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[Qemu-devel] [PATCH] KVM: emulate lapic tsc deadline timer for hvm


From: Liu, Jinsong
Subject: [Qemu-devel] [PATCH] KVM: emulate lapic tsc deadline timer for hvm
Date: Wed, 17 Aug 2011 12:19:34 +0800

>From a9670ddff84080c56183e2d678189e100f891174 Mon Sep 17 00:00:00 2001
From: Liu, Jinsong <address@hidden>
Date: Wed, 17 Aug 2011 11:36:28 +0800
Subject: [PATCH] KVM: emulate lapic tsc deadline timer for hvm

This patch emulate lapic tsc deadline timer for hvm:
Enumerate tsc deadline timer capacibility by CPUID;
Enable tsc deadline timer mode by LAPIC MMIO;
Start tsc deadline timer by MSR;

Signed-off-by: Liu, Jinsong <address@hidden>
---
 arch/x86/include/asm/apicdef.h    |    2 +
 arch/x86/include/asm/cpufeature.h |    1 +
 arch/x86/include/asm/kvm_host.h   |    1 +
 arch/x86/include/asm/msr-index.h  |    2 +
 arch/x86/kvm/kvm_timer.h          |    2 +
 arch/x86/kvm/lapic.c              |  119 ++++++++++++++++++++++++++++++-------
 arch/x86/kvm/lapic.h              |    3 +
 arch/x86/kvm/vmx.c                |   19 ++++++
 arch/x86/kvm/x86.c                |    6 ++
 9 files changed, 134 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/apicdef.h b/arch/x86/include/asm/apicdef.h
index 34595d5..3925d80 100644
--- a/arch/x86/include/asm/apicdef.h
+++ b/arch/x86/include/asm/apicdef.h
@@ -100,7 +100,9 @@
 #define                APIC_TIMER_BASE_CLKIN           0x0
 #define                APIC_TIMER_BASE_TMBASE          0x1
 #define                APIC_TIMER_BASE_DIV             0x2
+#define                APIC_LVT_TIMER_ONESHOT          (0 << 17)
 #define                APIC_LVT_TIMER_PERIODIC         (1 << 17)
+#define                APIC_LVT_TIMER_TSCDEADLINE      (2 << 17)
 #define                APIC_LVT_MASKED                 (1 << 16)
 #define                APIC_LVT_LEVEL_TRIGGER          (1 << 15)
 #define                APIC_LVT_REMOTE_IRR             (1 << 14)
diff --git a/arch/x86/include/asm/cpufeature.h 
b/arch/x86/include/asm/cpufeature.h
index 4258aac..28bcf48 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -120,6 +120,7 @@
 #define X86_FEATURE_X2APIC     (4*32+21) /* x2APIC */
 #define X86_FEATURE_MOVBE      (4*32+22) /* MOVBE instruction */
 #define X86_FEATURE_POPCNT      (4*32+23) /* POPCNT instruction */
+#define X86_FEATURE_TSC_DEADLINE_TIMER    (4*32+24) /* Tsc deadline timer */
 #define X86_FEATURE_AES                (4*32+25) /* AES instructions */
 #define X86_FEATURE_XSAVE      (4*32+26) /* XSAVE/XRSTOR/XSETBV/XGETBV */
 #define X86_FEATURE_OSXSAVE    (4*32+27) /* "" XSAVE enabled in the OS */
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 307e3cf..28f7128 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -635,6 +635,7 @@ struct kvm_x86_ops {
        int (*check_intercept)(struct kvm_vcpu *vcpu,
                               struct x86_instruction_info *info,
                               enum x86_intercept_stage stage);
+       u64 (*guest_to_host_tsc)(u64 guest_tsc);
 };
 
 struct kvm_arch_async_pf {
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index d52609a..a6962d9 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -229,6 +229,8 @@
 #define MSR_IA32_APICBASE_ENABLE       (1<<11)
 #define MSR_IA32_APICBASE_BASE         (0xfffff<<12)
 
+#define MSR_IA32_TSCDEADLINE           0x000006e0
+
 #define MSR_IA32_UCODE_WRITE           0x00000079
 #define MSR_IA32_UCODE_REV             0x0000008b
 
diff --git a/arch/x86/kvm/kvm_timer.h b/arch/x86/kvm/kvm_timer.h
index 64bc6ea..497dbaa 100644
--- a/arch/x86/kvm/kvm_timer.h
+++ b/arch/x86/kvm/kvm_timer.h
@@ -2,6 +2,8 @@
 struct kvm_timer {
        struct hrtimer timer;
        s64 period;                             /* unit: ns */
+       u32 timer_mode_mask;
+       u64 tscdeadline;
        atomic_t pending;                       /* accumulated triggered timers 
*/
        bool reinject;
        struct kvm_timer_ops *t_ops;
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2b2255b..780a5b0 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -135,9 +135,23 @@ static inline int apic_lvt_vector(struct kvm_lapic *apic, 
int lvt_type)
        return apic_get_reg(apic, lvt_type) & APIC_VECTOR_MASK;
 }
 
