domain: expose newly introduced hypercalls as XENFEAT

XENFEAT_runstate_phys_area is exposed to all architectures, while
XENFEAT_vcpu_time_phys_area is currently only implemented for x86, and hence
the feature flag is also only exposed on x86.

Additionally add dummy guards with TODOs in the respective hypercall
implementations, to signal the intention to control the availability of those
hypercalls on a guest-by-guest basis from the toolstack.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Henry Wang <Henry.Wang@arm.com>

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e33cf4e1b113de491b21fe15aeca0317297d504a..47ea9e275462a0f6d872cb6cce862585933cc627 100644 (file)
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
  - Add Intel Hardware P-States (HWP) cpufreq driver.
  - On Arm, experimental support for dynamic addition/removal of Xen device tree
    nodes using a device tree overlay binary (.dtbo).
+ - Introduce two new hypercalls to map the vCPU runstate and time areas by
+   physical rather than linear/virtual addresses.
 
 ### Removed
  - On x86, the "pku" command line option has been removed.  It has never

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 8e0af22781040e3ad7f587cb9e116a9b1e03f105..8d3d52034a6d2f1e403b93b4fc7fec48a7aa634e 100644 (file)
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1580,6 +1580,10 @@ long do_vcpu_op(int cmd, unsigned int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
     {
         struct vcpu_register_time_memory_area area;
 
+        rc = -ENOSYS;
+        if ( 0 /* TODO: Dom's XENFEAT_vcpu_time_phys_area setting */ )
+            break;
+
         rc = -EFAULT;
         if ( copy_from_guest(&area.addr.p, arg, 1) )
             break;

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 1468638ade8b87ce029ee6e5ef7bf9784fd3e395..8f9ab01c0cb79059efaf65e83eb7ca2338208c4b 100644 (file)
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -1998,6 +1998,10 @@ long common_vcpu_op(int cmd, struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg)
     {
         struct vcpu_register_runstate_memory_area area;
 
+        rc = -ENOSYS;
+        if ( 0 /* TODO: Dom's XENFEAT_runstate_phys_area setting */ )
+            break;
+
         rc = -EFAULT;
         if ( copy_from_guest(&area.addr.p, arg, 1) )
             break;

diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 52aa28762782bbdf6e541cfef52478dc44e93adb..b6302e44b34eda75e12320621e0ccc30da13e8cf 100644 (file)
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -607,7 +607,11 @@ long do_xen_version(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
         switch ( fi.submap_idx )
         {
         case 0:
-            fi.submap = (1U << XENFEAT_memory_op_vnode_supported);
+            fi.submap = (1U << XENFEAT_memory_op_vnode_supported) |
+#ifdef CONFIG_X86
+                        (1U << XENFEAT_vcpu_time_phys_area) |
+#endif
+                        (1U << XENFEAT_runstate_phys_area);
             if ( VM_ASSIST(d, pae_extended_cr3) )
                 fi.submap |= (1U << XENFEAT_pae_pgdir_above_4gb);
             if ( paging_mode_translate(d) )

diff --git a/xen/include/public/features.h b/xen/include/public/features.h
index d2a9175aae67b9242ad9082f86bf9c7747a5fda2..36936f6a4ee0b1f686e16147391c6f123e79e73e 100644 (file)
--- a/xen/include/public/features.h
+++ b/xen/include/public/features.h
@@ -111,6 +111,15 @@
 #define XENFEAT_not_direct_mapped         16
 #define XENFEAT_direct_mapped             17
 
+/*
+ * Signal whether the domain is able to use the following hypercalls:
+ *
+ * VCPUOP_register_runstate_phys_area
+ * VCPUOP_register_vcpu_time_phys_area
+ */
+#define XENFEAT_runstate_phys_area       18
+#define XENFEAT_vcpu_time_phys_area      19
+
 #define XENFEAT_NR_SUBMAPS 1
 
 #endif /* __XEN_PUBLIC_FEATURES_H__ */

diff --git a/xen/include/public/vcpu.h b/xen/include/public/vcpu.h
index 8fb0bd1b6c03c17d46ee2d03da9981fe7ef5855d..f7445ac0b08a4a0820f31e832e03136c62798820 100644 (file)
--- a/xen/include/public/vcpu.h
+++ b/xen/include/public/vcpu.h
@@ -236,6 +236,9 @@ DEFINE_XEN_GUEST_HANDLE(vcpu_register_time_memory_area_t);
  * Note that the area registered via VCPUOP_register_runstate_memory_area will
  * be updated in the same manner as the one registered via virtual address PLUS
  * VMASST_TYPE_runstate_update_flag engaged by the domain.
+ *
+ * XENFEAT_{runstate,vcpu_time}_phys_area feature bits signal the availability
+ * of these ops.
  */
 #define VCPUOP_register_runstate_phys_area      14
 #define VCPUOP_register_vcpu_time_phys_area     15