0 (VH950_149) hv:phyp pSeries Workqueue: events work_for_cpu_fn NIP: c00000000005cdac LR: c00000000005e830 CTR: 0000000000000000 REGS: c00001400c9ff770 TRAP: 0300 Not tainted (6.4.0-150600.23.14-default) MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24228448 XER: 00000001 CFAR: c00000000005cdd4 DAR: c00800005cd40000 DSISR: 40000000 IRQMASK: 0 GPR00: c00000000005e830 c00001400c9ffa10 c000000001987d00 c00001400c4fe800 GPR04: 0000080000000000 0000000000000001 0000000004000000 0000000000800000 GPR08: 0000000004000000...