+static inline int apic_lvtt_oneshot(struct kvm_lapic *apic)
+{
+       return ((apic_get_reg(apic, APIC_LVTT) & 
+               apic->lapic_timer.timer_mode_mask) == APIC_LVT_TIMER_ONESHOT);
+}
+
 static inline int apic_lvtt_period(struct kvm_lapic *apic)
 {
-       return apic_get_reg(apic, APIC_LVTT) & APIC_LVT_TIMER_PERIODIC;
+       return ((apic_get_reg(apic, APIC_LVTT) & 
+               apic->lapic_timer.timer_mode_mask) == APIC_LVT_TIMER_PERIODIC);
+}
+
+static inline int apic_lvtt_tscdeadline(struct kvm_lapic *apic)
+{
+       return ((apic_get_reg(apic, APIC_LVTT) & 
+               apic->lapic_timer.timer_mode_mask) == 
+                       APIC_LVT_TIMER_TSCDEADLINE);
 }
 
 static inline int apic_lvt_nmi_mode(u32 lvt_val)
@@ -166,7 +180,7 @@ static inline int apic_x2apic_mode(struct kvm_lapic *apic)
 }
 
 static unsigned int apic_lvt_mask[APIC_LVT_NUM] = {
-       LVT_MASK | APIC_LVT_TIMER_PERIODIC,     /* LVTT */
+       LVT_MASK ,      /* part LVTT mask, timer mode mask added at runtime */
        LVT_MASK | APIC_MODE_MASK,      /* LVTTHMR */
        LVT_MASK | APIC_MODE_MASK,      /* LVTPC */
        LINT_MASK, LINT_MASK,   /* LVT0-1 */
@@ -570,6 +584,9 @@ static u32 __apic_read(struct kvm_lapic *apic, unsigned int 
offset)
                break;
 
        case APIC_TMCCT:        /* Timer CCR */
+               if (apic_lvtt_tscdeadline(apic))
+                       return 0;
+
                val = apic_get_tmcct(apic);
                break;
 
@@ -665,28 +682,30 @@ static void update_divide_count(struct kvm_lapic *apic)
 static void start_apic_timer(struct kvm_lapic *apic)
 {
        ktime_t now = apic->lapic_timer.timer.base->get_time();
-
-       apic->lapic_timer.period = (u64)apic_get_reg(apic, APIC_TMICT) *
-                   APIC_BUS_CYCLE_NS * apic->divide_count;
        atomic_set(&apic->lapic_timer.pending, 0);
 
-       if (!apic->lapic_timer.period)
-               return;
-       /*
-        * Do not allow the guest to program periodic timers with small
-        * interval, since the hrtimers are not throttled by the host
-        * scheduler.
-        */
-       if (apic_lvtt_period(apic)) {
-               if (apic->lapic_timer.period < NSEC_PER_MSEC/2)
-                       apic->lapic_timer.period = NSEC_PER_MSEC/2;
-       }
+       /* lapic timer in oneshot or peroidic mode */
+       if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
+               apic->lapic_timer.period = (u64)apic_get_reg(apic, APIC_TMICT)
+                           * APIC_BUS_CYCLE_NS * apic->divide_count;
 
-       hrtimer_start(&apic->lapic_timer.timer,
-                     ktime_add_ns(now, apic->lapic_timer.period),
-                     HRTIMER_MODE_ABS);
+               if (!apic->lapic_timer.period)
+                       return;
+               /*
+                * Do not allow the guest to program periodic timers with small
+                * interval, since the hrtimers are not throttled by the host
+                * scheduler.
+                */
+               if (apic_lvtt_period(apic)) {
+                       if (apic->lapic_timer.period < NSEC_PER_MSEC/2)
+                               apic->lapic_timer.period = NSEC_PER_MSEC/2;
+               }
 
-       apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
+               hrtimer_start(&apic->lapic_timer.timer,
+                             ktime_add_ns(now, apic->lapic_timer.period),
+                             HRTIMER_MODE_ABS);
+
+               apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
                           PRIx64 ", "
                           "timer initial count 0x%x, period %lldns, "
                           "expire @ 0x%016" PRIx64 ".\n", __func__,
@@ -695,6 +714,26 @@ static void start_apic_timer(struct kvm_lapic *apic)
                           apic->lapic_timer.period,
                           ktime_to_ns(ktime_add_ns(now,
                                        apic->lapic_timer.period)));
+       }
+
+       /* lapic timer in tsc deadline mode */
+       if (apic_lvtt_tscdeadline(apic)) {
+               u64 tsc_now, tsc_target, tsc_delta, nsec;
+
+               if (!apic->lapic_timer.tscdeadline)
+                       return;
+
+               tsc_target = kvm_x86_ops->
+                       guest_to_host_tsc(apic->lapic_timer.tscdeadline);
+               rdtscll(tsc_now);
+               tsc_delta = tsc_target - tsc_now;
+               if (tsc_delta < 0)
+                       tsc_delta = 0;
+
+               nsec = tsc_delta * 1000000L / tsc_khz;
+               hrtimer_start(&apic->lapic_timer.timer, 
+                       ktime_add_ns(now, nsec), HRTIMER_MODE_ABS);
+       }
 }
 
 static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
@@ -782,7 +821,6 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, 
u32 val)
 
        case APIC_LVT0:
                apic_manage_nmi_watchdog(apic, val);
-       case APIC_LVTT:
        case APIC_LVTTHMR:
        case APIC_LVTPC:
        case APIC_LVT1:
@@ -796,7 +834,22 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, 
u32 val)
 
                break;
 
