From 2b036c6b861dc5da295c6fe19a3edcff7093fdeb Mon Sep 17 00:00:00 2001
From: Boris Ostrovsky <boris.ostrovsky@amd.com>
Date: Mon, 9 Jan 2012 14:00:35 -0500
Subject: KVM: SVM: Add support for AMD's OSVW feature in guests

In some cases guests should not provide workarounds for errata even when the
physical processor is affected. For example, because of erratum 400 on family
10h processors a Linux guest will read an MSR (resulting in VMEXIT) before
going to idle in order to avoid getting stuck in a non-C0 state. This is not
necessary: HLT and IO instructions are intercepted and therefore there is no
reason for erratum 400 workaround in the guest.

This patch allows us to present a guest with certain errata as fixed,
regardless of the state of actual hardware.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 52d6640a5ca..bd69c93da8f 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -478,6 +478,12 @@ struct kvm_vcpu_arch {
 		u32 id;
 		bool send_user_only;
 	} apf;
+
+	/* OSVW MSRs (AMD only) */
+	struct {
+		u64 length;
+		u64 status;
+	} osvw;
 };
 
 struct kvm_arch {
-- 
cgit v1.2.3-70-g09d2


From 3ea8b75e47ac70bdd0a2c0492102682d43bfa3c4 Mon Sep 17 00:00:00 2001
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Date: Tue, 17 Jan 2012 19:50:08 +0900
Subject: KVM: MMU: Remove unused kvm_pte_chain

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 7 -------
 1 file changed, 7 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index bd69c93da8f..46101661432 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -181,13 +181,6 @@ struct kvm_mmu_memory_cache {
 	void *objects[KVM_NR_MEM_OBJS];
 };
 
-#define NR_PTE_CHAIN_ENTRIES 5
-
-struct kvm_pte_chain {
-	u64 *parent_ptes[NR_PTE_CHAIN_ENTRIES];
-	struct hlist_node link;
-};
-
 /*
  * kvm_mmu_page_role, below, is defined as:
  *
-- 
cgit v1.2.3-70-g09d2


From a59cb29e4d81e025192550c2703f305637f016f6 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Fri, 3 Feb 2012 12:28:31 -0200
Subject: KVM: x86: increase recommended max vcpus to 160

Increase recommended max vcpus from 64 to 160 (tested internally
at Red Hat).

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 46101661432..782d973b071 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -29,7 +29,7 @@
 #include <asm/msr-index.h>
 
 #define KVM_MAX_VCPUS 254
-#define KVM_SOFT_MAX_VCPUS 64
+#define KVM_SOFT_MAX_VCPUS 160
 #define KVM_MEMORY_SLOTS 32
 /* memory slots that does not exposed to userspace */
 #define KVM_PRIVATE_MEM_SLOTS 4
-- 
cgit v1.2.3-70-g09d2


From cc578287e3224d0da196cc1d226bdae6b068faa7 Mon Sep 17 00:00:00 2001
From: Zachary Amsden <zamsden@gmail.com>
Date: Fri, 3 Feb 2012 15:43:50 -0200
Subject: KVM: Infrastructure for software and hardware based TSC rate scaling

This requires some restructuring; rather than use 'virtual_tsc_khz'
to indicate whether hardware rate scaling is in effect, we consider
each VCPU to always have a virtual TSC rate.  Instead, there is new
logic above the vendor-specific hardware scaling that decides whether
it is even necessary to use and updates all rate variables used by
common code.  This means we can simply query the virtual rate at
any point, which is needed for software rate scaling.

There is also now a threshold added to the TSC rate scaling; minor
differences and variations of measured TSC rate can accidentally
provoke rate scaling to be used when it is not needed.  Instead,
we have a tolerance variable called tsc_tolerance_ppm, which is
the maximum variation from user requested rate at which scaling
will be used.  The default is 250ppm, which is the half the
threshold for NTP adjustment, allowing for some hardware variation.

In the event that hardware rate scaling is not available, we can
kludge a bit by forcing TSC catchup to turn on when a faster than
hardware speed has been requested, but there is nothing available
yet for the reverse case; this requires a trap and emulate software
implementation for RDTSC, which is still forthcoming.

[avi: fix 64-bit division on i386]

Signed-off-by: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  9 +++--
 arch/x86/kvm/lapic.c            |  2 +-
 arch/x86/kvm/svm.c              | 20 ++++++----
 arch/x86/kvm/vmx.c              | 16 +++++---
 arch/x86/kvm/x86.c              | 82 +++++++++++++++++++++--------------------
 5 files changed, 71 insertions(+), 58 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 782d973b071..ddebbe01fff 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -422,10 +422,11 @@ struct kvm_vcpu_arch {
 	u64 last_kernel_ns;
 	u64 last_tsc_nsec;
 	u64 last_tsc_write;
-	u32 virtual_tsc_khz;
 	bool tsc_catchup;
-	u32  tsc_catchup_mult;
-	s8   tsc_catchup_shift;
+	bool tsc_always_catchup;
+	s8 virtual_tsc_shift;
+	u32 virtual_tsc_mult;
+	u32 virtual_tsc_khz;
 
 	atomic_t nmi_queued;  /* unprocessed asynchronous NMIs */
 	unsigned nmi_pending; /* NMI queued after currently running handler */
@@ -651,7 +652,7 @@ struct kvm_x86_ops {
 
 	bool (*has_wbinvd_exit)(void);
 
-	void (*set_tsc_khz)(struct kvm_vcpu *vcpu, u32 user_tsc_khz);
+	void (*set_tsc_khz)(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale);
 	void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
 
 	u64 (*compute_tsc_offset)(struct kvm_vcpu *vcpu, u64 target_tsc);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 3ee1d83c695..72975f758c8 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -731,7 +731,7 @@ static void start_apic_timer(struct kvm_lapic *apic)
 		u64 guest_tsc, tscdeadline = apic->lapic_timer.tscdeadline;
 		u64 ns = 0;
 		struct kvm_vcpu *vcpu = apic->vcpu;
-		unsigned long this_tsc_khz = vcpu_tsc_khz(vcpu);
+		unsigned long this_tsc_khz = vcpu->arch.virtual_tsc_khz;
 		unsigned long flags;
 
 		if (unlikely(!tscdeadline || !this_tsc_khz))
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 7bbd17cc348..e12026e5244 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -964,20 +964,25 @@ static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
 	return _tsc;
 }
 
-static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
+static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	u64 ratio;
 	u64 khz;
 
-	/* TSC scaling supported? */
-	if (!boot_cpu_has(X86_FEATURE_TSCRATEMSR))
+	/* Guest TSC same frequency as host TSC? */
+	if (!scale) {
+		svm->tsc_ratio = TSC_RATIO_DEFAULT;
 		return;
+	}
 
