Commit 1cac8d9f authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: Check for existing Hyper-V vCPU in kvm_hv_vcpu_init() 



When potentially allocating/initializing the Hyper-V vCPU struct, check
for an existing instance in kvm_hv_vcpu_init() instead of requiring
callers to perform the check.  Relying on callers to do the check is
risky as it's all too easy for KVM to overwrite vcpu->arch.hyperv and
leak memory, and it adds additional burden on callers without much
benefit.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarWei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20220830133737.1539624-5-vkuznets@redhat.com


Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent ce2196b8

arch/x86/kvm/hyperv.c

+12 −15
Original line number Diff line number Diff line
@@ -936,9 +936,12 @@ static void stimer_init(struct kvm_vcpu_hv_stimer *stimer, int timer_index) 


static int kvm_hv_vcpu_init(struct kvm_vcpu *vcpu)

{

	struct kvm_vcpu_hv *hv_vcpu;

	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);

	int i;



	if (hv_vcpu)

		return 0;



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

	if (!hv_vcpu)

		return -ENOMEM;
@@ -962,11 +965,9 @@ int kvm_hv_activate_synic(struct kvm_vcpu *vcpu, bool dont_zero_synic_pages) 
	struct kvm_vcpu_hv_synic *synic;

	int r;



	if (!to_hv_vcpu(vcpu)) {

	r = kvm_hv_vcpu_init(vcpu);

	if (r)

		return r;

	}



	synic = to_hv_synic(vcpu);
@@ -1660,10 +1661,8 @@ int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host) 
	if (!host && !vcpu->arch.hyperv_enabled)

		return 1;



	if (!to_hv_vcpu(vcpu)) {

	if (kvm_hv_vcpu_init(vcpu))

		return 1;

	}



	if (kvm_hv_msr_partition_wide(msr)) {

		int r;
@@ -1683,10 +1682,8 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) 
	if (!host && !vcpu->arch.hyperv_enabled)

		return 1;



	if (!to_hv_vcpu(vcpu)) {

	if (kvm_hv_vcpu_init(vcpu))

		return 1;

	}



	if (kvm_hv_msr_partition_wide(msr)) {

		int r;
@@ -2000,7 +1997,7 @@ void kvm_hv_set_cpuid(struct kvm_vcpu *vcpu) 
		return;

	}



	if (!to_hv_vcpu(vcpu) && kvm_hv_vcpu_init(vcpu))

	if (kvm_hv_vcpu_init(vcpu))

		return;



	hv_vcpu = to_hv_vcpu(vcpu);