Hi, Paul!
On 11/24/20 10:01 AM, Paul Durrant wrote:
> From: Paul Durrant <pdurr...@amazon.com>
>
> For the purposes of re-binding a device to its previous driver
> libxl__device_pci_assignable_add() writes the driver path into xenstore.
> This path is then read back in libxl__device_pci_assignable_remove().
>
> The functions that support this writing to and reading from xenstore are
> currently dedicated for this purpose and hence the node name 'driver_path'
> is hard-coded. This patch generalizes these utility functions and passes
> 'driver_path' as an argument. Subsequent patches will invoke them to
> access other nodes.
>
> NOTE: Because functions will have a broader use (other than storing a
> driver path in lieu of pciback) the base xenstore path is also
> changed from '/libxl/pciback' to '/libxl/pci'.
>
> Signed-off-by: Paul Durrant <pdurr...@amazon.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
Thank you,
Oleksandr
> ---
> Cc: Ian Jackson <i...@xenproject.org>
> Cc: Wei Liu <w...@xen.org>
> ---
> tools/libs/light/libxl_pci.c | 66
> +++++++++++++++++++++-----------------------
> 1 file changed, 32 insertions(+), 34 deletions(-)
>
> diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
> index 77edd27345..a5d5d2e78b 100644
> --- a/tools/libs/light/libxl_pci.c
> +++ b/tools/libs/light/libxl_pci.c
> @@ -737,48 +737,46 @@ static int pciback_dev_unassign(libxl__gc *gc,
> libxl_device_pci *pci)
> return 0;
> }
>
> -#define PCIBACK_INFO_PATH "/libxl/pciback"
> +#define PCI_INFO_PATH "/libxl/pci"
>
> -static void pci_assignable_driver_path_write(libxl__gc *gc,
> - libxl_device_pci *pci,
> - char *driver_path)
> +static char *pci_info_xs_path(libxl__gc *gc, libxl_device_pci *pci,
> + const char *node)
> {
> - char *path;
> + return node ?
> + GCSPRINTF(PCI_INFO_PATH"/"PCI_BDF_XSPATH"/%s",
> + pci->domain, pci->bus, pci->dev, pci->func,
> + node) :
> + GCSPRINTF(PCI_INFO_PATH"/"PCI_BDF_XSPATH,
> + pci->domain, pci->bus, pci->dev, pci->func);
> +}
> +
> +
> +static void pci_info_xs_write(libxl__gc *gc, libxl_device_pci *pci,
> + const char *node, const char *val)
> +{
> + char *path = pci_info_xs_path(gc, pci, node);
>
> - path = GCSPRINTF(PCIBACK_INFO_PATH"/"PCI_BDF_XSPATH"/driver_path",
> - pci->domain,
> - pci->bus,
> - pci->dev,
> - pci->func);
> - if ( libxl__xs_printf(gc, XBT_NULL, path, "%s", driver_path) < 0 ) {
> - LOGE(WARN, "Write of %s to node %s failed.", driver_path, path);
> + if ( libxl__xs_printf(gc, XBT_NULL, path, "%s", val) < 0 ) {
> + LOGE(WARN, "Write of %s to node %s failed.", val, path);
> }
> }
>
> -static char * pci_assignable_driver_path_read(libxl__gc *gc,
> - libxl_device_pci *pci)
> +static char *pci_info_xs_read(libxl__gc *gc, libxl_device_pci *pci,
> + const char *node)
> {
> - return libxl__xs_read(gc, XBT_NULL,
> - GCSPRINTF(
> - PCIBACK_INFO_PATH "/" PCI_BDF_XSPATH
> "/driver_path",
> - pci->domain,
> - pci->bus,
> - pci->dev,
> - pci->func));
> + char *path = pci_info_xs_path(gc, pci, node);
> +
> + return libxl__xs_read(gc, XBT_NULL, path);
> }
>
> -static void pci_assignable_driver_path_remove(libxl__gc *gc,
> - libxl_device_pci *pci)
> +static void pci_info_xs_remove(libxl__gc *gc, libxl_device_pci *pci,
> + const char *node)
> {
> + char *path = pci_info_xs_path(gc, pci, node);
> libxl_ctx *ctx = libxl__gc_owner(gc);
>
> /* Remove the xenstore entry */
> - xs_rm(ctx->xsh, XBT_NULL,
> - GCSPRINTF(PCIBACK_INFO_PATH "/" PCI_BDF_XSPATH,
> - pci->domain,
> - pci->bus,
> - pci->dev,
> - pci->func) );
> + xs_rm(ctx->xsh, XBT_NULL, path);
> }
>
> static int libxl__device_pci_assignable_add(libxl__gc *gc,
> @@ -824,9 +822,9 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
> /* Store driver_path for rebinding to dom0 */
> if ( rebind ) {
> if ( driver_path ) {
> - pci_assignable_driver_path_write(gc, pci, driver_path);
> + pci_info_xs_write(gc, pci, "driver_path", driver_path);
> } else if ( (driver_path =
> - pci_assignable_driver_path_read(gc, pci)) != NULL ) {
> + pci_info_xs_read(gc, pci, "driver_path")) != NULL ) {
> LOG(INFO, PCI_BDF" not bound to a driver, will be rebound to
> %s",
> dom, bus, dev, func, driver_path);
> } else {
> @@ -834,7 +832,7 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
> dom, bus, dev, func);
> }
> } else {
> - pci_assignable_driver_path_remove(gc, pci);
> + pci_info_xs_remove(gc, pci, "driver_path");
> }
>
> if ( pciback_dev_assign(gc, pci) ) {
> @@ -884,7 +882,7 @@ static int libxl__device_pci_assignable_remove(libxl__gc
> *gc,
> }
>
> /* Rebind if necessary */
> - driver_path = pci_assignable_driver_path_read(gc, pci);
> + driver_path = pci_info_xs_read(gc, pci, "driver_path");
>
> if ( driver_path ) {
> if ( rebind ) {
> @@ -897,7 +895,7 @@ static int libxl__device_pci_assignable_remove(libxl__gc
> *gc,
> return -1;
> }
>
> - pci_assignable_driver_path_remove(gc, pci);
> + pci_info_xs_remove(gc, pci, "driver_path");
> }
> } else {
> if ( rebind ) {
