On 27/05/20 10:54, Sean Christopherson wrote:
> Initialize vcpu->arch.tdp_level during vCPU creation to avoid consuming
> garbage if userspace calls KVM_RUN without first calling KVM_SET_CPUID.
>
> Fixes: e93fd3b3e89e9 ("KVM: x86/mmu: Capture TDP level when updating CPUID")
> Reported-by: syzbot+904752567107eefb7...@syzkaller.appspotmail.com
> Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
> ---
> arch/x86/kvm/x86.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index b226fb8abe41b..01a6304056197 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -9414,6 +9414,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> fx_init(vcpu);
>
> vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
> + vcpu->arch.tdp_level = kvm_x86_ops.get_tdp_level(vcpu);
>
> vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;
Queued, it is probably a good idea to add a selftests testcase for this
(it's even okay if it doesn't use the whole selftests infrastructure and
invokes KVM_CREATE_VM/KVM_CREATE_VCPU/KVM_RUN manually).
Paolo
