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Commit 7f187922 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Paolo Bonzini
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KVM: x86: update masterclock values on TSC writes 



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: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b2c9d43e

arch/x86/kvm/x86.c

+10 −9
Original line number Diff line number Diff line
@@ -1235,21 +1235,22 @@ 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,