published October 18, 2026
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Fix AArch32 DBGBXVR<n> handling
The consolidation of the breakpoint and watchpoint register accessors
switched DBGBXVR<n> from trap_bvr() to trap_dbg_wb_reg(). The latter
selects backing storage with demux_wb_reg(), which only handles Op2 values
4 through 7. Since DBGBXVR<n> uses Op2 1, an AArch32 guest access hits
KVM_BUG_ON() and marks the VM dead.
DBGBXVR<n> aliases DBGBVR<n>_EL1[63:32], and its AA32(HI) descriptor
already selects the upper half. Map Op2 1 to dbg_bvr[] alongside Op2 4,
restoring the pre-regression behavior.