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 <>
Message-Id: <>
Signed-off-by: default avatarPaolo Bonzini <>
parent f2bc14b6
......@@ -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;
......@@ -837,6 +837,9 @@ void kvm_hv_vcpu_uninit(struct kvm_vcpu *vcpu)
for (i = 0; i < ARRAY_SIZE(hv_vcpu->stimer); i++)
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)
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;
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)
......@@ -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);
......@@ -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;
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)
return 0;
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