diff mbox series

[v2,24/27] hw/xen: Implement soft reset for emulated gnttab

Message ID 20230307171750.2293175-25-dwmw2@infradead.org (mailing list archive)
State New, archived
Headers show
Series Enable PV backends with Xen/KVM emulation | expand

Commit Message

David Woodhouse March 7, 2023, 5:17 p.m. UTC 
From: David Woodhouse <dwmw@amazon.co.uk>

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).

Some more work on the actual PV back ends and xen-bus code is going to be
needed to really make soft reset and migration fully functional, and this
part is the basis for that.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
---
 hw/i386/kvm/xen_gnttab.c  | 26 ++++++++++++++++++++++++--
 hw/i386/kvm/xen_gnttab.h  |  1 +
 target/i386/kvm/xen-emu.c |  5 +++++
 3 files changed, 30 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/hw/i386/kvm/xen_gnttab.c b/hw/i386/kvm/xen_gnttab.c
index 2bf91d36c0..21c30e3659 100644
--- a/hw/i386/kvm/xen_gnttab.c
+++ b/hw/i386/kvm/xen_gnttab.c
@@ -72,13 +72,11 @@  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);
@@ -90,8 +88,11 @@  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;
@@ -523,3 +524,24 @@  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 3bdbe96191..ee215239b0 100644
--- 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 bad3131d08..0bb6c601c9 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -1406,6 +1406,11 @@  int kvm_xen_soft_reset(void)
         return err;
     }
 
+    err = xen_gnttab_reset();
+    if (err) {
+        return err;
+    }
+
     err = xen_xenstore_reset();
     if (err) {
         return err;