> From: Jason Gunthorpe <jgg@xxxxxxxx> > Sent: Monday, March 6, 2023 9:58 PM > > On Fri, Mar 03, 2023 at 05:54:26AM +0000, K V P, Satyanarayana wrote: > > Intel Platform Monitoring Technology (PMT) support is indicated by > presence > > of an Intel defined PCIe Designated Vendor Specific Extended Capabilities > > (DVSEC) structure with a PMT specific ID.However DVSEC structures may > also > > be used by Intel to indicate support for other features. The Out Of Band > Management > > Services Module (OOBMSM) uses DVSEC to enumerate several features, > including PMT. > > > > The current VFIO driver does not pass DVSEC capabilities to virtual machine > (VM) > > which makes intel_vsec driver not to work in the VM. This series adds > DVSEC > > capability to user visible list to allow its use with VFIO. > > > > Signed-off-by: K V P Satyanarayana <satyanarayana.k.v.p@xxxxxxxxx> > > --- > > drivers/vfio/pci/vfio_pci_config.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > Wasn't the IDXD/SIOV team proposing to use the fact that DVSEC doesn't > propogate to indicate that IMS doesn't work? > > Did this plan get abandoned? It seems at odds with this patch. No. Guest IMS will be indicated via hypercall/vIR as planned. > > Why would you use a "Platform Monitoring Technology" device with VFIO > anyhow? Ack. I guess it's a monitoring capability per PCI device to form a platform-level monitoring technology. But w/o all those background and usage description it's really strange to pass a 'platform' capability into a guest. > > Honestly I'm a bit reluctant to allow arbitary config space, some of > the stuff people put there can be dangerous. > Probably an allowed list to manage which DVSEC ID can be exposed to userspace via vfio-pci, e.g. if the PMT ID in this patch is proved to be safe for a meaningful usage?
