libxl: arm: Add grant_usage parameter for virtio devices

Currently, the grant mapping related device tree properties are added if
the backend domain is not Dom0. While Dom0 is privileged and can do
foreign mapping for the entire guest memory, it is still desired for
Dom0 to access guest's memory via grant mappings and hence map only what
is required.

This commit adds the "grant_usage" parameter for virtio devices, which
provides better control over the functionality.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: George Dunlap <george.dunlap@cloud.com>

diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 3979be2a590a7e7a4cd7baba220e3e0654e5ffcb..b6fc20ef01c842a477a3c90a1a9b10da4cbd4d50 100644 (file)
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -1619,6 +1619,14 @@ hexadecimal format, without the "0x" prefix and all in lower case, like
 Specifies the transport mechanism for the Virtio device, only "mmio" is
 supported for now.
 
+=item B<grant_usage=BOOLEAN>
+
+If this option is B<true>, the Xen grants are always enabled.
+If this option is B<false>, the Xen grants are always disabled.
+
+If this option is missing, then the default grant setting will be used,
+i.e. enable grants if backend-domid != 0.
+
 =back
 
 =item B<tee="STRING">

diff --git a/tools/golang/xenlight/helpers.gen.go b/tools/golang/xenlight/helpers.gen.go
index cd1a16e32eac79f8bd2af4faad72fdd95247b07c..3ecffdf0ef3a365251394c23c81e8c921fd0a1ff 100644 (file)
--- a/tools/golang/xenlight/helpers.gen.go
+++ b/tools/golang/xenlight/helpers.gen.go
@@ -1794,6 +1794,9 @@ func (x *DeviceVirtio) fromC(xc *C.libxl_device_virtio) error {
 x.BackendDomname = C.GoString(xc.backend_domname)
 x.Type = C.GoString(xc._type)
 x.Transport = VirtioTransport(xc.transport)
+if err := x.GrantUsage.fromC(&xc.grant_usage);err != nil {
+return fmt.Errorf("converting field GrantUsage: %v", err)
+}
 x.Devid = Devid(xc.devid)
 x.Irq = uint32(xc.irq)
 x.Base = uint64(xc.base)
@@ -1811,6 +1814,9 @@ xc.backend_domname = C.CString(x.BackendDomname)}
 if x.Type != "" {
 xc._type = C.CString(x.Type)}
 xc.transport = C.libxl_virtio_transport(x.Transport)
+if err := x.GrantUsage.toC(&xc.grant_usage); err != nil {
+return fmt.Errorf("converting field GrantUsage: %v", err)
+}
 xc.devid = C.libxl_devid(x.Devid)
 xc.irq = C.uint32_t(x.Irq)
 xc.base = C.uint64_t(x.Base)

diff --git a/tools/golang/xenlight/types.gen.go b/tools/golang/xenlight/types.gen.go
index b131a7eedc9da7293598e45a53219b1c0652e66f..4f40aac28c2ad761e35464ea776ce10fcf66833c 100644 (file)
--- a/tools/golang/xenlight/types.gen.go
+++ b/tools/golang/xenlight/types.gen.go
@@ -706,6 +706,7 @@ BackendDomid Domid
 BackendDomname string
 Type string
 Transport VirtioTransport
+GrantUsage Defbool
 Devid Devid
 Irq uint32
 Base uint64

diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c
index 35f76dfc21e4ef383e797d5e2984412529196577..f98e1affa2944f8a32bd5da4cb2785ccfac2bb79 100644 (file)
--- a/tools/libs/light/libxl_arm.c
+++ b/tools/libs/light/libxl_arm.c
@@ -930,7 +930,8 @@ static int make_xen_iommu_node(libxl__gc *gc, void *fdt)
 
 /* The caller is responsible to complete / close the fdt node */
 static int make_virtio_mmio_node_common(libxl__gc *gc, void *fdt, uint64_t base,
-                                        uint32_t irq, uint32_t backend_domid)
+                                        uint32_t irq, uint32_t backend_domid,
+                                        bool grant_usage)
 {
     int res;
     gic_interrupt intr;
@@ -953,7 +954,7 @@ static int make_virtio_mmio_node_common(libxl__gc *gc, void *fdt, uint64_t base,
     res = fdt_property(fdt, "dma-coherent", NULL, 0);
     if (res) return res;
 
-    if (backend_domid != LIBXL_TOOLSTACK_DOMID) {
+    if (grant_usage) {
         uint32_t iommus_prop[2];
 
         iommus_prop[0] = cpu_to_fdt32(GUEST_PHANDLE_IOMMU);
@@ -967,11 +968,12 @@ static int make_virtio_mmio_node_common(libxl__gc *gc, void *fdt, uint64_t base,
 }
 
 static int make_virtio_mmio_node(libxl__gc *gc, void *fdt, uint64_t base,
-                                 uint32_t irq, uint32_t backend_domid)
+                                 uint32_t irq, uint32_t backend_domid,
+                                 bool grant_usage)
 {
     int res;
 
