diff mbox series

[1/6] gnttab: allow setting max version per-domain

Message ID 20210917154625.89315-2-roger.pau@citrix.com (mailing list archive)
State Superseded
Headers show
Series gnttab: add per-domain controls | expand

Commit Message

Roger Pau Monné Sept. 17, 2021, 3:46 p.m. UTC
Introduce a new domain create field so that toolstack can specify the
maximum grant table version usable by the domain. This is plumbed into
xl and settable by the user as max_grant_version.

Previously this was only settable on a per host basis using the
gnttab command line option.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
NB: the stubdom max grant version is cloned from the domain one. Not
sure whether long term we might want to use different options for the
stubdom and the domain. In any case the attack surface will always be
max(stubdom, domain), so maybe it's just pointless to allow more fine
setting.
---
 docs/man/xl.cfg.5.pod.in             |  6 ++++++
 docs/man/xl.conf.5.pod.in            |  7 +++++++
 tools/helpers/init-xenstore-domain.c |  1 +
 tools/include/libxl.h                |  7 +++++++
 tools/libs/light/libxl_create.c      |  1 +
 tools/libs/light/libxl_dm.c          |  1 +
 tools/libs/light/libxl_types.idl     |  1 +
 tools/ocaml/libs/xc/xenctrl.ml       |  1 +
 tools/ocaml/libs/xc/xenctrl.mli      |  1 +
 tools/ocaml/libs/xc/xenctrl_stubs.c  |  5 ++++-
 tools/xl/xl.c                        |  8 ++++++++
 tools/xl/xl.h                        |  1 +
 tools/xl/xl_parse.c                  |  9 +++++++++
 xen/arch/arm/domain_build.c          |  2 ++
 xen/arch/x86/setup.c                 |  1 +
 xen/common/domain.c                  |  3 ++-
 xen/common/grant_table.c             | 21 +++++++++++++++++++--
 xen/include/public/domctl.h          |  5 +++--
 xen/include/xen/grant_table.h        |  5 +++--
 19 files changed, 78 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/docs/man/xl.cfg.5.pod.in b/docs/man/xl.cfg.5.pod.in
index 4b1e3028d2..a4bf2caafa 100644
--- a/docs/man/xl.cfg.5.pod.in
+++ b/docs/man/xl.cfg.5.pod.in
@@ -580,6 +580,12 @@  to have. This value controls how many pages of foreign domains can be accessed
 via the grant mechanism by this domain. The default value is settable via
 L<xl.conf(5)>.
 
+=item B<max_grant_version=NUMBER>
+
+Specify the maximum grant table version the domain is allowed to use. Current
+supported versions are 1 and 2. The default value is settable via
+L<xl.conf(5)>.
+
 =item B<nomigrate=BOOLEAN>
 
 Disable migration of this domain.  This enables certain other features
diff --git a/docs/man/xl.conf.5.pod.in b/docs/man/xl.conf.5.pod.in
index b48e99131a..0a70698a7c 100644
--- a/docs/man/xl.conf.5.pod.in
+++ b/docs/man/xl.conf.5.pod.in
@@ -101,6 +101,13 @@  Sets the default value for the C<max_maptrack_frames> domain config value.
 Default: value of Xen command line B<gnttab_max_maptrack_frames>
 parameter (or its default value if unspecified).
 
+=item B<max_grant_version=NUMBER>
+
+Sets the default value for the C<max_grant_version> domain config value.
+
+Default: value of Xen command line B<gnttab> parameter (or its default value if
+unspecified).
+
 =item B<vif.default.script="PATH">
 
 Configures the default hotplug script used by virtual network devices.
diff --git a/tools/helpers/init-xenstore-domain.c b/tools/helpers/init-xenstore-domain.c
index 6836002f0b..dae2b68f27 100644
--- a/tools/helpers/init-xenstore-domain.c
+++ b/tools/helpers/init-xenstore-domain.c
@@ -88,6 +88,7 @@  static int build(xc_interface *xch)
          */
         .max_grant_frames = 4,
         .max_maptrack_frames = 128,
+        .max_grant_version = 1,
     };
 
     xs_fd = open("/dev/xen/xenbus_backend", O_RDWR);
diff --git a/tools/include/libxl.h b/tools/include/libxl.h
index b9ba16d698..7a35833312 100644
--- a/tools/include/libxl.h
+++ b/tools/include/libxl.h
@@ -502,6 +502,13 @@ 
  */
 #define LIBXL_HAVE_X86_MSR_RELAXED 1
 
