[Xen-devel] [PATCH] Implement new hypercall to return domain id

[Felix Schmoll <eggi.innovations@xxxxxxxxx>]

Minimal implementation of a new hypercall that returns the domain
id of the invoking domain with adjustments in libxc.

Signed-off-by: Felix Schmoll <eggi.innovations@xxxxxxxxx>
---
 tools/libxc/include/xenctrl.h | 1 +
 tools/libxc/xc_private.c      | 6 ++++++
 xen/arch/arm/traps.c          | 1 +
 xen/arch/x86/hvm/hypercall.c  | 1 +
 xen/arch/x86/hypercall.c      | 1 +
 xen/arch/x86/pv/hypercall.c   | 1 +
 xen/common/kernel.c           | 6 ++++++
 xen/include/public/xen.h      | 1 +
 xen/include/xen/hypercall.h   | 3 +++
 9 files changed, 21 insertions(+)

diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
index 2d97d36c38..1e152c8a07 100644
--- a/tools/libxc/include/xenctrl.h
+++ b/tools/libxc/include/xenctrl.h
@@ -1569,6 +1569,7 @@ int xc_domctl(xc_interface *xch, struct xen_domctl 
*domctl);
 int xc_sysctl(xc_interface *xch, struct xen_sysctl *sysctl);
 
 int xc_version(xc_interface *xch, int cmd, void *arg);
+int xc_domid(xc_interface *xch);
 
 int xc_flask_op(xc_interface *xch, xen_flask_op_t *op);
 
diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index 72e6242417..37b11e41a9 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -530,6 +530,12 @@ int xc_version(xc_interface *xch, int cmd, void *arg)
     return rc;
 }
 
+int xc_domid(xc_interface *xch)
+{
+    return xencall0(xch->xcall, __HYPERVISOR_domain_id);
+}
+
+
 unsigned long xc_make_page_below_4G(
     xc_interface *xch, uint32_t domid, unsigned long mfn)
 {
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 614501f761..eddb264f2d 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -1297,6 +1297,7 @@ static arm_hypercall_t arm_hypercall_table[] = {
     HYPERCALL(platform_op, 1),
     HYPERCALL_ARM(vcpu_op, 3),
     HYPERCALL(vm_assist, 2),
+    HYPERCALL(domain_id, 0),
 };
 
 #ifndef NDEBUG
diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index e7238ce293..3d541e01e1 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -132,6 +132,7 @@ static const hypercall_table_t hvm_hypercall_table[] = {
     COMPAT_CALL(mmuext_op),
     HYPERCALL(xenpmu_op),
     COMPAT_CALL(dm_op),
+    HYPERCALL(domain_id),
     HYPERCALL(arch_1)
 };
 
diff --git a/xen/arch/x86/hypercall.c b/xen/arch/x86/hypercall.c
index e30181817a..184741bf16 100644
--- a/xen/arch/x86/hypercall.c
+++ b/xen/arch/x86/hypercall.c
@@ -67,6 +67,7 @@ const hypercall_args_t hypercall_args_table[NR_hypercalls] =
     ARGS(tmem_op, 1),
     ARGS(xenpmu_op, 2),
     ARGS(dm_op, 3),
+    ARGS(domain_id, 0),
     ARGS(mca, 1),
     ARGS(arch_1, 1),
 };
diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index 9d29d2f088..f12314b5ca 100644
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -79,6 +79,7 @@ static const hypercall_table_t pv_hypercall_table[] = {
 #endif
     HYPERCALL(xenpmu_op),
     COMPAT_CALL(dm_op),
+    HYPERCALL(domain_id),
     HYPERCALL(mca),
     HYPERCALL(arch_1),
 };
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 84618715dc..5107aacd06 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -431,6 +431,12 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     return -ENOSYS;
 }
 
+DO(domain_id)(void)
+{
+    struct domain *d = current->domain;
+    return d->domain_id;
+}
+
 DO(nmi_op)(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
 {
     struct xennmi_callback cb;
diff --git a/xen/include/public/xen.h b/xen/include/public/xen.h
index 91ba8bb48e..3a8c4af281 100644
--- a/xen/include/public/xen.h
+++ b/xen/include/public/xen.h
@@ -121,6 +121,7 @@ DEFINE_XEN_GUEST_HANDLE(xen_ulong_t);
 #define __HYPERVISOR_xc_reserved_op       39 /* reserved for XenClient */
 #define __HYPERVISOR_xenpmu_op            40
 #define __HYPERVISOR_dm_op                41
+#define __HYPERVISOR_domain_id            42
 
 /* Architecture-specific hypercall definitions. */
 #define __HYPERVISOR_arch_0               48
diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
index cc99aea57d..5c7bc6233e 100644
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -83,6 +83,9 @@ do_xen_version(
     XEN_GUEST_HANDLE_PARAM(void) arg);
 
 extern long
+do_domain_id(void);
+
+extern long
 do_console_io(
     int cmd,
     int count,
-- 
2.11.0


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