-	/* TSC-Scaling disabled or guest TSC same frequency as host TSC? */
-	if (user_tsc_khz == 0) {
-		vcpu->arch.virtual_tsc_khz = 0;
-		svm->tsc_ratio = TSC_RATIO_DEFAULT;
+	/* TSC scaling supported? */
+	if (!boot_cpu_has(X86_FEATURE_TSCRATEMSR)) {
+		if (user_tsc_khz > tsc_khz) {
+			vcpu->arch.tsc_catchup = 1;
+			vcpu->arch.tsc_always_catchup = 1;
+		} else
+			WARN(1, "user requested TSC rate below hardware speed\n");
 		return;
 	}
 
@@ -992,7 +997,6 @@ static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
 				user_tsc_khz);
 		return;
 	}
-	vcpu->arch.virtual_tsc_khz = user_tsc_khz;
 	svm->tsc_ratio             = ratio;
 }
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 3b4c8d8ad90..e6bf61fa1c0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1817,13 +1817,19 @@ u64 vmx_read_l1_tsc(struct kvm_vcpu *vcpu)
 }
 
 /*
- * 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
- * the changes effective.
+ * Engage any workarounds for mis-matched TSC rates.  Currently limited to
+ * software catchup for faster rates on slower CPUs.
  */
-static void vmx_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
+static void vmx_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
 {
-	/* Nothing to do here */
+	if (!scale)
+		return;
+
+	if (user_tsc_khz > tsc_khz) {
+		vcpu->arch.tsc_catchup = 1;
+		vcpu->arch.tsc_always_catchup = 1;
+	} else
+		WARN(1, "user requested TSC rate below hardware speed\n");
 }
 
 /*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2bd77a3a41e..41bb90acb23 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -96,6 +96,10 @@ EXPORT_SYMBOL_GPL(kvm_has_tsc_control);
 u32  kvm_max_guest_tsc_khz;
 EXPORT_SYMBOL_GPL(kvm_max_guest_tsc_khz);
 
+/* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */
+static u32 tsc_tolerance_ppm = 250;
+module_param(tsc_tolerance_ppm, uint, S_IRUGO | S_IWUSR);
+
 #define KVM_NR_SHARED_MSRS 16
 
 struct kvm_shared_msrs_global {
@@ -968,49 +972,50 @@ static inline u64 get_kernel_ns(void)
 static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz);
 unsigned long max_tsc_khz;
 
-static inline int kvm_tsc_changes_freq(void)
+static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
 {
-	int cpu = get_cpu();
-	int ret = !boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
-		  cpufreq_quick_get(cpu) != 0;
-	put_cpu();
-	return ret;
+	return pvclock_scale_delta(nsec, vcpu->arch.virtual_tsc_mult,
+				   vcpu->arch.virtual_tsc_shift);
 }
 
-u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu)
+static u32 adjust_tsc_khz(u32 khz, s32 ppm)
 {
-	if (vcpu->arch.virtual_tsc_khz)
-		return vcpu->arch.virtual_tsc_khz;
-	else
-		return __this_cpu_read(cpu_tsc_khz);
+	u64 v = (u64)khz * (1000000 + ppm);
+	do_div(v, 1000000);
+	return v;
 }
 
-static inline u64 nsec_to_cycles(struct kvm_vcpu *vcpu, u64 nsec)
+static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
 {
-	u64 ret;
+	u32 thresh_lo, thresh_hi;
+	int use_scaling = 0;
 
-	WARN_ON(preemptible());
-	if (kvm_tsc_changes_freq())
-		printk_once(KERN_WARNING
-		 "kvm: unreliable cycle conversion on adjustable rate TSC\n");
-	ret = nsec * vcpu_tsc_khz(vcpu);
-	do_div(ret, USEC_PER_SEC);
-	return ret;
-}
-
-static void kvm_init_tsc_catchup(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
-{
 	/* Compute a scale to convert nanoseconds in TSC cycles */
 	kvm_get_time_scale(this_tsc_khz, NSEC_PER_SEC / 1000,
-			   &vcpu->arch.tsc_catchup_shift,
-			   &vcpu->arch.tsc_catchup_mult);
+			   &vcpu->arch.virtual_tsc_shift,
+			   &vcpu->arch.virtual_tsc_mult);
+	vcpu->arch.virtual_tsc_khz = this_tsc_khz;
+
+	/*
+	 * Compute the variation in TSC rate which is acceptable
+	 * within the range of tolerance and decide if the
+	 * rate being applied is within that bounds of the hardware
+	 * rate.  If so, no scaling or compensation need be done.
+	 */
+	thresh_lo = adjust_tsc_khz(tsc_khz, -tsc_tolerance_ppm);
+	thresh_hi = adjust_tsc_khz(tsc_khz, tsc_tolerance_ppm);
+	if (this_tsc_khz < thresh_lo || this_tsc_khz > thresh_hi) {
+		pr_debug("kvm: requested TSC rate %u falls outside tolerance [%u,%u]\n", this_tsc_khz, thresh_lo, thresh_hi);
+		use_scaling = 1;
+	}
+	kvm_x86_ops->set_tsc_khz(vcpu, this_tsc_khz, use_scaling);
 }
 
 static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
 {
 	u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.last_tsc_nsec,
-				      vcpu->arch.tsc_catchup_mult,
-				      vcpu->arch.tsc_catchup_shift);
+				      vcpu->arch.virtual_tsc_mult,
+				      vcpu->arch.virtual_tsc_shift);
 	tsc += vcpu->arch.last_tsc_write;
 	return tsc;
 }
@@ -1077,7 +1082,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
 	local_irq_save(flags);
 	tsc_timestamp = kvm_x86_ops->read_l1_tsc(v);
 	kernel_ns = get_kernel_ns();
-	this_tsc_khz = vcpu_tsc_khz(v);
+	this_tsc_khz = __get_cpu_var(cpu_tsc_khz);
 	if (unlikely(this_tsc_khz == 0)) {
 		local_irq_restore(flags);
 		kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
@@ -2804,26 +2809,21 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		u32 user_tsc_khz;
 
 		r = -EINVAL;
-		if (!kvm_has_tsc_control)
-			break;
-
 		user_tsc_khz = (u32)arg;
 
 		if (user_tsc_khz >= kvm_max_guest_tsc_khz)
 			goto out;
 
-		kvm_x86_ops->set_tsc_khz(vcpu, user_tsc_khz);
+		if (user_tsc_khz == 0)
+			user_tsc_khz = tsc_khz;
+
+		kvm_set_tsc_khz(vcpu, user_tsc_khz);
 
 		r = 0;
 		goto out;
 	}
 	case KVM_GET_TSC_KHZ: {
-		r = -EIO;
-		if (check_tsc_unstable())
-			goto out;
-
-		r = vcpu_tsc_khz(vcpu);
-
+		r = vcpu->arch.virtual_tsc_khz;
 		goto out;
 	}
 	default:
@@ -5312,6 +5312,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		profile_hit(KVM_PROFILING, (void *)rip);
 	}
 
+	if (unlikely(vcpu->arch.tsc_always_catchup))
+		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
 
 	kvm_lapic_sync_from_vapic(vcpu);
 
@@ -6004,7 +6006,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	}
 	vcpu->arch.pio_data = page_address(page);
 
-	kvm_init_tsc_catchup(vcpu, max_tsc_khz);
+	kvm_set_tsc_khz(vcpu, max_tsc_khz);
 
 	r = kvm_mmu_create(vcpu);
 	if (r < 0)
-- 
cgit v1.2.3-70-g09d2


From 5d3cb0f6a8e3af018a522ae8d36f8f7d2511b5d8 Mon Sep 17 00:00:00 2001
From: Zachary Amsden <zamsden@gmail.com>
Date: Fri, 3 Feb 2012 15:43:51 -0200
Subject: KVM: Improve TSC offset matching

There are a few improvements that can be made to the TSC offset
matching code.  First, we don't need to call the 128-bit multiply
(especially on a constant number), the code works much nicer to
do computation in nanosecond units.

