aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorMarcelo Tosatti <mtosatti@redhat.com>2014-11-04 21:30:44 -0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-06 14:43:31 -0800
commitcd1fcaf59fcf82bb9a59695b06179f597d2a98b1 (patch)
treeb5bd3da05e7236c88b11749a1af044a4c1e93ecd
parent623347ab1c9885c235f90a5b9b75f8d4494b76c1 (diff)
downloadlinux-yocto-cd1fcaf59fcf82bb9a59695b06179f597d2a98b1.tar.gz
linux-yocto-cd1fcaf59fcf82bb9a59695b06179f597d2a98b1.tar.bz2
linux-yocto-cd1fcaf59fcf82bb9a59695b06179f597d2a98b1.zip
KVM: x86: update masterclock values on TSC writes
commit 7f187922ddf6b67f2999a76dcb71663097b75497 upstream. When the guest writes to the TSC, the masterclock TSC copy must be updated as well along with the TSC_OFFSET update, otherwise a negative tsc_timestamp is calculated at kvm_guest_time_update. Once "if (!vcpus_matched && ka->use_master_clock)" is simplified to "if (ka->use_master_clock)", the corresponding "if (!ka->use_master_clock)" becomes redundant, so remove the do_request boolean and collapse everything into a single condition. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kvm/x86.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fab97ade0fc8..1777f89875fb 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1207,21 +1207,22 @@ void kvm_track_tsc_matching(struct kvm_vcpu *vcpu)
{
#ifdef CONFIG_X86_64
bool vcpus_matched;
- bool do_request = false;
struct kvm_arch *ka = &vcpu->kvm->arch;
struct pvclock_gtod_data *gtod = &pvclock_gtod_data;
vcpus_matched = (ka->nr_vcpus_matched_tsc + 1 ==
atomic_read(&vcpu->kvm->online_vcpus));
- if (vcpus_matched && gtod->clock.vclock_mode == VCLOCK_TSC)
- if (!ka->use_master_clock)
- do_request = 1;
-
- if (!vcpus_matched && ka->use_master_clock)
- do_request = 1;
-
- if (do_request)
+ /*
+ * Once the masterclock is enabled, always perform request in
+ * order to update it.
+ *
+ * In order to enable masterclock, the host clocksource must be TSC
+ * and the vcpus need to have matched TSCs. When that happens,
+ * perform request to enable masterclock.
+ */
+ if (ka->use_master_clock ||
+ (gtod->clock.vclock_mode == VCLOCK_TSC && vcpus_matched))
kvm_make_request(KVM_REQ_MASTERCLOCK_UPDATE, vcpu);
trace_kvm_track_tsc(vcpu->vcpu_id, ka->nr_vcpus_matched_tsc,