1 files changed, 55 insertions, 46 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5d004da1e35d..0c76f7cfdb32 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -94,6 +94,9 @@ EXPORT_SYMBOL_GPL(kvm_x86_ops);
 static bool ignore_msrs = 0;
 module_param(ignore_msrs, bool, S_IRUGO | S_IWUSR);
 
+unsigned int min_timer_period_us = 500;
+module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
+
 bool kvm_has_tsc_control;
 EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
 u32  kvm_max_guest_tsc_khz;
@@ -719,6 +722,12 @@ unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_GPL(kvm_get_cr8);
 
+static void kvm_update_dr6(struct kvm_vcpu *vcpu)
+{
+        if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP))
+                kvm_x86_ops->set_dr6(vcpu, vcpu->arch.dr6);
+}
+
 static void kvm_update_dr7(struct kvm_vcpu *vcpu)
 {
         unsigned long dr7;
@@ -747,6 +756,7 @@ static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val)
                 if (val & 0xffffffff00000000ULL)
                         return -1; /* #GP */
                 vcpu->arch.dr6 = (val & DR6_VOLATILE) | DR6_FIXED_1;
+                kvm_update_dr6(vcpu);
                 break;
         case 5:
                 if (kvm_read_cr4_bits(vcpu, X86_CR4_DE))
@@ -788,7 +798,10 @@ static int _kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
                         return 1;
                 /* fall through */
         case 6:
-                *val = vcpu->arch.dr6;
+                if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)
+                        *val = vcpu->arch.dr6;
+                else
+                        *val = kvm_x86_ops->get_dr6(vcpu);
                 break;
         case 5:
                 if (kvm_read_cr4_bits(vcpu, X86_CR4_DE))
@@ -836,11 +849,12 @@ EXPORT_SYMBOL_GPL(kvm_rdpmc);
  * kvm-specific. Those are put in the beginning of the list.
  */
 
-#define KVM_SAVE_MSRS_BEGIN     10
+#define KVM_SAVE_MSRS_BEGIN     12
 static u32 msrs_to_save[] = {
         MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
         MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
         HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
+        HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC,
         HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
         MSR_KVM_PV_EOI_EN,
         MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
@@ -1275,8 +1289,6 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr)
         kvm->arch.last_tsc_write = data;
         kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz;
 
-        /* Reset of TSC must disable overshoot protection below */
-        vcpu->arch.hv_clock.tsc_timestamp = 0;
         vcpu->arch.last_guest_tsc = data;
 
         /* Keep track of which generation this VCPU has synchronized to */
@@ -1484,7 +1496,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
         unsigned long flags, this_tsc_khz;
         struct kvm_vcpu_arch *vcpu = &v->arch;
         struct kvm_arch *ka = &v->kvm->arch;
-        s64 kernel_ns, max_kernel_ns;
+        s64 kernel_ns;
         u64 tsc_timestamp, host_tsc;
         struct pvclock_vcpu_time_info guest_hv_clock;
         u8 pvclock_flags;
@@ -1543,37 +1555,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
         if (!vcpu->pv_time_enabled)
                 return 0;
 
-        /*
-         * Time as measured by the TSC may go backwards when resetting the base
-         * tsc_timestamp.  The reason for this is that the TSC resolution is
-         * higher than the resolution of the other clock scales.  Thus, many
-         * possible measurments of the TSC correspond to one measurement of any
-         * other clock, and so a spread of values is possible.  This is not a
-         * problem for the computation of the nanosecond clock; with TSC rates
-         * around 1GHZ, there can only be a few cycles which correspond to one
-         * nanosecond value, and any path through this code will inevitably
-         * take longer than that.  However, with the kernel_ns value itself,
-         * the precision may be much lower, down to HZ granularity.  If the
-         * first sampling of TSC against kernel_ns ends in the low part of the
-         * range, and the second in the high end of the range, we can get:
-         *
-         * (TSC - offset_low) * S + kns_old > (TSC - offset_high) * S + kns_new
-         *
-         * As the sampling errors potentially range in the thousands of cycles,
-         * it is possible such a time value has already been observed by the
-         * guest.  To protect against this, we must compute the system time as
-         * observed by the guest and ensure the new system time is greater.
-         */
-        max_kernel_ns = 0;
-        if (vcpu->hv_clock.tsc_timestamp) {
-                max_kernel_ns = vcpu->last_guest_tsc -
-                                vcpu->hv_clock.tsc_timestamp;
-                max_kernel_ns = pvclock_scale_delta(max_kernel_ns,
-                                    vcpu->hv_clock.tsc_to_system_mul,
-                                    vcpu->hv_clock.tsc_shift);
-                max_kernel_ns += vcpu->last_kernel_ns;
-        }
-
         if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {
                 kvm_get_time_scale(NSEC_PER_SEC / 1000, this_tsc_khz,
                                    &vcpu->hv_clock.tsc_shift,
@@ -1581,14 +1562,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
                 vcpu->hw_tsc_khz = this_tsc_khz;
         }
 
