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[PATCH v3 00/14] KVM: x86: break the xAPIC barrier

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  [PATCH v3 00/14] KVM: x86: break the xAPIC barrier Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 05/14] KVM: x86: use generic function for MSI parsing Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 10/14] KVM: pass struct kvm to kvm_set_routing_entry Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 03/14] KVM: x86: use physical LAPIC array for logical x2APIC Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 02/14] KVM: x86: add kvm_apic_map_get_dest_lapic Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
      Re: [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map Paolo Bonzini <pbonzini@redhat.com> - 2016-07-13 10:40 +0200
        Re: [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map Radim Krčmář <rkrcmar@redhat.com> - 2016-07-13 16:40 +0200
    [PATCH v3 01/14] KVM: x86: bump KVM_SOFT_MAX_VCPUS to 240 Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 06/14] KVM: x86: use hardware-compatible format for APIC ID register Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 13/14] KVM: x86: bump MAX_VCPUS to 288 Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200
    [PATCH v3 08/14] KVM: VMX: optimize APIC ID read with APICv Radim Krčmář <rkrcmar@redhat.com> - 2016-07-12 22:20 +0200

#1441711 — [PATCH v3 00/14] KVM: x86: break the xAPIC barrier

This series allows userspace to create and send interrupts to VCPUs with
APIC ID > 255.

v3:
[6/14] ignore APIC ID register in x2apic mode [Zhang and Paolo]
[10/14]
* use sub-feature flags -- they allow userspace to postpone enablement
* check invalid msi route in kvm_arch_set_irq_inatomic [Zhang]
[11/14] new

v2: http://www.spinics.net/lists/kvm/msg135220.html


Radim Krčmář (14):
  KVM: x86: bump KVM_SOFT_MAX_VCPUS to 240
  KVM: x86: add kvm_apic_map_get_dest_lapic
  KVM: x86: use physical LAPIC array for logical x2APIC
  KVM: x86: dynamic kvm_apic_map
  KVM: x86: use generic function for MSI parsing
  KVM: x86: use hardware-compatible format for APIC ID register
  KVM: x86: reset APIC ID when enabling LAPIC
  KVM: VMX: optimize APIC ID read with APICv
  KVM: x86: reset lapic base in kvm_lapic_reset
  KVM: pass struct kvm to kvm_set_routing_entry
  KVM: x86: add KVM_CAP_X2APIC_API
  KVM: x86: add a flag to disable KVM x2apic broadcast quirk
  KVM: x86: bump MAX_VCPUS to 288
  KVM: x86: bump KVM_MAX_VCPU_ID to 1023

 Documentation/virtual/kvm/api.txt |  45 +++++
 arch/powerpc/kvm/mpic.c           |   3 +-
 arch/s390/kvm/interrupt.c         |   3 +-
 arch/x86/include/asm/kvm_host.h   |  19 +-
 arch/x86/kvm/irq_comm.c           |  47 +++--
 arch/x86/kvm/lapic.c              | 408 ++++++++++++++++++++------------------
 arch/x86/kvm/lapic.h              |  14 +-
 arch/x86/kvm/vmx.c                |   5 +-
 arch/x86/kvm/x86.c                |  30 ++-
 include/linux/kvm_host.h          |   3 +-
 include/trace/events/kvm.h        |   5 +-
 include/uapi/linux/kvm.h          |   4 +
 virt/kvm/irqchip.c                |   7 +-
 13 files changed, 361 insertions(+), 232 deletions(-)

-- 
2.9.0

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#1441712 — [PATCH v3 05/14] KVM: x86: use generic function for MSI parsing

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/kvm/irq_comm.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index dfb4c6476877..47ad681a33fd 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -388,21 +388,16 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu,
 			       kvm->arch.nr_reserved_ioapic_pins);
 	for (i = 0; i < nr_ioapic_pins; ++i) {
 		hlist_for_each_entry(entry, &table->map[i], link) {
-			u32 dest_id, dest_mode;
-			bool level;
+			struct kvm_lapic_irq irq;
 
 			if (entry->type != KVM_IRQ_ROUTING_MSI)
 				continue;
-			dest_id = (entry->msi.address_lo >> 12) & 0xff;
-			dest_mode = (entry->msi.address_lo >> 2) & 0x1;
-			level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
-			if (level && kvm_apic_match_dest(vcpu, NULL, 0,
-						dest_id, dest_mode)) {
-				u32 vector = entry->msi.data & 0xff;
 
