From 483ad4439f7fc71e12d46dae516f2b9ab2b977ad Mon Sep 17 00:00:00 2001
From: Tamas K Lengyel <tlengyel@novetta.com>
Date: Fri, 5 Feb 2016 14:22:20 -0700
Subject: [PATCH] xen-access: minor fixes

Only copy the VCPU_PAUSED flag to the response. Copy the entire mem_access
struct which is useful and easily forgotten when also testing the emulate
response flags. Turn off singlestepping on the vCPUs once we are done
processing all events, as we might have turned on singlestep there and leave
the VM in an undesirable state.

Signed-off-by: Tamas K Lengyel <tlengyel@novetta.com>
Cc: Razvan Cojocaru <rcojocaru@bitdefender.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: Razvan Cojocaru <rcojocaru@bitdefender.com>
---
 tools/tests/xen-access/xen-access.c | 46 ++++++++++++++++-------------
 1 file changed, 25 insertions(+), 21 deletions(-)

diff --git a/tools/tests/xen-access/xen-access.c b/tools/tests/xen-access/xen-access.c
index 7993947419..ef892460f2 100644
--- a/tools/tests/xen-access/xen-access.c
+++ b/tools/tests/xen-access/xen-access.c
@@ -537,16 +537,10 @@ int main(int argc, char *argv[])
 
             if ( altp2m )
             {
-                uint32_t vcpu_id;
-
                 rc = xc_altp2m_switch_to_view( xch, domain_id, 0 );
                 rc = xc_altp2m_destroy_view(xch, domain_id, altp2m_view_id);
                 rc = xc_altp2m_set_domain_state(xch, domain_id, 0);
                 rc = xc_monitor_singlestep(xch, domain_id, 0);
-
-                for ( vcpu_id = 0; vcpu_id<XEN_LEGACY_MAX_VCPUS; vcpu_id++)
-                    rc = control_singlestep(xch, domain_id, vcpu_id, 0);
-
             } else {
                 rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx, ~0ull, 0);
                 rc = xc_set_mem_access(xch, domain_id, XENMEM_access_rwx, START_PFN,
@@ -570,8 +564,6 @@ int main(int argc, char *argv[])
 
         while ( RING_HAS_UNCONSUMED_REQUESTS(&xenaccess->vm_event.back_ring) )
         {
-            xenmem_access_t access;
-
             get_request(&xenaccess->vm_event, &req);
 
             if ( req.version != VM_EVENT_INTERFACE_VERSION )
@@ -584,16 +576,25 @@ int main(int argc, char *argv[])
             memset( &rsp, 0, sizeof (rsp) );
             rsp.version = VM_EVENT_INTERFACE_VERSION;
             rsp.vcpu_id = req.vcpu_id;
-            rsp.flags = req.flags;
+            rsp.flags = (req.flags & VM_EVENT_FLAG_VCPU_PAUSED);
+            rsp.reason = req.reason;
 
             switch (req.reason) {
             case VM_EVENT_REASON_MEM_ACCESS:
-                rc = xc_get_mem_access(xch, domain_id, req.u.mem_access.gfn, &access);
-                if (rc < 0)
+                if ( !shutting_down )
                 {
-                    ERROR("Error %d getting mem_access event\n", rc);
-                    interrupted = -1;
-                    continue;
+                    /*
+                     * This serves no other purpose here then demonstrating the use of the API.
+                     * At shutdown we have already reset all the permissions so really no use getting it again.
+                     */
+                    xenmem_access_t access;
+                    rc = xc_get_mem_access(xch, domain_id, req.u.mem_access.gfn, &access);
+                    if (rc < 0)
+                    {
+                        ERROR("Error %d getting mem_access event\n", rc);
+                        interrupted = -1;
+                        continue;
+                    }
                 }
 
                 printf("PAGE ACCESS: %c%c%c for GFN %"PRIx64" (offset %06"
@@ -614,11 +615,8 @@ int main(int argc, char *argv[])
                 {
                     DPRINTF("\tSwitching back to default view!\n");
 
-                    rsp.reason = req.reason;
-                    rsp.flags = req.flags;
+                    rsp.flags |= VM_EVENT_FLAG_TOGGLE_SINGLESTEP;
                     rsp.altp2m_idx = 0;
-
-                    control_singlestep(xch, domain_id, rsp.vcpu_id, 1);
                 }
                 else if ( default_access != after_first_access )
                 {
@@ -633,7 +631,7 @@ int main(int argc, char *argv[])
                     }
                 }
 
-                rsp.u.mem_access.gfn = req.u.mem_access.gfn;
+                rsp.u.mem_access = req.u.mem_access;
                 break;
             case VM_EVENT_REASON_SOFTWARE_BREAKPOINT:
                 printf("Breakpoint: rip=%016"PRIx64", gfn=%"PRIx64" (vcpu %d)\n",
@@ -662,12 +660,11 @@ int main(int argc, char *argv[])
                 {
                     printf("\tSwitching altp2m to view %u!\n", altp2m_view_id);
 
-                    rsp.reason = req.reason;
                     rsp.flags |= VM_EVENT_FLAG_ALTERNATE_P2M;
                     rsp.altp2m_idx = altp2m_view_id;
                 }
 
-                control_singlestep(xch, domain_id, req.vcpu_id, 0);
+                rsp.flags |= VM_EVENT_FLAG_TOGGLE_SINGLESTEP;
 
                 break;
             default:
@@ -694,6 +691,13 @@ int main(int argc, char *argv[])
     DPRINTF("xenaccess shut down on signal %d\n", interrupted);
 
 exit:
+    if ( altp2m )
+    {
+        uint32_t vcpu_id;
+        for ( vcpu_id = 0; vcpu_id<XEN_LEGACY_MAX_VCPUS; vcpu_id++)
+            rc = control_singlestep(xch, domain_id, vcpu_id, 0);
+    }
+
     /* Tear down domain xenaccess */
     rc1 = xenaccess_teardown(xch, xenaccess);
     if ( rc1 != 0 )
-- 
2.39.5