-        /* with a master <monotonic time, tsc value> tuple,
-         * pvclock clock reads always increase at the (scaled) rate
-         * of guest TSC - no need to deal with sampling errors.
-         */
-        if (!use_master_clock) {
-                if (max_kernel_ns > kernel_ns)
-                        kernel_ns = max_kernel_ns;
-        }
         /* With all the info we got, fill in the values */
         vcpu->hv_clock.tsc_timestamp = tsc_timestamp;
         vcpu->hv_clock.system_time = kernel_ns + v->kvm->arch.kvmclock_offset;
@@ -1826,6 +1799,8 @@ static bool kvm_hv_msr_partition_wide(u32 msr)
         switch (msr) {
         case HV_X64_MSR_GUEST_OS_ID:
         case HV_X64_MSR_HYPERCALL:
+        case HV_X64_MSR_REFERENCE_TSC:
+        case HV_X64_MSR_TIME_REF_COUNT:
                 r = true;
                 break;
         }
@@ -1867,6 +1842,20 @@ static int set_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data)
                 kvm->arch.hv_hypercall = data;
                 break;
         }
+        case HV_X64_MSR_REFERENCE_TSC: {
+                u64 gfn;
+                HV_REFERENCE_TSC_PAGE tsc_ref;
+                memset(&tsc_ref, 0, sizeof(tsc_ref));
+                kvm->arch.hv_tsc_page = data;
+                if (!(data & HV_X64_MSR_TSC_REFERENCE_ENABLE))
+                        break;
+                gfn = data >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
+                if (kvm_write_guest(kvm, data,
+                        &tsc_ref, sizeof(tsc_ref)))
+                        return 1;
+                mark_page_dirty(kvm, gfn);
+                break;
+        }
         default:
                 vcpu_unimpl(vcpu, "HYPER-V unimplemented wrmsr: 0x%x "
                             "data 0x%llx\n", msr, data);
@@ -2291,6 +2280,14 @@ static int get_msr_hyperv_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
         case HV_X64_MSR_HYPERCALL:
                 data = kvm->arch.hv_hypercall;
                 break;
+        case HV_X64_MSR_TIME_REF_COUNT: {
+                data =
+                     div_u64(get_kernel_ns() + kvm->arch.kvmclock_offset, 100);
+                break;
+        }
+        case HV_X64_MSR_REFERENCE_TSC:
+                data = kvm->arch.hv_tsc_page;
+                break;
         default:
                 vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr);
                 return 1;
@@ -2604,6 +2601,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
         case KVM_CAP_ASSIGN_DEV_IRQ:
         case KVM_CAP_PCI_2_3:
+        case KVM_CAP_HYPERV_TIME:
 #endif
                 r = 1;
                 break;
@@ -2972,8 +2970,11 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
 static void kvm_vcpu_ioctl_x86_get_debugregs(struct kvm_vcpu *vcpu,
                                              struct kvm_debugregs *dbgregs)
 {
+        unsigned long val;
+
         memcpy(dbgregs->db, vcpu->arch.db, sizeof(vcpu->arch.db));
-        dbgregs->dr6 = vcpu->arch.dr6;
+        _kvm_get_dr(vcpu, 6, &val);
+        dbgregs->dr6 = val;
         dbgregs->dr7 = vcpu->arch.dr7;
         dbgregs->flags = 0;
         memset(&dbgregs->reserved, 0, sizeof(dbgregs->reserved));
@@ -2987,7 +2988,9 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
 
         memcpy(vcpu->arch.db, dbgregs->db, sizeof(vcpu->arch.db));
         vcpu->arch.dr6 = dbgregs->dr6;
+        kvm_update_dr6(vcpu);
         vcpu->arch.dr7 = dbgregs->dr7;
+        kvm_update_dr7(vcpu);
 
         return 0;
 }
@@ -5834,6 +5837,11 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
         kvm_apic_update_tmr(vcpu, tmr);
 }
 
+/*
+ * Returns 1 to let __vcpu_run() continue the guest execution loop without
+ * exiting to the userspace.  Otherwise, the value will be returned to the
+ * userspace.
+ */
 static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 {
         int r;
@@ -6089,7 +6097,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
                 }
                 if (need_resched()) {
                         srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
-                        kvm_resched(vcpu);
+                        cond_resched();
                         vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
                 }
         }
@@ -6717,6 +6725,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu)
 
         memset(vcpu->arch.db, 0, sizeof(vcpu->arch.db));
         vcpu->arch.dr6 = DR6_FIXED_1;
+        kvm_update_dr6(vcpu);
         vcpu->arch.dr7 = DR7_FIXED_1;
         kvm_update_dr7(vcpu);