| Message ID | 20191001113830.13028-22-mika.westerberg@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | thunderbolt: Add support for USB4 | expand |
> -----Original Message----- > From: Mika Westerberg <mika.westerberg@linux.intel.com> > Sent: Tuesday, October 1, 2019 6:38 AM > To: linux-usb@vger.kernel.org > Cc: Andreas Noever; Michael Jamet; Mika Westerberg; Yehezkel Bernat; Rajmohan > Mani; Nicholas Johnson; Lukas Wunner; Greg Kroah-Hartman; Alan Stern; > Limonciello, Mario; Anthony Wong; linux-kernel@vger.kernel.org > Subject: [RFC PATCH 21/22] thunderbolt: Update documentation with the USB4 > information > > > [EXTERNAL EMAIL] > > Update user's and administrator's guide to mention USB4, how it relates > to Thunderbolt (it is public spec of Thunderbolt 3) and and how it is > supported in Linux. > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > --- > Documentation/admin-guide/thunderbolt.rst | 27 ++++++++++++++++++----- > 1 file changed, 22 insertions(+), 5 deletions(-) > > diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin- > guide/thunderbolt.rst > index 898ad78f3cc7..4cbed319133d 100644 > --- a/Documentation/admin-guide/thunderbolt.rst > +++ b/Documentation/admin-guide/thunderbolt.rst > @@ -1,6 +1,25 @@ > -============= > - Thunderbolt > -============= > +====================== > + Thunderbolt and USB4 > +====================== > +USB4 is the public spec of Thunderbolt 3 with some differences at the > +register level among other things. There are two different > +implementations available: firmware connection manager and software > +connection manager. Typically PCs come with a firmware connection > +manager for Thunderbolt 3 and early USB4 capable systems. Apple systems > +on the other hand use software connection manager and the future USB4 > +compliant PCs follow the suit. Future isn't going to age very well. Perhaps refer instead to "later" USB4 compliant PCs. Also, we should be seeing this stuff pop-up outside of PCs. So maybe better to just call out "devices". > + > +The Linux Thunderbolt driver supports both and can detect at runtime > +which connection manager implementation is to be used. To be on the safe > +side the software connection manager in Linux also advertises security > +level ``user`` which means PCIe tunneling is disabled by default. The > +documentation below applies to both implementations with the exception > +that the software connection manager only supports ``user`` security > +level and is expected to be accompanied with an IOMMU based DMA > +protection. > + > +Security levels and how to use them > +----------------------------------- > The interface presented here is not meant for end users. Instead there > should be a userspace tool that handles all the low-level details, keeps > a database of the authorized devices and prompts users for new connections. > @@ -18,8 +37,6 @@ This will authorize all devices automatically when they > appear. However, > keep in mind that this bypasses the security levels and makes the system > vulnerable to DMA attacks. > > -Security levels and how to use them > ------------------------------------ > Starting with Intel Falcon Ridge Thunderbolt controller there are 4 > security levels available. Intel Titan Ridge added one more security level > (usbonly). The reason for these is the fact that the connected devices can > -- > 2.23.0
On Tue, Oct 01, 2019 at 02:17:01PM +0000, Mario.Limonciello@dell.com wrote: > > > > -----Original Message----- > > From: Mika Westerberg <mika.westerberg@linux.intel.com> > > Sent: Tuesday, October 1, 2019 6:38 AM > > To: linux-usb@vger.kernel.org > > Cc: Andreas Noever; Michael Jamet; Mika Westerberg; Yehezkel Bernat; Rajmohan > > Mani; Nicholas Johnson; Lukas Wunner; Greg Kroah-Hartman; Alan Stern; > > Limonciello, Mario; Anthony Wong; linux-kernel@vger.kernel.org > > Subject: [RFC PATCH 21/22] thunderbolt: Update documentation with the USB4 > > information > > > > > > [EXTERNAL EMAIL] > > > > Update user's and administrator's guide to mention USB4, how it relates > > to Thunderbolt (it is public spec of Thunderbolt 3) and and how it is > > supported in Linux. > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > --- > > Documentation/admin-guide/thunderbolt.rst | 27 ++++++++++++++++++----- > > 1 file changed, 22 insertions(+), 5 deletions(-) > > > > diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin- > > guide/thunderbolt.rst > > index 898ad78f3cc7..4cbed319133d 100644 > > --- a/Documentation/admin-guide/thunderbolt.rst > > +++ b/Documentation/admin-guide/thunderbolt.rst > > @@ -1,6 +1,25 @@ > > -============= > > - Thunderbolt > > -============= > > +====================== > > + Thunderbolt and USB4 > > +====================== > > +USB4 is the public spec of Thunderbolt 3 with some differences at the > > +register level among other things. There are two different > > +implementations available: firmware connection manager and software > > +connection manager. Typically PCs come with a firmware connection > > +manager for Thunderbolt 3 and early USB4 capable systems. Apple systems > > +on the other hand use software connection manager and the future USB4 > > +compliant PCs follow the suit. > > Future isn't going to age very well. Perhaps refer instead to "later" USB4 compliant > PCs. Yup. > Also, we should be seeing this stuff pop-up outside of PCs. So maybe better > to just call out "devices". Indeed, I'll update this accordingly.
diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 898ad78f3cc7..4cbed319133d 100644 --- a/Documentation/admin-guide/thunderbolt.rst +++ b/Documentation/admin-guide/thunderbolt.rst @@ -1,6 +1,25 @@ -============= - Thunderbolt -============= +====================== + Thunderbolt and USB4 +====================== +USB4 is the public spec of Thunderbolt 3 with some differences at the +register level among other things. There are two different +implementations available: firmware connection manager and software +connection manager. Typically PCs come with a firmware connection +manager for Thunderbolt 3 and early USB4 capable systems. Apple systems +on the other hand use software connection manager and the future USB4 +compliant PCs follow the suit. + +The Linux Thunderbolt driver supports both and can detect at runtime +which connection manager implementation is to be used. To be on the safe +side the software connection manager in Linux also advertises security +level ``user`` which means PCIe tunneling is disabled by default. The +documentation below applies to both implementations with the exception +that the software connection manager only supports ``user`` security +level and is expected to be accompanied with an IOMMU based DMA +protection. + +Security levels and how to use them +----------------------------------- The interface presented here is not meant for end users. Instead there should be a userspace tool that handles all the low-level details, keeps a database of the authorized devices and prompts users for new connections. @@ -18,8 +37,6 @@ This will authorize all devices automatically when they appear. However, keep in mind that this bypasses the security levels and makes the system vulnerable to DMA attacks. -Security levels and how to use them ------------------------------------ Starting with Intel Falcon Ridge Thunderbolt controller there are 4 security levels available. Intel Titan Ridge added one more security level (usbonly). The reason for these is the fact that the connected devices can
Update user's and administrator's guide to mention USB4, how it relates to Thunderbolt (it is public spec of Thunderbolt 3) and and how it is supported in Linux. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> --- Documentation/admin-guide/thunderbolt.rst | 27 ++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-)