On Fri, Dec 10, 2021 at 16:47:13 +0000, Daniel P. Berrangé wrote:
> Set the kernel-hashes property on the sev-guest object if
> the config asked for it explicitly. While QEMU machine
> types currently default to having this setting off, it
> is not guaranteed to remain this way.
>
> Signed-off-by: Daniel P. Berrangé <berrange@xxxxxxxxxx>
> ---
> src/qemu/qemu_command.c | 1 +
> src/qemu/qemu_validate.c | 7 ++++
> ...unch-security-sev-direct.x86_64-6.2.0.args | 40 +++++++++++++++++++
> .../launch-security-sev-direct.xml | 39 ++++++++++++++++++
> tests/qemuxml2argvtest.c | 1 +
> 5 files changed, 88 insertions(+)
> create mode 100644 tests/qemuxml2argvdata/launch-security-sev-direct.x86_64-6.2.0.args
> create mode 100644 tests/qemuxml2argvdata/launch-security-sev-direct.xml
>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 613f7a5d2a..dfbf4973f5 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -9894,6 +9894,7 @@ qemuBuildSEVCommandLine(virDomainObj *vm, virCommand *cmd,
> "u:policy", sev->policy,
> "S:dh-cert-file", dhpath,
> "S:session-file", sessionpath,
> + "T:kernel-hashes", sev->kernel_hashes,
Since this is an '-object' ...
> NULL) < 0)
> return -1;
>
> diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
> index 29b01495ad..c0dc1f7b53 100644
> --- a/src/qemu/qemu_validate.c
> +++ b/src/qemu/qemu_validate.c
> @@ -1200,6 +1200,13 @@ qemuValidateDomainDef(const virDomainDef *def,
> "this QEMU binary"));
> return -1;
> }
> +
> + if (def->sec->data.sev.kernel_hashes == VIR_TRISTATE_BOOL_YES &&
> + !virQEMUCapsGet(qemuCaps, QEMU_CAPS_SEV_GUEST_KERNEL_HASHES)) {
... and this flag means that the 'sev-guest' actually has the
'kernel-hashes' property, the above check should be
if (def->sec->data.sev.kernel_hashes != VIR_TRISTATE_BOOL_ABSENT && ...
as an explicit disable will also cause a qemu error when the property is
not defined inside sev-guest.
Other option is to use 'B:kernel-hashes' above and extract the value of
sev->kernel_hashes into a temporary bool initialized to false via
virTristateBoolToBool which preserves the default. In such case it will
be always omitted when not enabled.
Reviewed-by: Peter Krempa <pkrempa@xxxxxxxxxx>
