Patch-mainline: v6.1-rc1
Git-commit: 1cac8d9f6bd25df3713103e44e2d9ca0c2e03c33
References: bsc#1206616
From: Sean Christopherson <seanjc@google.com>
Date: Tue, 30 Aug 2022 15:37:08 +0200
Subject: [PATCH] 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: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20220830133737.1539624-5-vkuznets@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/kvm/hyperv.c | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 611c349a08bf..8aadd31ed058 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -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;
- }
+ 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_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_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);
--
2.35.3