Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-30 Thread Jonathan Cameron
On Mon, 29 Mar 2021 09:46:15 -0700 Dan Williams wrote: > On Fri, Mar 26, 2021 at 9:12 AM Bjorn Helgaas wrote: > > > > [+cc Christoph] > > > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > > configurati

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-29 Thread Dan Williams
On Fri, Mar 26, 2021 at 9:12 AM Bjorn Helgaas wrote: > > [+cc Christoph] > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > configuration cycles. It assumes one initiator at a time is > > reading/writing the

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-27 Thread Greg Kroah-Hartman
On Fri, Mar 26, 2021 at 11:12:47AM -0500, Bjorn Helgaas wrote: > [+cc Christoph] > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > configuration cycles. It assumes one initiator at a time is > > reading/writ

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-26 Thread Bjorn Helgaas
[+cc Christoph] On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > configuration cycles. It assumes one initiator at a time is > reading/writing the data registers. If userspace reads from the response > data payload

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-26 Thread Greg Kroah-Hartman
On Thu, Mar 25, 2021 at 10:43:41AM -0700, Dan Williams wrote: > On Wed, Mar 24, 2021 at 11:55 PM Greg Kroah-Hartman > wrote: > > > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > > configuration cycles. It

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-26 Thread Greg Kroah-Hartman
On Thu, Mar 25, 2021 at 10:55:01AM -0700, Dan Williams wrote: > On Thu, Mar 25, 2021 at 1:29 AM Christoph Hellwig wrote: > > > > On Thu, Mar 25, 2021 at 07:54:59AM +0100, Greg Kroah-Hartman wrote: > > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > > > The PCIE Data Object Exch

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-25 Thread Dan Williams
On Thu, Mar 25, 2021 at 1:29 AM Christoph Hellwig wrote: > > On Thu, Mar 25, 2021 at 07:54:59AM +0100, Greg Kroah-Hartman wrote: > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > > configuration cycles. It

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-25 Thread Dan Williams
On Wed, Mar 24, 2021 at 11:55 PM Greg Kroah-Hartman wrote: > > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > configuration cycles. It assumes one initiator at a time is > > reading/writing the data registers

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-25 Thread Christoph Hellwig
On Thu, Mar 25, 2021 at 07:54:59AM +0100, Greg Kroah-Hartman wrote: > On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > > configuration cycles. It assumes one initiator at a time is > > reading/writing the data reg

Re: [PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-24 Thread Greg Kroah-Hartman
On Wed, Mar 24, 2021 at 06:23:54PM -0700, Dan Williams wrote: > The PCIE Data Object Exchange (DOE) mailbox is a protocol run over > configuration cycles. It assumes one initiator at a time is > reading/writing the data registers. That sounds like a horrible protocol for a multi-processor system.

[PATCH] PCI: Allow drivers to claim exclusive access to config regions

2021-03-24 Thread Dan Williams
The PCIE Data Object Exchange (DOE) mailbox is a protocol run over configuration cycles. It assumes one initiator at a time is reading/writing the data registers. If userspace reads from the response data payload it may steal data that a kernel driver was expecting to read. If userspace writes to t