Re: [PULL 06/26] target/ppc: Improve logging in Radix MMU

[Peter Maydell]

On Tue, 4 Jan 2022 at 07:31, Cédric Le Goater <clg@kaod.org> wrote:
>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Message-Id: <20211222071002.1568894-1-clg@kaod.org>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  target/ppc/mmu-radix64.c | 55 +++++++++++++++++++++++++++++++++++++---
>  1 file changed, 52 insertions(+), 3 deletions(-)

Hi; Coverity reports that this change introduces a use of
an uninitialized variable:

> @@ -306,6 +321,15 @@ static int ppc_radix64_partition_scoped_xlate(PowerPCCPU 
> *cpu,
>      hwaddr pte_addr;
>      uint64_t pte;
>
> +    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx
> +                  " mmu_idx %u (prot %c%c%c) 0x%"HWADDR_PRIx"\n",
> +                  __func__, access_str(access_type),
> +                  eaddr, mmu_idx,
> +                  *h_prot & PAGE_READ ? 'r' : '-',
> +                  *h_prot & PAGE_WRITE ? 'w' : '-',
> +                  *h_prot & PAGE_EXEC ? 'x' : '-',
> +                  g_raddr);

At the top of this function we now read the value at h_prot to
do this logging, but all the callsites pass in an uninitialized
value:

   int h_prot;
   ...
           ret = ppc_radix64_partition_scoped_xlate(cpu, 0, eaddr, prtbe_addr,
                                                 pate, &h_raddr, &h_prot, etc);


Are the callsites wrong (should be initializing h_prot), or is the
logging wrong (and it's this function itself which is supposed to
initialize *h_prot as an extra return value) ?

This is CID 1468942.

thanks
-- PMM