Re: [PATCH v2 03/18] KVM: x86/mmu: WARN if PAE roots linger after kvm_mmu_unload

Sean Christopherson
2022-02-18T17:15:04Z

On Thu, Feb 17, 2022, Paolo Bonzini wrote:
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/kvm/mmu/mmu.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 296f8723f9ae..a67071ac80f3 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -5086,12 +5086,21 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
> return r;
> }
>
> +static void __kvm_mmu_unload(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu)
> +{
> + int i;
> + kvm_mmu_free_roots(vcpu, mmu, KVM_MMU_ROOTS_ALL);
> + WARN_ON(VALID_PAGE(mmu->root_hpa));
> + if (mmu->pae_root) {
> + for (i = 0; i < 4; ++i)
> + WARN_ON(IS_VALID_PAE_ROOT(mmu->pae_root[i]));
> + }
> +}
> +
> void kvm_mmu_unload(struct kvm_vcpu *vcpu)
> {
> - kvm_mmu_free_roots(vcpu, &vcpu->arch.root_mmu, KVM_MMU_ROOTS_ALL);
> - WARN_ON(VALID_PAGE(vcpu->arch.root_mmu.root_hpa));
> - kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL);
> - WARN_ON(VALID_PAGE(vcpu->arch.guest_mmu.root_hpa));
> + __kvm_mmu_unload(vcpu, &vcpu->arch.root_mmu);
> + __kvm_mmu_unload(vcpu, &vcpu->arch.guest_mmu);

Can we just drop this one? Checkpatch doesn't like it, and IMO the existing asserts
are unnecessary. IIRC you said this one never actually fired?

WARNING: Missing commit description - Add an appropriate one

WARNING: Missing a blank line after declarations
#22: FILE: arch/x86/kvm/mmu/mmu.c:5092:
+ int i;
+ kvm_mmu_free_roots(vcpu, mmu, KVM_MMU_ROOTS_ALL);

> }
>
> static bool need_remote_flush(u64 old, u64 new)
> --
> 2.31.1
>
>