On Fri, Apr 23, 2021, Sean Christopherson wrote:
> Remove the @reset_roots param from kvm_init_mmu(), the one user,
> kvm_mmu_reset_context() has already unloaded the MMU and thus freed and
> invalidated all roots. This also happens to be why the reset_roots=true
> paths doesn't leak roots; they're already invalid.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.h | 2 +-
> arch/x86/kvm/mmu/mmu.c | 13 ++-----------
> arch/x86/kvm/svm/nested.c | 2 +-
> arch/x86/kvm/vmx/nested.c | 2 +-
> 4 files changed, 5 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> index 88d0ed5225a4..63b49725fb24 100644
> --- a/arch/x86/kvm/mmu.h
> +++ b/arch/x86/kvm/mmu.h
> @@ -65,7 +65,7 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only);
> void
> reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
>
> -void kvm_init_mmu(struct kvm_vcpu *vcpu, bool reset_roots);
> +void kvm_init_mmu(struct kvm_vcpu *vcpu);
> void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, u32 cr0, u32 cr4, u32 efer,
> gpa_t nested_cr3);
> void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 930ac8a7e7c9..ff3e200b32dd 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4793,17 +4793,8 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
> update_last_nonleaf_level(vcpu, g_context);
> }
>
> -void kvm_init_mmu(struct kvm_vcpu *vcpu, bool reset_roots)
> +void kvm_init_mmu(struct kvm_vcpu *vcpu)
> {
> - if (reset_roots) {
> - uint i;
> -
> - vcpu->arch.mmu->root_hpa = INVALID_PAGE;
> -
> - for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++)
> - vcpu->arch.mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID;
Egad! This is wrong. mmu->root_hpa is guaranteed to be INVALID_PAGE, but the
prev_roots are not! I'll drop this patch and do cleanup of this code in a
separate series.
> - }
> -
> if (mmu_is_nested(vcpu))
> init_kvm_nested_mmu(vcpu);
> else if (tdp_enabled)