Second, the way everything is setup with software TSC rate scaling,
we currently have per-cpu rates.  Obviously this isn't too desirable
to use in practice, but if for some reason we do change the rate of
all VCPUs at runtime, then reset the TSCs, we will only want to
match offsets for VCPUs running at the same rate.

Finally, for the case where we have an unstable host TSC, but
rate scaling is being done in hardware, we should call the platform
code to compute the TSC offset, so the math is reorganized to recompute
the base instead, then transform the base into an offset using the
existing API.

[avi: fix 64-bit division on i386]

Signed-off-by: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

KVM: Fix 64-bit division in kvm_write_tsc()

Breaks i386 build.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/x86.c              | 44 +++++++++++++++++++++++++++--------------
 2 files changed, 30 insertions(+), 15 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ddebbe01fff..8a34fca6c57 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -513,6 +513,7 @@ struct kvm_arch {
 	u64 last_tsc_nsec;
 	u64 last_tsc_offset;
 	u64 last_tsc_write;
+	u32 last_tsc_khz;
 
 	struct kvm_xen_hvm_config xen_hvm_config;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 41bb90acb23..4390f42b371 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1025,33 +1025,46 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
 	struct kvm *kvm = vcpu->kvm;
 	u64 offset, ns, elapsed;
 	unsigned long flags;
-	s64 sdiff;
+	s64 nsdiff;
 
 	raw_spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags);
 	offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
 	ns = get_kernel_ns();
 	elapsed = ns - kvm->arch.last_tsc_nsec;
-	sdiff = data - kvm->arch.last_tsc_write;
-	if (sdiff < 0)
-		sdiff = -sdiff;
+
+	/* n.b - signed multiplication and division required */
+	nsdiff = data - kvm->arch.last_tsc_write;
+#ifdef CONFIG_X86_64
+	nsdiff = (nsdiff * 1000) / vcpu->arch.virtual_tsc_khz;
+#else
+	/* do_div() only does unsigned */
+	asm("idivl %2; xor %%edx, %%edx"
+	    : "=A"(nsdiff)
+	    : "A"(nsdiff * 1000), "rm"(vcpu->arch.virtual_tsc_khz));
+#endif
+	nsdiff -= elapsed;
+	if (nsdiff < 0)
+		nsdiff = -nsdiff;
 
 	/*
-	 * Special case: close write to TSC within 5 seconds of
-	 * another CPU is interpreted as an attempt to synchronize
-	 * The 5 seconds is to accommodate host load / swapping as
-	 * well as any reset of TSC during the boot process.
-	 *
-	 * In that case, for a reliable TSC, we can match TSC offsets,
-	 * or make a best guest using elapsed value.
-	 */
-	if (sdiff < nsec_to_cycles(vcpu, 5ULL * NSEC_PER_SEC) &&
-	    elapsed < 5ULL * NSEC_PER_SEC) {
+	 * Special case: TSC write with a small delta (1 second) of virtual
+	 * cycle time against real time is interpreted as an attempt to
+	 * synchronize the CPU.
+         *
+	 * For a reliable TSC, we can match TSC offsets, and for an unstable
+	 * TSC, we add elapsed time in this computation.  We could let the
+	 * compensation code attempt to catch up if we fall behind, but
+	 * it's better to try to match offsets from the beginning.
+         */
+	if (nsdiff < NSEC_PER_SEC &&
+	    vcpu->arch.virtual_tsc_khz == kvm->arch.last_tsc_khz) {
 		if (!check_tsc_unstable()) {
 			offset = kvm->arch.last_tsc_offset;
 			pr_debug("kvm: matched tsc offset for %llu\n", data);
 		} else {
 			u64 delta = nsec_to_cycles(vcpu, elapsed);
-			offset += delta;
+			data += delta;
+			offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
 			pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
 		}
 		ns = kvm->arch.last_tsc_nsec;
@@ -1059,6 +1072,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
 	kvm->arch.last_tsc_nsec = ns;
 	kvm->arch.last_tsc_write = data;
 	kvm->arch.last_tsc_offset = offset;
+	kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz;
 	kvm_x86_ops->write_tsc_offset(vcpu, offset);
 	raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
 
-- 
cgit v1.2.3-70-g09d2


From 6f526ec5383dcd5fa5ffc7b3ac1d62099a0b46ad Mon Sep 17 00:00:00 2001
From: Zachary Amsden <zamsden@gmail.com>
Date: Fri, 3 Feb 2012 15:43:54 -0200
Subject: KVM: Add last_host_tsc tracking back to KVM

The variable last_host_tsc was removed from upstream code.  I am adding
it back for two reasons.  First, it is unnecessary to use guest TSC
computation to conclude information about the host TSC.  The guest may
set the TSC backwards (this case handled by the previous patch), but
the computation of guest TSC (and fetching an MSR) is significanlty more
work and complexity than simply reading the hardware counter.  In addition,
we don't actually need the guest TSC for any part of the computation,
by always recomputing the offset, we can eliminate the need to deal with
the current offset and any scaling factors that may apply.

The second reason is that later on, we are going to be using the host
TSC value to restore TSC offsets after a host S4 suspend, so we need to
be reading the host values, not the guest values here.

