Commit 4592b7ea authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini
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KVM: x86: hyper-v: Allocate 'struct kvm_vcpu_hv' dynamically 



Hyper-V context is only needed for guests which use Hyper-V emulation in
KVM (e.g. Windows/Hyper-V guests). 'struct kvm_vcpu_hv' is, however, quite
big, it accounts for more than 1/4 of the total 'struct kvm_vcpu_arch'
which is also quite big already. This all looks like a waste.

Allocate 'struct kvm_vcpu_hv' dynamically. This patch does not bring any
(intentional) functional change as we still allocate the context
unconditionally but it paves the way to doing that only when needed.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210126134816.1880136-13-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f2bc14b6

arch/x86/include/asm/kvm_host.h

+2 −1
Original line number Diff line number Diff line
@@ -519,6 +519,7 @@ struct kvm_vcpu_hv_synic { 


/* Hyper-V per vcpu emulation context */

struct kvm_vcpu_hv {

	struct kvm_vcpu *vcpu;

	u32 vp_index;

	u64 hv_vapic;

	s64 runtime_offset;
@@ -735,7 +736,7 @@ struct kvm_vcpu_arch { 
	/* used for guest single stepping over the given code position */

	unsigned long singlestep_rip;



	struct kvm_vcpu_hv hyperv;

	struct kvm_vcpu_hv *hyperv;

	struct kvm_vcpu_xen xen;



	cpumask_var_t wbinvd_dirty_mask;

arch/x86/kvm/hyperv.c

+14 −2
Original line number Diff line number Diff line
@@ -837,6 +837,9 @@ void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu) 


	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)

		stimer_cleanup(&hv_vcpu->stimer[i]);



	kfree(hv_vcpu);

	vcpu->arch.hyperv = NULL;

}



bool kvm_hv_assist_page_enabled(struct kvm_vcpu *vcpu)
@@ -886,16 +889,25 @@ static void stimer_init(struct kvm_vcpu_hv_stimer *stimer, int timer_index) 
	stimer_prepare_msg(stimer);

}



void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)

int kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)

{

	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

	struct kvm_vcpu_hv *hv_vcpu;

	int i;



	hv_vcpu = kzalloc(sizeof(struct kvm_vcpu_hv), GFP_KERNEL_ACCOUNT);

	if (!hv_vcpu)

		return -ENOMEM;



	vcpu->arch.hyperv = hv_vcpu;

	hv_vcpu->vcpu = vcpu;



	synic_init(&hv_vcpu->synic);



	bitmap_zero(hv_vcpu->stimer_pending_bitmap, HV_SYNIC_STIMER_COUNT);

	for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)

		stimer_init(&hv_vcpu->stimer[i], i);



	return 0;

}



void kvm_hv_vcpu_postcreate(struct kvm_vcpu *vcpu)

arch/x86/kvm/hyperv.h

+6 −7
Original line number Diff line number Diff line
@@ -57,20 +57,19 @@ static inline struct kvm_hv *to_kvm_hv(struct kvm *kvm) 


static inline struct kvm_vcpu_hv *to_hv_vcpu(struct kvm_vcpu *vcpu)

{

	return &vcpu->arch.hyperv;

	return vcpu->arch.hyperv;

}



static inline struct kvm_vcpu *hv_vcpu_to_vcpu(struct kvm_vcpu_hv *hv_vcpu)

{

	struct kvm_vcpu_arch *arch;



	arch = container_of(hv_vcpu, struct kvm_vcpu_arch, hyperv);

	return container_of(arch, struct kvm_vcpu, arch);

	return hv_vcpu->vcpu;

}



static inline struct kvm_vcpu_hv_synic *to_hv_synic(struct kvm_vcpu *vcpu)

{

	return &vcpu->arch.hyperv.synic;

	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);



	return &hv_vcpu->synic;

}



static inline struct kvm_vcpu *hv_synic_to_vcpu(struct kvm_vcpu_hv_synic *synic)
@@ -101,7 +100,7 @@ int kvm_hv_synic_set_irq(struct kvm *kvm, u32 vcpu_id, u32 sint); 
void kvm_hv_synic_send_eoi(struct kvm_vcpu *vcpu, int vector);

int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages);



void kvm_hv_vcpu_init(struct kvm_vcpu *vcpu);

int kvm_hv_vcpu_init(struct kvm_vcpu *vcpu);

void kvm_hv_vcpu_postcreate(struct kvm_vcpu *vcpu);

void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu);

arch/x86/kvm/x86.c

+5 −2
Original line number Diff line number Diff line
@@ -10083,11 +10083,12 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) 
	vcpu->arch.pending_external_vector = -1;

	vcpu->arch.preempted_in_kernel = false;



	kvm_hv_vcpu_init(vcpu);

	if (kvm_hv_vcpu_init(vcpu))

		goto free_guest_fpu;



	r = static_call(kvm_x86_vcpu_create)(vcpu);

	if (r)

		goto free_guest_fpu;

		goto free_hv_vcpu;



	vcpu->arch.arch_capabilities = kvm_get_arch_capabilities();

	vcpu->arch.msr_platform_info = MSR_PLATFORM_INFO_CPUID_FAULT;
@@ -10098,6 +10099,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) 
	vcpu_put(vcpu);

	return 0;



free_hv_vcpu:

	kvm_hv_vcpu_uninit(vcpu);

free_guest_fpu:

	kvm_free_guest_fpu(vcpu);

free_user_fpu: