Add a new config parameter to configure a dom0less VM with static allocation.
DOMU_STATIC_MEM[number]="baseaddr1 size1 ... baseaddrN sizeN"
The parameter specifies the host physical address regions to be statically
allocated to the VM. Each region is defined by its start address and size.

For instance,
DOMU_STATIC_MEM[0]="0x30000000 0x10000000 0x50000000 0x20000000"
indicates that the host memory regions [0x30000000, 0x40000000) and
[0x50000000, 0x70000000) are statically allocated to the first dom0less VM.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
---

Notes:
    v2: in add_device_tree_static_mem(), replace i with val because variable i
        is already in use as an index

 README.md                |  4 ++++
 scripts/uboot-script-gen | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/README.md b/README.md
index 8ce13f0..876e46d 100644
--- a/README.md
+++ b/README.md
@@ -154,6 +154,10 @@ Where:
   automatically at boot as dom0-less guest. It can still be created
   later from Dom0.
 
+- DOMU_STATIC_MEM[number]="baseaddr1 size1 ... baseaddrN sizeN"
+  if specified, indicates the host physical address regions
+  [baseaddr, baseaddr + size) to be reserved to the VM for static allocation.
+
 - LINUX is optional but specifies the Linux kernel for when Xen is NOT
   used.  To enable this set any LINUX\_\* variables and do NOT set the
   XEN variable.
diff --git a/scripts/uboot-script-gen b/scripts/uboot-script-gen
index 0adf523..3a5f720 100755
--- a/scripts/uboot-script-gen
+++ b/scripts/uboot-script-gen
@@ -108,6 +108,22 @@ function add_device_tree_passthrough()
     dt_set "$path/module$addr" "reg" "hex"  "0x0 $addr 0x0 $(printf "0x%x" $size)"
 }
 
+function add_device_tree_static_mem()
+{
+    local path=$1
+    local regions=$2
+
+    dt_set "$path" "#xen,static-mem-address-cells" "hex" "0x2"
+    dt_set "$path" "#xen,static-mem-size-cells" "hex" "0x2"
+
+    for val in ${regions[@]}
+    do
+	cells+=("$(printf "0x%x 0x%x" $(($val >> 32)) $(($val & ((1 << 32) - 1))))")
+    done
+
+    dt_set "$path" "xen,static-mem" "hex" "${cells[*]}"
+}
+
 function xen_device_tree_editing()
 {
     dt_set "/chosen" "#address-cells" "hex" "0x2"
@@ -143,6 +159,10 @@ function xen_device_tree_editing()
         dt_set "/chosen/domU$i" "#size-cells" "hex" "0x2"
         dt_set "/chosen/domU$i" "memory" "int" "0 ${DOMU_MEM[$i]}"
         dt_set "/chosen/domU$i" "cpus" "int" "${DOMU_VCPUS[$i]}"
+	if test "${DOMU_STATIC_MEM[$i]}"
+        then
+	    add_device_tree_static_mem "/chosen/domU$i" "${DOMU_STATIC_MEM[$i]}"
+        fi
         dt_set "/chosen/domU$i" "vpl011" "hex" "0x1"
         add_device_tree_kernel "/chosen/domU$i" ${domU_kernel_addr[$i]} ${domU_kernel_size[$i]} "${DOMU_CMD[$i]}"
         if test "${domU_ramdisk_addr[$i]}"
-- 
2.34.1

On Wed, 15 Jun 2022, Xenia Ragiadakou wrote:
> Add a new config parameter to configure a dom0less VM with static allocation.
> DOMU_STATIC_MEM[number]="baseaddr1 size1 ... baseaddrN sizeN"
> The parameter specifies the host physical address regions to be statically
> allocated to the VM. Each region is defined by its start address and size.
> 
> For instance,
> DOMU_STATIC_MEM[0]="0x30000000 0x10000000 0x50000000 0x20000000"
> indicates that the host memory regions [0x30000000, 0x40000000) and
> [0x50000000, 0x70000000) are statically allocated to the first dom0less VM.
> 
> Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>

Hi Xenia, thanks for the patch!

It looks fine as is, only two minor code style issues (tabs instead of
spaces for indentation.)

