On 30/09/2025 06.13, Philippe Mathieu-Daudé wrote:
> flatview_translate()'s @plen argument is output-only and can be NULL.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> include/system/memory.h | 5 +++--
> system/physmem.c | 6 +++---
> 2 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/include/system/memory.h b/include/system/memory.h
> index aa85fc27a10..3e5bf3ef05e 100644
> --- a/include/system/memory.h
> +++ b/include/system/memory.h
> @@ -2992,13 +2992,14 @@ IOMMUTLBEntry address_space_get_iotlb_entry(AddressSpace *as, hwaddr addr,
> * @addr: address within that address space
> * @xlat: pointer to address within the returned memory region section's
> * #MemoryRegion.
> - * @len: pointer to length
> + * @plen_out: pointer to valid read/write length of the translated address.
> + * It can be @NULL when we don't care about it.
> * @is_write: indicates the transfer direction
> * @attrs: memory attributes
> */
> MemoryRegion *flatview_translate(FlatView *fv,
> hwaddr addr, hwaddr *xlat,
> - hwaddr *len, bool is_write,
> + hwaddr *plen_out, bool is_write,
> MemTxAttrs attrs);
>
> static inline MemoryRegion *address_space_translate(AddressSpace *as,
> diff --git a/system/physmem.c b/system/physmem.c
> index 8a8be3a80e2..2d1697fce4c 100644
> --- a/system/physmem.c
> +++ b/system/physmem.c
> @@ -566,7 +566,7 @@ iotlb_fail:
>
> /* Called from RCU critical section */
> MemoryRegion *flatview_translate(FlatView *fv, hwaddr addr, hwaddr *xlat,
> - hwaddr *plen, bool is_write,
> + hwaddr *plen_out, bool is_write,
> MemTxAttrs attrs)
> {
> MemoryRegion *mr;
> @@ -574,13 +574,13 @@ MemoryRegion *flatview_translate(FlatView *fv, hwaddr addr, hwaddr *xlat,
> AddressSpace *as = NULL;
>
> /* This can be MMIO, so setup MMIO bit. */
> - section = flatview_do_translate(fv, addr, xlat, plen, NULL,
> + section = flatview_do_translate(fv, addr, xlat, plen_out, NULL,
> is_write, true, &as, attrs);
> mr = section.mr;
>
> if (xen_enabled() && memory_access_is_direct(mr, is_write, attrs)) {
> hwaddr page = ((addr & TARGET_PAGE_MASK) + TARGET_PAGE_SIZE) - addr;
> - *plen = MIN(page, *plen);
> + *plen_out = MIN(page, *plen_out);
There is no check for a NULL pointer here, so plen_out must *not* be NULL?
Or did I miss something?
Thomas
> }
>
> return mr;