From: Jean-philippe Brucker <jphilippe.brucker-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> To: Bjorn Helgaas <helgaas-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Cc: Mark Rutland <Mark.Rutland-5wv7dgnIgG8@public.gmane.org>, "peter.maydell-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" <peter.maydell-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, "kevin.tian-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org" <kevin.tian-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, "tnowicki-M3mlKVOIwJVv6pq1l3V1OdBPR1lH4CV8@public.gmane.org" <tnowicki-M3mlKVOIwJVv6pq1l3V1OdBPR1lH4CV8@public.gmane.org>, "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "jasowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" <jasowang-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" <mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Will Deacon <Will.Deacon-5wv7dgnIgG8@public.gmane.org>, "virtualization-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" <virtualization-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" <iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, "robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org, Marc Zyngier <Marc.Zyngier-5wv7dgnIgG8@public.gmane.org>, Robin Murphy <Robin.Murphy-5wv7dgnIgG8@public.gmane.org>, "kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org" <kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org> Subject: Re: [PATCH v3 3/7] PCI: OF: Allow endpoints to bypass the iommu Date: Mon, 15 Oct 2018 20:45:47 +0100 [thread overview] Message-ID: <6abc7321-c46a-5618-1ce7-4be85fcc38ec@gmail.com> (raw) In-Reply-To: <20181012194158.GX5906-1RhO1Y9PlrlHTL0Zs8A6p5iNqAH0jzoTYJqu5kTmcBRl57MIdRCFDg@public.gmane.org> [Replying with my personal address because we're having SMTP issues] On 12/10/2018 20:41, Bjorn Helgaas wrote: > s/iommu/IOMMU/ in subject > > On Fri, Oct 12, 2018 at 03:59:13PM +0100, Jean-Philippe Brucker wrote: >> Using the iommu-map binding, endpoints in a given PCI domain can be >> managed by different IOMMUs. Some virtual machines may allow a subset of >> endpoints to bypass the IOMMU. In some case the IOMMU itself is presented > > s/case/cases/ > >> as a PCI endpoint (e.g. AMD IOMMU and virtio-iommu). Currently, when a >> PCI root complex has an iommu-map property, the driver requires all >> endpoints to be described by the property. Allow the iommu-map property to >> have gaps. > > I'm not an IOMMU or virtio expert, so it's not obvious to me why it is > safe to allow devices to bypass the IOMMU. Does this mean a typo in > iommu-map could inadvertently allow devices to bypass it? As Robin said, a device that is absent from iommu-map will be ignored by the IOMMU layer, so it depends on the specific IOMMU implementation and driver. By default the SMMU and virtio-iommu drivers disable bypass, but I'm not sure about the others. I'll try to find a more accurate title for this patch > Should we > indicate something in dmesg (and/or sysfs) about devices that bypass > it? Good idea, I'll replace the pr_err() below with a pr_info(), instead of simply removing it. >> Relaxing of_pci_map_rid also allows the msi-map property to have gaps, > > s/of_pci_map_rid/of_pci_map_rid()/ > >> which is invalid since MSIs always reach an MSI controller. Thankfully >> Linux will error out later, when attempting to find an MSI domain for the >> device. > > Not clear to me what "error out" means here. In a userspace program, > I would infer that the program exits with an error message, but I > doubt you mean that Linux exits. Right, I'll clarify this. It's pci_msi_setup_msi_irqs() that returns an error if the device is missing from msi-map, so the device driver won't be able to request MSIs. Thanks, Jean >> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> >> --- >> drivers/pci/of.c | 7 ++++--- >> 1 file changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/pci/of.c b/drivers/pci/of.c >> index 1836b8ddf292..2f5015bdb256 100644 >> --- a/drivers/pci/of.c >> +++ b/drivers/pci/of.c >> @@ -451,9 +451,10 @@ int of_pci_map_rid(struct device_node *np, u32 rid, >> return 0; >> } >> >> - pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on %pOF\n", >> - np, map_name, rid, target && *target ? *target : NULL); >> - return -EFAULT; >> + /* Bypasses translation */ >> + if (id_out) >> + *id_out = rid; >> + return 0; >> } >> >> #if IS_ENABLED(CONFIG_OF_IRQ) >> -- >> 2.19.1 >> >
WARNING: multiple messages have this Message-ID (diff)
