hypervisor/xen/tools: Remove the XENMEM_get_oustanding_pages and provide the data via xc_phys_info

During the review of the patches it was noticed that there exists
a race wherein the 'free_memory' value consists of information from
two hypercalls. That is the XEN_SYSCTL_physinfo and XENMEM_get_outstanding_pages.

The free memory the host has available for guest is the difference between
the 'free_pages' (from XEN_SYSCTL_physinfo) and 'outstanding_pages'. As they
are two hypercalls many things can happen in between the execution of them.

This patch resolves this by eliminating the XENMEM_get_outstanding_pages
hypercall and providing the free_pages and outstanding_pages information
via the xc_phys_info structure.

It also removes the XSM hooks and adds locking as needed.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Tim Deegan <tim@xen.org>
Acked-by: Keir Fraser <keir.xen@gmail.com>

2 files changed, 0 insertions, 12 deletions

diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index a87205661d..cc0a5a8301 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -259,12 +259,6 @@ static XSM_INLINE int xsm_claim_pages(XSM_DEFAULT_ARG struct domain *d)
     return xsm_default_action(action, current->domain, d);
 }
 
-static XSM_INLINE int xsm_xenmem_get_outstanding_pages(XSM_DEFAULT_VOID)
-{
-    XSM_ASSERT_ACTION(XSM_PRIV);
-    return xsm_default_action(action, current->domain, NULL);
-}
-
 static XSM_INLINE int xsm_evtchn_unbound(XSM_DEFAULT_ARG struct domain *d, struct evtchn *chn,
                                          domid_t id2)
 {
diff --git a/xen/include/xsm/xsm.h b/xen/include/xsm/xsm.h
index 58a4fbb1d1..193945323e 100644
--- a/xen/include/xsm/xsm.h
+++ b/xen/include/xsm/xsm.h
@@ -93,7 +93,6 @@ struct xsm_operations {
     int (*add_to_physmap) (struct domain *d1, struct domain *d2);
     int (*remove_from_physmap) (struct domain *d1, struct domain *d2);
     int (*claim_pages) (struct domain *d);
-    int (*xenmem_get_outstanding_pages) (void);
 
     int (*console_io) (struct domain *d, int cmd);
 
@@ -360,11 +359,6 @@ static inline int xsm_claim_pages(xsm_default_t def, struct domain *d)
     return xsm_ops->claim_pages(d);
 }
 
-static inline int xsm_xenmem_get_outstanding_pages(xsm_default_t def)
-{
-    return xsm_ops->xenmem_get_outstanding_pages();
-}
-
 static inline int xsm_console_io (xsm_default_t def, struct domain *d, int cmd)
 {
     return xsm_ops->console_io(d, cmd);