From a323b409820c8afd33fbd841f5534eb84b406e8d Mon Sep 17 00:00:00 2001 From: =?utf8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Date: Thu, 30 Oct 2014 15:06:46 +0100 Subject: [PATCH] KVM: x86: detect LVTT changes under APICv MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit APIC-write VM exits are "trap-like": they save CS:RIP values for the instruction after the write, and more importantly, the handler will already see the new value in the virtual-APIC page. This means that apic_reg_write cannot use kvm_apic_get_reg to omit timer cancelation when mode changes. timer_mode_mask shouldn't be changing as it depends on cpuid. Signed-off-by: Radim Krčmář Signed-off-by: Paolo Bonzini --- arch/x86/kvm/lapic.c | 12 ++++++++---- arch/x86/kvm/lapic.h | 1 + 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 80df439d4086..fa3c6f7fdca4 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1242,17 +1242,20 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) break; - case APIC_LVTT: - if ((kvm_apic_get_reg(apic, APIC_LVTT) & - apic->lapic_timer.timer_mode_mask) != - (val & apic->lapic_timer.timer_mode_mask)) + case APIC_LVTT: { + u32 timer_mode = val & apic->lapic_timer.timer_mode_mask; + + if (apic->lapic_timer.timer_mode != timer_mode) { + apic->lapic_timer.timer_mode = timer_mode; hrtimer_cancel(&apic->lapic_timer.timer); + } if (!kvm_apic_sw_enabled(apic)) val |= APIC_LVT_MASKED; val &= (apic_lvt_mask[0] | apic->lapic_timer.timer_mode_mask); apic_set_reg(apic, APIC_LVTT, val); break; + } case APIC_TMICT: if (apic_lvtt_tscdeadline(apic)) @@ -1483,6 +1486,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu) for (i = 0; i < APIC_LVT_NUM; i++) apic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED); + apic->lapic_timer.timer_mode = 0; apic_set_reg(apic, APIC_LVT0, SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT)); diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 87e0fae1f4c6..35d83dcae8f9 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -11,6 +11,7 @@ struct kvm_timer { struct hrtimer timer; s64 period; /* unit: ns */ + u32 timer_mode; u32 timer_mode_mask; u64 tscdeadline; atomic_t pending; /* accumulated triggered timers */ -- 2.20.1