Re: [Qemu-devel] [PATCH v2 3/3] edu: uses uint64_t in dma operation

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 4/20/19 6:14 PM, Li Qiang wrote:
> The dma related variable is dma_addr_t, it is uint64_t in
> x64 platform. Change these usage from uint32_to uint64_t to
> avoid trancation.

"to avoid address truncation"?

> 
> Signed-off-by: Li Qiang <liq3ea@163.com>
> ---
> Change since v1:
> Fix format compile error on Windows
> 
>  hw/misc/edu.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/misc/edu.c b/hw/misc/edu.c
> index 4018dddcb8..f4a6d5f1c5 100644
> --- a/hw/misc/edu.c
> +++ b/hw/misc/edu.c
> @@ -98,23 +98,24 @@ static void edu_lower_irq(EduState *edu, uint32_t val)
>      }
>  }
>  
> -static bool within(uint32_t addr, uint32_t start, uint32_t end)
> +static bool within(uint64_t addr, uint64_t start, uint64_t end)

OK.

>  {
>      return start <= addr && addr < end;
>  }
>  
> -static void edu_check_range(uint32_t addr, uint32_t size1, uint32_t start,
> +static void edu_check_range(uint64_t addr, uint64_t size1, uint64_t start,
>                  uint32_t size2)

OK for addr. MMIO range is 1MiB so you can keep uint32_t for
size1/size2. Up to the maintainer (personally I'd prefer keep u32).

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

>  {
> -    uint32_t end1 = addr + size1;
> -    uint32_t end2 = start + size2;
> +    uint64_t end1 = addr + size1;
> +    uint64_t end2 = start + size2;
>  
>      if (within(addr, start, end2) &&
>              end1 > addr && within(end1, start, end2)) {
>          return;
>      }
>  
> -    hw_error("EDU: DMA range 0x%.8x-0x%.8x out of bounds (0x%.8x-0x%.8x)!",
> +    hw_error("EDU: DMA range 0x%016"PRIx64"-0x%016"PRIx64
> +             " out of bounds (0x%016"PRIx64"-0x%016"PRIx64")!",
>              addr, end1 - 1, start, end2 - 1);
>  }
>  
> @@ -139,13 +140,13 @@ static void edu_dma_timer(void *opaque)
>      }
>  
>      if (EDU_DMA_DIR(edu->dma.cmd) == EDU_DMA_FROM_PCI) {
> -        uint32_t dst = edu->dma.dst;
> +        uint64_t dst = edu->dma.dst;
>          edu_check_range(dst, edu->dma.cnt, DMA_START, DMA_SIZE);
>          dst -= DMA_START;
>          pci_dma_read(&edu->pdev, edu_clamp_addr(edu, edu->dma.src),
>                  edu->dma_buf + dst, edu->dma.cnt);
>      } else {
> -        uint32_t src = edu->dma.src;
> +        uint64_t src = edu->dma.src;
>          edu_check_range(src, edu->dma.cnt, DMA_START, DMA_SIZE);
>          src -= DMA_START;
>          pci_dma_write(&edu->pdev, edu_clamp_addr(edu, edu->dma.dst),
>