+/*
+ * LIBXL_HAVE_MAX_GRANT_VERSION indicates libxl_domain_build_info has a
+ * max_grant_version field for setting the max grant table version per
+ * domain.
+ */
+#define LIBXL_HAVE_MAX_GRANT_VERSION 1
+
 /*
  * libxl ABI compatibility
  *
diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
index e356b2106d..69b5419416 100644
--- a/tools/libs/light/libxl_create.c
+++ b/tools/libs/light/libxl_create.c
@@ -606,6 +606,7 @@  int libxl__domain_make(libxl__gc *gc, libxl_domain_config *d_config,
             .max_evtchn_port = b_info->event_channels,
             .max_grant_frames = b_info->max_grant_frames,
             .max_maptrack_frames = b_info->max_maptrack_frames,
+            .max_grant_version = b_info->max_grant_version,
             .vmtrace_size = ROUNDUP(b_info->vmtrace_buf_kb << 10, XC_PAGE_SHIFT),
         };
 
diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index 9d93056b5c..9a8ddbe188 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -2320,6 +2320,7 @@  void libxl__spawn_stub_dm(libxl__egc *egc, libxl__stub_dm_spawn_state *sdss)
 
     dm_config->b_info.max_grant_frames = guest_config->b_info.max_grant_frames;
     dm_config->b_info.max_maptrack_frames = guest_config->b_info.max_maptrack_frames;
+    dm_config->b_info.max_grant_version = guest_config->b_info.max_grant_version;
 
     dm_config->b_info.u.pv.features = "";
 
diff --git a/tools/libs/light/libxl_types.idl b/tools/libs/light/libxl_types.idl
index 3f9fff653a..37789a568c 100644
--- a/tools/libs/light/libxl_types.idl
+++ b/tools/libs/light/libxl_types.idl
@@ -518,6 +518,7 @@  libxl_domain_build_info = Struct("domain_build_info",[
 
     ("max_grant_frames",    uint32, {'init_val': 'LIBXL_MAX_GRANT_DEFAULT'}),
     ("max_maptrack_frames", uint32, {'init_val': 'LIBXL_MAX_GRANT_DEFAULT'}),
+    ("max_grant_version",   integer, {'init_val': '-1'}),
     
     ("device_model_version", libxl_device_model_version),
     ("device_model_stubdomain", libxl_defbool),
diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml
index a5588c643f..6a8658bfec 100644
--- a/tools/ocaml/libs/xc/xenctrl.ml
+++ b/tools/ocaml/libs/xc/xenctrl.ml
@@ -83,6 +83,7 @@  type domctl_create_config =
 	max_evtchn_port: int;
 	max_grant_frames: int;
 	max_maptrack_frames: int;
+	max_grant_version: int;
 	arch: arch_domainconfig;
 }
 
diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli
index 6e94940a8a..5933d32c70 100644
--- a/tools/ocaml/libs/xc/xenctrl.mli
+++ b/tools/ocaml/libs/xc/xenctrl.mli
@@ -75,6 +75,7 @@  type domctl_create_config = {
   max_evtchn_port: int;
   max_grant_frames: int;
   max_maptrack_frames: int;
+  max_grant_version: int;
   arch: arch_domainconfig;
 }
 
diff --git a/tools/ocaml/libs/xc/xenctrl_stubs.c b/tools/ocaml/libs/xc/xenctrl_stubs.c
index ad953d36bd..aad3c6a726 100644
--- a/tools/ocaml/libs/xc/xenctrl_stubs.c
+++ b/tools/ocaml/libs/xc/xenctrl_stubs.c
@@ -188,7 +188,8 @@  CAMLprim value stub_xc_domain_create(value xch, value wanted_domid, value config
 #define VAL_MAX_EVTCHN_PORT     Field(config, 5)
 #define VAL_MAX_GRANT_FRAMES    Field(config, 6)
 #define VAL_MAX_MAPTRACK_FRAMES Field(config, 7)
-#define VAL_ARCH                Field(config, 8)
+#define VAL_MAX_GRANT_VERSION   Field(config, 8)
+#define VAL_ARCH                Field(config, 9)
 
 	uint32_t domid = Int_val(wanted_domid);
 	int result;
@@ -198,6 +199,7 @@  CAMLprim value stub_xc_domain_create(value xch, value wanted_domid, value config
 		.max_evtchn_port = Int_val(VAL_MAX_EVTCHN_PORT),
 		.max_grant_frames = Int_val(VAL_MAX_GRANT_FRAMES),
 		.max_maptrack_frames = Int_val(VAL_MAX_MAPTRACK_FRAMES),
+		.max_grant_version = Int_val(VAL_MAX_GRANT_VERSION),
 	};
 
 	domain_handle_of_uuid_string(cfg.handle, String_val(VAL_HANDLE));
@@ -251,6 +253,7 @@  CAMLprim value stub_xc_domain_create(value xch, value wanted_domid, value config
 	}
 
