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: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 3 ++-
arch/x86/kvm/hyperv.c | 16 ++++++++++++++--
arch/x86/kvm/hyperv.h | 13 ++++++-------
arch/x86/kvm/x86.c | 7 +++++--
4 files changed, 27 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3ab7b46087b7..94d00926b7ad 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -510,6 +510,7 @@ 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;
@@ -717,7 +718,7 @@ 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;
cpumask_var_t wbinvd_dirty_mask;
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 77deaadb8575..df7101b721e7 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -838,6 +838,9 @@ 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)
@@ -887,16 +890,25 @@ 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 = 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)
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 9ec7d686145a..a19e298463d0 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -52,20 +52,19 @@
static inline struct kvm_vcpu_hv *vcpu_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 *vcpu_to_synic(struct kvm_vcpu *vcpu)
{
- return &vcpu->arch.hyperv.synic;
+ struct kvm_vcpu_hv *hv_vcpu = vcpu_to_hv_vcpu(vcpu);
+
+ return &hv_vcpu->synic;
}
static inline struct kvm_vcpu *synic_to_vcpu(struct kvm_vcpu_hv_synic *synic)
@@ -96,7 +95,7 @@ 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);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fa077b47c0ed..e08209f570f0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9990,11 +9990,12 @@ 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 = kvm_x86_ops.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;
@@ -10005,6 +10006,8 @@ 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:
--
2.29.2
