Generic acpi and reset of PCI audio device

Lenovo X1 PCI audio device needs to be reset when audioVM shuts down Generic version that allows configuration for other platforms Signed-off-by: Jon Sahlberg <[email protected]>
tiiuae · Dec 9, 2024 · 8938072 · 8938072
1 parent 745a6df
commit 8938072
Show file tree

Hide file tree

Showing 5 changed files with 54 additions and 11 deletions.
diff --git a/modules/hardware/definition.nix b/modules/hardware/definition.nix
@@ -266,6 +266,21 @@ in
       };
 
       audio = {
+        removePciDevice = mkOption {
+          description = "PCI Device path to remove at VM reboot";
+          type = types.nullOr types.str;
+          default = null;
+        };
+        rescanPciDevice = mkOption {
+          description = "PCI Device path to rescan at VM reboot";
+          type = types.nullOr types.str;
+          default = null;
+        };
+        acpiPath = mkOption {
+          description = "Path to ACPI file to add to a VM";
+          type = types.nullOr types.str;
+          default = null;
+        };
         # With the current implementation, the whole PCI IOMMU group 14:
         #   00:1f.x in the example from Lenovo X1 Carbon
         #   must be defined for passthrough to AudioVM

diff --git a/modules/microvm/virtualization/microvm/audiovm.nix b/modules/microvm/virtualization/microvm/audiovm.nix
@@ -12,6 +12,7 @@ let
   vmName = "audio-vm";
   macAddress = "02:00:00:03:03:03";
   isGuiVmEnabled = config.ghaf.virtualization.microvm.guivm.enable;
+  has_acpi_path = config.ghaf.hardware.definition.audio.acpiPath != null;
 
   sshKeysHelper = pkgs.callPackage ../../../../packages/ssh-keys-helper {
     inherit pkgs;
@@ -119,12 +120,15 @@ let
                   aarch64-linux = "virt";
                 }
                 .${configHost.nixpkgs.hostPlatform.system};
-              extraArgs = [
-                "-device"
-                "qemu-xhci"
-                "-acpitable"
-                "file=/sys/firmware/acpi/tables/NHLT"
-              ];
+              extraArgs =
+                [
+                  "-device"
+                  "qemu-xhci"
+                ]
+                ++ lib.optionals has_acpi_path [
+                  "-acpitable"
+                  "file=${config.ghaf.hardware.definition.audio.acpiPath}"
+                ];
             };
           };
 

diff --git a/modules/microvm/virtualization/microvm/microvm-host.nix b/modules/microvm/virtualization/microvm/microvm-host.nix
@@ -9,6 +9,14 @@
 }:
 let
   cfg = config.ghaf.virtualization.microvm-host;
+  has_remove_pci_device = config.ghaf.hardware.definition.audio.removePciDevice != null;
+  has_rescan_pci_device = config.ghaf.hardware.definition.audio.rescanPciDevice != null;
+  has_acpi_path = config.ghaf.hardware.definition.audio.acpiPath != null;
+  rescan_pci_device =
+    if has_rescan_pci_device then
+      config.ghaf.hardware.definition.audio.rescanPciDevice
+    else
+      config.ghaf.hardware.definition.audio.removePciDevice;
 in
 {
   imports = [
@@ -62,21 +70,21 @@ in
         lib.optionalAttrs config.ghaf.virtualization.microvm.audiovm.enable
           {
             # The + here is a systemd feature to make the script run as root.
-            ExecStartPre = [
+            ExecStartPre = lib.mkIf has_acpi_path [
               "+${pkgs.writeShellScript "ACPI-table-permission" ''
                 # The script gives permissionf sot a microvm user
                 # to read ACPI tables of soundcaed mic array.
-                ${pkgs.coreutils}/bin/chmod 444 /sys/firmware/acpi/tables/NHLT
+                ${pkgs.coreutils}/bin/chmod 444 ${config.ghaf.hardware.definition.audio.acpiPath}
               ''}"
             ];
-            ExecStopPost = [
+            ExecStopPost = lib.mkIf has_remove_pci_device [
               "+${pkgs.writeShellScript "reload-audio" ''
                 # The script makes audio device internal state to reset
                 # This fixes issue of audio device getting into some unexpected
                 # state when the VM is being shutdown during audio mic recording
-                echo "1" > /sys/bus/pci/devices/0000:00:1f.3/remove
+                echo "1" > ${config.ghaf.hardware.definition.audio.removePciDevice}
                 sleep 0.1
-                echo "1" > /sys/bus/pci/devices/0000:00:1f.0/rescan
+                echo "1" > ${rescan_pci_device}
               ''}"
             ];
           };

diff --git a/modules/reference/hardware/lenovo-x1/definitions/x1-gen10.nix b/modules/reference/hardware/lenovo-x1/definitions/x1-gen10.nix
@@ -89,6 +89,13 @@
   #   00:1f.x in the Lenovo X1 Carbon 10 gen
   #   must be defined for passthrough to AudioVM
   audio = {
+    # Force a PCI device reset to the device to get pci device to the default state at shutdown
+    removePciDevice = "0000:00:1f.3";
+    # Force a PCI device rescan after resetting a device to refind the device on host
+    rescanPciDevice = "0000:00:1f.0";
+    # Add acpi table to audioVM to enable microphone array profile
+    acpiPath = "/sys/firmware/acpi/tables/NHLT";
+
     pciDevices = [
       {
         # ISA bridge: Intel Corporation Alder Lake PCH eSPI Controller(rev 01)

diff --git a/modules/reference/hardware/lenovo-x1/definitions/x1-gen11.nix b/modules/reference/hardware/lenovo-x1/definitions/x1-gen11.nix
@@ -99,6 +99,15 @@
   #   00:1f.x in the example from Lenovo X1 Carbon
   #   must be defined for passthrough to AudioVM
   audio = {
+    # Force a PCI device reset to the audio device
+    # This is to get the pci hardware device to the default state at shutdown
+    removePciDevice = "0000:00:1f.3";
+    # Force a PCI device rescan after resetting a device
+    # to refind the device on host after reset
+    rescanPciDevice = "0000:00:1f.0";
+    # Add acpi table file to audioVM to enable Lenovo X1 microphone array profile
+    acpiPath = "/sys/firmware/acpi/tables/NHLT";
+
     pciDevices = [
       {
         # ISA bridge: Intel Corporation Raptor Lake LPC/eSPI Controller (rev 01)