From 248223259e22118b679aecfa27374b3f1c2e6ea6 Mon Sep 17 00:00:00 2001
From: Steffen Vogel <post@steffenvogel.de>
Date: Wed, 21 Dec 2022 11:50:03 +0100
Subject: [PATCH] use C++ STL for handling file IO
Signed-off-by: Steffen Vogel <post@steffenvogel.de>
---
common/include/villas/kernel/pci.hpp | 15 ++-
common/lib/kernel/pci.cpp | 141 +++++++++------------------
common/lib/kernel/vfio_container.cpp | 10 +-
3 files changed, 63 insertions(+), 103 deletions(-)
diff --git a/common/include/villas/kernel/pci.hpp b/common/include/villas/kernel/pci.hpp
index cc34aab4b..caa914a54 100644
--- a/common/include/villas/kernel/pci.hpp
+++ b/common/include/villas/kernel/pci.hpp
@@ -8,10 +8,12 @@
#pragma once
+#include <list>
+#include <fstream>
+
#include <cstddef>
#include <cstdint>
-#include <list>
#include <villas/log.hpp>
namespace villas {
@@ -97,23 +99,26 @@ public:
std::list<Region> getRegions() const;
// Write 32-bit BAR value from to the PCI configuration space
- bool writeBar(uint32_t new_bar);
+ void writeBar(uint32_t addr, unsigned bar = 0);
// If BAR values in config space and in the kernel do not match, rewrite
// the BAR value of the kernel to PCIe config space.
- bool rewriteBar();
+ void rewriteBar(unsigned bar = 0);
// Read 32-bit BAR value from the PCI configuration space.
- bool readBar(uint32_t &bar) const;
+ uint32_t readBar(unsigned bar = 0) const;
// Read 32-bit BAR value from the devices resource file. This is what the kernel
// thinks the BAR should be.
- bool readHostBar(uint32_t &bar) const;
+ uint32_t readHostBar(unsigned bar = 0) const;
Id id;
Slot slot;
private:
villas::Logger log;
+
+protected:
+ std::fstream openSysFs(const std::string subPath, std::ios_base::openmode mode = std::ios_base::in | std::ios_base::out) const;
};
class DeviceList : public std::list<std::shared_ptr<Device>> {
diff --git a/common/lib/kernel/pci.cpp b/common/lib/kernel/pci.cpp
index 8f3203476..32666f527 100644
--- a/common/lib/kernel/pci.cpp
+++ b/common/lib/kernel/pci.cpp
@@ -362,124 +362,64 @@ bool Device::attachDriver(const std::string &driver) const
return true;
}
-
-bool Device::readHostBar(uint32_t &bar) const
+uint32_t Device::readHostBar(unsigned bar) const
{
- unsigned long long start, end, size, flags;
+ auto file = openSysFs("resource", std::ios_base::in);
- char *path = NULL;
- if (asprintf(&path, "%s/bus/pci/devices/%04x:%02x:%02x.%x/resource", SYSFS_PATH,
- slot.domain, slot.bus, slot.device, slot.function) == -1) {
- log->error("could not allocate memory for path");
- return false;
- }
+ std::string line;
- FILE *file = fopen(path, "r");
- if (!file) {
- log->error("error opening resource file");
- return false;
- }
+ unsigned i;
+ for (i = 0; i <= bar && !file.eof(); i++)
+ std::getline(file, line);
- if (fscanf(file, "%llx %llx %llx", &start, &end, &flags) != 3) {
- log->error("error reading resource file");
- fclose(file);
- return false;
- }
+ if (i != bar && file.eof())
+ throw RuntimeError("Failed to read resource file");
+
+ unsigned long long start, end, flags;
+ std::istringstream(line) >> std::hex >> start >> end >> flags;
if (end > start)
- size = end - start + 1;
- else {
- log->error("error reading bar size");
- fclose(file);
- return false;
- }
+ throw SystemError("Invalid BAR: start={}, end={}", start, end);
- log->debug("Start: {:#x}, end: {:#x}, size: {:#x}, flags: {:#x}", start, end, size, flags);
+ log->debug("Host BAR: start={:#x}, end={:#x}, flags={:#x}", start, end, flags);
- fclose(file);
- bar = start;
-
- return true;
+ return start;
}
-bool Device::rewriteBar()
+void Device::rewriteBar(unsigned bar)
{
- uint32_t hostbar, configbar;
- if (!readHostBar(hostbar)) {
- log->error("Error reading host bar");
- return false;
- }
+ auto hostBar = readHostBar(bar);