-				__set_bit(vector,
-					  ioapic_handled_vectors);
-			}
+			kvm_set_msi_irq(entry, &irq);
+
+			if (irq.level && kvm_apic_match_dest(vcpu, NULL, 0,
+						irq.dest_id, irq.dest_mode))
+				__set_bit(irq.vector, ioapic_handled_vectors);
 		}
 	}
 	srcu_read_unlock(&kvm->irq_srcu, idx);
-- 
2.9.0

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#1441713 — [PATCH v3 10/14] KVM: pass struct kvm to kvm_set_routing_entry

Arch-specific code will use it.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/powerpc/kvm/mpic.c   | 3 ++-
 arch/s390/kvm/interrupt.c | 3 ++-
 arch/x86/kvm/irq_comm.c   | 3 ++-
 include/linux/kvm_host.h  | 3 ++-
 virt/kvm/irqchip.c        | 7 ++++---
 5 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kvm/mpic.c b/arch/powerpc/kvm/mpic.c
index 6249cdc834d1..ed38f8114118 100644
--- a/arch/powerpc/kvm/mpic.c
+++ b/arch/powerpc/kvm/mpic.c
@@ -1823,7 +1823,8 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 	return 0;
 }
 
-int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+int kvm_set_routing_entry(struct kvm *kvm,
+			  struct kvm_kernel_irq_routing_entry *e,
 			  const struct kvm_irq_routing_entry *ue)
 {
 	int r = -EINVAL;
diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index ca19627779db..24524c0f3ef8 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -2246,7 +2246,8 @@ static int set_adapter_int(struct kvm_kernel_irq_routing_entry *e,
 	return ret;
 }
 
-int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+int kvm_set_routing_entry(struct kvm *kvm,
+			  struct kvm_kernel_irq_routing_entry *e,
 			  const struct kvm_irq_routing_entry *ue)
 {
 	int ret;
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 47ad681a33fd..889563d50c55 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -248,7 +248,8 @@ static int kvm_hv_set_sint(struct kvm_kernel_irq_routing_entry *e,
 	return kvm_hv_synic_set_irq(kvm, e->hv_sint.vcpu, e->hv_sint.sint);
 }
 
-int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+int kvm_set_routing_entry(struct kvm *kvm,
+			  struct kvm_kernel_irq_routing_entry *e,
 			  const struct kvm_irq_routing_entry *ue)
 {
 	int r = -EINVAL;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 66b2f6159aad..60d339faa94c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1011,7 +1011,8 @@ int kvm_set_irq_routing(struct kvm *kvm,
 			const struct kvm_irq_routing_entry *entries,
 			unsigned nr,
 			unsigned flags);
-int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+int kvm_set_routing_entry(struct kvm *kvm,
+			  struct kvm_kernel_irq_routing_entry *e,
 			  const struct kvm_irq_routing_entry *ue);
 void kvm_free_irq_routing(struct kvm *kvm);
 
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 8db197bb6c7a..df99e9c3b64d 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -135,7 +135,8 @@ void kvm_free_irq_routing(struct kvm *kvm)
 	free_irq_routing_table(rt);
 }
 
-static int setup_routing_entry(struct kvm_irq_routing_table *rt,
+static int setup_routing_entry(struct kvm *kvm,
+			       struct kvm_irq_routing_table *rt,
 			       struct kvm_kernel_irq_routing_entry *e,
 			       const struct kvm_irq_routing_entry *ue)
 {
@@ -154,7 +155,7 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 
 	e->gsi = ue->gsi;
 	e->type = ue->type;
-	r = kvm_set_routing_entry(e, ue);
+	r = kvm_set_routing_entry(kvm, e, ue);
 	if (r)
 		goto out;
 	if (e->type == KVM_IRQ_ROUTING_IRQCHIP)
@@ -211,7 +212,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
 			kfree(e);
 			goto out;
 		}
-		r = setup_routing_entry(new, e, ue);
+		r = setup_routing_entry(kvm, new, e, ue);
 		if (r) {
 			kfree(e);
 			goto out;
-- 
2.9.0

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#1441714 — [PATCH v3 03/14] KVM: x86: use physical LAPIC array for logical x2APIC

Logical x2APIC IDs map injectively to physical x2APIC IDs, so we can
reuse the physical array for them.  This allows us to save space by
separating logical xAPIC maps.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  6 ++--
 arch/x86/kvm/lapic.c            | 69 +++++++++++++++++++++--------------------
 2 files changed, 39 insertions(+), 36 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 53d39771842b..3194b19b9c7b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -683,8 +683,10 @@ struct kvm_apic_map {
 	struct rcu_head rcu;
 	u8 mode;
 	struct kvm_lapic *phys_map[256];
-	/* first index is cluster id second is cpu id in a cluster */
-	struct kvm_lapic *logical_map[16][16];
+	union {
+		struct kvm_lapic *xapic_flat_map[8];
+		struct kvm_lapic *xapic_cluster_map[16][4];
+	};
 };
 
