Re: [PATCH] KVM: arm64: Fix AArch32 DBGBXVR<n> handling

[Oliver Upton]

On Sat, Sep 19, 2026 at 11:11:14AM -0700, Oliver Upton wrote:
> On Mon, 10 Aug 2026 02:56:16 +0200, Karl Mehltretter wrote:
> > 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.
> > 
> > [...]
> 
> Thanks for pinging, this slipped between the cracks.
> 
> Applied to fixes, thanks!
> 
> [1/1] KVM: arm64: Fix AArch32 DBGBXVR<n> handling
>       https://git.kernel.org/kvmarm/kvmarm/c/239763bda716

This is now 6b1bca1b1ab7, didn't grab the Cc: stable in the first pass.

Thanks,
Oliver