Signed-off-by: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/x86.c              | 11 +++--------
 2 files changed, 4 insertions(+), 8 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8a34fca6c57..b23682900f4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -422,6 +422,7 @@ struct kvm_vcpu_arch {
 	u64 last_kernel_ns;
 	u64 last_tsc_nsec;
 	u64 last_tsc_write;
+	u64 last_host_tsc;
 	bool tsc_catchup;
 	bool tsc_always_catchup;
 	s8 virtual_tsc_shift;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2a59f76d96f..39a57dac884 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2253,13 +2253,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	kvm_x86_ops->vcpu_load(vcpu, cpu);
 	if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {
-		/* Make sure TSC doesn't go backwards */
-		s64 tsc_delta;
-		u64 tsc;
-
-		tsc = kvm_x86_ops->read_l1_tsc(vcpu);
-		tsc_delta = tsc - vcpu->arch.last_guest_tsc;
-
+		s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :
+				native_read_tsc() - vcpu->arch.last_host_tsc;
 		if (tsc_delta < 0)
 			mark_tsc_unstable("KVM discovered backwards TSC");
 		if (check_tsc_unstable()) {
@@ -2282,7 +2277,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
 	kvm_x86_ops->vcpu_put(vcpu);
 	kvm_put_guest_fpu(vcpu);
-	vcpu->arch.last_guest_tsc = kvm_x86_ops->read_l1_tsc(vcpu);
+	vcpu->arch.last_host_tsc = native_read_tsc();
 }
 
 static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
-- 
cgit v1.2.3-70-g09d2


From f1e2b26003c41e581243c09ceed7567677449468 Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Fri, 3 Feb 2012 15:43:55 -0200
Subject: KVM: Allow adjust_tsc_offset to be in host or guest cycles

Redefine the API to take a parameter indicating whether an
adjustment is in host or guest cycles.

Signed-off-by: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 13 ++++++++++++-
 arch/x86/kvm/svm.c              |  6 +++++-
 arch/x86/kvm/vmx.c              |  2 +-
 arch/x86/kvm/x86.c              |  2 +-
 4 files changed, 19 insertions(+), 4 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b23682900f4..dd439f13df8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -646,7 +646,7 @@ struct kvm_x86_ops {
 	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
 	int (*get_lpage_level)(void);
 	bool (*rdtscp_supported)(void);
-	void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment);
+	void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment, bool host);
 
 	void (*set_tdp_cr3)(struct kvm_vcpu *vcpu, unsigned long cr3);
 
@@ -676,6 +676,17 @@ struct kvm_arch_async_pf {
 
 extern struct kvm_x86_ops *kvm_x86_ops;
 
+static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
+					   s64 adjustment)
+{
+	kvm_x86_ops->adjust_tsc_offset(vcpu, adjustment, false);
+}
+
+static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment)
+{
+	kvm_x86_ops->adjust_tsc_offset(vcpu, adjustment, true);
+}
+
 int kvm_mmu_module_init(void);
 void kvm_mmu_module_exit(void);
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index e12026e5244..0b7690ee20b 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1016,10 +1016,14 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
 	mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
 }
 
-static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
+static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool host)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	WARN_ON(adjustment < 0);
+	if (host)
+		adjustment = svm_scale_tsc(vcpu, adjustment);
+
 	svm->vmcb->control.tsc_offset += adjustment;
 	if (is_guest_mode(vcpu))
 		svm->nested.hsave->control.tsc_offset += adjustment;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e6bf61fa1c0..575fb742a6f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1856,7 +1856,7 @@ static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
 	}
 }
 
-static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
+static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool host)
 {
 	u64 offset = vmcs_read64(TSC_OFFSET);
 	vmcs_write64(TSC_OFFSET, offset + adjustment);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 39a57dac884..3b931302fa5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1116,7 +1116,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
 	if (vcpu->tsc_catchup) {
 		u64 tsc = compute_guest_tsc(v, kernel_ns);
 		if (tsc > tsc_timestamp) {
-			kvm_x86_ops->adjust_tsc_offset(v, tsc - tsc_timestamp);
+			adjust_tsc_offset_guest(v, tsc - tsc_timestamp);
 			tsc_timestamp = tsc;
 		}
 	}
-- 
cgit v1.2.3-70-g09d2


From 0dd6a6edb0124e6c71931ff575b18e15ed6e8603 Mon Sep 17 00:00:00 2001
From: Zachary Amsden <zamsden@gmail.com>
Date: Fri, 3 Feb 2012 15:43:56 -0200
Subject: KVM: Dont mark TSC unstable due to S4 suspend

During a host suspend, TSC may go backwards, which KVM interprets
as an unstable TSC.  Technically, KVM should not be marking the
TSC unstable, which causes the TSC clocksource to go bad, but we
need to be adjusting the TSC offsets in such a case.

Dealing with this issue is a little tricky as the only place we
can reliably do it is before much of the timekeeping infrastructure
is up and running.  On top of this, we are not in a KVM thread
context, so we may not be able to safely access VCPU fields.
Instead, we compute our best known hardware offset at power-up and
stash it to be applied to all VCPUs when they actually start running.

Signed-off-by: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/x86.c              | 93 ++++++++++++++++++++++++++++++++++++++---
 2 files changed, 89 insertions(+), 5 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index dd439f13df8..4fbeb84b181 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -423,6 +423,7 @@ struct kvm_vcpu_arch {
 	u64 last_tsc_nsec;
 	u64 last_tsc_write;
 	u64 last_host_tsc;
+	u64 tsc_offset_adjustment;
 	bool tsc_catchup;
 	bool tsc_always_catchup;
 	s8 virtual_tsc_shift;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3b931302fa5..4e9bd23d522 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2252,6 +2252,14 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	}
 
 	kvm_x86_ops->vcpu_load(vcpu, cpu);
+
+	/* Apply any externally detected TSC adjustments (due to suspend) */
+	if (unlikely(vcpu->arch.tsc_offset_adjustment)) {
+		adjust_tsc_offset_host(vcpu, vcpu->arch.tsc_offset_adjustment);
+		vcpu->arch.tsc_offset_adjustment = 0;
+		set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests);
+	}
+
 	if (unlikely(vcpu->cpu != cpu) || check_tsc_unstable()) {
 		s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 :
 				native_read_tsc() - vcpu->arch.last_host_tsc;
@@ -5964,13 +5972,88 @@ int kvm_arch_hardware_enable(void *garbage)
 	struct kvm *kvm;
 	struct kvm_vcpu *vcpu;
 	int i;
+	int ret;
+	u64 local_tsc;
+	u64 max_tsc = 0;
+	bool stable, backwards_tsc = false;
 