 /* Hyper-V emulation context */
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2987843657db..9880d03f533d 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -115,26 +115,36 @@ static inline int apic_enabled(struct kvm_lapic *apic)
 	(LVT_MASK | APIC_MODE_MASK | APIC_INPUT_POLARITY | \
 	 APIC_LVT_REMOTE_IRR | APIC_LVT_LEVEL_TRIGGER)
 
-/* The logical map is definitely wrong if we have multiple
- * modes at the same time.  (Physical map is always right.)
- */
-static inline bool kvm_apic_logical_map_valid(struct kvm_apic_map *map)
-{
-	return !(map->mode & (map->mode - 1));
-}
+static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map,
+		u32 dest_id, struct kvm_lapic ***cluster, u16 *mask) {
+	switch (map->mode) {
+	case KVM_APIC_MODE_X2APIC: {
+		u32 offset = (dest_id >> 16) * 16;
+		u32 max_apic_id = ARRAY_SIZE(map->phys_map) - 1;
 
-static inline void
-apic_logical_id(struct kvm_apic_map *map, u32 dest_id, u16 *cid, u16 *lid)
-{
-	unsigned lid_bits;
+		if (offset <= max_apic_id) {
+			u8 cluster_size = min(max_apic_id - offset + 1, 16U);
 
-	BUILD_BUG_ON(KVM_APIC_MODE_XAPIC_CLUSTER !=  4);
-	BUILD_BUG_ON(KVM_APIC_MODE_XAPIC_FLAT    !=  8);
-	BUILD_BUG_ON(KVM_APIC_MODE_X2APIC        != 16);
-	lid_bits = map->mode;
+			*cluster = &map->phys_map[offset];
+			*mask = dest_id & (0xffff >> (16 - cluster_size));
+		} else {
+			*mask = 0;
+		}
 
-	*cid = dest_id >> lid_bits;
-	*lid = dest_id & ((1 << lid_bits) - 1);
+		return true;
+		}
+	case KVM_APIC_MODE_XAPIC_FLAT:
+		*cluster = map->xapic_flat_map;
+		*mask = dest_id & 0xff;
+		return true;
+	case KVM_APIC_MODE_XAPIC_CLUSTER:
+		*cluster = map->xapic_cluster_map[dest_id >> 4];
+		*mask = dest_id & 0xf;
+		return true;
+	default:
+		/* Not optimized. */
+		return false;
+	}
 }
 
 static void recalculate_apic_map(struct kvm *kvm)
@@ -152,7 +162,8 @@ static void recalculate_apic_map(struct kvm *kvm)
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		struct kvm_lapic *apic = vcpu->arch.apic;
-		u16 cid, lid;
+		struct kvm_lapic **cluster;
+		u16 mask;
 		u32 ldr, aid;
 
 		if (!kvm_apic_present(vcpu))
@@ -174,13 +185,11 @@ static void recalculate_apic_map(struct kvm *kvm)
 				new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER;
 		}
 
-		if (!kvm_apic_logical_map_valid(new))
+		if (!kvm_apic_map_get_logical_dest(new, ldr, &cluster, &mask))
 			continue;
 
-		apic_logical_id(new, ldr, &cid, &lid);
-
-		if (lid && cid < ARRAY_SIZE(new->logical_map))
-			new->logical_map[cid][ffs(lid) - 1] = apic;
+		if (mask)
+			cluster[ffs(mask) - 1] = apic;
 	}
 out:
 	old = rcu_dereference_protected(kvm->arch.apic_map,
@@ -685,7 +694,6 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
 {
 	int i, lowest;
 	bool x2apic_ipi;
-	u16 cid;
 
 	if (irq->shorthand == APIC_DEST_SELF && src) {
 		*dst = src;
@@ -711,18 +719,11 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
 		return true;
 	}
 
-	if (!kvm_apic_logical_map_valid(map))
+	*bitmap = 0;
+	if (!kvm_apic_map_get_logical_dest(map, irq->dest_id, dst,
+				(u16 *)bitmap))
 		return false;
 
-	apic_logical_id(map, irq->dest_id, &cid, (u16 *)bitmap);
-
-	if (cid >= ARRAY_SIZE(map->logical_map)) {
-		*bitmap = 0;
-		return true;
-	}
-
-	*dst = map->logical_map[cid];
-
 	if (!kvm_lowest_prio_delivery(irq))
 		return true;
 
-- 
2.9.0

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#1441716 — [PATCH v3 02/14] KVM: x86: add kvm_apic_map_get_dest_lapic

kvm_irq_delivery_to_apic_fast and kvm_intr_is_single_vcpu_fast both
compute the interrupt destination.  Factor the code.

