Re: [RFC][PATCH 10/13] tools: extend XENMEM_set_memory_map

[Wei Liu <wei.liu2@citrix.com>]

On Fri, Apr 10, 2015 at 05:22:01PM +0800, Tiejun Chen wrote:
> Here we'll construct a basic guest e820 table via
> XENMEM_set_memory_map. This table includes lowmem, highmem
> and RDMs if they exist. And hvmloader would need this info
> later.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> ---
>  tools/libxl/libxl_dom.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 72 insertions(+)
> 
> diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
> index ee67282..82468be 100644
> --- a/tools/libxl/libxl_dom.c
> +++ b/tools/libxl/libxl_dom.c
> @@ -787,6 +787,70 @@ out:
>      return rc;
>  }
>  
> +static int libxl__domain_construct_memmap(libxl_ctx *ctx,

Internal function should take libxl__gc *gc.

> +                                          libxl_domain_config *d_config,
> +                                          uint32_t domid,
> +                                          struct xc_hvm_build_args *args,
> +                                          int num_pcidevs,
> +                                          libxl_device_pci *pcidevs)

I think domid, num_pcidevs and pcidevs should be in d_config by the
time you call this function? At least num_pcidevs and pcidevs should be
available.

That said, I don't see pci stuff being used anywhere in the function, so
please just delete them.

> +{
> +    unsigned int nr = 0, i;
> +    /* We always own at least one lowmem entry. */
> +    unsigned int e820_entries = 1;
> +    uint64_t highmem_end = 0, highmem_size = args->mem_size - args->lowmem_size;

FWIW there are some new output fields called lowmem_end, highmem_end and
mmio_start in xc_hvm_build_args. Those might be useful as well?

Note that they are only available *after* calling xc_hvm_build, which
seems to *not* be the case for you.

So if you somehow find those fields useful you might want to consider
moving the callsite a bit later.

> +    struct e820entry *e820 = NULL;
> +
> +    /* Add all rdm entries. */
> +    e820_entries += d_config->num_rdms;
> +
> +    /* If we should have a highmem range. */
> +    if (highmem_size)
> +    {
> +        highmem_end = (1ull<<32) + highmem_size;
> +        e820_entries++;
> +    }
> +
> +    e820 = malloc(sizeof(struct e820entry) * e820_entries);

You can use libxl__malloc(gc, ...).

> +    if (!e820) {
> +        return -1;
> +    }

No need to check if you use libxl__malloc.

> +
> +    /* Low memory */
> +    e820[nr].addr = 0x100000;

Hardcoded value?

> +    e820[nr].size = args->lowmem_size - 0x100000;
> +    e820[nr].type = E820_RAM;
> +    nr++;
> +
> +    /* RDM mapping */
> +    for (i = 0; i < d_config->num_rdms; i++) {
> +        /*
> +         * We should drop this kind of rdm entry.
> +         */
> +        if (d_config->rdms[i].flag == LIBXL_RDM_RESERVE_FLAG_INVALID)
> +            continue;
> +
> +        e820[nr].addr = d_config->rdms[i].start;
> +        e820[nr].size = d_config->rdms[i].size;
> +        e820[nr].type = E820_RESERVED;
> +        nr++;
> +    }
> +
> +    /* High memory */
> +    if (highmem_size) {
> +        e820[nr].addr = ((uint64_t)1 << 32);
> +        e820[nr].size = highmem_size;
> +        e820[nr].type = E820_RAM;
> +    }
> +
> +    if (xc_domain_set_memory_map(ctx->xch, domid, e820, e820_entries) != 0) {
> +        free(e820);

No need to free if you use libxl__malloc(gc, ...).

> +        return -1;
> +    }
> +
> +    free(e820);

Ditto.

Wei.

> +    return 0;
> +}
> +
>  int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
>                libxl_domain_config *d_config,
>                libxl__domain_build_state *state)
> @@ -836,6 +900,14 @@ int libxl__build_hvm(libxl__gc *gc, uint32_t domid,
>          goto out;
>      }
>  
> +    if (libxl__domain_construct_memmap(ctx, d_config, domid,
> +                                       &args,
> +                                       d_config->num_pcidevs,
> +                                       d_config->pcidevs)) {
> +        LOG(ERROR, "setting domain rdm memory map failed");
> +        goto out;
> +    }
> +
>      if (libxl__domain_firmware(gc, info, &args)) {
>          LOG(ERROR, "initializing domain firmware failed");
>          goto out;
> -- 
> 1.9.1