[Xen-changelog] [xen-unstable] libxl: support reset file on sysfs

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
# Date 1277309131 -3600
# Node ID f2f0b687f74d640bd0761c64272e8edbc56c2fab
# Parent  f3d3fb7da2c976ae996abf681626b8ca5a0e9eff
libxl: support reset file on sysfs

Recent kernels have a reset file on sysfs per PCI device, to allow PCI
device reset from userspace.
This patch adds support to libxl for resetting PCI devices using the
reset file on sysfs, in case the do_flr file is not preset.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 tools/libxl/libxl.c          |    4 ++--
 tools/libxl/libxl_device.c   |   38 +++++++++++++++++++++++++++-----------
 tools/libxl/libxl_internal.h |    4 ++--
 3 files changed, 31 insertions(+), 15 deletions(-)

diff -r f3d3fb7da2c9 -r f2f0b687f74d tools/libxl/libxl.c
--- a/tools/libxl/libxl.c       Wed Jun 23 17:04:26 2010 +0100
+++ b/tools/libxl/libxl.c       Wed Jun 23 17:05:31 2010 +0100
@@ -2381,7 +2381,7 @@ int libxl_device_pci_add(struct libxl_ct
 
     /* TODO: check if the device can be assigned */
 
-    libxl_device_pci_flr(ctx, pcidev->domain, pcidev->bus, pcidev->dev, 
pcidev->func);
+    libxl_device_pci_reset(ctx, pcidev->domain, pcidev->bus, pcidev->dev, 
pcidev->func);
 
     stubdomid = libxl_get_stubdom_id(ctx, domid);
     if (stubdomid != 0) {
@@ -2551,7 +2551,7 @@ skip1:
         fclose(f);
     }
 out:
-    libxl_device_pci_flr(ctx, pcidev->domain, pcidev->bus, pcidev->dev, 
pcidev->func);
+    libxl_device_pci_reset(ctx, pcidev->domain, pcidev->bus, pcidev->dev, 
pcidev->func);
 
     if (!libxl_is_stubdom(ctx, domid, NULL)) {
         rc = xc_deassign_device(ctx->xch, domid, pcidev->value);
diff -r f3d3fb7da2c9 -r f2f0b687f74d tools/libxl/libxl_device.c
--- a/tools/libxl/libxl_device.c        Wed Jun 23 17:04:26 2010 +0100
+++ b/tools/libxl/libxl_device.c        Wed Jun 23 17:05:31 2010 +0100
@@ -22,6 +22,8 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <fcntl.h>
+
 
 #include "libxl.h"
 #include "libxl_internal.h"
@@ -389,22 +391,36 @@ int libxl_device_del(struct libxl_ctx *c
     return 0;
 }
 
-int libxl_device_pci_flr(struct libxl_ctx *ctx, unsigned int domain, unsigned 
int bus,
+int libxl_device_pci_reset(struct libxl_ctx *ctx, unsigned int domain, 
unsigned int bus,
                          unsigned int dev, unsigned int func)
 {
-    char *do_flr = "/sys/bus/pci/drivers/pciback/do_flr";
-    FILE *fd;
-
-    fd = fopen(do_flr, "w");
-    if (fd != NULL) {
-        fprintf(fd, PCI_BDF, domain, bus, dev, func);
-        fclose(fd);
-        return 0;
+    char *reset = "/sys/bus/pci/drivers/pciback/do_flr";
+    int fd, rc;
+
+    fd = open(reset, O_WRONLY);
+    if (fd > 0) {
+        char *buf = libxl_sprintf(ctx, PCI_BDF, domain, bus, dev, func);
+        rc = write(fd, buf, strlen(buf));
+        if (rc < 0)
+            XL_LOG(ctx, XL_LOG_ERROR, "write to %s returned %d", reset, rc);
+        close(fd);
+        return rc < 0 ? rc : 0;
+    }
+    if (errno != ENOENT)
+        XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "Failed to access pciback path %s", 
reset);
+    reset = libxl_sprintf(ctx, "/sys/bus/pci/devices/"PCI_BDF"/reset", domain, 
bus, dev, func);
+    fd = open(reset, O_WRONLY);
+    if (fd > 0) {
+        rc = write(fd, "1", 1);
+        if (rc < 0)
+            XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "write to %s returned %d", reset, 
rc);
+        close(fd);
+        return rc < 0 ? rc : 0;
     }
     if (errno == ENOENT) {
-        XL_LOG(ctx, XL_LOG_ERROR, "Pciback doesn't support do_flr, cannot flr 
the device");
+        XL_LOG(ctx, XL_LOG_ERROR, "The kernel doesn't support PCI device reset 
from sysfs");
     } else {
-        XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "Failed to access pciback path %s", 
do_flr);
+        XL_LOG_ERRNO(ctx, XL_LOG_ERROR, "Failed to access reset path %s", 
reset);
     }
     return -1;
 }
diff -r f3d3fb7da2c9 -r f2f0b687f74d tools/libxl/libxl_internal.h
--- a/tools/libxl/libxl_internal.h      Wed Jun 23 17:04:26 2010 +0100
+++ b/tools/libxl/libxl_internal.h      Wed Jun 23 17:05:31 2010 +0100
@@ -162,8 +162,8 @@ int libxl_wait_for_device_model(struct l
                                                       void *userdata),
                                 void *check_callback_userdata);
 int libxl_wait_for_backend(struct libxl_ctx *ctx, char *be_path, char *state);
-int libxl_device_pci_flr(struct libxl_ctx *ctx, unsigned int domain, unsigned 
int bus,
-                         unsigned int dev, unsigned int func);
+int libxl_device_pci_reset(struct libxl_ctx *ctx, unsigned int domain, 
unsigned int bus,
+                           unsigned int dev, unsigned int func);
 
 /* from xenguest (helper */
 int hvm_build_set_params(xc_interface *handle, uint32_t domid,

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