[Xen-changelog] [xen stable-4.9] x86: don't enable XPTI on idle domain

[patchbot@xxxxxxx]

commit 1c6b8f23b9c5099cdf9a530e0d044b1ab5a83511
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed May 30 13:34:33 2018 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed May 30 13:34:33 2018 +0200

    x86: don't enable XPTI on idle domain
    
    While the involved code (in pv_domain_initialise()) sits behind an
    !is_idle_domain() check already in 4.10, we need to add one here.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/domain.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index c116b39f4f..fa0fe3153e 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -714,20 +714,15 @@ int arch_domain_create(struct domain *d, unsigned int 
domcr_flags,
         if ( (rc = hvm_domain_initialise(d)) != 0 )
             goto fail;
     }
-    else
+    else if ( !is_idle_domain(d) )
     {
         static const struct arch_csw pv_csw = {
             .from = paravirt_ctxt_switch_from,
             .to   = paravirt_ctxt_switch_to,
             .tail = continue_nonidle_domain,
         };
-        static const struct arch_csw idle_csw = {
-            .from = paravirt_ctxt_switch_from,
-            .to   = paravirt_ctxt_switch_to,
-            .tail = continue_idle_domain,
-        };
 
-        d->arch.ctxt_switch = is_idle_domain(d) ? &idle_csw : &pv_csw;
+        d->arch.ctxt_switch = &pv_csw;
 
         /* 64-bit PV guest by default. */
         d->arch.is_32bit_pv = d->arch.has_32bit_shinfo = 0;
@@ -758,6 +753,16 @@ int arch_domain_create(struct domain *d, unsigned int 
domcr_flags,
                 break;
             }
     }
+    else
+    {
+        static const struct arch_csw idle_csw = {
+            .from = paravirt_ctxt_switch_from,
+            .to   = paravirt_ctxt_switch_to,
+            .tail = continue_idle_domain,
+        };
+
+        d->arch.ctxt_switch = &idle_csw;
+    }
 
     /* initialize default tsc behavior in case tools don't */
     tsc_set_info(d, TSC_MODE_DEFAULT, 0UL, 0, 0);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.9

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