'struct kvm_lapic **dst = NULL' had to be added to silence GCC.
GCC might complain about potential NULL access in the future, because it
missed conditions that avoided uninitialized uses of dst.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/kvm/lapic.c | 242 ++++++++++++++++++++++-----------------------------
 1 file changed, 104 insertions(+), 138 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 22a6474af220..2987843657db 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -671,14 +671,99 @@ static void kvm_apic_disabled_lapic_found(struct kvm *kvm)
 	}
 }
 
+/* Return true if the interrupt can be handled by using *bitmap as index mask
+ * for valid destinations in *dst array.
+ * Return false if kvm_apic_map_get_dest_lapic did nothing useful.
+ * Note: we may have zero kvm_lapic destinations when we return true, which
+ * means that the interrupt should be dropped.  In this case, *bitmap would be
+ * zero and *dst undefined.
+ */
+static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
+		struct kvm_lapic **src, struct kvm_lapic_irq *irq,
+		struct kvm_apic_map *map, struct kvm_lapic ***dst,
+		unsigned long *bitmap)
+{
+	int i, lowest;
+	bool x2apic_ipi;
+	u16 cid;
+
+	if (irq->shorthand == APIC_DEST_SELF && src) {
+		*dst = src;
+		*bitmap = 1;
+		return true;
+	} else if (irq->shorthand)
+		return false;
+
+	x2apic_ipi = src && *src && apic_x2apic_mode(*src);
+	if (irq->dest_id == (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCAST))
+		return false;
+
+	if (!map)
+		return false;
+
+	if (irq->dest_mode == APIC_DEST_PHYSICAL) {
+		if (irq->dest_id >= ARRAY_SIZE(map->phys_map)) {
+			*bitmap = 0;
+		} else {
+			*dst = &map->phys_map[irq->dest_id];
+			*bitmap = 1;
+		}
+		return true;
+	}
+
+	if (!kvm_apic_logical_map_valid(map))
+		return false;
+
+	apic_logical_id(map, irq->dest_id, &cid, (u16 *)bitmap);
+
+	if (cid >= ARRAY_SIZE(map->logical_map)) {
+		*bitmap = 0;
+		return true;
+	}
+
+	*dst = map->logical_map[cid];
+
+	if (!kvm_lowest_prio_delivery(irq))
+		return true;
+
+	if (!kvm_vector_hashing_enabled()) {
+		lowest = -1;
+		for_each_set_bit(i, bitmap, 16) {
+			if (!(*dst)[i])
+				continue;
+			if (lowest < 0)
+				lowest = i;
+			else if (kvm_apic_compare_prio((*dst)[i]->vcpu,
+						(*dst)[lowest]->vcpu) < 0)
+				lowest = i;
+		}
+	} else {
+		if (!*bitmap)
+			return true;
+
+		lowest = kvm_vector_to_index(irq->vector, hweight16(*bitmap),
+				bitmap, 16);
+
+		if (!(*dst)[lowest]) {
+			kvm_apic_disabled_lapic_found(kvm);
+			*bitmap = 0;
+			return true;
+		}
+	}
+
+	*bitmap = (lowest >= 0) ? 1 << lowest : 0;
+
+	return true;
+}
+
 bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
 		struct kvm_lapic_irq *irq, int *r, struct dest_map *dest_map)
 {
 	struct kvm_apic_map *map;
-	unsigned long bitmap = 1;
-	struct kvm_lapic **dst;
+	unsigned long bitmap;
+	struct kvm_lapic **dst = NULL;
 	int i;
-	bool ret, x2apic_ipi;
+	bool ret;
 
 	*r = -1;
 
@@ -687,86 +772,19 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
 		return true;
 	}
 
-	if (irq->shorthand)
-		return false;
-
-	x2apic_ipi = src && apic_x2apic_mode(src);
-	if (irq->dest_id == (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCAST))
-		return false;
-
-	ret = true;
 	rcu_read_lock();
 	map = rcu_dereference(kvm->arch.apic_map);
 
