On 02/03/2023 15:34, David Woodhouse wrote:
From: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
hw/i386/kvm/xen_xenstore.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/hw/i386/kvm/xen_xenstore.c b/hw/i386/kvm/xen_xenstore.c
index 028f80499e..f9b7387024 100644
--- a/hw/i386/kvm/xen_xenstore.c
+++ b/hw/i386/kvm/xen_xenstore.c
@@ -21,6 +21,7 @@
#include "hw/sysbus.h"
#include "hw/xen/xen.h"
+#include "hw/xen/xen_backend_ops.h"
#include "xen_overlay.h"
#include "xen_evtchn.h"
#include "xen_xenstore.h"
@@ -34,6 +35,7 @@
#include "hw/xen/interface/io/xs_wire.h"
#include "hw/xen/interface/event_channel.h"
+#include "hw/xen/interface/grant_table.h"
#define TYPE_XEN_XENSTORE "xen-xenstore"
OBJECT_DECLARE_SIMPLE_TYPE(XenXenstoreState, XEN_XENSTORE)
@@ -66,6 +68,9 @@ struct XenXenstoreState {
uint8_t *impl_state;
uint32_t impl_state_size;
+
+ struct xengntdev_handle *gt;
+ void *granted_xs;
};
struct XenXenstoreState *xen_xenstore_singleton;
@@ -1452,6 +1457,17 @@ int xen_xenstore_reset(void)
}
s->be_port = err;
+ /*
+ * We don't actually access the guest's page through the grant, because
+ * this isn't real Xen, and we can just use the page we gave it in the
+ * first place. Map the grant anyway, mostly for cosmetic purposes so
+ * it *looks* like it's in use in the guest-visible grant table.
Might be useful to stick this text in the commit comment too.
Reviewed-by: Paul Durrant <p...@xen.org>
+ */
+ s->gt = qemu_xen_gnttab_open();
+ uint32_t xs_gntref = GNTTAB_RESERVED_XENSTORE;
+ s->granted_xs = qemu_xen_gnttab_map_refs(s->gt, 1, xen_domid, &xs_gntref,
+ PROT_READ | PROT_WRITE);
+
return 0;
}