 #undef VAL_ARCH
+#undef VAL_MAX_GRANT_VERSION
 #undef VAL_MAX_MAPTRACK_FRAMES
 #undef VAL_MAX_GRANT_FRAMES
 #undef VAL_MAX_EVTCHN_PORT
diff --git a/tools/xl/xl.c b/tools/xl/xl.c
index 4107d10fd4..0fde879cf4 100644
--- a/tools/xl/xl.c
+++ b/tools/xl/xl.c
@@ -55,6 +55,7 @@  bool progress_use_cr = 0;
 bool timestamps = 0;
 int max_grant_frames = -1;
 int max_maptrack_frames = -1;
+int max_grant_version = -1;
 libxl_domid domid_policy = INVALID_DOMID;
 
 xentoollog_level minmsglevel = minmsglevel_default;
@@ -213,6 +214,13 @@  static void parse_global_config(const char *configfile,
     else if (e != ESRCH)
         exit(1);
 
+    e = xlu_cfg_get_bounded_long (config, "max_grant_version", 0,
+                                  INT_MAX, &l, 1);
+    if (!e)
+        max_grant_version = l;
+    else if (e != ESRCH)
+        exit(1);
+
     libxl_cpu_bitmap_alloc(ctx, &global_vm_affinity_mask, 0);
     libxl_cpu_bitmap_alloc(ctx, &global_hvm_affinity_mask, 0);
     libxl_cpu_bitmap_alloc(ctx, &global_pv_affinity_mask, 0);
diff --git a/tools/xl/xl.h b/tools/xl/xl.h
index 7e23f30192..cf12c79a9b 100644
--- a/tools/xl/xl.h
+++ b/tools/xl/xl.h
@@ -282,6 +282,7 @@  extern char *default_colo_proxy_script;
 extern char *blkdev_start;
 extern int max_grant_frames;
 extern int max_maptrack_frames;
+extern int max_grant_version;
 extern libxl_bitmap global_vm_affinity_mask;
 extern libxl_bitmap global_hvm_affinity_mask;
 extern libxl_bitmap global_pv_affinity_mask;
diff --git a/tools/xl/xl_parse.c b/tools/xl/xl_parse.c
index 17dddb4cd5..1206d7ea51 100644
--- a/tools/xl/xl_parse.c
+++ b/tools/xl/xl_parse.c
@@ -1431,6 +1431,15 @@  void parse_config_data(const char *config_source,
     else
         exit(1);
 
+    e = xlu_cfg_get_bounded_long (config, "max_grant_version", 0,
+                                  INT_MAX, &l, 1);
+    if (e == ESRCH) /* not specified */
+        b_info->max_grant_version = max_grant_version;
+    else if (!e)
+        b_info->max_grant_version = l;
+    else
+        exit(1);
+
     libxl_defbool_set(&b_info->claim_mode, claim_mode);
 
     if (xlu_cfg_get_string (config, "on_poweroff", &buf, 0))
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 206038d1c0..e9a34f2f8d 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -2484,6 +2484,7 @@  void __init create_domUs(void)
             .max_evtchn_port = -1,
             .max_grant_frames = -1,
             .max_maptrack_frames = -1,
+            .max_grant_version = -1,
         };
 
         if ( !dt_device_is_compatible(node, "xen,domain") )
@@ -2591,6 +2592,7 @@  void __init create_dom0(void)
         .max_evtchn_port = -1,
         .max_grant_frames = gnttab_dom0_frames(),
         .max_maptrack_frames = -1,
+        .max_grant_version = -1,
     };
 
