linux-kernel - [PATCH 3/3] KVM: x86: thoroughly disarm LAPIC timer around TSC deadline switch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri,  6 Oct 2017 19:25:55 +0200
From:   Radim Krčmář <rkrcmar@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Wanpeng Li <kernellwp@...il.com>
Subject: [PATCH 3/3] KVM: x86: thoroughly disarm LAPIC timer around TSC deadline switch

Our routines look at tscdeadline and period when deciding state of a
timer.  The timer is disarmed when switching between TSC deadline and
other modes, so we should set everything to disarmed state.

Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
---
 arch/x86/kvm/lapic.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 96ade848ae0b..a778f1ae2927 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1330,8 +1330,10 @@ static void apic_update_lvtt(struct kvm_lapic *apic)
 	if (apic->lapic_timer.timer_mode != timer_mode) {
 		if (apic_lvtt_tscdeadline(apic) != (timer_mode ==
 				APIC_LVT_TIMER_TSCDEADLINE)) {
-			kvm_lapic_set_reg(apic, APIC_TMICT, 0);
 			hrtimer_cancel(&apic->lapic_timer.timer);
+			kvm_lapic_set_reg(apic, APIC_TMICT, 0);
+			apic->lapic_timer.period = 0;
+			apic->lapic_timer.tscdeadline = 0;
 		}
 		apic->lapic_timer.timer_mode = timer_mode;
 		limit_periodic_timer_frequency(apic);
-- 
2.14.2