+       case APIC_LVTT:
+               if ((apic_get_reg(apic, APIC_LVTT) & 
+                    apic->lapic_timer.timer_mode_mask) !=
+                   (val & apic->lapic_timer.timer_mode_mask))
+                       hrtimer_cancel(&apic->lapic_timer.timer);
+
+               if (!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))
+                       break;
+
                hrtimer_cancel(&apic->lapic_timer.timer);
                apic_set_reg(apic, APIC_TMICT, val);
                start_apic_timer(apic);
@@ -883,6 +936,28 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu)
  *----------------------------------------------------------------------
  */
 
+u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
+{
+       struct kvm_lapic *apic = vcpu->arch.apic;
+
+       if (apic_lvtt_oneshot(apic) || apic_lvtt_period(apic))
+               return 0;
+
+       return apic->lapic_timer.tscdeadline;
+}
+
+void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data)
+{
+       struct kvm_lapic *apic = vcpu->arch.apic;
+
+       if (apic_lvtt_oneshot(apic) || apic_lvtt_period(apic))
+               return;
+
+       hrtimer_cancel(&apic->lapic_timer.timer);
+       apic->lapic_timer.tscdeadline = data;
+       start_apic_timer(apic);
+}
+
 void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8)
 {
        struct kvm_lapic *apic = vcpu->arch.apic;
@@ -1076,6 +1151,8 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
        apic->lapic_timer.kvm = vcpu->kvm;
        apic->lapic_timer.vcpu = vcpu;
 
+       apic->lapic_timer.timer_mode_mask = (1 << 17);
+
        apic->base_address = APIC_DEFAULT_PHYS_BASE;
        vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE;
 
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 52c9e6b..10c6ee6 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -41,6 +41,9 @@ int kvm_lapic_enabled(struct kvm_vcpu *vcpu);
 bool kvm_apic_present(struct kvm_vcpu *vcpu);
 int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);
 
+u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu);
+void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data);
+
 void kvm_lapic_set_vapic_addr(struct kvm_vcpu *vcpu, gpa_t vapic_addr);
 void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu);
 void kvm_lapic_sync_to_vapic(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e26629f..f4ec4d3 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1747,6 +1747,14 @@ static u64 guest_read_tsc(void)
        return host_tsc + tsc_offset;
 }
 
+static u64 vmx_guest_to_host_tsc(u64 guest_tsc)
+{
+       u64 tsc_offset;
+
+       tsc_offset = vmcs_read64(TSC_OFFSET);
+       return guest_tsc - tsc_offset;
+}
+
 /*
  * Empty call-back. Needs to be implemented when VMX enables the SET_TSC_KHZ
  * ioctl. In this case the call-back should update internal vmx state to make
@@ -6270,6 +6278,16 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
                        }
                }
        }
+
+       /* 
+        * Emulate Intel lapic tsc deadline timer even if host not support it.
+        * Open CPUID.1.ECX[24] and use bit17/18 as timer mode mask.
+        */
+       best = kvm_find_cpuid_entry(vcpu, 1, 0);
+       if (best) {
+               best->ecx |= bit(X86_FEATURE_TSC_DEADLINE_TIMER);
+               vcpu->arch.apic->lapic_timer.timer_mode_mask = (3 << 17);
+       }
 }
 
 static void vmx_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
@@ -7015,6 +7033,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
        .set_tdp_cr3 = vmx_set_cr3,
 
        .check_intercept = vmx_check_intercept,
+       .guest_to_host_tsc = vmx_guest_to_host_tsc,
 };
 
 static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6cb353c..c409fbe 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1564,6 +1564,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, 
u64 data)
                break;
        case APIC_BASE_MSR ... APIC_BASE_MSR + 0x3ff:
                return kvm_x2apic_msr_write(vcpu, msr, data);
+       case MSR_IA32_TSCDEADLINE:
+               kvm_set_lapic_tscdeadline_msr(vcpu, data);
+               break;
        case MSR_IA32_MISC_ENABLE:
                vcpu->arch.ia32_misc_enable_msr = data;
                break;
@@ -1891,6 +1894,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, 
u64 *pdata)
        case APIC_BASE_MSR ... APIC_BASE_MSR + 0x3ff:
                return kvm_x2apic_msr_read(vcpu, msr, pdata);
                break;
+       case MSR_IA32_TSCDEADLINE:
+               data = kvm_get_lapic_tscdeadline_msr(vcpu);
+               break;
        case MSR_IA32_MISC_ENABLE:
                data = vcpu->arch.ia32_misc_enable_msr;
                break;
-- 
1.6.5.6

Attachment: kvm-lapic-tdt.patch
Description: kvm-lapic-tdt.patch


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