e22dff17f5
Allow setting the owner, group and mode of the `/dev/sev-guest` device, similar to what is already possible for `/dev/sev` through the `hardware.cpu.amd.sev` options. The `/dev/sev` device is available to AMD SEV hosts, e.g., to start an AMD SEV-SNP guest. In contrast, the `/dev/sev-guest` device is only available within SEV-SNP guests. The guest uses the device, for example, to request an attestation report. Linux has in-tree support for SEV-SNP guests since 5.19.
81 lines
2.3 KiB
Nix
81 lines
2.3 KiB
Nix
{ config, options, lib, ... }:
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with lib;
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let
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cfgSev = config.hardware.cpu.amd.sev;
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cfgSevGuest = config.hardware.cpu.amd.sevGuest;
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optionsFor = device: group: {
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enable = mkEnableOption (lib.mdDoc "access to the AMD ${device} device");
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user = mkOption {
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description = lib.mdDoc "Owner to assign to the ${device} device.";
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type = types.str;
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default = "root";
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};
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group = mkOption {
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description = lib.mdDoc "Group to assign to the ${device} device.";
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type = types.str;
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default = group;
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};
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mode = mkOption {
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description = lib.mdDoc "Mode to set for the ${device} device.";
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type = types.str;
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default = "0660";
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};
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};
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in
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with lib; {
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options.hardware.cpu.amd.sev = optionsFor "SEV" "sev";
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options.hardware.cpu.amd.sevGuest = optionsFor "SEV guest" "sev-guest";
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config = mkMerge [
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# /dev/sev
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(mkIf cfgSev.enable {
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assertions = [
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{
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assertion = hasAttr cfgSev.user config.users.users;
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message = "Given user does not exist";
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}
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{
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assertion = (cfgSev.group == options.hardware.cpu.amd.sev.group.default) || (hasAttr cfgSev.group config.users.groups);
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message = "Given group does not exist";
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}
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];
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boot.extraModprobeConfig = ''
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options kvm_amd sev=1
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'';
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users.groups = optionalAttrs (cfgSev.group == options.hardware.cpu.amd.sev.group.default) {
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"${cfgSev.group}" = { };
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};
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services.udev.extraRules = with cfgSev; ''
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KERNEL=="sev", OWNER="${user}", GROUP="${group}", MODE="${mode}"
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'';
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})
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# /dev/sev-guest
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(mkIf cfgSevGuest.enable {
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assertions = [
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{
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assertion = hasAttr cfgSevGuest.user config.users.users;
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message = "Given user does not exist";
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}
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{
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assertion = (cfgSevGuest.group == options.hardware.cpu.amd.sevGuest.group.default) || (hasAttr cfgSevGuest.group config.users.groups);
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message = "Given group does not exist";
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}
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];
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users.groups = optionalAttrs (cfgSevGuest.group == options.hardware.cpu.amd.sevGuest.group.default) {
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"${cfgSevGuest.group}" = { };
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};
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services.udev.extraRules = with cfgSevGuest; ''
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KERNEL=="sev-guest", OWNER="${user}", GROUP="${group}", MODE="${mode}"
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'';
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})
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];
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}
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