+ auto configBar = readBar(bar);
- if (!readBar(configbar)) {
- log->error("Error reading config bar");
- return false;
- }
- log->debug("Host BAR: {:#x}, configbar: {:#x}", hostbar, configbar);
+ log->debug("Host BAR: {:#x}, configbar: {:#x}", hostBar, configBar);
- if (hostbar == configbar) {
+ if (hostBar == configBar) {
log->debug("BAR is already correct");
- return true;
- } else {
- log->debug("BAR is incorrect, rewriting");
- return writeBar(hostbar);
+ return;
}
+
+ log->debug("BAR is incorrect, rewriting");
+
+ writeBar(hostBar, bar);
}
-bool Device::readBar(uint32_t &bar) const
+uint32_t Device::readBar(unsigned bar) const
{
- off_t pos = PCI_BASE_ADDRESS_0;
- uint32_t read_buf;
- char *path = NULL;
- if (asprintf(&path, "%s/bus/pci/devices/%04x:%02x:%02x.%x/config", SYSFS_PATH,
- slot.domain, slot.bus, slot.device, slot.function) == -1) {
- log->error("could not allocate memory for path");
- return false;
- }
+ uint32_t addr;
+ auto file = openSysFs("config", std::ios_base::in);
- int fd = open(path, O_RDWR);
- if (fd < 0) {
- log->error("could not open config space");
- return false;
- }
+ file.seekg(PCI_BASE_ADDRESS_0 + sizeof(uint32_t) * bar);
+ file.read(reinterpret_cast<char *>(&addr), sizeof(addr));
- if (pread(fd, &read_buf, sizeof(read_buf), pos) != sizeof(read_buf)) {
- log->error("error reading from {:#x}", pos);
- close(fd);
- return false;
- }
-
- bar = read_buf;
- close(fd);
-
- return true;
+ return addr;
}
-bool Device::writeBar(uint32_t new_bar)
+void Device::writeBar(uint32_t addr, unsigned bar)
{
- uint32_t write_buf = new_bar;
- off_t pos = PCI_BASE_ADDRESS_0;
- char *path = NULL;
+ auto file = openSysFs("config", std::ios_base::out);
- if (asprintf(&path, "%s/bus/pci/devices/%04x:%02x:%02x.%x/config", SYSFS_PATH,
- slot.domain, slot.bus, slot.device, slot.function) == -1) {
- log->error("could not allocate memory for path");
- return false;
- }
-
- int fd = open(path, O_RDWR);
- if (fd < 0) {
- log->error("could not open config space");
- return false;
- }
-
- if (pwrite(fd, &write_buf, sizeof(write_buf), pos) != sizeof(write_buf)) {
- log->error("error writing to {:#x}", pos);
- close(fd);
- return false;
- }
-
- close(fd);
- return true;
+ file.seekp(PCI_BASE_ADDRESS_0 + sizeof(uint32_t) * bar);
+ file.write(reinterpret_cast<char *>(&addr), sizeof(addr));
}
int Device::getIommuGroup() const
@@ -502,3 +442,16 @@ int Device::getIommuGroup() const
return atoi(group);
}
+
+std::fstream Device::openSysFs(const std::string subPath, std::ios_base::openmode mode) const
+{
+ std::fstream file;
+
+ auto sysFsFilename = fmt::format("{}/bus/pci/devices/{:04x}:{:02x}:{:02x}.{:x}/{}", SYSFS_PATH,
+ slot.domain, slot.bus, slot.device, slot.function, subPath);
+
+ file.exceptions(std::ifstream::failbit | std::ifstream::badbit);
+ file.open(sysFsFilename, mode);
+
+ return file;
+}
diff --git a/common/lib/kernel/vfio_container.cpp b/common/lib/kernel/vfio_container.cpp
index c63b3c8b7..03f1af557 100644
--- a/common/lib/kernel/vfio_container.cpp
+++ b/common/lib/kernel/vfio_container.cpp
@@ -207,10 +207,12 @@ std::shared_ptr<Device> Container::attachDevice(pci::Device &pdev)
log->debug("Bind PCI card to kernel driver '{}'", kernelDriver);
pdev.attachDriver(kernelDriver);
}
- if (!pdev.rewriteBar()) {
- log->error("BAR of device is in inconsistent state. Rewriting the BAR "
- "failed. Please remove, rescan and reset the device and try again.");
- throw RuntimeError("Failed to rewrite BAR of device");
+
+ try {
+ pdev.rewriteBar();
+ } catch (std::exception &e) {
+ throw RuntimeError("BAR of device is in inconsistent state. Rewriting the BAR "
+ "failed. Please remove, rescan and reset the device and try again.");
}
// Get IOMMU group of device