     /* The vGIC for DOM0 is exactly emulating the hardware GIC */
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 8105dc36bb..af69e20029 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -750,6 +750,7 @@  static struct domain *__init create_dom0(const module_t *image,
         .max_evtchn_port = -1,
         .max_grant_frames = -1,
         .max_maptrack_frames = -1,
+        .max_grant_version = -1,
         .max_vcpus = dom0_max_vcpus(),
         .arch = {
             .misc_flags = opt_dom0_msr_relaxed ? XEN_X86_MSR_RELAXED : 0,
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6ee5d033b0..0c85d89419 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -669,7 +669,8 @@  struct domain *domain_create(domid_t domid,
         init_status |= INIT_evtchn;
 
         if ( (err = grant_table_init(d, config->max_grant_frames,
-                                     config->max_maptrack_frames)) != 0 )
+                                     config->max_maptrack_frames,
+                                     config->max_grant_version)) != 0 )
             goto fail;
         init_status |= INIT_gnttab;
 
diff --git a/xen/common/grant_table.c b/xen/common/grant_table.c
index e80f8d044d..d01c6813d1 100644
--- a/xen/common/grant_table.c
+++ b/xen/common/grant_table.c
@@ -53,6 +53,7 @@  struct grant_table {
     percpu_rwlock_t       lock;
     /* Lock protecting the maptrack limit */
     spinlock_t            maptrack_lock;
+    unsigned int          max_grant_version;
     /*
      * Defaults to v1.  May be changed with GNTTABOP_set_version.  All other
      * values are invalid.
@@ -1917,11 +1918,26 @@  active_alloc_failed:
 }
 
 int grant_table_init(struct domain *d, int max_grant_frames,
-                     int max_maptrack_frames)
+                     int max_maptrack_frames, int max_grant_version)
 {
     struct grant_table *gt;
     int ret = -ENOMEM;
 
+    if ( max_grant_version < 0 )
+        max_grant_version = opt_gnttab_max_version;
+    if ( !max_grant_version )
+    {
+        dprintk(XENLOG_INFO, "Invalid grant table version 0 requested\n");
+        return -EINVAL;
+    }
+    if ( max_grant_version > opt_gnttab_max_version )
+    {
+        dprintk(XENLOG_INFO,
+                "Requested grant version (%u) greater than supported (%u)\n",
+                max_grant_version, opt_gnttab_max_version);
+        return -EINVAL;
+    }
+
     /* Default to maximum value if no value was specified */
     if ( max_grant_frames < 0 )
         max_grant_frames = opt_max_grant_frames;
@@ -1947,6 +1963,7 @@  int grant_table_init(struct domain *d, int max_grant_frames,
     gt->gt_version = 1;
     gt->max_grant_frames = max_grant_frames;
     gt->max_maptrack_frames = max_maptrack_frames;
+    gt->max_grant_version = max_grant_version;
 
     /* Install the structure early to simplify the error path. */
     gt->domain = d;
@@ -3076,7 +3093,7 @@  gnttab_set_version(XEN_GUEST_HANDLE_PARAM(gnttab_set_version_t) uop)
         goto out;
 
     res = -ENOSYS;
-    if ( op.version == 2 && opt_gnttab_max_version == 1 )
+    if ( op.version == 2 && gt->max_grant_version == 1 )
         goto out; /* Behave as before set_version was introduced. */
 
     res = 0;
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 96696e3842..7f8456c50e 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -87,13 +87,14 @@  struct xen_domctl_createdomain {
     /*
      * Various domain limits, which impact the quantity of resources
      * (global mapping space, xenheap, etc) a guest may consume.  For
-     * max_grant_frames and max_maptrack_frames, < 0 means "use the
-     * default maximum value in the hypervisor".
+     * max_grant_frames, max_maptrack_frames and max_gnttab_version < 0
+     * means "use the default maximum value in the hypervisor".
      */
     uint32_t max_vcpus;
     uint32_t max_evtchn_port;
     int32_t max_grant_frames;
     int32_t max_maptrack_frames;
+    int32_t max_grant_version;
 
     /* Per-vCPU buffer size in bytes.  0 to disable. */
     uint32_t vmtrace_size;
diff --git a/xen/include/xen/grant_table.h b/xen/include/xen/grant_table.h
index 41713e2726..d6da067fc1 100644
--- a/xen/include/xen/grant_table.h
+++ b/xen/include/xen/grant_table.h
@@ -36,7 +36,7 @@  extern unsigned int opt_max_grant_frames;
 
 /* Create/destroy per-domain grant table context. */
 int grant_table_init(struct domain *d, int max_grant_frames,
-                     int max_maptrack_frames);
+                     int max_maptrack_frames, int max_grant_version);
 void grant_table_destroy(
     struct domain *d);
 void grant_table_init_vcpu(struct vcpu *v);
@@ -67,7 +67,8 @@  int gnttab_acquire_resource(
 
 static inline int grant_table_init(struct domain *d,
                                    int max_grant_frames,
-                                   int max_maptrack_frames)
+                                   int max_maptrack_frames,
+                                   int max_grant_version)
 {
     return 0;
 }