Messages in this thread | | | Date | Wed, 28 Sep 2022 20:51:33 +0000 | From | Sean Christopherson <> | Subject | Re: [PATCH v3 1/6] KVM: x86/mmu: Fix wrong gfn range of tlb flushing in validate_direct_spte() |
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On Fri, Sep 23, 2022, Hou Wenlong wrote: > The spte pointing to the children SP is dropped, so the > whole gfn range covered by the children SP should be flushed. > Although, Hyper-V may treat a 1-page flush the same if the > address points to a huge page, it still would be better > to use the correct size of huge page. Also introduce > a helper function to do range-based flushing when a direct > SP is dropped, which would help prevent future buggy use > of kvm_flush_remote_tlbs_with_address() in such case.
Please wrap closer to ~75 chars.
> Fixes: c3134ce240eed ("KVM: Replace old tlb flush function with new one to flush a specified range.") > Suggested-by: David Matlack <dmatlack@google.com> > Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> > --- > arch/x86/kvm/mmu/mmu.c | 9 ++++++++- > arch/x86/kvm/mmu/mmu_internal.h | 10 ++++++++++ > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index e418ef3ecfcb..ae9f84b0fc64 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -260,6 +260,13 @@ void kvm_flush_remote_tlbs_with_address(struct kvm *kvm, > kvm_flush_remote_tlbs_with_range(kvm, &range); > } > > +/* Flush all memory mapped by the given direct SP. */ > +static void kvm_flush_remote_tlbs_direct_sp(struct kvm *kvm, struct kvm_mmu_page *sp) > +{ > + WARN_ON_ONCE(!sp->role.direct); > + kvm_flush_remote_tlbs_gfn(kvm, sp->gfn, sp->role.level + 1); > +} > + > static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn, > unsigned int access) > { > @@ -2341,7 +2348,7 @@ static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, > return; > > drop_parent_pte(child, sptep); > - kvm_flush_remote_tlbs_with_address(vcpu->kvm, child->gfn, 1); > + kvm_flush_remote_tlbs_direct_sp(vcpu->kvm, child);
As mentioned very belatedly[*], I would rather move this patch later in the series and use kvm_flush_remote_tlbs_sptep() instead of introducing a one-off helper.
[*] https://lore.kernel.org/all/YzMoWghqNJdYBlaE@google.com
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