[v2,18/23] hyperv: add synic event flag signaling

Commit Message

Roman Kagan June 21, 2017, 4:24 p.m. UTC

Add infrastructure to signal SynIC event flags by atomically setting the
corresponding bit in the event flags page and firing a SINT if
necessary.

Signed-off-by: Roman Kagan <[e-mail]>
---
v1 -> v2:
 - swapped kvm_hv_sint_route_set_sint and memory_region_set_dirty

 target/i386/hyperv.h |  2 ++
 target/i386/hyperv.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

Patch

diff --git a/target/i386/hyperv.h b/target/i386/hyperv.h
index cc08ebb..f171f7b 100644
--- a/target/i386/hyperv.h
+++ b/target/i386/hyperv.h
@@ -41,4 +41,6 @@  bool hyperv_synic_usable(void);
 
 int hyperv_post_msg(HvSintRoute *sint_route, struct hyperv_message *msg);
 
+int hyperv_set_evt_flag(HvSintRoute *sint_route, unsigned evtno);
+
 #endif
diff --git a/target/i386/hyperv.c b/target/i386/hyperv.c
index 768dc2b..a96b03b 100644
--- a/target/i386/hyperv.c
+++ b/target/i386/hyperv.c
@@ -17,6 +17,7 @@ 
 #include "hw/qdev-properties.h"
 #include "exec/address-spaces.h"
 #include "sysemu/cpus.h"
+#include "qemu/bitops.h"
 #include "migration/vmstate.h"
 #include "hyperv.h"
 #include "hyperv_proto.h"
@@ -203,6 +204,37 @@  int hyperv_post_msg(HvSintRoute *sint_route, struct hyperv_message *src_msg)
     return 0;
 }
 
+/*
+ * Set given event flag for a given sint on a given vcpu, and signal the sint.
+ */
+int hyperv_set_evt_flag(HvSintRoute *sint_route, unsigned evtno)
+{
+    int ret;
+    SynICState *synic = sint_route->synic;
+    unsigned long *flags, set_mask;
+    unsigned set_idx;
+
+    if (evtno > HV_EVENT_FLAGS_COUNT) {
+        return -EINVAL;
+    }
+    if (!synic->enabled || !synic->evt_page_addr) {
+        return -ENXIO;
+    }
+
+    set_idx = BIT_WORD(evtno);
+    set_mask = BIT_MASK(evtno);
+    flags = synic->evt_page->slot[sint_route->sint].flags;
+
+    if ((atomic_fetch_or(&flags[set_idx], set_mask) & set_mask) != set_mask) {
+        memory_region_set_dirty(&synic->evt_page_mr, 0,
+                                sizeof(*synic->evt_page));
+        ret = kvm_hv_sint_route_set_sint(sint_route);
+    } else {
+        ret = 0;
+    }
+    return ret;
+}
+
 static void async_synic_update(CPUState *cs, run_on_cpu_data data)
 {
     SynICState *synic = data.host_ptr;