Re: [Qemu-devel] [PATCH v2 2/2] postcopy: Check for shared memory

[Juan Quintela]

"Dr. David Alan Gilbert (git)" <address@hidden> wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> Postcopy doesn't support migration of RAM shared with another process
> yet (we've got a bunch of things to understand).
> Check for the case and don't allow postcopy to be enabled.
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
>  migration/postcopy-ram.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> index effbeb6..dc80dbb 100644
> --- a/migration/postcopy-ram.c
> +++ b/migration/postcopy-ram.c
> @@ -95,6 +95,19 @@ static bool ufd_version_check(int ufd)
>      return true;
>  }
>  
> +/* Callback from postcopy_ram_supported_by_host block iterator.
> + */
> +static int test_range_shared(const char *block_name, void *host_addr,
> +                             ram_addr_t offset, ram_addr_t length, void 
> *opaque)


Direct question for the name?

ram_range_is_shared?



> +{
> +    if (qemu_ram_is_shared(qemu_ram_block_by_name(block_name))) {
> +        error_report("Postcopy on shared RAM (%s) is not yet supported",
> +                     block_name);
> +        return 1;
> +    }
> +    return 0;
> +}

Wow, we still predate use of bool for questions :-p


> +
>  /*
>   * Note: This has the side effect of munlock'ing all of RAM, that's
>   * normally fine since if the postcopy succeeds it gets turned back on at the
> @@ -127,6 +140,11 @@ bool postcopy_ram_supported_by_host(void)
>          goto out;
>      }
>  
> +    /* We don't support postcopy with shared RAM yet */
> +    if (qemu_ram_foreach_block(test_range_shared, NULL)) {
> +        goto out;
> +    }
> +
>      /*
>       * userfault and mlock don't go together; we'll put it back later if
>       * it was enabled.

As my comments are only aestetic,

Reviewed-by: Juan Quintela <address@hidden>