Hi Bjorn,
On 1/18/20 8:18 AM, Bjorn Helgaas wrote:
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.
Signed-off-by: Lu Baolu <[email protected]>
---
.../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;
+}
This duplicates a lot of the code in pci_disable_acs_redir(). That
needs to be factored out somehow so we don't duplicate it.
Sure. I will try to refactor the code in the next version.
Bjorn
Best regards,
baolu
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