On Wed, Jun 28, 2023 at 06:30:30PM -0300, Daniel Henrique Barboza wrote:
> KVM-specific properties are being created inside target/riscv/kvm.c. But
> at this moment we're gathering all the remaining properties from TCG and
> adding them as is when running KVM. This creates a situation where
> non-KVM properties are setting flags to 'true' due to its default
> settings (e.g. Zawrs). Users can also freely enable them via command
> line.
>
> This doesn't impact runtime per se because KVM doesn't care about these
> flags, but code such as riscv_isa_string_ext() take those flags into
> account. The result is that, for a KVM guest, setting non-KVM properties
> will make them appear in the riscv,isa DT.
>
> We want to keep the same API for both TCG and KVM and at the same time,
> when running KVM, forbid non-KVM extensions to be enabled internally. We
> accomplish both by changing riscv_cpu_add_user_properties() to add a
> mock boolean property for every non-KVM extension in
> riscv_cpu_extensions[]. Then, when running KVM, users are still free to
> set extensions at will, but we'll error out if a non-KVM extension is
> enabled. Setting such extension to 'false' will be ignored.
>
> Signed-off-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
> ---
> target/riscv/cpu.c | 36 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 79c8ffe6b7..6d7a0bc4ae 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -1731,6 +1731,26 @@ static Property riscv_cpu_extensions[] = {
> DEFINE_PROP_END_OF_LIST(),
> };
>
> +
> +#ifndef CONFIG_USER_ONLY
> +static void cpu_set_cfg_unavailable(Object *obj, Visitor *v,
> + const char *name,
> + void *opaque, Error **errp)
> +{
> + const char *propname = opaque;
> + bool value;
> +
> + if (!visit_type_bool(v, name, &value, errp)) {
> + return;
> + }
> +
> + if (value) {
> + error_setg(errp, "extension %s is not available with KVM",
> + propname);
> + }
> +}
> +#endif
> +
> /*
> * Add CPU properties with user-facing flags.
> *
> @@ -1759,6 +1779,22 @@ static void riscv_cpu_add_user_properties(Object *obj)
> if (object_property_find(obj, prop->name)) {
> continue;
> }
> +
> + /*
> + * Set the default to disabled for every extension
> + * unknown to KVM and error out if the user attempts
> + * to enable any of them.
> + *
> + * We're giving a pass for non-bool properties since they're
> + * not related to the availability of extensions and can be
> + * safely ignored as is.
> + */
> + if (prop->info == &qdev_prop_bool) {
> + object_property_add(obj, prop->name, "bool",
> + NULL, cpu_set_cfg_unavailable,
> + NULL, (void *)prop->name);
> + continue;
> + }
> }
> #endif
> qdev_property_add_static(dev, prop);
> --
> 2.41.0
>
Reviewed-by: Andrew Jones <ajo...@ventanamicro.com>
