Messages in this thread | | | Date | Sat, 19 Feb 2022 00:22:50 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH v2 13/18] KVM: x86: reset and reinitialize the MMU in __set_sregs_common |
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On Thu, Feb 17, 2022, Paolo Bonzini wrote: > Do a full unload of the MMU in KVM_SET_SREGS and KVM_SEST_REGS2, in > preparation for not doing so in kvm_mmu_reset_context. There is no > need to delay the reset until after the return, so do it directly in > the __set_sregs_common function and remove the mmu_reset_needed output > parameter. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > ---
Reviewed-by: Sean Christopherson <seanjc@google.com>
> + kvm_init_mmu(vcpu); > if (update_pdptrs) { > idx = srcu_read_lock(&vcpu->kvm->srcu); > - if (is_pae_paging(vcpu)) { > + if (is_pae_paging(vcpu)) > load_pdptrs(vcpu, kvm_read_cr3(vcpu)); > - *mmu_reset_needed = 1;
Eww (not your code, just this whole pile). It might be worth calling out in the changelog that calling kvm_init_mmu() before load_pdptrs() will (subtly) _not_ impact the functionality of load_pdptrs(). If the MMU is nested, kvm_init_mmu() will modify vcpu->arch.nested_mmu, whereas kvm_translate_gpa() will walk vcpu->arch.guest_mmu. And if the MMU is not nested, kvm_translate_gpa() will not consuming vcpu->arch.mmu other than to check if it's == &guest_mmu.
> - } > srcu_read_unlock(&vcpu->kvm->srcu, idx); > } >
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