Commit 3b5a5ffa authored by Radim Krčmář's avatar Radim Krčmář Committed by Paolo Bonzini
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KVM: x86: simplify kvm_apic_map 



recalculate_apic_map() uses two passes over all VCPUs.  This is a relic
from time when we selected a global mode in the first pass and set up
the optimized table in the second pass (to have a consistent mode).

Recent changes made mixed mode unoptimized and we can do it in one pass.
Format of logical MDA is a function of the mode, so we encode it in
apic_logical_id() and drop obsoleted variables from the struct.

Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-5-git-send-email-rkrcmar@redhat.com>
[Add lid_bits temporary in apic_logical_id. - Paolo]
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3548a259

arch/x86/include/asm/kvm_host.h

+0 −3
Original line number Diff line number Diff line
@@ -562,9 +562,6 @@ struct kvm_arch_memory_slot { 
struct kvm_apic_map {

	struct rcu_head rcu;

	u8 mode;

	u8 ldr_bits;

	/* fields bellow are used to decode ldr values in different modes */

	u32 cid_shift, cid_mask, lid_mask;

	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];

arch/x86/kvm/lapic.c

+28 −50
Original line number Diff line number Diff line
@@ -141,6 +141,20 @@ static inline bool kvm_apic_logical_map_valid(struct kvm_apic_map *map) 
	return !(map->mode & (map->mode - 1));

}



static inline void

apic_logical_id(struct kvm_apic_map *map, u32 dest_id, u16 *cid, u16 *lid)

{

	unsigned lid_bits;



	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;



	*cid = dest_id >> lid_bits;

	*lid = dest_id & ((1 << lid_bits) - 1);

}



static void recalculate_apic_map(struct kvm *kvm)

{

	struct kvm_apic_map *new, *old = NULL;
@@ -154,49 +168,6 @@ static void recalculate_apic_map(struct kvm *kvm) 
	if (!new)

		goto out;



	new->ldr_bits = 8;

	/* flat mode is default */

	new->cid_shift = 8;

	new->cid_mask = 0;

	new->lid_mask = 0xff;



	kvm_for_each_vcpu(i, vcpu, kvm) {

		struct kvm_lapic *apic = vcpu->arch.apic;



		if (!kvm_apic_present(vcpu))

			continue;



		if (apic_x2apic_mode(apic)) {

			new->ldr_bits = 32;

			new->cid_shift = 16;

			new->cid_mask = new->lid_mask = 0xffff;

			new->mode |= KVM_APIC_MODE_X2APIC;

		} else if (kvm_apic_get_reg(apic, APIC_LDR)) {

			if (kvm_apic_get_reg(apic, APIC_DFR) ==

							APIC_DFR_CLUSTER) {

				new->cid_shift = 4;

				new->cid_mask = 0xf;

				new->lid_mask = 0xf;

				new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER;

			} else {

				new->cid_shift = 8;

				new->cid_mask = 0;

				new->lid_mask = 0xff;

				new->mode |= KVM_APIC_MODE_XAPIC_FLAT;

			}

		}



		/*

		 * All APICs have to be configured in the same mode by an OS.

		 * We take advatage of this while building logical id loockup

		 * table. After reset APICs are in software disabled mode, so if

		 * we find apic with different setting we assume this is the mode

		 * OS wants all apics to be in; build lookup table accordingly.

		 */

		if (kvm_apic_sw_enabled(apic))

			break;

	}



	kvm_for_each_vcpu(i, vcpu, kvm) {

		struct kvm_lapic *apic = vcpu->arch.apic;

		u16 cid, lid;
@@ -207,15 +178,25 @@ static void recalculate_apic_map(struct kvm *kvm) 


		aid = kvm_apic_id(apic);

		ldr = kvm_apic_get_reg(apic, APIC_LDR);

		cid = apic_cluster_id(new, ldr);

		lid = apic_logical_id(new, ldr);



		if (aid < ARRAY_SIZE(new->phys_map))

			new->phys_map[aid] = apic;



		if (!kvm_apic_logical_map_valid(new));

		if (apic_x2apic_mode(apic)) {

			new->mode |= KVM_APIC_MODE_X2APIC;

		} else if (ldr) {

			ldr = GET_APIC_LOGICAL_ID(ldr);

			if (kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_FLAT)

				new->mode |= KVM_APIC_MODE_XAPIC_FLAT;

			else

				new->mode |= KVM_APIC_MODE_XAPIC_CLUSTER;

		}



		if (!kvm_apic_logical_map_valid(new))

			continue;



		apic_logical_id(new, ldr, &cid, &lid);



		if (lid && cid < ARRAY_SIZE(new->logical_map))

			new->logical_map[cid][ffs(lid) - 1] = apic;

	}
@@ -732,7 +713,6 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src, 


		dst = &map->phys_map[irq->dest_id];

	} else {

		u32 mda = irq->dest_id << (32 - map->ldr_bits);

		u16 cid;



		if (!kvm_apic_logical_map_valid(map)) {
@@ -740,15 +720,13 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src, 
			goto out;

		}



		cid = apic_cluster_id(map, mda);

		apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap);



		if (cid >= ARRAY_SIZE(map->logical_map))

			goto out;



		dst = map->logical_map[cid];



		bitmap = apic_logical_id(map, mda);



		if (irq->delivery_mode == APIC_DM_LOWEST) {

			int l = -1;

			for_each_set_bit(i, &bitmap, 16) {

arch/x86/kvm/lapic.h

+0 −15
Original line number Diff line number Diff line
@@ -148,21 +148,6 @@ static inline bool kvm_apic_vid_enabled(struct kvm *kvm) 
	return kvm_x86_ops->vm_has_apicv(kvm);

}



static inline u16 apic_cluster_id(struct kvm_apic_map *map, u32 ldr)

{

	u16 cid;

	ldr >>= 32 - map->ldr_bits;

	cid = (ldr >> map->cid_shift) & map->cid_mask;



	return cid;

}



static inline u16 apic_logical_id(struct kvm_apic_map *map, u32 ldr)

{

	ldr >>= (32 - map->ldr_bits);

	return ldr & map->lid_mask;

}



static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)

{

	return vcpu->arch.apic->pending_events;

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