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drivers: Correct isPCIeDevice logic

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Currently, isPCIeDevice() attempts to determine if a (host) device is
PCI-Express capable by looking up its link speed via the PCI slots
information in sysfs.  This is a) complicated and b) wrong.  PCI-e
devices don't have to have slots information, so this frequently fails.

Instead determine if devices are PCI-e by checking for the presence of
PCIe extended configuration space by looking at the size of the "config"
file in sysfs.

Forward ported from 6bf93b23 in the Kata 1.x runtime repository.

Fixes: #611

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
David Gibson 2020-08-19 16:06:22 +10:00
parent c422d061cb
commit 92dfa4634b
2 changed files with 12 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/runtime/virtcontainers/device/config/config.go
View File

@ -89,9 +89,6 @@ var SysIOMMUPath = "/sys/kernel/iommu_groups"
// SysBusPciDevicesPath is static string of /sys/bus/pci/devices
var SysBusPciDevicesPath = "/sys/bus/pci/devices"
// SysBusPciSlotsPath is static string of /sys/bus/pci/slots
var SysBusPciSlotsPath = "/sys/bus/pci/slots"
var getSysDevPath = getSysDevPathImpl
// DeviceInfo is an embedded type that contains device data common to all types of devices.

38
src/runtime/virtcontainers/device/drivers/utils.go
View File

@ -9,6 +9,7 @@ package drivers
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
@ -22,6 +23,8 @@ const (
PCIDomain = "0000"
PCIeKeyword = "PCIe"
PCIConfigSpaceSize = 256
)
type PCISysFsType string
@ -52,23 +55,17 @@ func isPCIeDevice(bdf string) bool {
if len(strings.Split(bdf, ":")) == 2 {
bdf = PCIDomain + ":" + bdf
}
slots, err := ioutil.ReadDir(config.SysBusPciSlotsPath)
configPath := filepath.Join(config.SysBusPciDevicesPath, bdf, "config")
fi, err := os.Stat(configPath)
if err != nil {
deviceLogger().WithError(err).WithField("path", config.SysBusPciSlotsPath).Warn("failed to list pci slots")
return false
deviceLogger().WithField("dev-bdf", bdf).WithField("error", err).Warning("Couldn't stat() configuration space file")
return false //Who knows?
}
b := strings.Split(bdf, ".")[0]
for _, slot := range slots {
address := getPCISlotProperty(slot.Name(), PCISysFsSlotsAddress)
if b == address {
maxBusSpeed := getPCISlotProperty(slot.Name(), PCISysFsSlotsMaxBusSpeed)
if strings.Contains(maxBusSpeed, PCIeKeyword) {
return true
}
}
}
deviceLogger().WithField("dev-bdf", bdf).Debug("can not find slot for bdf of pci device")
return false
// Plain PCI devices hav 256 bytes of configuration space,
// PCI-Express devices have 4096 bytes
return fi.Size() > PCIConfigSpaceSize
}
// read from /sys/bus/pci/devices/xxx/property
@ -85,17 +82,6 @@ func getPCIDeviceProperty(bdf string, property PCISysFsProperty) string {
return rlt
}
// read from /sys/bus/pci/slots/xxx/property
func getPCISlotProperty(slot string, property PCISysFsProperty) string {
propertyPath := filepath.Join(config.SysBusPciSlotsPath, slot, string(property))
rlt, err := readPCIProperty(propertyPath)
if err != nil {
deviceLogger().WithError(err).WithField("path", propertyPath).Warn("failed to read pci slot property")
return ""
}
return rlt
}
func readPCIProperty(propertyPath string) (string, error) {
var (
buf []byte