-	if (!map) {
-		ret = false;
-		goto out;
-	}
-
-	if (irq->dest_mode == APIC_DEST_PHYSICAL) {
-		if (irq->dest_id >= ARRAY_SIZE(map->phys_map))
-			goto out;
-
-		dst = &map->phys_map[irq->dest_id];
-	} else {
-		u16 cid;
-
-		if (!kvm_apic_logical_map_valid(map)) {
-			ret = false;
-			goto out;
+	ret = kvm_apic_map_get_dest_lapic(kvm, &src, irq, map, &dst, &bitmap);
+	if (ret)
+		for_each_set_bit(i, &bitmap, 16) {
+			if (!dst[i])
+				continue;
+			if (*r < 0)
+				*r = 0;
+			*r += kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
 		}
 
-		apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);
-
-		if (cid >= ARRAY_SIZE(map->logical_map))
-			goto out;
-
-		dst = map->logical_map[cid];
-
-		if (!kvm_lowest_prio_delivery(irq))
-			goto set_irq;
-
-		if (!kvm_vector_hashing_enabled()) {
-			int l = -1;
-			for_each_set_bit(i, &bitmap, 16) {
-				if (!dst[i])
-					continue;
-				if (l < 0)
-					l = i;
-				else if (kvm_apic_compare_prio(dst[i]->vcpu,
-							dst[l]->vcpu) < 0)
-					l = i;
-			}
-			bitmap = (l >= 0) ? 1 << l : 0;
-		} else {
-			int idx;
-			unsigned int dest_vcpus;
-
-			dest_vcpus = hweight16(bitmap);
-			if (dest_vcpus == 0)
-				goto out;
-
-			idx = kvm_vector_to_index(irq->vector,
-				dest_vcpus, &bitmap, 16);
-
-			if (!dst[idx]) {
-				kvm_apic_disabled_lapic_found(kvm);
-				goto out;
-			}
-
-			bitmap = (idx >= 0) ? 1 << idx : 0;
-		}
-	}
-
-set_irq:
-	for_each_set_bit(i, &bitmap, 16) {
-		if (!dst[i])
-			continue;
-		if (*r < 0)
-			*r = 0;
-		*r += kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
-	}
-out:
 	rcu_read_unlock();
 	return ret;
 }
@@ -789,8 +807,9 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
 			struct kvm_vcpu **dest_vcpu)
 {
 	struct kvm_apic_map *map;
+	unsigned long bitmap;
+	struct kvm_lapic **dst = NULL;
 	bool ret = false;
-	struct kvm_lapic *dst = NULL;
 
 	if (irq->shorthand)
 		return false;
@@ -798,69 +817,16 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
 	rcu_read_lock();
 	map = rcu_dereference(kvm->arch.apic_map);
 
-	if (!map)
-		goto out;
+	if (kvm_apic_map_get_dest_lapic(kvm, NULL, irq, map, &dst, &bitmap) &&
+			hweight16(bitmap) == 1) {
+		unsigned long i = find_first_bit(&bitmap, 16);
 
-	if (irq->dest_mode == APIC_DEST_PHYSICAL) {
-		if (irq->dest_id == 0xFF)
-			goto out;
-
-		if (irq->dest_id >= ARRAY_SIZE(map->phys_map))
-			goto out;
-
-		dst = map->phys_map[irq->dest_id];
-		if (dst && kvm_apic_present(dst->vcpu))
-			*dest_vcpu = dst->vcpu;
-		else
-			goto out;
-	} else {
-		u16 cid;
-		unsigned long bitmap = 1;
-		int i, r = 0;
-
-		if (!kvm_apic_logical_map_valid(map))
-			goto out;
-
-		apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);
-
-		if (cid >= ARRAY_SIZE(map->logical_map))
-			goto out;
-
-		if (kvm_vector_hashing_enabled() &&
-				kvm_lowest_prio_delivery(irq)) {
-			int idx;
-			unsigned int dest_vcpus;
-
-			dest_vcpus = hweight16(bitmap);
-			if (dest_vcpus == 0)
-				goto out;
-
-			idx = kvm_vector_to_index(irq->vector, dest_vcpus,
-						  &bitmap, 16);
-
-			dst = map->logical_map[cid][idx];
-			if (!dst) {
-				kvm_apic_disabled_lapic_found(kvm);
-				goto out;
-			}
-
-			*dest_vcpu = dst->vcpu;
-		} else {
-			for_each_set_bit(i, &bitmap, 16) {
-				dst = map->logical_map[cid][i];
-				if (++r == 2)
-					goto out;
-			}
-
-			if (dst && kvm_apic_present(dst->vcpu))
-				*dest_vcpu = dst->vcpu;
-			else
-				goto out;
+		if (dst[i]) {
+			*dest_vcpu = dst[i]->vcpu;
+			ret = true;
 		}
 	}
 
