[RFC,FUTURE,2/3] tools: libxc: add virtual_sbdf parameter to xc_assign_device

Commit Message

Volodymyr Babchuk Dec. 13, 2023, 11:44 p.m. UTC

Now, when "assign_device" domctl supports virtual_sbdf option, make it
available to libxc users. This is an optional parameter, if it is not
provided, xc_assign_device() will ask hypervisor to allocate a free
vSBDF.

Signed-off-by: Volodymyr Babchuk <[e-mail]>

--

This clearly breaks libxc API. So I wanted to discuss a proper way of
doing this. Should I introduce a new xc_assign_device() function with
an extra parameter?
---
 tools/include/xenctrl.h             |  1 +
 tools/libs/ctrl/xc_domain.c         | 14 ++++++++++++--
 tools/libs/light/libxl_pci.c        |  4 ++--
 tools/ocaml/libs/xc/xenctrl_stubs.c |  2 +-
 tools/python/xen/lowlevel/xc/xc.c   |  2 +-
 5 files changed, 17 insertions(+), 6 deletions(-)

Patch

diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 2ef8b4e054..ccc0745c35 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -1689,6 +1689,7 @@  int xc_get_hvm_param(xc_interface *handle, uint32_t dom, int param, unsigned lon
 int xc_assign_device(xc_interface *xch,
                      uint32_t domid,
                      uint32_t machine_sbdf,
+                     uint32_t *virtual_sbdf,
                      uint32_t flag);
 
 int xc_get_device_group(xc_interface *xch,
diff --git a/tools/libs/ctrl/xc_domain.c b/tools/libs/ctrl/xc_domain.c
index 2405e39517..ca60b13a89 100644
--- a/tools/libs/ctrl/xc_domain.c
+++ b/tools/libs/ctrl/xc_domain.c
@@ -1497,18 +1497,28 @@  int xc_assign_device(
     xc_interface *xch,
     uint32_t domid,
     uint32_t machine_sbdf,
+    uint32_t *virtual_sbdf,
     uint32_t flags)
 {
+    int rc;
     struct xen_domctl domctl = {};
 
     domctl.cmd = XEN_DOMCTL_assign_device;
     domctl.domain = domid;
     domctl.u.assign_device.dev = XEN_DOMCTL_DEV_PCI;
     domctl.u.assign_device.u.pci.machine_sbdf = machine_sbdf;
-    domctl.u.assign_device.u.pci.virtual_sbdf = XEN_DOMCTL_DEV_SDBF_ANY;
+    if (!virtual_sbdf)
+        domctl.u.assign_device.u.pci.virtual_sbdf = XEN_DOMCTL_DEV_SDBF_ANY;
+    else
+        domctl.u.assign_device.u.pci.virtual_sbdf = *virtual_sbdf;
     domctl.u.assign_device.flags = flags;
 
-    return do_domctl(xch, &domctl);
+    rc = do_domctl(xch, &domctl);
+
+    if (!rc && virtual_sbdf)
+        *virtual_sbdf = domctl.u.assign_device.u.pci.virtual_sbdf;
+
+    return rc;
 }
 
 int xc_get_device_group(
diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
index 96cb4da079..723e577ef5 100644
--- a/tools/libs/light/libxl_pci.c
+++ b/tools/libs/light/libxl_pci.c
@@ -842,7 +842,7 @@  name:
      * so always pass XEN_DOMCTL_DEV_RDM_RELAXED to avoid assignment being
      * unnecessarily denied.
      */
-    rc = xc_assign_device(ctx->xch, DOMID_IO, pci_encode_bdf(pci),
+    rc = xc_assign_device(ctx->xch, DOMID_IO, pci_encode_bdf(pci), NULL,
                           XEN_DOMCTL_DEV_RDM_RELAXED);
     if ( rc < 0 ) {
         LOG(ERROR, "failed to quarantine "PCI_BDF, dom, bus, dev, func);
@@ -1524,7 +1524,7 @@  out_no_irq:
             rc = ERROR_FAIL;
             goto out;
         }
-        r = xc_assign_device(ctx->xch, domid, pci_encode_bdf(pci), flag);
+        r = xc_assign_device(ctx->xch, domid, pci_encode_bdf(pci), NULL, flag);
         if (r < 0 && (hvm || errno != ENOSYS)) {
             LOGED(ERROR, domainid, "xc_assign_device failed");
             rc = ERROR_FAIL;
diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c b/tools/ocaml/libs/xc/xenctrl_stubs.c
index 3703f48c74..55d257abbb 100644
--- a/tools/ocaml/libs/xc/xenctrl_stubs.c
+++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
@@ -1323,7 +1323,7 @@  CAMLprim value stub_xc_domain_assign_device(value xch_val, value domid, value de
 	func = Int_val(Field(desc, 3));
 	sbdf = encode_sbdf(domain, bus, dev, func);
 
-	ret = xc_assign_device(xch, Int_val(domid), sbdf,
+	ret = xc_assign_device(xch, Int_val(domid), sbdf, NULL,
 			       XEN_DOMCTL_DEV_RDM_RELAXED);
 
 	if (ret < 0)
diff --git a/tools/python/xen/lowlevel/xc/xc.c b/tools/python/xen/lowlevel/xc/xc.c
index d3ea350e07..1e210c78b7 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -587,7 +587,7 @@  static PyObject *pyxc_assign_device(XcObject *self,
         sbdf |= (dev & 0x1f) << 3;
         sbdf |= (func & 0x7);
 
-        if ( xc_assign_device(self->xc_handle, dom, sbdf, 0) != 0 )
+        if ( xc_assign_device(self->xc_handle, dom, sbdf, NULL, 0) != 0 )
         {
             if (errno == ENOSYS)
                 sbdf = -1;