i386/xen: handle PV timers in hypervisor

This tells the hypervisor that PV timers will be handled in hypervisor,
and as such we won't receive userspace exits for oneshot modes.

Also introduce 'xen-pvclock' to toggle kvmclock usage. This cpu
feature controls whether version hypercall exposes the
XENFEAT_hvm_safe_pvclock bit.

Signed-off-by: Joao Martins <joao.m.martins@oracle.com>

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index b1911d49f3d5f5636b9d645cba6369d2bcb0ab59..afe27d0ed352cafd8c202e89b9cca599df6e9015 100644 (file)
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -5810,6 +5810,7 @@ static Property x86_cpu_properties[] = {
     DEFINE_PROP_BOOL("legacy-cache", X86CPU, legacy_cache, true),
     DEFINE_PROP_BOOL("xen", X86CPU, xen, false),
     DEFINE_PROP_BOOL("xen-vapic", X86CPU, xen_vapic, false),
+    DEFINE_PROP_BOOL("xen-pvclock", X86CPU, xen_pvclock, true),
     DEFINE_PROP_UINT32("xen-major-version", X86CPU, xen_major_version, 3),
     DEFINE_PROP_UINT32("xen-minor-version", X86CPU, xen_minor_version, 2),
 

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 687b2b887962cdb7fcf587f43810ce2e6aaa361d..3e0644b239440292c8cc3d6b28d1033f27d84cc0 100644 (file)
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1488,6 +1488,7 @@ struct X86CPU {
 
     bool xen;
     bool xen_vapic;
+    bool xen_pvclock;
     uint32_t xen_major_version;
     uint32_t xen_minor_version;
 };

diff --git a/target/i386/xen.c b/target/i386/xen.c
index c20fa5629d3b9e056d85014c3057497a4f056ce0..2ee2bc3a0cff66bf78cae12853d10bd30dd79a20 100644 (file)
--- a/target/i386/xen.c
+++ b/target/i386/xen.c
@@ -180,6 +180,11 @@ static int kvm_xen_hcall_xen_version(struct kvm_xen_exit *exit, X86CPU *cpu,
              */
             fi->submap = (1U << XENFEAT_auto_translated_physmap) |
                          (1U << XENFEAT_hvm_callback_vector);
+
+            if (cpu->xen_pvclock) {
+                fi->submap |= (1U << XENFEAT_hvm_safe_pvclock);
+            }
+
             break;
          }
     }

diff --git a/target/i386/xen_evtchn.c b/target/i386/xen_evtchn.c
index e058a9aba2c0aeb32f7909d1e5474d1cf50659ed..fab8fb27fc7223adb198686f27afc21ac9c6d704 100644 (file)
--- a/target/i386/xen_evtchn.c
+++ b/target/i386/xen_evtchn.c
@@ -330,6 +330,11 @@ int kvm_xen_evtchn_bind_virq(X86CPU *cpu, void *arg)
 
     kvm_xen_run_on_cpu(dest, xen_vcpu_set_evtchn, evtchn);
 
+    /* We want to offload timers where possible */
+    if (evtchn->virq == VIRQ_TIMER) {
+        kvm_set_xen_event(dest->kvm_state, evtchn, NULL);
+    }
+
     out->port = evtchn->port;
 
     return 0;