Re: [PATCH v2 11/39] x86/ibt,kvm: Add ENDBR to fastops

[Kees Cook]

On Thu, Feb 24, 2022 at 03:51:49PM +0100, Peter Zijlstra wrote:
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---
>  arch/x86/kvm/emulate.c |    6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -189,7 +189,7 @@
>  #define X16(x...) X8(x), X8(x)
>  
>  #define NR_FASTOP (ilog2(sizeof(ulong)) + 1)
> -#define FASTOP_SIZE 8
> +#define FASTOP_SIZE (8 * (1 + HAS_KERNEL_IBT))

Err, is this right? FASTOP_SIZE is used both as a size and an alignment.
But the ENDBR instruction is 4 bytes? Commit log maybe needed to
describe this.

-- 
Kees Cook