Re: [PATCH v4 04/14] PCI/P2PDMA: Clear ACS P2P flags for all devices behind switches

Randy Dunlap
2018-04-24T03:33:47Z

On 04/23/2018 04:30 PM, Logan Gunthorpe wrote:> > Signed-off-by: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>> ---
> drivers/pci/Kconfig | 9 +++++++++> drivers/pci/p2pdma.c | 45 ++++++++++++++++++++++++++++++---------------> drivers/pci/pci.c | 6 ++++++> include/linux/pci-p2pdma.h | 5 +++++> 4 files changed, 50 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
> index b2396c22b53e..b6db41d4b708 100644
> --- a/drivers/pci/Kconfig
> +++ b/drivers/pci/Kconfig
> @@ -139,6 +139,15 @@ config PCI_P2PDMA
> transations must be between devices behind the same root port.
> (Typically behind a network of PCIe switches).
>
> + Enabling this option will also disable ACS on all ports behind
> + any PCIe switch. This effectively puts all devices behind any
> + switch heirarchy into the same IOMMU group. Which implies that

hierarchy group, which

and sames fixes in the commit description...

> + individual devices behind any switch will not be able to be
> + assigned to separate VMs because there is no isolation between
> + them. Additionally, any malicious PCIe devices will be able to
> + DMA to memory exposed by other EPs in the same domain as TLPs
> + will not be checked by the IOMMU.
> +
> If unsure, say N.
>
> config PCI_LABEL

--
~Randy