From c4851c0d710c39e54d7ee0b8e522e136f290f09d Mon Sep 17 00:00:00 2001
From: Artturi <Artturin@artturin.com>
Date: Wed, 24 Nov 2021 02:33:53 +0200
Subject: [PATCH] Revert msize related commits (#147180)

---
 nixos/modules/virtualisation/qemu-vm.nix |  2 +-
 nixos/tests/hibernate.nix                |  1 -
 nixos/tests/installer.nix                |  6 +++---
 pkgs/build-support/vm/default.nix        | 11 ++---------
 4 files changed, 6 insertions(+), 14 deletions(-)

diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index 493c407222f7..91356ac1d984 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -306,7 +306,7 @@ in
     virtualisation.msize =
       mkOption {
         type = types.ints.positive;
-        default = pkgs.vmTools.default9PMsizeBytes;
+        default = 16384;
         description =
           ''
             The msize (maximum packet size) option passed to 9p file systems, in
diff --git a/nixos/tests/hibernate.nix b/nixos/tests/hibernate.nix
index fc6857e2fd02..4f05b99a5a11 100644
--- a/nixos/tests/hibernate.nix
+++ b/nixos/tests/hibernate.nix
@@ -51,7 +51,6 @@ in makeTest {
         connect-timeout = 1
       '';
 
-      virtualisation.memorySize = 2048;
       virtualisation.diskSize = 8 * 1024;
       virtualisation.emptyDiskImages = [
         # Small root disk for installer
diff --git a/nixos/tests/installer.nix b/nixos/tests/installer.nix
index 0748a74ee176..513d2506e941 100644
--- a/nixos/tests/installer.nix
+++ b/nixos/tests/installer.nix
@@ -76,8 +76,8 @@ let
       def assemble_qemu_flags():
           flags = "-cpu max"
           ${if (system == "x86_64-linux" || system == "i686-linux")
-            then ''flags += " -m 1500"''
-            else ''flags += " -m 1000 -enable-kvm -machine virt,gic-version=host"''
+            then ''flags += " -m 1024"''
+            else ''flags += " -m 768 -enable-kvm -machine virt,gic-version=host"''
           }
           return flags
 
@@ -288,7 +288,7 @@ let
           # builds stuff in the VM, needs more juice
           virtualisation.diskSize = 8 * 1024;
           virtualisation.cores = 8;
-          virtualisation.memorySize = 3096;
+          virtualisation.memorySize = 1536;
 
           # Use a small /dev/vdb as the root disk for the
           # installer. This ensures the target disk (/dev/vda) is
diff --git a/pkgs/build-support/vm/default.nix b/pkgs/build-support/vm/default.nix
index 3f176db36c2b..7b517333d9e3 100644
--- a/pkgs/build-support/vm/default.nix
+++ b/pkgs/build-support/vm/default.nix
@@ -110,7 +110,7 @@ rec {
 
     echo "mounting Nix store..."
     mkdir -p /fs${storeDir}
-    mount -t 9p store /fs${storeDir} -o trans=virtio,version=9p2000.L,cache=loose,msize=${toString default9PMsizeBytes}
+    mount -t 9p store /fs${storeDir} -o trans=virtio,version=9p2000.L,cache=loose
 
     mkdir -p /fs/tmp /fs/run /fs/var
     mount -t tmpfs -o "mode=1777" none /fs/tmp
@@ -119,7 +119,7 @@ rec {
 
     echo "mounting host's temporary directory..."
     mkdir -p /fs/tmp/xchg
-    mount -t 9p xchg /fs/tmp/xchg -o trans=virtio,version=9p2000.L,msize=${toString default9PMsizeBytes}
+    mount -t 9p xchg /fs/tmp/xchg -o trans=virtio,version=9p2000.L
 
     mkdir -p /fs/proc
     mount -t proc none /fs/proc
@@ -1174,11 +1174,4 @@ rec {
      `debDistros' sets. */
   diskImages = lib.mapAttrs (name: f: f {}) diskImageFuns;
 
-  # The default 9P msize value is 8 KiB, which according to QEMU is
-  # insufficient and would degrade performance.
-  # See: https://wiki.qemu.org/Documentation/9psetup#msize
-  # Use 128KiB which is the default in linux 5.15+
-  # https://github.com/torvalds/linux/commit/9c4d94dc9a64426d2fa0255097a3a84f6ff2eebe
-  # TODO: actually set it to 128KiB, it was causing failures in many tests due to memory usage
-  default9PMsizeBytes = 16 * 1024;
 }