This patch is for enabling AMD SEV-SNP support.
Where applicable, it extends support for existing SEV(-ES) variables
to SEV-SNP.
The default policy value is identical to QEMU’s, and the therefore
required option has been added to configure SMT support.
The code was tested by running a VM without SEV, with SEV, SEV-ES,
SEV-SNP. Each configuration was tested with and without an EFI disk
attached. For SEV-enabled configurations it was also verified that the
kernel actually used the respective feature.
Signed-off-by: Philipp Giersfeld <philipp.giersf...@canarybit.eu>
---
PVE/API2/Qemu.pm | 9 +++--
PVE/QemuServer.pm | 57 +++++++++++++++++++++++---------
PVE/QemuServer/CPUConfig.pm | 66 ++++++++++++++++++++++++++++---------
3 files changed, 99 insertions(+), 33 deletions(-)
diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index 295260e7..35c76dc2 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -548,8 +548,13 @@ my sub create_disks : prototype($$$$$$$$$$$) {
my $volid;
if ($ds eq 'efidisk0') {
my $smm =
PVE::QemuServer::Machine::machine_type_is_q35($conf);
- ($volid, $size) = PVE::QemuServer::create_efidisk(
- $storecfg, $storeid, $vmid, $fmt, $arch, $disk, $smm);
+ my $amd_sev_type =
PVE::QemuServer::CPUConfig::get_amd_sev_type($conf);
+ if($amd_sev_type && $amd_sev_type eq 'snp') {
+ die "SEV-SNP only uses consolidated read-only
firmware";
+ } else {
+ ($volid, $size) = PVE::QemuServer::create_efidisk(
+ $storecfg, $storeid, $vmid, $fmt, $arch, $disk,
$smm, $amd_sev_type);
+ }
} elsif ($ds eq 'tpmstate0') {
# swtpm can only use raw volumes, and uses a fixed size
$size =
PVE::Tools::convert_size(PVE::QemuServer::Drive::TPMSTATE_DISK_SIZE, 'b' =>
'kb');
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 808c0e1c..e46b3434 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -52,7 +52,7 @@ use PVE::QemuConfig;
use PVE::QemuServer::Helpers qw(config_aware_timeout min_version
kvm_user_version windows_version);
use PVE::QemuServer::Cloudinit;
use PVE::QemuServer::CGroup;
-use PVE::QemuServer::CPUConfig qw(print_cpu_device get_cpu_options
get_cpu_bitness is_native_arch get_amd_sev_object);
+use PVE::QemuServer::CPUConfig qw(print_cpu_device get_cpu_options
get_cpu_bitness is_native_arch get_amd_sev_object get_amd_sev_type);
use PVE::QemuServer::Drive qw(is_valid_drivename checked_volume_format
drive_is_cloudinit drive_is_cdrom drive_is_read_only parse_drive print_drive);
use PVE::QemuServer::Machine;
use PVE::QemuServer::Memory qw(get_current_memory);
