[+cc linux-pci, thread at https://lore.kernel.org/r/20200101052648.14295-1-baolu.lu@xxxxxxxxxxxxxxx] On Wed, Jan 01, 2020 at 01:26:46PM +0800, Lu Baolu wrote: > The new parameter takes a list of devices separated by a semicolon. > Each device specified will have its iommu_passthrough bit in struct > device set. This is very similar to the existing 'disable_acs_redir' > parameter. Almost all of this patchset is in drivers/iommu. Should the parameter be "iommu ..." instead of "pci=iommu_passthrough=..."? There is already an "iommu.passthrough=" argument. Would this fit better there? Since the iommu_passthrough bit is generic, it seems like you anticipate similar situations for non-PCI devices. > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> > --- > .../admin-guide/kernel-parameters.txt | 5 +++ > drivers/pci/pci.c | 34 +++++++++++++++++++ > drivers/pci/pci.h | 1 + > drivers/pci/probe.c | 2 ++ > 4 files changed, 42 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index ade4e6ec23e0..d3edc2cb6696 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3583,6 +3583,11 @@ > may put more devices in an IOMMU group. > force_floating [S390] Force usage of floating interrupts. > nomio [S390] Do not use MIO instructions. > + iommu_passthrough=<pci_dev>[; ...] > + Specify one or more PCI devices (in the format > + specified above) separated by semicolons. > + Each device specified will bypass IOMMU DMA > + translation. > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > Management. > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 90dbd7c70371..05bf3f4acc36 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6401,6 +6401,37 @@ void __weak pci_fixup_cardbus(struct pci_bus *bus) > } > EXPORT_SYMBOL(pci_fixup_cardbus); > > +static const char *iommu_passthrough_param; > +bool pci_iommu_passthrough_match(struct pci_dev *dev) > +{ > + int ret = 0; > + const char *p = iommu_passthrough_param; > + > + if (!p) > + return false; > + > + while (*p) { > + ret = pci_dev_str_match(dev, p, &p); > + if (ret < 0) { > + pr_info_once("PCI: Can't parse iommu_passthrough parameter: %s\n", > + iommu_passthrough_param); > + > + break; > + } else if (ret == 1) { > + pci_info(dev, "PCI: IOMMU passthrough\n"); > + return true; > + } > + > + if (*p != ';' && *p != ',') { > + /* End of param or invalid format */ > + break; > + } > + p++; > + } > + > + return false; > +} > + > static int __init pci_setup(char *str) > { > while (str) { > @@ -6462,6 +6493,8 @@ static int __init pci_setup(char *str) > pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); > } else if (!strncmp(str, "disable_acs_redir=", 18)) { > disable_acs_redir_param = str + 18; > + } else if (!strncmp(str, "iommu_passthrough=", 18)) { > + iommu_passthrough_param = str + 18; > } else { > pr_err("PCI: Unknown option `%s'\n", str); > } > @@ -6486,6 +6519,7 @@ static int __init pci_realloc_setup_params(void) > resource_alignment_param = kstrdup(resource_alignment_param, > GFP_KERNEL); > disable_acs_redir_param = kstrdup(disable_acs_redir_param, GFP_KERNEL); > + iommu_passthrough_param = kstrdup(iommu_passthrough_param, GFP_KERNEL); > > return 0; > } > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index a0a53bd05a0b..95f6af06aba6 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -288,6 +288,7 @@ void pci_reassigndev_resource_alignment(struct pci_dev *dev); > void pci_disable_bridge_window(struct pci_dev *dev); > struct pci_bus *pci_bus_get(struct pci_bus *bus); > void pci_bus_put(struct pci_bus *bus); > +bool pci_iommu_passthrough_match(struct pci_dev *dev); > > /* PCIe link information */ > #define PCIE_SPEED2STR(speed) \ > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 512cb4312ddd..4c571ee75621 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -2404,6 +2404,8 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus) > > dev->state_saved = false; > > + dev->dev.iommu_passthrough = pci_iommu_passthrough_match(dev); > + > pci_init_capabilities(dev); > > /* > -- > 2.17.1 >
