[Qemu-devel] [PULL 2/9] target-i386: do not special case TSC writeback

[Paolo Bonzini]

From: Fernando Luis Vázquez Cao <address@hidden>

Newer kernels are capable of synchronizing TSC values of multiple VCPUs
on writeback, but we were excluding the power up case, which is not needed
anymore.

Signed-off-by: Fernando Luis Vazquez Cao <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>

Signed-off-by: Fernando Luis Vázquez Cao <address@hidden>
---
 target-i386/kvm.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 01ebca2..312a46b 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -1151,15 +1151,7 @@ static int kvm_put_msrs(X86CPU *cpu, int level)
     }
 #endif
     if (level == KVM_PUT_FULL_STATE) {
-        /*
-         * KVM is yet unable to synchronize TSC values of multiple VCPUs on
-         * writeback. Until this is fixed, we only write the offset to SMP
-         * guests after migration, desynchronizing the VCPUs, but avoiding
-         * huge jump-backs that would occur without any writeback at all.
-         */
-        if (smp_cpus == 1 || env->tsc != 0) {
-            kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
-        }
+        kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
     }
     /*
      * The following MSRs have side effects on the guest or are too heavy
-- 
1.8.3.1