 	kvm_shared_msr_cpu_online();
-	list_for_each_entry(kvm, &vm_list, vm_list)
-		kvm_for_each_vcpu(i, vcpu, kvm)
-			if (vcpu->cpu == smp_processor_id())
-				kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
-	return kvm_x86_ops->hardware_enable(garbage);
+	ret = kvm_x86_ops->hardware_enable(garbage);
+	if (ret != 0)
+		return ret;
+
+	local_tsc = native_read_tsc();
+	stable = !check_tsc_unstable();
+	list_for_each_entry(kvm, &vm_list, vm_list) {
+		kvm_for_each_vcpu(i, vcpu, kvm) {
+			if (!stable && vcpu->cpu == smp_processor_id())
+				set_bit(KVM_REQ_CLOCK_UPDATE, &vcpu->requests);
+			if (stable && vcpu->arch.last_host_tsc > local_tsc) {
+				backwards_tsc = true;
+				if (vcpu->arch.last_host_tsc > max_tsc)
+					max_tsc = vcpu->arch.last_host_tsc;
+			}
+		}
+	}
+
+	/*
+	 * Sometimes, even reliable TSCs go backwards.  This happens on
+	 * platforms that reset TSC during suspend or hibernate actions, but
+	 * maintain synchronization.  We must compensate.  Fortunately, we can
+	 * detect that condition here, which happens early in CPU bringup,
+	 * before any KVM threads can be running.  Unfortunately, we can't
+	 * bring the TSCs fully up to date with real time, as we aren't yet far
+	 * enough into CPU bringup that we know how much real time has actually
+	 * elapsed; our helper function, get_kernel_ns() will be using boot
+	 * variables that haven't been updated yet.
+	 *
+	 * So we simply find the maximum observed TSC above, then record the
+	 * adjustment to TSC in each VCPU.  When the VCPU later gets loaded,
+	 * the adjustment will be applied.  Note that we accumulate
+	 * adjustments, in case multiple suspend cycles happen before some VCPU
+	 * gets a chance to run again.  In the event that no KVM threads get a
+	 * chance to run, we will miss the entire elapsed period, as we'll have
+	 * reset last_host_tsc, so VCPUs will not have the TSC adjusted and may
+	 * loose cycle time.  This isn't too big a deal, since the loss will be
+	 * uniform across all VCPUs (not to mention the scenario is extremely
+	 * unlikely). It is possible that a second hibernate recovery happens
+	 * much faster than a first, causing the observed TSC here to be
+	 * smaller; this would require additional padding adjustment, which is
+	 * why we set last_host_tsc to the local tsc observed here.
+	 *
+	 * N.B. - this code below runs only on platforms with reliable TSC,
+	 * as that is the only way backwards_tsc is set above.  Also note
+	 * that this runs for ALL vcpus, which is not a bug; all VCPUs should
+	 * have the same delta_cyc adjustment applied if backwards_tsc
+	 * is detected.  Note further, this adjustment is only done once,
+	 * as we reset last_host_tsc on all VCPUs to stop this from being
+	 * called multiple times (one for each physical CPU bringup).
+	 *
+	 * Platforms with unnreliable TSCs don't have to deal with this, they
+	 * will be compensated by the logic in vcpu_load, which sets the TSC to
+	 * catchup mode.  This will catchup all VCPUs to real time, but cannot
+	 * guarantee that they stay in perfect synchronization.
+	 */
+	if (backwards_tsc) {
+		u64 delta_cyc = max_tsc - local_tsc;
+		list_for_each_entry(kvm, &vm_list, vm_list) {
+			kvm_for_each_vcpu(i, vcpu, kvm) {
+				vcpu->arch.tsc_offset_adjustment += delta_cyc;
+				vcpu->arch.last_host_tsc = local_tsc;
+			}
+
+			/*
+			 * We have to disable TSC offset matching.. if you were
+			 * booting a VM while issuing an S4 host suspend....
+			 * you may have some problem.  Solving this issue is
+			 * left as an exercise to the reader.
+			 */
+			kvm->arch.last_tsc_nsec = 0;
+			kvm->arch.last_tsc_write = 0;
+		}
+
+	}
+	return 0;
 }
 
 void kvm_arch_hardware_disable(void *garbage)
-- 
cgit v1.2.3-70-g09d2


From e26101b116a6235bcd80b3a4c38c9fe91286cd79 Mon Sep 17 00:00:00 2001
From: Zachary Amsden <zamsden@gmail.com>
Date: Fri, 3 Feb 2012 15:43:57 -0200
Subject: KVM: Track TSC synchronization in generations

This allows us to track the original nanosecond and counter values
at each phase of TSC writing by the guest.  This gets us perfect
offset matching for stable TSC systems, and perfect software
computed TSC matching for machines with unstable TSC.

Signed-off-by: Zachary Amsden <zamsden@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 10 +++++++---
 arch/x86/kvm/x86.c              | 41 +++++++++++++++++++++++++++++++++--------
 2 files changed, 40 insertions(+), 11 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 4fbeb84b181..c24125cd0c6 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -420,10 +420,11 @@ struct kvm_vcpu_arch {
 
 	u64 last_guest_tsc;
 	u64 last_kernel_ns;
-	u64 last_tsc_nsec;
-	u64 last_tsc_write;
 	u64 last_host_tsc;
 	u64 tsc_offset_adjustment;
+	u64 this_tsc_nsec;
+	u64 this_tsc_write;
+	u8  this_tsc_generation;
 	bool tsc_catchup;
 	bool tsc_always_catchup;
 	s8 virtual_tsc_shift;
@@ -513,9 +514,12 @@ struct kvm_arch {
 	s64 kvmclock_offset;
 	raw_spinlock_t tsc_write_lock;
 	u64 last_tsc_nsec;
-	u64 last_tsc_offset;
 	u64 last_tsc_write;
 	u32 last_tsc_khz;
+	u64 cur_tsc_nsec;
+	u64 cur_tsc_write;
+	u64 cur_tsc_offset;
+	u8  cur_tsc_generation;
 
 	struct kvm_xen_hvm_config xen_hvm_config;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4e9bd23d522..e86f9b22eac 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1013,10 +1013,10 @@ static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
 
 static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns)
 {
-	u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.last_tsc_nsec,
+	u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.this_tsc_nsec,
 				      vcpu->arch.virtual_tsc_mult,
 				      vcpu->arch.virtual_tsc_shift);
-	tsc += vcpu->arch.last_tsc_write;
+	tsc += vcpu->arch.this_tsc_write;
 	return tsc;
 }
 
@@ -1059,7 +1059,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
 	if (nsdiff < NSEC_PER_SEC &&
 	    vcpu->arch.virtual_tsc_khz == kvm->arch.last_tsc_khz) {
 		if (!check_tsc_unstable()) {
-			offset = kvm->arch.last_tsc_offset;
+			offset = kvm->arch.cur_tsc_offset;
 			pr_debug("kvm: matched tsc offset for %llu\n", data);
 		} else {
 			u64 delta = nsec_to_cycles(vcpu, elapsed);
@@ -1067,20 +1067,45 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data)
 			offset = kvm_x86_ops->compute_tsc_offset(vcpu, data);
 			pr_debug("kvm: adjusted tsc offset by %llu\n", delta);
 		}
+	} else {
+		/*
+		 * We split periods of matched TSC writes into generations.
+		 * For each generation, we track the original measured
+		 * nanosecond time, offset, and write, so if TSCs are in
+		 * sync, we can match exact offset, and if not, we can match
+		 * exact software computaion in compute_guest_tsc()
+		 *
+		 * These values are tracked in kvm->arch.cur_xxx variables.
+		 */
+		kvm->arch.cur_tsc_generation++;
+		kvm->arch.cur_tsc_nsec = ns;
+		kvm->arch.cur_tsc_write = data;
+		kvm->arch.cur_tsc_offset = offset;
+		pr_debug("kvm: new tsc generation %u, clock %llu\n",
+			 kvm->arch.cur_tsc_generation, data);
 	}
+
+	/*
+	 * We also track th most recent recorded KHZ, write and time to
+	 * allow the matching interval to be extended at each write.
+	 */
 	kvm->arch.last_tsc_nsec = ns;
 	kvm->arch.last_tsc_write = data;
-	kvm->arch.last_tsc_offset = offset;
 	kvm->arch.last_tsc_khz = vcpu->arch.virtual_tsc_khz;
-	kvm_x86_ops->write_tsc_offset(vcpu, offset);
-	raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
 
