Re: [PATCH] x86/hvm: Fix Misra Rule 19.1 regression

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 10 Apr 2024, Andrew Cooper wrote:
> Despite noticing an impending Rule 19.1 violation, the adjustment made (the
> uint32_t cast) wasn't sufficient to avoid it.  Try again.
> 
> Fixes: 6a98383b0877 ("x86/HVM: clear upper halves of GPRs upon entry from 
> 32-bit code")
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> CC: Jan Beulich <JBeulich@xxxxxxxx>
> CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> CC: consulting@xxxxxxxxxxx <consulting@xxxxxxxxxxx>
> CC: Roberto Bagnara <roberto.bagnara@xxxxxxxxxxx>
> CC: Federico Serafini <federico.serafini@xxxxxxxxxxx>
> CC: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
> ---
>  xen/arch/x86/include/asm/hvm/hvm.h | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/xen/arch/x86/include/asm/hvm/hvm.h 
> b/xen/arch/x86/include/asm/hvm/hvm.h
> index 595253babeaf..899233fb257b 100644
> --- a/xen/arch/x86/include/asm/hvm/hvm.h
> +++ b/xen/arch/x86/include/asm/hvm/hvm.h
> @@ -575,16 +575,16 @@ static inline void hvm_sanitize_regs_fields(struct 
> cpu_user_regs *regs,
>      if ( compat )
>      {
>          /* Clear GPR upper halves, to counteract guests playing games. */
> -        regs->rbp = (uint32_t)regs->ebp;
> -        regs->rbx = (uint32_t)regs->ebx;
> -        regs->rax = (uint32_t)regs->eax;
> -        regs->rcx = (uint32_t)regs->ecx;
> -        regs->rdx = (uint32_t)regs->edx;
> -        regs->rsi = (uint32_t)regs->esi;
> -        regs->rdi = (uint32_t)regs->edi;
> -        regs->rip = (uint32_t)regs->eip;
> -        regs->rflags = (uint32_t)regs->eflags;
> -        regs->rsp = (uint32_t)regs->esp;
> +        regs->rbp = (uint32_t)regs->rbp;
> +        regs->rbx = (uint32_t)regs->rbx;
> +        regs->rax = (uint32_t)regs->rax;
> +        regs->rcx = (uint32_t)regs->rcx;
> +        regs->rdx = (uint32_t)regs->rdx;
> +        regs->rsi = (uint32_t)regs->rsi;
> +        regs->rdi = (uint32_t)regs->rdi;
> +        regs->rip = (uint32_t)regs->rip;
> +        regs->rflags = (uint32_t)regs->rflags;
> +        regs->rsp = (uint32_t)regs->rsp;
>      }
>  
>  #ifndef NDEBUG
> 
> base-commit: f48299cad5c3c69fdc2c101517a6dab9c9827ea5
> -- 
> 2.30.2
>