* [PATCH] KVM: svm: Avoid NULL pointer dereference in svm_hv_update_vp_id()
@ 2021-06-14 11:38 Vitaly Kuznetsov
2021-06-14 13:31 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Vitaly Kuznetsov @ 2021-06-14 11:38 UTC (permalink / raw)
To: kvm, Paolo Bonzini
Cc: Vineeth Pillai, Sean Christopherson, Wanpeng Li, Jim Mattson,
Maxim Levitsky, linux-kernel
Hyper-V context is allocated dynamically when Hyper-V features are enabled
on a vCPU but svm_hv_update_vp_id() is called unconditionally from
svm_vcpu_run(), this leads to dereferencing to_hv_vcpu(vcpu) which can
be NULL. Use kvm_hv_get_vpindex() wrapper to avoid the problem.
Fixes: 4ba0d72aaa32 ("KVM: SVM: hyper-v: Direct Virtual Flush support")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
- The patch introducing the issue is currently in kvm/queue.
---
arch/x86/kvm/svm/svm_onhyperv.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
index ce23149670ea..9b9a55abc29f 100644
--- a/arch/x86/kvm/svm/svm_onhyperv.h
+++ b/arch/x86/kvm/svm/svm_onhyperv.h
@@ -99,9 +99,10 @@ static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
{
struct hv_enlightenments *hve =
(struct hv_enlightenments *)vmcb->control.reserved_sw;
+ u32 vp_index = kvm_hv_get_vpindex(vcpu);
- if (hve->hv_vp_id != to_hv_vcpu(vcpu)->vp_index) {
- hve->hv_vp_id = to_hv_vcpu(vcpu)->vp_index;
+ if (hve->hv_vp_id != vp_index) {
+ hve->hv_vp_id = vp_index;
vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
}
}
--
2.31.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] KVM: svm: Avoid NULL pointer dereference in svm_hv_update_vp_id()
2021-06-14 11:38 [PATCH] KVM: svm: Avoid NULL pointer dereference in svm_hv_update_vp_id() Vitaly Kuznetsov
@ 2021-06-14 13:31 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2021-06-14 13:31 UTC (permalink / raw)
To: Vitaly Kuznetsov, kvm
Cc: Vineeth Pillai, Sean Christopherson, Wanpeng Li, Jim Mattson,
Maxim Levitsky, linux-kernel
On 14/06/21 13:38, Vitaly Kuznetsov wrote:
> Hyper-V context is allocated dynamically when Hyper-V features are enabled
> on a vCPU but svm_hv_update_vp_id() is called unconditionally from
> svm_vcpu_run(), this leads to dereferencing to_hv_vcpu(vcpu) which can
> be NULL. Use kvm_hv_get_vpindex() wrapper to avoid the problem.
>
> Fixes: 4ba0d72aaa32 ("KVM: SVM: hyper-v: Direct Virtual Flush support")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> - The patch introducing the issue is currently in kvm/queue.
> ---
> arch/x86/kvm/svm/svm_onhyperv.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> index ce23149670ea..9b9a55abc29f 100644
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -99,9 +99,10 @@ static inline void svm_hv_update_vp_id(struct vmcb *vmcb,
> {
> struct hv_enlightenments *hve =
> (struct hv_enlightenments *)vmcb->control.reserved_sw;
> + u32 vp_index = kvm_hv_get_vpindex(vcpu);
>
> - if (hve->hv_vp_id != to_hv_vcpu(vcpu)->vp_index) {
> - hve->hv_vp_id = to_hv_vcpu(vcpu)->vp_index;
> + if (hve->hv_vp_id != vp_index) {
> + hve->hv_vp_id = vp_index;
> vmcb_mark_dirty(vmcb, VMCB_HV_NESTED_ENLIGHTENMENTS);
> }
> }
>
Squashed, thanks.
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2021-06-14 13:32 UTC | newest]
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2021-06-14 11:38 [PATCH] KVM: svm: Avoid NULL pointer dereference in svm_hv_update_vp_id() Vitaly Kuznetsov
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