 	/* Reset of TSC must disable overshoot protection below */
 	vcpu->arch.hv_clock.tsc_timestamp = 0;
-	vcpu->arch.last_tsc_write = data;
-	vcpu->arch.last_tsc_nsec = ns;
 	vcpu->arch.last_guest_tsc = data;
+
+	/* Keep track of which generation this VCPU has synchronized to */
+	vcpu->arch.this_tsc_generation = kvm->arch.cur_tsc_generation;
+	vcpu->arch.this_tsc_nsec = kvm->arch.cur_tsc_nsec;
+	vcpu->arch.this_tsc_write = kvm->arch.cur_tsc_write;
+
+	kvm_x86_ops->write_tsc_offset(vcpu, offset);
+	raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
 }
+
 EXPORT_SYMBOL_GPL(kvm_write_tsc);
 
 static int kvm_guest_time_update(struct kvm_vcpu *v)
-- 
cgit v1.2.3-70-g09d2


From db3fe4eb45f3555d91a7124e18cf3a2f2a30eb90 Mon Sep 17 00:00:00 2001
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Date: Wed, 8 Feb 2012 13:02:18 +0900
Subject: KVM: Introduce kvm_memory_slot::arch and move lpage_info into it

Some members of kvm_memory_slot are not used by every architecture.

This patch is the first step to make this difference clear by
introducing kvm_memory_slot::arch;  lpage_info is moved into it.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/ia64/include/asm/kvm_host.h    |  3 ++
 arch/ia64/kvm/kvm-ia64.c            | 10 ++++++
 arch/powerpc/include/asm/kvm_host.h |  3 ++
 arch/powerpc/kvm/powerpc.c          | 10 ++++++
 arch/s390/include/asm/kvm_host.h    |  3 ++
 arch/s390/kvm/kvm-s390.c            | 10 ++++++
 arch/x86/include/asm/kvm_host.h     |  9 +++++
 arch/x86/kvm/mmu.c                  |  2 +-
 arch/x86/kvm/x86.c                  | 59 +++++++++++++++++++++++++++++++
 include/linux/kvm_host.h            | 11 +++---
 virt/kvm/kvm_main.c                 | 70 +++++--------------------------------
 11 files changed, 122 insertions(+), 68 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 2689ee54a1c..e35b3a84a40 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -459,6 +459,9 @@ struct kvm_sal_data {
 	unsigned long boot_gp;
 };
 
+struct kvm_arch_memory_slot {
+};
+
 struct kvm_arch {
 	spinlock_t dirty_log_lock;
 
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 8ca7261e7b3..d8ddbba6fe7 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1571,6 +1571,16 @@ int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 	return VM_FAULT_SIGBUS;
 }
 
+void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont)
+{
+}
+
+int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
+{
+	return 0;
+}
+
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 		struct kvm_memory_slot *memslot,
 		struct kvm_memory_slot old,
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 1843d5d2a3b..52eb9c1f4fe 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -213,6 +213,9 @@ struct revmap_entry {
 #define KVMPPC_PAGE_WRITETHRU	HPTE_R_W	/* 0x40 */
 #define KVMPPC_GOT_PAGE		0x80
 
+struct kvm_arch_memory_slot {
+};
+
 struct kvm_arch {
 #ifdef CONFIG_KVM_BOOK3S_64_HV
 	unsigned long hpt_virt;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 0e21d155eea..00d7e345b3f 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -281,6 +281,16 @@ long kvm_arch_dev_ioctl(struct file *filp,
 	return -EINVAL;
 }
 
+void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont)
+{
+}
+
+int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
+{
+	return 0;
+}
+
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
                                    struct kvm_memory_slot *memslot,
                                    struct kvm_memory_slot old,
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index e6304268ea2..7343872890a 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -245,6 +245,9 @@ struct kvm_vm_stat {
 	u32 remote_tlb_flush;
 };
 
+struct kvm_arch_memory_slot {
+};
+
 struct kvm_arch{
 	struct sca_block *sca;
 	debug_info_t *dbf;
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index cf3c0a91d04..17ad69d596f 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -814,6 +814,16 @@ int kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 	return VM_FAULT_SIGBUS;
 }
 
+void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont)
+{
+}
+
+int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
+{
+	return 0;
+}
+
 /* Section: memory related */
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				   struct kvm_memory_slot *memslot,
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c24125cd0c6..74c9edf2bb1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -483,6 +483,15 @@ struct kvm_vcpu_arch {
 	} osvw;
 };
 
+struct kvm_lpage_info {
+	unsigned long rmap_pde;
+	int write_count;
+};
+
+struct kvm_arch_memory_slot {
+	struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1];
+};
+
 struct kvm_arch {
 	unsigned int n_used_mmu_pages;
 	unsigned int n_requested_mmu_pages;
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 37e7f100a0e..ff053ca3230 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -689,7 +689,7 @@ static struct kvm_lpage_info *lpage_info_slot(gfn_t gfn,
 	unsigned long idx;
 
 	idx = gfn_to_index(gfn, slot->base_gfn, level);
-	return &slot->lpage_info[level - 2][idx];
+	return &slot->arch.lpage_info[level - 2][idx];
 }
 
 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3df0b7a140b..ca74c1dadf3 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6239,6 +6239,65 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 		put_page(kvm->arch.ept_identity_pagetable);
 }
 
+void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont)
+{
+	int i;
+
+	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
+		if (!dont || free->arch.lpage_info[i] != dont->arch.lpage_info[i]) {
+			vfree(free->arch.lpage_info[i]);
+			free->arch.lpage_info[i] = NULL;
+		}
+	}
+}
+
+int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages)
+{
+	int i;
+
+	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
+		unsigned long ugfn;
+		int lpages;
+		int level = i + 2;
+
+		lpages = gfn_to_index(slot->base_gfn + npages - 1,
+				      slot->base_gfn, level) + 1;
+
+		slot->arch.lpage_info[i] =
+			vzalloc(lpages * sizeof(*slot->arch.lpage_info[i]));
+		if (!slot->arch.lpage_info[i])
+			goto out_free;
+
+		if (slot->base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
+			slot->arch.lpage_info[i][0].write_count = 1;
+		if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
+			slot->arch.lpage_info[i][lpages - 1].write_count = 1;
+		ugfn = slot->userspace_addr >> PAGE_SHIFT;
+		/*
+		 * If the gfn and userspace address are not aligned wrt each
+		 * other, or if explicitly asked to, disable large page
+		 * support for this slot
+		 */
+		if ((slot->base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1) ||
+		    !kvm_largepages_enabled()) {
+			unsigned long j;
+
+			for (j = 0; j < lpages; ++j)
+				slot->arch.lpage_info[i][j].write_count = 1;
+		}
+	}
+
+	return 0;
+
+out_free:
+	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
+		vfree(slot->arch.lpage_info[i]);
+		slot->arch.lpage_info[i] = NULL;
+	}
+	return -ENOMEM;
+}
+
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				struct kvm_memory_slot *memslot,
 				struct kvm_memory_slot old,
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 7a08496b974..355e44555c3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -171,11 +171,6 @@ static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu)
  */
 #define KVM_MEM_MAX_NR_PAGES ((1UL << 31) - 1)
 
