Messages in this thread | | | Date | Thu, 15 Mar 2012 11:53:06 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH] KVM: VMX: call invvpid only when EPT is disabled |
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On 03/15/2012 03:44 AM, Davidlohr Bueso wrote: > From: Davidlohr Bueso <dave@gnu.org> > > With EPT enabled it is not required to explicitly run invvpid to invalidate tagged TLB entries, as > KVM does not force vm-exits for cr3 writes and invlpg. Run invvpid only when these instructions > are emulated and shadow pages are used. > > Signed-off-by: Davidlohr Bueso <dave@gnu.org> > --- > arch/x86/kvm/vmx.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 2c22fc7..51c7fb9 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -2861,12 +2861,13 @@ static void exit_lmode(struct kvm_vcpu *vcpu) > > static void vmx_flush_tlb(struct kvm_vcpu *vcpu) > { > - vpid_sync_context(to_vmx(vcpu)); > if (enable_ept) { > if (!VALID_PAGE(vcpu->arch.mmu.root_hpa)) > return; > ept_sync_context(construct_eptp(vcpu->arch.mmu.root_hpa)); > } > + else > + vpid_sync_context(to_vmx(vcpu)); > } > > static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
This is wrong, cr3 can still be written from host userspace.
To perform this optimization you need to separate the concept of flushing the guest tlb and the host tlb. I doubt it's worthwhile though, won't the ept invalidation flush the entire tlb anyway?
-- error compiling committee.c: too many arguments to function
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