From: Jean-philippe Brucker <jphilippe.brucker@gmail.com> To: Bjorn Helgaas <helgaas@kernel.org> Cc: "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>, "kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>, "peter.maydell@linaro.org" <peter.maydell@linaro.org>, "joro@8bytes.org" <joro@8bytes.org>, "mst@redhat.com" <mst@redhat.com>, "jasowang@redhat.com" <jasowang@redhat.com>, "robh+dt@kernel.org" <robh+dt@kernel.org>, Mark Rutland <Mark.Rutland@arm.com>, "eric.auger@redhat.com" <eric.auger@redhat.com>, "tnowicki@caviumnetworks.com" <tnowicki@caviumnetworks.com>, "kevin.tian@intel.com" <kevin.tian@intel.com>, Marc Zyngier <Marc.Zyngier@arm.com>, Robin Murphy <Robin.Murphy@arm.com>, Will Deacon <Will.Deacon@arm.com>, Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>, jean-philippe.brucker@arm.com Subject: Re: [PATCH v3 3/7] PCI: OF: Allow endpoints to bypass the iommu Date: Mon, 15 Oct 2018 20:45:47 +0100 [thread overview] Message-ID: <6abc7321-c46a-5618-1ce7-4be85fcc38ec@gmail.com> (raw) In-Reply-To: <20181012194158.GX5906@bhelgaas-glaptop.roam.corp.google.com> [Replying with my personal address because we're having SMTP issues] On 12/10/2018 20:41, Bjorn Helgaas wrote: > s/iommu/IOMMU/ in subject > > On Fri, Oct 12, 2018 at 03:59:13PM +0100, Jean-Philippe Brucker wrote: >> Using the iommu-map binding, endpoints in a given PCI domain can be >> managed by different IOMMUs. Some virtual machines may allow a subset of >> endpoints to bypass the IOMMU. In some case the IOMMU itself is presented > > s/case/cases/ > >> as a PCI endpoint (e.g. AMD IOMMU and virtio-iommu). Currently, when a >> PCI root complex has an iommu-map property, the driver requires all >> endpoints to be described by the property. Allow the iommu-map property to >> have gaps. > > I'm not an IOMMU or virtio expert, so it's not obvious to me why it is > safe to allow devices to bypass the IOMMU. Does this mean a typo in > iommu-map could inadvertently allow devices to bypass it? As Robin said, a device that is absent from iommu-map will be ignored by the IOMMU layer, so it depends on the specific IOMMU implementation and driver. By default the SMMU and virtio-iommu drivers disable bypass, but I'm not sure about the others. I'll try to find a more accurate title for this patch > Should we > indicate something in dmesg (and/or sysfs) about devices that bypass > it? Good idea, I'll replace the pr_err() below with a pr_info(), instead of simply removing it. >> Relaxing of_pci_map_rid also allows the msi-map property to have gaps, > > s/of_pci_map_rid/of_pci_map_rid()/ > >> which is invalid since MSIs always reach an MSI controller. Thankfully >> Linux will error out later, when attempting to find an MSI domain for the >> device. > > Not clear to me what "error out" means here. In a userspace program, > I would infer that the program exits with an error message, but I > doubt you mean that Linux exits. Right, I'll clarify this. It's pci_msi_setup_msi_irqs() that returns an error if the device is missing from msi-map, so the device driver won't be able to request MSIs. Thanks, Jean >> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> >> --- >> drivers/pci/of.c | 7 ++++--- >> 1 file changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/pci/of.c b/drivers/pci/of.c >> index 1836b8ddf292..2f5015bdb256 100644 >> --- a/drivers/pci/of.c >> +++ b/drivers/pci/of.c >> @@ -451,9 +451,10 @@ int of_pci_map_rid(struct device_node *np, u32 rid, >> return 0; >> } >> >> - pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on %pOF\n", >> - np, map_name, rid, target && *target ? *target : NULL); >> - return -EFAULT; >> + /* Bypasses translation */ >> + if (id_out) >> + *id_out = rid; >> + return 0; >> } >> >> #if IS_ENABLED(CONFIG_OF_IRQ) >> -- >> 2.19.1 >> >
next prev parent reply other threads:[~2018-10-15 19:45 UTC|newest] Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-12 14:59 [PATCH v3 0/7] Add virtio-iommu driver Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` [PATCH v3 1/7] dt-bindings: virtio-mmio: Add IOMMU description Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-18 0:30 ` Rob Herring [not found] ` <20181012145917.6840-2-jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> 2018-10-18 0:30 ` Rob Herring 2018-10-18 0:30 ` Rob Herring 2018-11-15 8:45 ` Auger Eric 2018-11-15 8:45 ` Auger Eric 2018-10-12 14:59 ` [PATCH v3 2/7] dt-bindings: virtio: Add virtio-pci-iommu node Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-18 