-struct kvm_lpage_info {
-	unsigned long rmap_pde;
-	int write_count;
-};
-
 struct kvm_memory_slot {
 	gfn_t base_gfn;
 	unsigned long npages;
@@ -184,7 +179,7 @@ struct kvm_memory_slot {
 	unsigned long *dirty_bitmap;
 	unsigned long *dirty_bitmap_head;
 	unsigned long nr_dirty_pages;
-	struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1];
+	struct kvm_arch_memory_slot arch;
 	unsigned long userspace_addr;
 	int user_alloc;
 	int id;
@@ -376,6 +371,9 @@ int kvm_set_memory_region(struct kvm *kvm,
 int __kvm_set_memory_region(struct kvm *kvm,
 			    struct kvm_userspace_memory_region *mem,
 			    int user_alloc);
+void kvm_arch_free_memslot(struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont);
+int kvm_arch_create_memslot(struct kvm_memory_slot *slot, unsigned long npages);
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				struct kvm_memory_slot *memslot,
 				struct kvm_memory_slot old,
@@ -385,6 +383,7 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 				struct kvm_userspace_memory_region *mem,
 				struct kvm_memory_slot old,
 				int user_alloc);
+bool kvm_largepages_enabled(void);
 void kvm_disable_largepages(void);
 void kvm_arch_flush_shadow(struct kvm *kvm);
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a30447c5eb4..8340e0e6203 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -535,21 +535,13 @@ static void kvm_destroy_dirty_bitmap(struct kvm_memory_slot *memslot)
 static void kvm_free_physmem_slot(struct kvm_memory_slot *free,
 				  struct kvm_memory_slot *dont)
 {
-	int i;
-
 	if (!dont || free->rmap != dont->rmap)
 		vfree(free->rmap);
 
 	if (!dont || free->dirty_bitmap != dont->dirty_bitmap)
 		kvm_destroy_dirty_bitmap(free);
 
-
-	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
-		if (!dont || free->lpage_info[i] != dont->lpage_info[i]) {
-			vfree(free->lpage_info[i]);
-			free->lpage_info[i] = NULL;
-		}
-	}
+	kvm_arch_free_memslot(free, dont);
 
 	free->npages = 0;
 	free->rmap = NULL;
@@ -685,53 +677,6 @@ void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new)
 	slots->generation++;
 }
 
-#ifndef CONFIG_S390
-static int create_lpage_info(struct kvm_memory_slot *slot, unsigned long npages)
-{
-	int i;
-
-	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
-		unsigned long ugfn;
-		int lpages;
-		int level = i + 2;
-
-		lpages = gfn_to_index(slot->base_gfn + npages - 1,
-				      slot->base_gfn, level) + 1;
-
-		slot->lpage_info[i] = vzalloc(lpages * sizeof(*slot->lpage_info[i]));
-		if (!slot->lpage_info[i])
-			goto out_free;
-
-		if (slot->base_gfn & (KVM_PAGES_PER_HPAGE(level) - 1))
-			slot->lpage_info[i][0].write_count = 1;
-		if ((slot->base_gfn + npages) & (KVM_PAGES_PER_HPAGE(level) - 1))
-			slot->lpage_info[i][lpages - 1].write_count = 1;
-		ugfn = slot->userspace_addr >> PAGE_SHIFT;
-		/*
-		 * If the gfn and userspace address are not aligned wrt each
-		 * other, or if explicitly asked to, disable large page
-		 * support for this slot
-		 */
-		if ((slot->base_gfn ^ ugfn) & (KVM_PAGES_PER_HPAGE(level) - 1) ||
-		    !largepages_enabled) {
-			unsigned long j;
-
-			for (j = 0; j < lpages; ++j)
-				slot->lpage_info[i][j].write_count = 1;
-		}
-	}
-
-	return 0;
-
-out_free:
-	for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i) {
-		vfree(slot->lpage_info[i]);
-		slot->lpage_info[i] = NULL;
-	}
-	return -ENOMEM;
-}
-#endif /* not defined CONFIG_S390 */
-
 /*
  * Allocate some memory and give it an address in the guest physical address
  * space.
@@ -819,10 +764,9 @@ int __kvm_set_memory_region(struct kvm *kvm,
 		new.rmap = vzalloc(npages * sizeof(*new.rmap));
 		if (!new.rmap)
 			goto out_free;
-
-		if (create_lpage_info(&new, npages))
-			goto out_free;
 #endif /* not defined CONFIG_S390 */
+		if (kvm_arch_create_memslot(&new, npages))
+			goto out_free;
 	}
 
 	/* Allocate page dirty bitmap if needed */
@@ -880,8 +824,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	if (!npages) {
 		new.rmap = NULL;
 		new.dirty_bitmap = NULL;
-		for (i = 0; i < KVM_NR_PAGE_SIZES - 1; ++i)
-			new.lpage_info[i] = NULL;
+		memset(&new.arch, 0, sizeof(new.arch));
 	}
 
 	update_memslots(slots, &new);
@@ -968,6 +911,11 @@ out:
 	return r;
 }
 
+bool kvm_largepages_enabled(void)
+{
+	return largepages_enabled;
+}
+
 void kvm_disable_largepages(void)
 {
 	largepages_enabled = false;
-- 
cgit v1.2.3-70-g09d2


From 7f3d35fddd173e52886d03bc34b5b5d6f5bea343 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Wed, 8 Feb 2012 14:34:38 +0100
Subject: KVM: x86 emulator: Fix task switch privilege checks

Currently, all task switches check privileges against the DPL of the
TSS. This is only correct for jmp/call to a TSS. If a task gate is used,
the DPL of this take gate is used for the check instead. Exceptions,
external interrupts and iret shouldn't perform any check.