-	ret = true;
-out:
 	rcu_read_unlock();
 	return ret;
 }
-- 
2.9.0

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#1441717 — [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map

x2APIC supports up to 2^32-1 LAPICs, but most guest in coming years will
have slighly less VCPUs.  Dynamic size saves memory at the cost of
turning one constant into a variable.

apic_map mutex had to be moved before allocation to avoid races with cpu
hotplug.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/include/asm/kvm_host.h |  3 ++-
 arch/x86/kvm/lapic.c            | 18 +++++++++++++-----
 arch/x86/kvm/lapic.h            |  2 +-
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3194b19b9c7b..643e3dffcd85 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -682,11 +682,12 @@ struct kvm_arch_memory_slot {
 struct kvm_apic_map {
 	struct rcu_head rcu;
 	u8 mode;
-	struct kvm_lapic *phys_map[256];
+	u32 max_apic_id;
 	union {
 		struct kvm_lapic *xapic_flat_map[8];
 		struct kvm_lapic *xapic_cluster_map[16][4];
 	};
+	struct kvm_lapic *phys_map[];
 };
 
 /* Hyper-V emulation context */
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 9880d03f533d..224fc1c5fcc6 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -120,7 +120,7 @@ static inline bool kvm_apic_map_get_logical_dest(struct kvm_apic_map *map,
 	switch (map->mode) {
 	case KVM_APIC_MODE_X2APIC: {
 		u32 offset = (dest_id >> 16) * 16;
-		u32 max_apic_id = ARRAY_SIZE(map->phys_map) - 1;
+		u32 max_apic_id = map->max_apic_id;
 
 		if (offset <= max_apic_id) {
 			u8 cluster_size = min(max_apic_id - offset + 1, 16U);
@@ -152,14 +152,22 @@ static void recalculate_apic_map(struct kvm *kvm)
 	struct kvm_apic_map *new, *old = NULL;
 	struct kvm_vcpu *vcpu;
 	int i;
-
-	new = kzalloc(sizeof(struct kvm_apic_map), GFP_KERNEL);
+	u32 max_id = 255;
 
 	mutex_lock(&kvm->arch.apic_map_lock);
 
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		if (kvm_apic_present(vcpu))
+			max_id = max(max_id, kvm_apic_id(vcpu->arch.apic));
+
+	new = kzalloc(sizeof(struct kvm_apic_map) +
+	              sizeof(struct kvm_lapic *) * (max_id + 1), GFP_KERNEL);
+
 	if (!new)
 		goto out;
 
+	new->max_apic_id = max_id;
+
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		struct kvm_lapic *apic = vcpu->arch.apic;
 		struct kvm_lapic **cluster;
@@ -172,7 +180,7 @@ static void recalculate_apic_map(struct kvm *kvm)
 		aid = kvm_apic_id(apic);
 		ldr = kvm_lapic_get_reg(apic, APIC_LDR);
 
-		if (aid < ARRAY_SIZE(new->phys_map))
+		if (aid <= new->max_apic_id)
 			new->phys_map[aid] = apic;
 
 		if (apic_x2apic_mode(apic)) {
@@ -710,7 +718,7 @@ static inline bool kvm_apic_map_get_dest_lapic(struct kvm *kvm,
 		return false;
 
 	if (irq->dest_mode == APIC_DEST_PHYSICAL) {
-		if (irq->dest_id >= ARRAY_SIZE(map->phys_map)) {
+		if (irq->dest_id > map->max_apic_id) {
 			*bitmap = 0;
 		} else {
 			*dst = &map->phys_map[irq->dest_id];
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 336ba51bb16e..8d811139d2b3 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -200,7 +200,7 @@ static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu)
 	return lapic_in_kernel(vcpu) && test_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
 }
 
-static inline int kvm_apic_id(struct kvm_lapic *apic)
+static inline u32 kvm_apic_id(struct kvm_lapic *apic)
 {
 	return (kvm_lapic_get_reg(apic, APIC_ID) >> 24) & 0xff;
 }
-- 
2.9.0

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#1442178 — Re: [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map

On 12/07/2016 22:09, Radim Krčmář wrote:
> x2APIC supports up to 2^32-1 LAPICs, but most guest in coming years will
> have slighly less VCPUs.

It's "fewer", not "less" (that's important to make the joke less uncanny
for native speakers :)).  Less goes with uncountable nouns such as milk.