@@ -88,6 +88,13 @@ my $OVMF = {
"$EDK2_FW_BASE/OVMF_CODE_4M.secboot.fd",
"$EDK2_FW_BASE/OVMF_VARS_4M.ms.fd",
],
+ '4m-sev' => [
+ "$EDK2_FW_BASE/OVMF_CVM_CODE_4M.fd",
+ "$EDK2_FW_BASE/OVMF_CVM_VARS_4M.fd",
+ ],
+ '4m-snp' => [
+ "$EDK2_FW_BASE/OVMF_CVM_4M.fd",
+ ],
# FIXME: These are legacy 2MB-sized images that modern OVMF doesn't
supports to build
# anymore. how can we deperacate this sanely without breaking existing
instances, or using
# older backups and snapshot?
@@ -3172,19 +3179,28 @@ sub vga_conf_has_spice {
return $1 || 1;
}
-sub get_ovmf_files($$$) {
- my ($arch, $efidisk, $smm) = @_;
+sub get_ovmf_files($$$$) {
+ my ($arch, $efidisk, $smm, $amd_sev_type) = @_;
my $types = $OVMF->{$arch}
or die "no OVMF images known for architecture '$arch'\n";
my $type = 'default';
if ($arch eq 'x86_64') {
- if (defined($efidisk->{efitype}) && $efidisk->{efitype} eq '4m') {
- $type = $smm ? "4m" : "4m-no-smm";
- $type .= '-ms' if $efidisk->{'pre-enrolled-keys'};
+ if ($amd_sev_type && $amd_sev_type eq 'snp') {
+ $type = "4m-snp";
+ my ($ovmf) = $types->{$type}->@*;
+ die "EFI base image '$ovmf' not found\n" if ! -f $ovmf;
+ return ($ovmf);
+ } elsif ($amd_sev_type) {
+ $type = "4m-sev";
} else {
- # TODO: log_warn about use of legacy images for x86_64 with Promxox
VE 9
+ if (defined($efidisk->{efitype}) && $efidisk->{efitype} eq '4m') {
+ $type = $smm ? "4m" : "4m-no-smm";
+ $type .= '-ms' if $efidisk->{'pre-enrolled-keys'};
+ } else {
+ # TODO: log_warn about use of legacy images for x86_64 with
Promxox VE 9
+ }
}
}
@@ -3329,7 +3345,8 @@ my sub print_ovmf_drive_commandlines {
my $d = $conf->{efidisk0} ? parse_drive('efidisk0', $conf->{efidisk0}) :
undef;
- my ($ovmf_code, $ovmf_vars) = get_ovmf_files($arch, $d, $q35);
+ my $amd_sev_type = get_amd_sev_type($conf);
+ my ($ovmf_code, $ovmf_vars) = get_ovmf_files($arch, $d, $q35,
$amd_sev_type);
my $var_drive_str = "if=pflash,unit=1,id=drive-efidisk0";
if ($d) {
@@ -3526,10 +3543,17 @@ sub config_to_command {
die "OVMF (UEFI) BIOS is not supported on 32-bit CPU types\n"
if !$forcecpu && get_cpu_bitness($conf->{cpu}, $arch) == 32;
- my ($code_drive_str, $var_drive_str) =
- print_ovmf_drive_commandlines($conf, $storecfg, $vmid, $arch, $q35,
$version_guard);
- push $cmd->@*, '-drive', $code_drive_str;
- push $cmd->@*, '-drive', $var_drive_str;
+ my $amd_sev_type = get_amd_sev_type($conf);
+ if ($amd_sev_type && $amd_sev_type eq 'snp') {
+ my $arch = PVE::QemuServer::Helpers::get_vm_arch($conf);
+ my $d = $conf->{efidisk0} ? parse_drive('efidisk0',
$conf->{efidisk0}) : undef;
+ push $cmd->@*, '-bios', get_ovmf_files($arch, $d, undef,
$amd_sev_type);
+ } else {
+ my ($code_drive_str, $var_drive_str) =
print_ovmf_drive_commandlines(
+ $conf, $storecfg, $vmid, $arch, $q35, $version_guard);
+ push $cmd->@*, '-drive', $code_drive_str;
+ push $cmd->@*, '-drive', $var_drive_str;
+ }
}
if ($q35) { # tell QEMU to load q35 config early
@@ -8337,7 +8361,8 @@ sub get_efivars_size {
my $arch = PVE::QemuServer::Helpers::get_vm_arch($conf);
$efidisk //= $conf->{efidisk0} ? parse_drive('efidisk0',
$conf->{efidisk0}) : undef;
my $smm = PVE::QemuServer::Machine::machine_type_is_q35($conf);
- my (undef, $ovmf_vars) = get_ovmf_files($arch, $efidisk, $smm);
+ my $amd_sev_type = get_amd_sev_type($conf);
+ my (undef, $ovmf_vars) = get_ovmf_files($arch, $efidisk, $smm,
$amd_sev_type);
return -s $ovmf_vars;
}
@@ -8361,10 +8386,10 @@ sub update_tpmstate_size {
$conf->{tpmstate0} = print_drive($disk);
}
-sub create_efidisk($$$$$$$) {
- my ($storecfg, $storeid, $vmid, $fmt, $arch, $efidisk, $smm) = @_;
+sub create_efidisk($$$$$$$$) {
+ my ($storecfg, $storeid, $vmid, $fmt, $arch, $efidisk, $smm,
$amd_sev_type) = @_;
- my (undef, $ovmf_vars) = get_ovmf_files($arch, $efidisk, $smm);
+ my (undef, $ovmf_vars) = get_ovmf_files($arch, $efidisk, $smm,
$amd_sev_type);
my $vars_size_b = -s $ovmf_vars;
my $vars_size = PVE::Tools::convert_size($vars_size_b, 'b' => 'kb');
diff --git a/PVE/QemuServer/CPUConfig.pm b/PVE/QemuServer/CPUConfig.pm
index e65d8c26..dbc31462 100644
--- a/PVE/QemuServer/CPUConfig.pm