[avi: kill kvm-kmod remnants]

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/include/asm/kvm_emulate.h |  2 +-
 arch/x86/include/asm/kvm_host.h    |  4 +--
 arch/x86/kvm/emulate.c             | 53 +++++++++++++++++++++++++++++++++-----
 arch/x86/kvm/svm.c                 |  5 +++-
 arch/x86/kvm/vmx.c                 |  8 +++---
 arch/x86/kvm/x86.c                 |  6 ++---
 6 files changed, 61 insertions(+), 17 deletions(-)

(limited to 'arch/x86/include/asm/kvm_host.h')

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 7b9cfc4878a..df437b68f42 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -388,7 +388,7 @@ bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt);
 #define EMULATION_INTERCEPTED 2
 int x86_emulate_insn(struct x86_emulate_ctxt *ctxt);
 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
-			 u16 tss_selector, int reason,
+			 u16 tss_selector, int idt_index, int reason,
 			 bool has_error_code, u32 error_code);
 int emulate_int_real(struct x86_emulate_ctxt *ctxt, int irq);
 #endif /* _ASM_X86_KVM_X86_EMULATE_H */
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 74c9edf2bb1..e216ba066e7 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -768,8 +768,8 @@ int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
 void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
 int kvm_load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, int seg);
 
-int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
-		    bool has_error_code, u32 error_code);
+int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
+		    int reason, bool has_error_code, u32 error_code);
 
 int kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
 int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 71450aca3b8..fa310a48591 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1152,6 +1152,22 @@ static int pio_in_emulated(struct x86_emulate_ctxt *ctxt,
 	return 1;
 }
 
+static int read_interrupt_descriptor(struct x86_emulate_ctxt *ctxt,
+				     u16 index, struct desc_struct *desc)
+{
+	struct desc_ptr dt;
+	ulong addr;
+
+	ctxt->ops->get_idt(ctxt, &dt);
+
+	if (dt.size < index * 8 + 7)
+		return emulate_gp(ctxt, index << 3 | 0x2);
+
+	addr = dt.address + index * 8;
+	return ctxt->ops->read_std(ctxt, addr, desc, sizeof *desc,
+				   &ctxt->exception);
+}
+
 static void get_descriptor_table_ptr(struct x86_emulate_ctxt *ctxt,
 				     u16 selector, struct desc_ptr *dt)
 {
@@ -2421,7 +2437,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
 }
 
 static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
-				   u16 tss_selector, int reason,
+				   u16 tss_selector, int idt_index, int reason,
 				   bool has_error_code, u32 error_code)
 {
 	struct x86_emulate_ops *ops = ctxt->ops;
@@ -2443,12 +2459,35 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
 
 	/* FIXME: check that next_tss_desc is tss */
 
-	if (reason != TASK_SWITCH_IRET) {
-		if ((tss_selector & 3) > next_tss_desc.dpl ||
-		    ops->cpl(ctxt) > next_tss_desc.dpl)
-			return emulate_gp(ctxt, 0);
+	/*
+	 * Check privileges. The three cases are task switch caused by...
+	 *
+	 * 1. jmp/call/int to task gate: Check against DPL of the task gate
+	 * 2. Exception/IRQ/iret: No check is performed
+	 * 3. jmp/call to TSS: Check agains DPL of the TSS
+	 */
+	if (reason == TASK_SWITCH_GATE) {
+		if (idt_index != -1) {
+			/* Software interrupts */
+			struct desc_struct task_gate_desc;
+			int dpl;
+
+			ret = read_interrupt_descriptor(ctxt, idt_index,
+							&task_gate_desc);
+			if (ret != X86EMUL_CONTINUE)
+				return ret;
+
+			dpl = task_gate_desc.dpl;
+			if ((tss_selector & 3) > dpl || ops->cpl(ctxt) > dpl)
+				return emulate_gp(ctxt, (idt_index << 3) | 0x2);
+		}
+	} else if (reason != TASK_SWITCH_IRET) {
+		int dpl = next_tss_desc.dpl;
+		if ((tss_selector & 3) > dpl || ops->cpl(ctxt) > dpl)
+			return emulate_gp(ctxt, tss_selector);
 	}
 
+
 	desc_limit = desc_limit_scaled(&next_tss_desc);
 	if (!next_tss_desc.p ||
 	    ((desc_limit < 0x67 && (next_tss_desc.type & 8)) ||
@@ -2501,7 +2540,7 @@ static int emulator_do_task_switch(struct x86_emulate_ctxt *ctxt,
 }
 
 int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
-			 u16 tss_selector, int reason,
+			 u16 tss_selector, int idt_index, int reason,
 			 bool has_error_code, u32 error_code)
 {
 	int rc;
@@ -2509,7 +2548,7 @@ int emulator_task_switch(struct x86_emulate_ctxt *ctxt,
 	ctxt->_eip = ctxt->eip;
 	ctxt->dst.type = OP_NONE;
 
-	rc = emulator_do_task_switch(ctxt, tss_selector, reason,
+	rc = emulator_do_task_switch(ctxt, tss_selector, idt_index, reason,
 				     has_error_code, error_code);
 
 	if (rc == X86EMUL_CONTINUE)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 0b7690ee20b..95cdeaf9c71 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2799,7 +2799,10 @@ static int task_switch_interception(struct vcpu_svm *svm)
 	     (int_vec == OF_VECTOR || int_vec == BP_VECTOR)))
 		skip_emulated_instruction(&svm->vcpu);
 
-	if (kvm_task_switch(&svm->vcpu, tss_selector, reason,
+	if (int_type != SVM_EXITINTINFO_TYPE_SOFT)
+		int_vec = -1;
+
+	if (kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,
 				has_error_code, error_code) == EMULATE_FAIL) {
 		svm->vcpu.run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 		svm->vcpu.run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d2bd719925a..124a0952a04 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4658,9 +4658,10 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
 	bool has_error_code = false;
 	u32 error_code = 0;
 	u16 tss_selector;
-	int reason, type, idt_v;
+	int reason, type, idt_v, idt_index;
 
 	idt_v = (vmx->idt_vectoring_info & VECTORING_INFO_VALID_MASK);
+	idt_index = (vmx->idt_vectoring_info & VECTORING_INFO_VECTOR_MASK);
 	type = (vmx->idt_vectoring_info & VECTORING_INFO_TYPE_MASK);
 
 	exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
@@ -4698,8 +4699,9 @@ static int handle_task_switch(struct kvm_vcpu *vcpu)
 		       type != INTR_TYPE_NMI_INTR))
 		skip_emulated_instruction(vcpu);
 
-	if (kvm_task_switch(vcpu, tss_selector, reason,
-				has_error_code, error_code) == EMULATE_FAIL) {
+	if (kvm_task_switch(vcpu, tss_selector,
+			    type == INTR_TYPE_SOFT_INTR ? idt_index : -1, reason,
+			    has_error_code, error_code) == EMULATE_FAIL) {
 		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
 		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
 		vcpu->run->internal.ndata = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ca74c1dadf3..490a1b1a255 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5655,15 +5655,15 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
-int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason,
-		    bool has_error_code, u32 error_code)
+int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
+		    int reason, bool has_error_code, u32 error_code)
 {
 	struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
 	int ret;
 
 	init_emulate_ctxt(vcpu);
 
-	ret = emulator_task_switch(ctxt, tss_selector, reason,
+	ret = emulator_task_switch(ctxt, tss_selector, idt_index, reason,
 				   has_error_code, error_code);
 
 	if (ret)
-- 
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