The qemu driver does support qcow2 images for the firmware and nvram
pflash devices, but we do not do the full backing chain setup for them
as we don't expect that those images would actually have a backing
store. We don't tell that to qemu though which theoretically can lead to
qemu probing the backing store from the image itself. We don't want that
for now.

Deny qemu probing the backing store by installing a "terminator" empty
virStorageSource as 'backingStore' for pflash and nvram.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
---
 src/qemu/qemu_domain.c                                        | 2 ++
 .../firmware-auto-efi-aarch64.aarch64-latest.abi-update.args  | 4 ++--
 ...auto-efi-format-loader-qcow2-nvram-path.x86_64-latest.args | 4 ++--
 .../firmware-auto-efi-format-loader-qcow2.x86_64-latest.args  | 4 ++--
 ...auto-efi-format-nvram-qcow2-network-nbd.x86_64-latest.args | 4 ++--
 ...rmware-auto-efi-format-nvram-qcow2-path.x86_64-latest.args | 4 ++--
 .../firmware-auto-efi-format-nvram-qcow2.x86_64-latest.args   | 4 ++--
 ...mware-auto-efi-loader-secure.x86_64-latest.abi-update.args | 4 ++--
 .../firmware-auto-efi-riscv64.riscv64-latest.abi-update.args  | 4 ++--
 .../firmware-auto-efi.x86_64-latest.abi-update.args           | 4 ++--
 10 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 7b702cfc6b..a256775960 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -12069,11 +12069,13 @@ qemuDomainInitializePflashStorageSource(virDomainObj *vm,
     pflash0->format = def->os.loader->format;
     pflash0->path = g_strdup(def->os.loader->path);
     pflash0->readonly = false;
+    pflash0->backingStore = virStorageSourceNew(); /* terminator */
     virTristateBoolToBool(def->os.loader->readonly, &pflash0->readonly);
     qemuBlockStorageSourceSetFormatNodename(pflash0, g_strdup("libvirt-pflash0-format"));
     qemuBlockStorageSourceSetStorageNodename(pflash0, g_strdup("libvirt-pflash0-storage"));

     if (def->os.loader->nvram) {
+        def->os.loader->nvram->backingStore = virStorageSourceNew(); /* terminator */
         if (qemuDomainPrepareStorageSourceBlockdevNodename(NULL,
                                                            def->os.loader->nvram,
                                                            "libvirt-pflash1",
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-aarch64.aarch64-latest.abi-update.args b/tests/qemuxmlconfdata/firmware-auto-efi-aarch64.aarch64-latest.abi-update.args
index 30f86aa046..3e20cb4aa5 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-aarch64.aarch64-latest.abi-update.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-aarch64.aarch64-latest.abi-update.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/aarch64/QEMU_EFI-silent-pflash.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine virt-4.0,usb=off,gic-version=2,dump-guest-core=off,memory-backend=mach-virt.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel tcg \
 -cpu cortex-a15 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2-nvram-path.x86_64-latest.args b/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2-nvram-path.x86_64-latest.args
index e8d7d580f7..2694e0676f 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2-nvram-path.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2-nvram-path.x86_64-latest.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.secboot.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/path/to/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-q35-4.0,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel kvm \
 -cpu qemu64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2.x86_64-latest.args b/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2.x86_64-latest.args
index 790fb619e8..2bc7a1b9d5 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-format-loader-qcow2.x86_64-latest.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.secboot.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-q35-4.0,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel kvm \
 -cpu qemu64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-network-nbd.x86_64-latest.args b/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-network-nbd.x86_64-latest.args
index f78b4e7abf..e8e6157f67 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-network-nbd.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-network-nbd.x86_64-latest.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"nbd","server":{"type":"inet","host":"example.org","port":"6000"},"node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-i440fx-4.0,usb=off,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel tcg \
 -cpu qemu64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-path.x86_64-latest.args b/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-path.x86_64-latest.args
index e8d7d580f7..2694e0676f 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-path.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2-path.x86_64-latest.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.secboot.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/path/to/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-q35-4.0,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel kvm \
 -cpu qemu64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2.x86_64-latest.args b/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2.x86_64-latest.args
index 790fb619e8..2bc7a1b9d5 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2.x86_64-latest.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-format-nvram-qcow2.x86_64-latest.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.secboot.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-q35-4.0,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel kvm \
 -cpu qemu64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-loader-secure.x86_64-latest.abi-update.args b/tests/qemuxmlconfdata/firmware-auto-efi-loader-secure.x86_64-latest.abi-update.args
index 790fb619e8..2bc7a1b9d5 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-loader-secure.x86_64-latest.abi-update.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-loader-secure.x86_64-latest.abi-update.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.secboot.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-q35-4.0,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel kvm \
 -cpu qemu64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi-riscv64.riscv64-latest.abi-update.args b/tests/qemuxmlconfdata/firmware-auto-efi-riscv64.riscv64-latest.abi-update.args
index e10575bf81..f467f71d72 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi-riscv64.riscv64-latest.abi-update.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi-riscv64.riscv64-latest.abi-update.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/riscv/RISCV_VIRT_CODE.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine virt,usb=off,dump-guest-core=off,memory-backend=riscv_virt_board.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=off \
 -accel tcg \
 -cpu rv64 \
diff --git a/tests/qemuxmlconfdata/firmware-auto-efi.x86_64-latest.abi-update.args b/tests/qemuxmlconfdata/firmware-auto-efi.x86_64-latest.abi-update.args
index 790fb619e8..2bc7a1b9d5 100644
--- a/tests/qemuxmlconfdata/firmware-auto-efi.x86_64-latest.abi-update.args
+++ b/tests/qemuxmlconfdata/firmware-auto-efi.x86_64-latest.abi-update.args
@@ -11,9 +11,9 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
 -S \
 -object '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}' \
 -blockdev '{"driver":"file","filename":"/usr/share/edk2/ovmf/OVMF_CODE_4M.secboot.qcow2","node-name":"libvirt-pflash0-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash0-format","read-only":true,"driver":"qcow2","file":"libvirt-pflash0-storage","backing":null}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/qemu/nvram/guest_VARS.qcow2","node-name":"libvirt-pflash1-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage"}' \
+-blockdev '{"node-name":"libvirt-pflash1-format","read-only":false,"driver":"qcow2","file":"libvirt-pflash1-storage","backing":null}' \
 -machine pc-q35-4.0,usb=off,smm=on,dump-guest-core=off,memory-backend=pc.ram,pflash0=libvirt-pflash0-format,pflash1=libvirt-pflash1-format,acpi=on \
 -accel kvm \
 -cpu qemu64 \
-- 
2.47.0