On Thu, Jul 31, 2025 at 02:01:21PM -0700, dan.j.williams@xxxxxxxxx wrote:
> Xu Yilun wrote:
> > > +static const struct attribute_group *tdx_subsys_groups[] = {
> > > + SEAMLDR_GROUP,
> > > + NULL,
> > > +};
> > > +
> > > static void tdx_subsys_init(void)
> > > {
> > > struct tdx_tsm *tdx_tsm;
> > > int err;
> > >
> > > + err = get_seamldr_info();
> > > + if (err) {
> > > + pr_err("failed to get seamldr info %d\n", err);
> > > + return;
> > > + }
> > > +
> > > /* Establish subsystem for global TDX module attributes */
> > > - err = subsys_virtual_register(&tdx_subsys, NULL);
> > > + err = subsys_virtual_register(&tdx_subsys, tdx_subsys_groups);
> > > if (err) {
> > > pr_err("failed to register tdx_subsys %d\n", err);
> > > return;
> >
> > As mentioned, TDX Connect also uses this virtual TSM device. And I tend
> > to extend it to TDX guest, also make the guest TSM management run on
> > the virtual device which represents the TDG calls and TDG_VP_VM calls.
> >
> > So I'm considering extract the common part of tdx_subsys_init() out of
> > TDX host and into a separate file, e.g.
> >
> > ---
> >
> > +source "drivers/virt/coco/tdx-tsm/Kconfig"
> > +
> > config TSM
> > bool
> > diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile
> > index c0c3733be165..a54d3cb5b4e9 100644
> > --- a/drivers/virt/coco/Makefile
> > +++ b/drivers/virt/coco/Makefile
> > @@ -10,3 +10,4 @@ obj-$(CONFIG_INTEL_TDX_GUEST) += tdx-guest/
> > obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest/
> > obj-$(CONFIG_TSM) += tsm-core.o
> > obj-$(CONFIG_TSM_GUEST) += guest/
> > +obj-y += tdx-tsm/
> > diff --git a/drivers/virt/coco/tdx-tsm/Kconfig b/drivers/virt/coco/tdx-tsm/Kconfig
> > new file mode 100644
> > index 000000000000..768175f8bb2c
> > --- /dev/null
> > +++ b/drivers/virt/coco/tdx-tsm/Kconfig
> > @@ -0,0 +1,2 @@
> > +config TDX_TSM_BUS
> > + bool
> > diff --git a/drivers/virt/coco/tdx-tsm/Makefile b/drivers/virt/coco/tdx-tsm/Makefile
> > new file mode 100644
> > index 000000000000..09f0ac08988a
> > --- /dev/null
> > +++ b/drivers/virt/coco/tdx-tsm/Makefile
> > @@ -0,0 +1 @@
> > +obj-$(CONFIG_TDX_TSM_BUS) += tdx-tsm-bus.o
>
> Just name it bus.c.
I'm about to make the change but I see there is already tdx-guest misc
virtual device in Guest OS:
What: /sys/devices/virtual/misc/tdx_guest/xxxx
And if we add another tdx_subsys, we have:
What: /sys/devices/virtual/tdx/xxxx
Do we really want 2 virtual devices? What's their relationship? I can't
figure out.
So I'm considering reuse the misc/tdx_guest device as a tdx root device
in guest. And that removes the need to have a common tdx tsm bus.
What do you think?
>
> > ---
> >
> > And put the tdx_subsys_init() in tdx-tsm-bus.c. We need to move host
> > specific initializations out of tdx_subsys_init(), e.g. seamldr_group &
> > seamldr fw upload.
>
> Just to be clear on the plan here as I think this TD Preserving set
> should land before we start upstreamming any TDX Connect bits.
>
> - Create drivers/virt/coco/tdx-tsm/bus.c for registering the tdx_subsys.
> The tdx_subsys has sysfs attributes like "version" (host and guest
> need this, but have different calls to get at the information) and
> "firmware" (only host needs that). So the common code will take sysfs
> groups passed as a parameter.
>
> - The "tdx_tsm" device which is unused in this patch set can be
It is used in this patch, Chao creates tdx module 'version' attr on this
device. But I assume you have different opinion: tdx_subsys represents
the whole tdx_module and should have the 'version', and tdx_tsm is a
sub device dedicate for TDX Connect, is it?
Thanks,
Yilun
> registered on the "tdx" bus to move feature support like TDX Connect
> into a typical driver model.
>
> So the change for this set is create a bus.c that is host/guest
> agnostic, drop the tdx_tsm device and leave that to the TDX Connect
> patches to add back.
>
> The TDX Connect pathes will register the tdx_tsm device near where the
> bus is registered for the host and guest cases.
>
> Concerns?
>
> In the meantime, until this set lands in tip we can work out the
> organization in tsm.git#staging.
