From 4e139026b506e2339c6ce224e2f7ad1e4bb4fa4b Mon Sep 17 00:00:00 2001
From: Jared Baur <jaredbaur@fastmail.com>
Date: Fri, 26 Jan 2024 22:26:46 -0800
Subject: [PATCH 1/2] nixos/repart: add option for configuring sector size

This option is helpful for situations when the target host disk's sector
size differs from that of the build host.
---
 nixos/modules/image/repart-image.nix |  2 ++
 nixos/modules/image/repart.nix       | 12 +++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/image/repart-image.nix b/nixos/modules/image/repart-image.nix
index a12b4fb14fb1..7ac47ee32ff4 100644
--- a/nixos/modules/image/repart-image.nix
+++ b/nixos/modules/image/repart-image.nix
@@ -32,6 +32,7 @@
 , split
 , seed
 , definitionsDirectory
+, sectorSize
 }:
 
 let
@@ -94,6 +95,7 @@ runCommand imageFileBasename
     --definitions="$amendedRepartDefinitions" \
     --split="${lib.boolToString split}" \
     --json=pretty \
+    ${lib.optionalString (sectorSize != null) "--sector-size=${toString sectorSize}"} \
     ${imageFileBasename}.raw \
     | tee repart-output.json
 
diff --git a/nixos/modules/image/repart.nix b/nixos/modules/image/repart.nix
index ed584d9bf997..6a933f0d83cc 100644
--- a/nixos/modules/image/repart.nix
+++ b/nixos/modules/image/repart.nix
@@ -135,6 +135,16 @@ in
       '';
     };
 
+    sectorSize = lib.mkOption {
+      type = with lib.types; nullOr int;
+      default = 512;
+      example = lib.literalExpression "4096";
+      description = lib.mdDoc ''
+        The sector size of the disk image produced by systemd-repart. This
+        value must be a power of 2 between 512 and 4096.
+      '';
+    };
+
     package = lib.mkPackageOption pkgs "systemd-repart" {
       # We use buildPackages so that repart images are built with the build
       # platform's systemd, allowing for cross-compiled systems to work.
@@ -232,7 +242,7 @@ in
       in
       pkgs.callPackage ./repart-image.nix {
         systemd = cfg.package;
-        inherit (cfg) imageFileBasename compression split seed;
+        inherit (cfg) imageFileBasename compression split seed sectorSize;
         inherit fileSystems definitionsDirectory partitions;
       };
 

From 0bf5f3be2512b2770bb8c4f45a7b7b1956909300 Mon Sep 17 00:00:00 2001
From: Jared Baur <jaredbaur@fastmail.com>
Date: Fri, 26 Jan 2024 22:27:50 -0800
Subject: [PATCH 2/2] appliance-repart-image: fix OVMF not detecting disk

With the update of systemd to v255, the repart tool switched to use 4K
sector sizes by default. This change sets the appliance-repart-image
test to use a sector size of 512B to fit in with the existing NixOS VM
test infrastructure using qemu disks with 512B sector sizes.
---
 nixos/tests/appliance-repart-image.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/nixos/tests/appliance-repart-image.nix b/nixos/tests/appliance-repart-image.nix
index b18968d3b963..861369b9f3ca 100644
--- a/nixos/tests/appliance-repart-image.nix
+++ b/nixos/tests/appliance-repart-image.nix
@@ -40,6 +40,8 @@ in
 
     image.repart = {
       name = "appliance-gpt-image";
+      # OVMF does not work with the default repart sector size of 4096
+      sectorSize = 512;
       partitions = {
         "esp" = {
           contents =