-    res = make_virtio_mmio_node_common(gc, fdt, base, irq, backend_domid);
+    res = make_virtio_mmio_node_common(gc, fdt, base, irq, backend_domid, grant_usage);
     if (res) return res;
 
     return fdt_end_node(fdt);
@@ -1027,11 +1029,11 @@ static int make_virtio_mmio_node_gpio(libxl__gc *gc, void *fdt)
 
 static int make_virtio_mmio_node_device(libxl__gc *gc, void *fdt, uint64_t base,
                                         uint32_t irq, const char *type,
-                                        uint32_t backend_domid)
+                                        uint32_t backend_domid, bool grant_usage)
 {
     int res;
 
-    res = make_virtio_mmio_node_common(gc, fdt, base, irq, backend_domid);
+    res = make_virtio_mmio_node_common(gc, fdt, base, irq, backend_domid, grant_usage);
     if (res) return res;
 
     /* Add device specific nodes */
@@ -1371,7 +1373,8 @@ next_resize:
                     iommu_needed = true;
 
                 FDT( make_virtio_mmio_node(gc, fdt, disk->base, disk->irq,
-                                           disk->backend_domid) );
+                                           disk->backend_domid,
+                                           disk->backend_domid != LIBXL_TOOLSTACK_DOMID) );
             }
         }
 
@@ -1381,12 +1384,13 @@ next_resize:
             if (virtio->transport != LIBXL_VIRTIO_TRANSPORT_MMIO)
                 continue;
 
-            if (virtio->backend_domid != LIBXL_TOOLSTACK_DOMID)
+            if (libxl_defbool_val(virtio->grant_usage))
                 iommu_needed = true;
 
             FDT( make_virtio_mmio_node_device(gc, fdt, virtio->base,
                                               virtio->irq, virtio->type,
-                                              virtio->backend_domid) );
+                                              virtio->backend_domid,
+                                              libxl_defbool_val(virtio->grant_usage)) );
         }
 
         /*

diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl
index 9e48bb7726465598f4517dfa3f97305f4d61d389..700b44a164f42b3b62adefa5e6d7f68ba959e074 100644 (file)
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -762,6 +762,7 @@ libxl_device_virtio = Struct("device_virtio", [
     ("backend_domname", string),
     ("type", string),
     ("transport", libxl_virtio_transport),
+    ("grant_usage", libxl_defbool),
     ("devid", libxl_devid),
     # Note that virtio-mmio parameters (irq and base) are for internal
     # use by libxl and can't be modified.

diff --git a/tools/libs/light/libxl_virtio.c b/tools/libs/light/libxl_virtio.c
index f8a78e22d156aaacd5f564a61de24e1542d56f33..e5e321adc5c46b2908dfdae9461fd1a93cd837a9 100644 (file)
--- a/tools/libs/light/libxl_virtio.c
+++ b/tools/libs/light/libxl_virtio.c
@@ -23,8 +23,16 @@ static int libxl__device_virtio_setdefault(libxl__gc *gc, uint32_t domid,
                                            libxl_device_virtio *virtio,
                                            bool hotplug)
 {
-    return libxl__resolve_domid(gc, virtio->backend_domname,
-                                &virtio->backend_domid);
+    int rc;
+
+    rc = libxl__resolve_domid(gc, virtio->backend_domname,
+                              &virtio->backend_domid);
+    if (rc < 0) return rc;
+
+    libxl_defbool_setdefault(&virtio->grant_usage,
+                             virtio->backend_domid != LIBXL_TOOLSTACK_DOMID);
+
+    return 0;
 }
 
 static int libxl__device_from_virtio(libxl__gc *gc, uint32_t domid,
@@ -53,6 +61,8 @@ static int libxl__set_xenstore_virtio(libxl__gc *gc, uint32_t domid,
     flexarray_append_pair(back, "base", GCSPRINTF("%#"PRIx64, virtio->base));
     flexarray_append_pair(back, "type", GCSPRINTF("%s", virtio->type));
     flexarray_append_pair(back, "transport", GCSPRINTF("%s", transport));
+    flexarray_append_pair(back, "grant_usage",
+                          libxl_defbool_val(virtio->grant_usage) ? "1" : "0");
 
     return 0;
 }
@@ -104,6 +114,15 @@ static int libxl__virtio_from_xenstore(libxl__gc *gc, const char *libxl_path,
         }
     }
 
+    tmp = NULL;
+    rc = libxl__xs_read_checked(gc, XBT_NULL,
+                                GCSPRINTF("%s/grant_usage", be_path), &tmp);
+    if (rc) goto out;
+
+    if (tmp) {
+        libxl_defbool_set(&virtio->grant_usage, strtoul(tmp, NULL, 0));
+    }
+
     tmp = NULL;
     rc = libxl__xs_read_checked(gc, XBT_NULL,
                                GCSPRINTF("%s/type", be_path), &tmp);

diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index f036e56fc2392854ff7608729a3c67b93d75a6f8..dfd432ca02e2220c71649adbd35ca0638112cf1f 100644 (file)
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1215,6 +1215,8 @@ static int parse_virtio_config(libxl_device_virtio *virtio, char *token)
     } else if (MATCH_OPTION("transport", token, oparg)) {
         rc = libxl_virtio_transport_from_string(oparg, &virtio->transport);
         if (rc) return rc;
+    } else if (MATCH_OPTION("grant_usage", token, oparg)) {
+        libxl_defbool_set(&virtio->grant_usage, strtoul(oparg, NULL, 0));
     } else {
         fprintf(stderr, "Unknown string \"%s\" in virtio spec\n", token);
         return -1;