Paolo

> Dynamic size saves memory at the cost of
> turning one constant into a variable.

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#1442501 — Re: [PATCH v3 04/14] KVM: x86: dynamic kvm_apic_map

2016-07-13 10:29+0200, Paolo Bonzini:
> On 12/07/2016 22:09, Radim Krčmář wrote:
>> x2APIC supports up to 2^32-1 LAPICs, but most guest in coming years will
>> have slighly less VCPUs.
> 
> It's "fewer", not "less" (that's important to make the joke less uncanny
> for native speakers :)).  Less goes with uncountable nouns such as milk.

Thanks.  My syntax should be enough to creep native speakers. :)

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#1441718 — [PATCH v3 01/14] KVM: x86: bump KVM_SOFT_MAX_VCPUS to 240

240 has been well tested by Red Hat.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7a628fb6a2c2..53d39771842b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -35,7 +35,7 @@
 #include <asm/kvm_page_track.h>
 
 #define KVM_MAX_VCPUS 255
-#define KVM_SOFT_MAX_VCPUS 160
+#define KVM_SOFT_MAX_VCPUS 240
 #define KVM_USER_MEM_SLOTS 509
 /* memory slots that are not exposed to userspace */
 #define KVM_PRIVATE_MEM_SLOTS 3
-- 
2.9.0

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#1441719 — [PATCH v3 06/14] KVM: x86: use hardware-compatible format for APIC ID register

We currently always shift APIC ID as if APIC was in xAPIC mode.
x2APIC mode wants to use more bits and storing a hardware-compabible
value is the the sanest option.

KVM API to set the lapic expects that bottom 8 bits of APIC ID are in
top 8 bits of APIC_ID register, so the register needs to be shifted in
x2APIC mode.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 v3: ignore APIC ID register in x2apic mode [Zhang and Paolo]

 arch/x86/kvm/lapic.c | 52 +++++++++++++++++++++++++++++++++++++---------------
 arch/x86/kvm/lapic.h | 12 +++++++++---
 arch/x86/kvm/x86.c   | 10 ++++++----
 3 files changed, 52 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 224fc1c5fcc6..41089dbeeafc 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -227,7 +227,7 @@ static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val)
 	}
 }
 
-static inline void kvm_apic_set_id(struct kvm_lapic *apic, u8 id)
+static inline void kvm_apic_set_xapic_id(struct kvm_lapic *apic, u8 id)
 {
 	kvm_lapic_set_reg(apic, APIC_ID, id << 24);
 	recalculate_apic_map(apic->vcpu->kvm);
@@ -239,11 +239,11 @@ static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id)
 	recalculate_apic_map(apic->vcpu->kvm);
 }
 
-static inline void kvm_apic_set_x2apic_id(struct kvm_lapic *apic, u8 id)
+static inline void kvm_apic_set_x2apic_id(struct kvm_lapic *apic, u32 id)
 {
 	u32 ldr = ((id >> 4) << 16) | (1 << (id & 0xf));
 
-	kvm_lapic_set_reg(apic, APIC_ID, id << 24);
+	kvm_lapic_set_reg(apic, APIC_ID, id);
 	kvm_lapic_set_reg(apic, APIC_LDR, ldr);
 	recalculate_apic_map(apic->vcpu->kvm);
 }
@@ -1102,12 +1102,6 @@ static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
 		return 0;
 
 	switch (offset) {
-	case APIC_ID:
-		if (apic_x2apic_mode(apic))
-			val = kvm_apic_id(apic);
-		else
-			val = kvm_apic_id(apic) << 24;
-		break;
 	case APIC_ARBPRI:
 		apic_debug("Access APIC ARBPRI register which is for P6\n");
 		break;
@@ -1465,7 +1459,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
 	switch (reg) {
 	case APIC_ID:		/* Local APIC ID */
 		if (!apic_x2apic_mode(apic))
-			kvm_apic_set_id(apic, val >> 24);
+			kvm_apic_set_xapic_id(apic, val >> 24);
 		else
 			ret = 1;
 		break;
@@ -1769,7 +1763,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
 	hrtimer_cancel(&apic->lapic_timer.timer);
 
 	if (!init_event)
-		kvm_apic_set_id(apic, vcpu->vcpu_id);
+		kvm_apic_set_xapic_id(apic, vcpu->vcpu_id);
 	kvm_apic_set_version(apic->vcpu);
 
 	for (i = 0; i < KVM_APIC_LVT_NUM; i++)
@@ -1990,17 +1984,43 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
 	return vector;
 }
 