+++ b/PVE/QemuServer/CPUConfig.pm
@@ -18,6 +18,7 @@ get_cpu_options
get_cpu_bitness
is_native_arch
get_amd_sev_object
+get_amd_sev_type
);
# under certain race-conditions, this module might be loaded before pve-cluster
@@ -231,25 +232,32 @@ my $cpu_fmt = {
my $sev_fmt = {
type => {
description => "Enable standard SEV with type='std' or enable"
- ." experimental SEV-ES with the 'es' option.",
+ ." experimental SEV-ES with the 'es' option or enable "
+ ."experimental SEV-SNP with the 'snp option.",
type => 'string',
default_key => 1,
format_description => "sev-type",
- enum => ['std', 'es'],
+ enum => ['std', 'es', 'snp'],
maxLength => 3,
},
'no-debug' => {
- description => "Sets policy bit 0 to 1 to disallow debugging of guest",
+ description => "Sets policy bit to disallow debugging of guest",
type => 'boolean',
default => 0,
optional => 1,
},
'no-key-sharing' => {
- description => "Sets policy bit 1 to 1 to disallow key sharing with
other guests",
+ description => "Sets policy bit to disallow key sharing with other
guests",
type => 'boolean',
default => 0,
optional => 1,
},
+ 'allow-smt' => {
+ description => "Sets policy bit to allow SMT",
+ type => 'boolean',
+ default => 1,
+ optional => 1,
+ },
"kernel-hashes" => {
description => "Add kernel hashes to guest firmware for measured linux
kernel launch",
type => 'boolean',
@@ -823,6 +831,16 @@ sub get_hw_capabilities {
}
return $hw_capabilities;
}
+sub get_amd_sev_type {
+ my ($conf) = @_;
+
+ if ($conf->{'amd-sev'}) {
+ return PVE::JSONSchema::parse_property_string($sev_fmt,
$conf->{'amd-sev'})->{type};
+ }
+ else {
+ return undef;
+ }
+}
sub get_amd_sev_object {
my ($amd_sev, $bios) = @_;
@@ -836,22 +854,40 @@ sub get_amd_sev_object {
if ($amd_sev_conf->{type} eq 'es' && !$sev_hw_caps->{'sev-support-es'}) {
die "Your CPU does not support AMD SEV-ES.\n";
}
+ if ($amd_sev_conf->{type} eq 'snp' && !$sev_hw_caps->{'sev-support-snp'}) {
+ die "Your CPU does not support AMD SEV-SNP.\n";
+ }
if (!$bios || $bios ne 'ovmf') {
die "To use AMD SEV, you need to change the BIOS to OVMF.\n";
}
- my $sev_mem_object = 'sev-guest,id=sev0';
- $sev_mem_object .= ',cbitpos='.$sev_hw_caps->{cbitpos};
- $sev_mem_object .=
',reduced-phys-bits='.$sev_hw_caps->{'reduced-phys-bits'};
+ my $sev_mem_object = '';
+ my $policy;
+ if ($amd_sev_conf->{type} eq 'es' || $amd_sev_conf->{type} eq 'std') {
+ $sev_mem_object .= 'sev-guest,id=sev0';
+ $sev_mem_object .= ',cbitpos='.$sev_hw_caps->{cbitpos};
+ $sev_mem_object .=
',reduced-phys-bits='.$sev_hw_caps->{'reduced-phys-bits'};
+
+ # guest policy bit calculation as described here:
+ #
https://documentation.suse.com/sles/15-SP5/html/SLES-amd-sev/article-amd-sev.html#table-guestpolicy
+ $policy = 0b0000;
+ $policy += 0b0001 if $amd_sev_conf->{'no-debug'};
+ $policy += 0b0010 if $amd_sev_conf->{'no-key-sharing'};
+ $policy += 0b0100 if $amd_sev_conf->{type} eq 'es';
+ # disable migration with bit 3 nosend to prevent
amd-sev-migration-attack
+ $policy += 0b1000;
+ } elsif ($amd_sev_conf->{type} eq 'snp') {
+ $sev_mem_object .= 'sev-snp-guest,id=sev0';
+ $sev_mem_object .= ',cbitpos='.$sev_hw_caps->{cbitpos};
+ $sev_mem_object .=
',reduced-phys-bits='.$sev_hw_caps->{'reduced-phys-bits'};
+
+ # guest policy bit calculation as described here:
+ # https://libvirt.org/formatdomain.html#id121
+ $policy = 0x20000;
+ $policy += 0x80000 if $amd_sev_conf->{'no-debug'};
+ $policy += 0x10000 if $amd_sev_conf->{'allow-smt'};
+ }
- # guest policy bit calculation as described here:
- #
https://documentation.suse.com/sles/15-SP5/html/SLES-amd-sev/article-amd-sev.html#table-guestpolicy
- my $policy = 0b0000;
- $policy += 0b0001 if $amd_sev_conf->{'no-debug'};
- $policy += 0b0010 if $amd_sev_conf->{'no-key-sharing'};
- $policy += 0b0100 if $amd_sev_conf->{type} eq 'es';
- # disable migration with bit 3 nosend to prevent amd-sev-migration-attack
- $policy += 0b1000;
$sev_mem_object .= ',policy='.sprintf("%#x", $policy);
$sev_mem_object .= ',kernel-hashes=on' if
($amd_sev_conf->{'kernel-hashes'});
--
2.39.5
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