0:35 ` Rob Herring 2018-10-18 0:35 ` Rob Herring 2018-10-18 0:35 ` Rob Herring 2018-11-15 8:45 ` Auger Eric 2018-11-15 8:45 ` Auger Eric 2018-11-15 8:45 ` Auger Eric 2018-10-12 14:59 ` [PATCH v3 3/7] PCI: OF: Allow endpoints to bypass the iommu Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker [not found] ` <20181012145917.6840-4-jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> 2018-10-12 19:41 ` Bjorn Helgaas 2018-10-12 19:41 ` Bjorn Helgaas 2018-10-15 10:52 ` Michael S. Tsirkin 2018-10-15 11:32 ` Robin Murphy [not found] ` <20181012194158.GX5906-1RhO1Y9PlrlHTL0Zs8A6p5iNqAH0jzoTYJqu5kTmcBRl57MIdRCFDg@public.gmane.org> 2018-10-15 10:52 ` Michael S. Tsirkin 2018-10-15 10:52 ` Michael S. Tsirkin [not found] ` <20181015065024-mutt-send-email-mst-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> 2018-10-15 19:46 ` Jean-philippe Brucker 2018-10-15 19:46 ` Jean-philippe Brucker 2018-10-17 15:14 ` Michael S. Tsirkin 2018-10-17 15:14 ` Michael S. Tsirkin 2018-10-18 10:47 ` Robin Murphy 2018-10-18 10:47 ` Robin Murphy 2018-10-18 10:47 ` Robin Murphy [not found] ` <20181017111100-mutt-send-email-mst-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> 2018-10-22 11:27 ` Jean-Philippe Brucker 2018-10-22 11:27 ` Jean-Philippe Brucker 2018-10-22 11:27 ` Jean-Philippe Brucker 2018-10-15 11:32 ` Robin Murphy 2018-10-15 11:32 ` Robin Murphy 2018-10-15 19:45 ` Jean-philippe Brucker [this message] 2018-10-15 19:45 ` Jean-philippe Brucker 2018-10-12 14:59 ` [PATCH v3 4/7] PCI: OF: Initialize dev->fwnode appropriately Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker [not found] ` <20181012145917.6840-5-jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> 2018-10-12 19:44 ` Bjorn Helgaas 2018-10-12 19:44 ` Bjorn Helgaas 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` [PATCH v3 5/7] iommu: Add virtio-iommu driver Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 16:35 ` Michael S. Tsirkin 2018-10-12 16:35 ` Michael S. Tsirkin 2018-10-12 16:35 ` Michael S. Tsirkin [not found] ` <20181012120953-mutt-send-email-mst-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> 2018-10-12 18:54 ` Jean-Philippe Brucker 2018-10-12 18:54 ` Jean-Philippe Brucker 2018-10-12 18:54 ` Jean-Philippe Brucker 2018-11-08 14:51 ` Auger Eric 2018-11-08 14:51 ` Auger Eric 2018-11-08 16:46 ` Jean-Philippe Brucker 2018-11-08 16:46 ` Jean-Philippe Brucker 2018-11-08 16:46 ` Jean-Philippe Brucker 2018-11-08 14:51 ` Auger Eric 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` [PATCH v3 6/7] iommu/virtio: Add probe request Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 16:42 ` Michael S. Tsirkin 2018-10-12 16:42 ` Michael S. Tsirkin 2018-11-08 14:48 ` Auger Eric [not found] ` <20181012145917.6840-7-jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> 2018-11-08 14:48 ` Auger Eric 2018-11-08 14:48 ` Auger Eric [not found] ` <295d30bb-5aef-2727-01c0-ec10c7a8fa8c-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> 2018-11-08 16:46 ` Jean-Philippe Brucker 2018-11-08 16:46 ` Jean-Philippe Brucker 2018-11-08 16:46 ` Jean-Philippe Brucker 2018-11-15 13:20 ` Auger Eric 2018-11-15 13:20 ` Auger Eric 2018-11-15 16:22 ` Jean-Philippe Brucker 2018-11-15 16:22 ` Jean-Philippe Brucker 2018-11-15 16:22 ` Jean-Philippe Brucker 2018-11-15 13:20 ` Auger Eric 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` [PATCH v3 7/7] iommu/virtio: Add event queue Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 14:59 ` Jean-Philippe Brucker 2018-10-12 17:00 ` [PATCH v3 0/7] Add virtio-iommu driver Michael S. Tsirkin [not found] ` <20181012145917.6840-1-jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> 2018-10-12 17:00 ` Michael S. Tsirkin 2018-10-12 17:00 ` Michael S. Tsirkin 2018-10-12 18:55 ` Jean-Philippe Brucker [not found] ` <20181012125443-mutt-send-email-mst-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> 2018-10-12 18:55 ` Jean-Philippe Brucker 2018-10-12 18:55 ` Jean-Philippe Brucker 2018-10-16 9:25 ` Auger Eric 2018-10-16 9:25 ` Auger Eric 2018-10-16 18:44 ` Jean-Philippe Brucker 2018-10-16 18:44 ` Jean-Philippe Brucker 2018-10-16 20:31 ` Auger Eric 2018-10-16 20:31 ` Auger Eric 2018-10-17 11:54 ` Jean-Philippe Brucker 2018-10-17 11:54 ` Jean-Philippe Brucker 2018-10-17 15:23 ` Michael S. Tsirkin 2018-10-17 15:23 ` Michael S. Tsirkin 2018-10-17 15:23 ` Michael S. Tsirkin 2018-10-16 18:44 ` Jean-Philippe Brucker 2018-10-16 9:25 ` Auger Eric
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