-void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
-		struct kvm_lapic_state *s)
+static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
+		struct kvm_lapic_state *s, bool set)
+{
+	if (apic_x2apic_mode(vcpu->arch.apic)) {
+		u32 *id = (u32 *)(s->regs + APIC_ID);
+
+		if (set)
+			*id >>= 24;
+		else
+			*id <<= 24;
+	}
+
+	return 0;
+}
+
+int kvm_apic_get_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
+{
+	memcpy(s->regs, vcpu->arch.apic->regs, sizeof(*s));
+	return kvm_apic_state_fixup(vcpu, s, false);
+}
+
+int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
+	int r;
+
 
 	kvm_lapic_set_base(vcpu, vcpu->arch.apic_base);
 	/* set SPIV separately to get count of SW disabled APICs right */
 	apic_set_spiv(apic, *((u32 *)(s->regs + APIC_SPIV)));
+
+	r = kvm_apic_state_fixup(vcpu, s, true);
+	if (r)
+		return r;
 	memcpy(vcpu->arch.apic->regs, s->regs, sizeof *s);
-	/* call kvm_apic_set_id() to put apic into apic_map */
-	kvm_apic_set_id(apic, kvm_apic_id(apic));
+
+	recalculate_apic_map(vcpu->kvm);
 	kvm_apic_set_version(vcpu);
 
 	apic_update_ppr(apic);
@@ -2026,6 +2046,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
 		kvm_rtc_eoi_tracking_restore_one(vcpu);
 
 	vcpu->arch.apic_arb_prio = 0;
+
+	return 0;
 }
 
 void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 8d811139d2b3..f60d01c29d51 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -81,8 +81,8 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
 
 u64 kvm_get_apic_base(struct kvm_vcpu *vcpu);
 int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
-void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
-		struct kvm_lapic_state *s);
+int kvm_apic_get_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
+int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
 int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);
 
 u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu);
@@ -202,7 +202,13 @@ static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu)
 
 static inline u32 kvm_apic_id(struct kvm_lapic *apic)
 {
-	return (kvm_lapic_get_reg(apic, APIC_ID) >> 24) & 0xff;
+	/* To avoid a race between apic_base and following APIC_ID update when
+	 * switching to x2apic_mode, the x2apic mode returns initial x2apic id.
+	 */
+	if (apic_x2apic_mode(apic))
+		return apic->vcpu->vcpu_id;
+
+	return kvm_lapic_get_reg(apic, APIC_ID) >> 24;
 }
 
 bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0cc6cf834cdd..b178c8c12717 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2779,15 +2779,17 @@ static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
 	if (vcpu->arch.apicv_active)
 		kvm_x86_ops->sync_pir_to_irr(vcpu);
 
-	memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);
-
-	return 0;
+	return kvm_apic_get_state(vcpu, s);
 }
 
 static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
 				    struct kvm_lapic_state *s)
 {
-	kvm_apic_post_state_restore(vcpu, s);
+	int r;
+
+	r = kvm_apic_set_state(vcpu, s);
+	if (r)
+		return r;
 	update_cr8_intercept(vcpu);
 
 	return 0;
-- 
2.9.0

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#1441721 — [PATCH v3 13/14] KVM: x86: bump MAX_VCPUS to 288

288 is in high demand because of Knights Landing CPU.
We cannot set the limit to 640k, because that would be wasting space.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 25bf9d627c15..276d6f449d13 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -34,7 +34,7 @@
 #include <asm/asm.h>
 #include <asm/kvm_page_track.h>
 
-#define KVM_MAX_VCPUS 255
+#define KVM_MAX_VCPUS 288
 #define KVM_SOFT_MAX_VCPUS 240
 #define KVM_USER_MEM_SLOTS 509
 /* memory slots that are not exposed to userspace */
-- 
2.9.0

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#1441722 — [PATCH v3 08/14] KVM: VMX: optimize APIC ID read with APICv

The register is in hardware-compatible format now, so there is not need
to intercept.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 arch/x86/kvm/vmx.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e51503063181..24b505fda7ad 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6456,9 +6456,6 @@ static __init int hardware_setup(void)
 	for (msr = 0x800; msr <= 0x8ff; msr++)
 		vmx_disable_intercept_msr_read_x2apic(msr);
 
-	/* According SDM, in x2apic mode, the whole id reg is used.  But in
-	 * KVM, it only use the highest eight bits. Need to intercept it */
-	vmx_enable_intercept_msr_read_x2apic(0x802);
 	/* TMCCT */
 	vmx_enable_intercept_msr_read_x2apic(0x839);
 	/* TPR */
-- 
2.9.0

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