| Message ID | 20210126155723.9388-3-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | thunderbolt / ACPI: Add support for USB4 _OSC | expand |
On Tue, Jan 26, 2021 at 5:57 PM Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > > Recent Intel Thunderbolt firmware connection manager has support for > another security level, SL5, that disables PCIe tunneling. This option > can be turned on from the BIOS. > > When this is set the driver exposes a new security level "nopcie" to the > userspace and hides the authorized attribute under connected devices. > > While there we also hide it when "dponly" security level is enabled > since it is not really usable in that case anyway. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > --- Looks good to me, I'm just not sure I understand how this is different from dponly mode. Is this just because it comes from the new _OSC?
On Tue, Jan 26, 2021 at 06:18:47PM +0200, Yehezkel Bernat wrote: > On Tue, Jan 26, 2021 at 5:57 PM Mika Westerberg > <mika.westerberg@linux.intel.com> wrote: > > > > Recent Intel Thunderbolt firmware connection manager has support for > > another security level, SL5, that disables PCIe tunneling. This option > > can be turned on from the BIOS. > > > > When this is set the driver exposes a new security level "nopcie" to the > > userspace and hides the authorized attribute under connected devices. > > > > While there we also hide it when "dponly" security level is enabled > > since it is not really usable in that case anyway. > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > --- > > Looks good to me, I'm just not sure I understand how this is different from > dponly mode. Is this just because it comes from the new _OSC? The firmware connection manager reports this new security level instead of dponly so we reflect that to the userspace, and while at it take advantage of the nopcie when USB4 _OSC disables PCIe tunneling so they both look the same from userspace perspective.
On Tue, Jan 26, 2021 at 6:26 PM Mika Westerberg <mika.westerberg@linux.intel.com> wrote: > > On Tue, Jan 26, 2021 at 06:18:47PM +0200, Yehezkel Bernat wrote: > > On Tue, Jan 26, 2021 at 5:57 PM Mika Westerberg > > <mika.westerberg@linux.intel.com> wrote: > > > > > > Recent Intel Thunderbolt firmware connection manager has support for > > > another security level, SL5, that disables PCIe tunneling. This option > > > can be turned on from the BIOS. > > > > > > When this is set the driver exposes a new security level "nopcie" to the > > > userspace and hides the authorized attribute under connected devices. > > > > > > While there we also hide it when "dponly" security level is enabled > > > since it is not really usable in that case anyway. > > > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > > --- > > > > Looks good to me, I'm just not sure I understand how this is different from > > dponly mode. Is this just because it comes from the new _OSC? > > The firmware connection manager reports this new security level instead > of dponly so we reflect that to the userspace, and while at it take > advantage of the nopcie when USB4 _OSC disables PCIe tunneling so they > both look the same from userspace perspective. Makes sense. Thanks for the clarification!
diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt index 581dea95245b..d7f09d011b6d 100644 --- a/Documentation/ABI/testing/sysfs-bus-thunderbolt +++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt @@ -85,6 +85,8 @@ Description: This attribute holds current Thunderbolt security level usbonly Automatically tunnel USB controller of the connected Thunderbolt dock (and Display Port). All PCIe links downstream of the dock are removed. + nopcie USB4 system where PCIe tunneling is disabled from + the BIOS. ======= ================================================== What: /sys/bus/thunderbolt/devices/.../authorized diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 0d4348445f91..f18e881373c4 100644 --- a/Documentation/admin-guide/thunderbolt.rst +++ b/Documentation/admin-guide/thunderbolt.rst @@ -47,6 +47,9 @@ be DMA masters and thus read contents of the host memory without CPU and OS knowing about it. There are ways to prevent this by setting up an IOMMU but it is not always available for various reasons. +Some USB4 systems have a BIOS setting to disable PCIe tunneling. This is +treated as another security level (nopcie). + The security levels are as follows: none @@ -77,6 +80,10 @@ The security levels are as follows: Display Port in a dock. All PCIe links downstream of the dock are removed. + nopcie + PCIe tunneling is disabled/forbidden from the BIOS. Available in some + USB4 systems. + The current security level can be read from ``/sys/bus/thunderbolt/devices/domainX/security`` where ``domainX`` is the Thunderbolt domain the host controller manages. There is typically diff --git a/drivers/thunderbolt/domain.c b/drivers/thunderbolt/domain.c index 9ba2181464cc..a1c79c9c4f66 100644 --- a/drivers/thunderbolt/domain.c +++ b/drivers/thunderbolt/domain.c @@ -118,6 +118,7 @@ static const char * const tb_security_names[] = { [TB_SECURITY_SECURE] = "secure", [TB_SECURITY_DPONLY] = "dponly", [TB_SECURITY_USBONLY] = "usbonly", + [TB_SECURITY_NOPCIE] = "nopcie", }; static ssize_t boot_acl_show(struct device *dev, struct device_attribute *attr, @@ -243,8 +244,14 @@ static ssize_t deauthorization_show(struct device *dev, char *buf) { const struct tb *tb = container_of(dev, struct tb, dev); + bool deauthorization = false; - return sprintf(buf, "%d\n", !!tb->cm_ops->disapprove_switch); + /* Only meaningful if authorization is supported */ + if (tb->security_level == TB_SECURITY_USER || + tb->security_level == TB_SECURITY_SECURE) + deauthorization = !!tb->cm_ops->disapprove_switch; + + return sprintf(buf, "%d\n", deauthorization); } static DEVICE_ATTR_RO(deauthorization); @@ -452,6 +459,9 @@ int tb_domain_add(struct tb *tb) goto err_ctl_stop; } + tb_dbg(tb, "security level set to %s\n", + tb_security_names[tb->security_level]); + ret = device_add(&tb->dev); if (ret) goto err_ctl_stop; diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index cdba05e72486..60fd92113740 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -1768,7 +1768,11 @@ static umode_t switch_attr_is_visible(struct kobject *kobj, struct device *dev = kobj_to_dev(kobj); struct tb_switch *sw = tb_to_switch(dev); - if (attr == &dev_attr_device.attr) { + if (attr == &dev_attr_authorized.attr) { + if (sw->tb->security_level == TB_SECURITY_NOPCIE || + sw->tb->security_level == TB_SECURITY_DPONLY) + return 0; + } else if (attr == &dev_attr_device.attr) { if (!sw->device) return 0; } else if (attr == &dev_attr_device_name.attr) { diff --git a/include/linux/thunderbolt.h b/include/linux/thunderbolt.h index 034dccf93955..659a0a810fa1 100644 --- a/include/linux/thunderbolt.h +++ b/include/linux/thunderbolt.h @@ -45,6 +45,8 @@ enum tb_cfg_pkg_type { * @TB_SECURITY_USBONLY: Only tunnel USB controller of the connected * Thunderbolt dock (and Display Port). All PCIe * links downstream of the dock are removed. + * @TB_SECURITY_NOPCIE: For USB4 systems this level is used when the + * PCIe tunneling is disabled from the BIOS. */ enum tb_security_level { TB_SECURITY_NONE, @@ -52,6 +54,7 @@ enum tb_security_level { TB_SECURITY_SECURE, TB_SECURITY_DPONLY, TB_SECURITY_USBONLY, + TB_SECURITY_NOPCIE, }; /**
Recent Intel Thunderbolt firmware connection manager has support for another security level, SL5, that disables PCIe tunneling. This option can be turned on from the BIOS. When this is set the driver exposes a new security level "nopcie" to the userspace and hides the authorized attribute under connected devices. While there we also hide it when "dponly" security level is enabled since it is not really usable in that case anyway. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- Documentation/ABI/testing/sysfs-bus-thunderbolt | 2 ++ Documentation/admin-guide/thunderbolt.rst | 7 +++++++ drivers/thunderbolt/domain.c | 12 +++++++++++- drivers/thunderbolt/switch.c | 6 +++++- include/linux/thunderbolt.h | 3 +++ 5 files changed, 28 insertions(+), 2 deletions(-)