I think this would work. However, when static-mem is specified also the
total memory for the guest needs to match. So for instance:

  #xen,static-mem-address-cells = <0x1>;
  #xen,static-mem-size-cells = <0x1>;
  xen,static-mem = <0x30000000 0x20000000>;

In this case memory has to be:

  memory = <0x0 0x80000>;

memory is in kilobytes, so 0x20000000/1024=0x80000.

In ImageBuilder "memory" is normally set by the DOMU_MEM variable,
although that is in megabytes.

I think it would make sense to automatically calculate "memory" DOMU_MEM
based on the sizes passed via DOMU_STATIC_MEM when DOMU_STATIC_MEM is
specified: summing all the sizes together and dividing by 1024.

That could be done either with something like

    if test "${DOMU_STATIC_MEM[$i]}"
    then
        local memory=[calculate memory]
        dt_set "/chosen/domU$i" "memory" "int" "0 $memory"
        add_device_tree_static_mem "/chosen/domU$i" "${DOMU_STATIC_MEM[$i]}"

Or it could be done by changing DOMU_MEM to be in kilobytes and simply
setting DOMU_MEM based on the DOMU_STATIC_MEM values when
DOMU_STATIC_MEM is specified.

Would you be OK to add that to this patch? If not, that's OK. This patch
is also good to have as is.



> ---
> 
> Notes:
>     v2: in add_device_tree_static_mem(), replace i with val because variable i
>         is already in use as an index
> 
>  README.md                |  4 ++++
>  scripts/uboot-script-gen | 20 ++++++++++++++++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/README.md b/README.md
> index 8ce13f0..876e46d 100644
> --- a/README.md
> +++ b/README.md
> @@ -154,6 +154,10 @@ Where:
>    automatically at boot as dom0-less guest. It can still be created
>    later from Dom0.
>  
> +- DOMU_STATIC_MEM[number]="baseaddr1 size1 ... baseaddrN sizeN"
> +  if specified, indicates the host physical address regions
> +  [baseaddr, baseaddr + size) to be reserved to the VM for static allocation.
> +
>  - LINUX is optional but specifies the Linux kernel for when Xen is NOT
>    used.  To enable this set any LINUX\_\* variables and do NOT set the
>    XEN variable.
> diff --git a/scripts/uboot-script-gen b/scripts/uboot-script-gen
> index 0adf523..3a5f720 100755
> --- a/scripts/uboot-script-gen
> +++ b/scripts/uboot-script-gen
> @@ -108,6 +108,22 @@ function add_device_tree_passthrough()
>      dt_set "$path/module$addr" "reg" "hex"  "0x0 $addr 0x0 $(printf "0x%x" $size)"
>  }
>  
> +function add_device_tree_static_mem()
> +{
> +    local path=$1
> +    local regions=$2
> +
> +    dt_set "$path" "#xen,static-mem-address-cells" "hex" "0x2"
> +    dt_set "$path" "#xen,static-mem-size-cells" "hex" "0x2"
> +
> +    for val in ${regions[@]}
> +    do
> +	cells+=("$(printf "0x%x 0x%x" $(($val >> 32)) $(($val & ((1 << 32) - 1))))")
> +    done
> +
> +    dt_set "$path" "xen,static-mem" "hex" "${cells[*]}"
> +}
> +
>  function xen_device_tree_editing()
>  {
>      dt_set "/chosen" "#address-cells" "hex" "0x2"
> @@ -143,6 +159,10 @@ function xen_device_tree_editing()
>          dt_set "/chosen/domU$i" "#size-cells" "hex" "0x2"
>          dt_set "/chosen/domU$i" "memory" "int" "0 ${DOMU_MEM[$i]}"
>          dt_set "/chosen/domU$i" "cpus" "int" "${DOMU_VCPUS[$i]}"
> +	if test "${DOMU_STATIC_MEM[$i]}"
> +        then
> +	    add_device_tree_static_mem "/chosen/domU$i" "${DOMU_STATIC_MEM[$i]}"
> +        fi
>          dt_set "/chosen/domU$i" "vpl011" "hex" "0x1"
>          add_device_tree_kernel "/chosen/domU$i" ${domU_kernel_addr[$i]} ${domU_kernel_size[$i]} "${DOMU_CMD[$i]}"
>          if test "${domU_ramdisk_addr[$i]}"
> -- 
> 2.34.1
>