Re: [PATCH v3 1/3] xen/riscv: disable fpu

[Bobby Eshleman <bobbyeshleman@xxxxxxxxx>]

On Fri, Mar 03, 2023 at 12:24:22PM +0200, Oleksii Kurochko wrote:
> Disable FPU to detect illegal usage of floating point in kernel
> space.
> 
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
> ---
>  xen/arch/riscv/riscv64/head.S | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/xen/arch/riscv/riscv64/head.S b/xen/arch/riscv/riscv64/head.S
> index ffd95f9f89..52fa41c778 100644
> --- a/xen/arch/riscv/riscv64/head.S
> +++ b/xen/arch/riscv/riscv64/head.S
> @@ -6,6 +6,13 @@ ENTRY(start)
>          /* Mask all interrupts */
>          csrw    CSR_SIE, zero
>  
> +        /*
> +         * Disable FPU to detect illegal usage of
> +         * floating point in kernel space
> +         */
> +        li      t0, SSTATUS_FS
> +        csrc    CSR_SSTATUS, t0
> +
>          la      sp, cpu0_boot_stack
>          li      t0, STACK_SIZE
>          add     sp, sp, t0
> -- 
> 2.39.0
> 
> 

Acked-by: Bobby Eshleman <bobbyeshleman@xxxxxxxxx>