Re: [PATCH 11/14] hw/intc/arm_gicv3_its: Make GITS_BASER<n> RAZ/WI for unimplemented registers

[Richard Henderson]

On 1/23/22 05:24, Peter Maydell wrote:
> The ITS has a bank of 8 GITS_BASER<n> registers, which allow the
> guest to specify the base address of various data tables.  Each
> register has a read-only type field indicating which table it is for
> and a read-write field where the guest can write in the base address
> (among other things).  We currently allow the guest to write the
> writeable fields for all eight registers, even if the type field is 0
> indicating "Unimplemented".  This means the guest can provoke QEMU
> into asserting by writing an address into one of these unimplemented
> base registers, which bypasses the "if (!value) continue" check in
> extract_table_params() and lets us hit the assertion that the type
> field is one of the permitted table types.
>
> Prevent the assertion by not allowing the guest to write to the
> unimplemented base registers. This means their value will remain 0
> and extract_table_params() will ignore them.
>
>
> Signed-off-by: Peter Maydell<peter.maydell@linaro.org>
> ---
>   hw/intc/arm_gicv3_its.c | 8 ++++++++
>   1 file changed, 8 insertions(+)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~