hw/xen: Implement soft reset for emulated gnttab

This is only part of it; we will also need to get the PV back end drivers
to tear down their own mappings (or do it for them, but they kind of need
to stop using the pointers too).

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/hw/i386/kvm/xen_gnttab.c b/hw/i386/kvm/xen_gnttab.c
index c581ea400c0c62246f08bf79b0abd869dbcf42fb..a441ff29912949a944958618379618af597a57ce 100644 (file)
--- a/hw/i386/kvm/xen_gnttab.c
+++ b/hw/i386/kvm/xen_gnttab.c
@@ -73,13 +73,11 @@ static void xen_gnttab_realize(DeviceState *dev, Error **errp)
         error_setg(errp, "Xen grant table support is for Xen emulation");
         return;
     }
-    s->nr_frames = 0;
     s->max_frames = kvm_xen_get_gnttab_max_frames();
     memory_region_init_ram(&s->gnt_frames, OBJECT(dev), "xen:grant_table",
                            XEN_PAGE_SIZE * s->max_frames, &error_abort);
     memory_region_set_enabled(&s->gnt_frames, true);
     s->entries.v1 = memory_region_get_ram_ptr(&s->gnt_frames);
-    memset(s->entries.v1, 0, XEN_PAGE_SIZE * s->max_frames);
 
     /* Create individual page-sizes aliases for overlays */
     s->gnt_aliases = (void *)g_new0(MemoryRegion, s->max_frames);
@@ -91,8 +89,11 @@ static void xen_gnttab_realize(DeviceState *dev, Error **errp)
         s->gnt_frame_gpas[i] = INVALID_GPA;
     }
 
+    s->nr_frames = 0;
+    memset(s->entries.v1, 0, XEN_PAGE_SIZE * s->max_frames);
     s->entries.v1[GNTTAB_RESERVED_XENSTORE].flags = GTF_permit_access;
     s->entries.v1[GNTTAB_RESERVED_XENSTORE].frame = XEN_SPECIAL_PFN(XENSTORE);
+
     qemu_mutex_init(&s->gnt_lock);
 
     xen_gnttab_singleton = s;
@@ -519,3 +520,24 @@ static struct gnttab_backend_ops emu_gnttab_backend_ops = {
     .unmap = xen_be_gnttab_unmap,
 };
 
+int xen_gnttab_reset(void)
+{
+    XenGnttabState *s = xen_gnttab_singleton;
+
+    if (!s) {
+        return -ENOTSUP;
+    }
+
+    QEMU_LOCK_GUARD(&s->gnt_lock);
+
+    s->nr_frames = 0;
+
+    memset(s->entries.v1, 0, XEN_PAGE_SIZE * s->max_frames);
+
+    s->entries.v1[GNTTAB_RESERVED_XENSTORE].flags = GTF_permit_access;
+    s->entries.v1[GNTTAB_RESERVED_XENSTORE].frame = XEN_SPECIAL_PFN(XENSTORE);
+
+    memset(s->map_track, 0, s->max_frames * ENTRIES_PER_FRAME_V1);
+
+    return 0;
+}

diff --git a/hw/i386/kvm/xen_gnttab.h b/hw/i386/kvm/xen_gnttab.h
index 3bdbe961914762c0d3109efde6b05c90cba4bf9f..ee215239b00810d74e0d955e1c3b369bc338a38a 100644 (file)
--- a/hw/i386/kvm/xen_gnttab.h
+++ b/hw/i386/kvm/xen_gnttab.h
@@ -13,6 +13,7 @@
 #define QEMU_XEN_GNTTAB_H
 
 void xen_gnttab_create(void);
+int xen_gnttab_reset(void);
 int xen_gnttab_map_page(uint64_t idx, uint64_t gfn);
 
 struct gnttab_set_version;

diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index 34706ca033ab863f16976484931932f1b4025050..10579df503cbe8bbae153d6712ea7c5954ebd740 100644 (file)
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -1384,6 +1384,11 @@ int kvm_xen_soft_reset(void)
         return err;
     }
 
+    err = xen_gnttab_reset();
+    if (err) {
+        return err;
+    }
+
     err = xen_xenstore_reset();
     if (err) {
         return err;