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KVM: vmx: hyper-v: don't pass EPT configuration info to vmx_hv_remote…
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…_flush_tlb()

I'm observing random crashes in multi-vCPU L2 guests running on KVM on
Hyper-V. I bisected the issue to the commit 877ad95 ("KVM: vmx: Add
tlb_remote_flush callback support"). Hyper-V TLFS states:

"AddressSpace specifies an address space ID (an EPT PML4 table pointer)"

So apparently, Hyper-V doesn't expect us to pass naked EPTP, only PML4
pointer should be used. Strip off EPT configuration information before
calling into vmx_hv_remote_flush_tlb().

Fixes: 877ad95 ("KVM: vmx: Add tlb_remote_flush callback support")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Vitaly Kuznetsov authored and Paolo Bonzini committed Oct 13, 2018
1 parent 4cebf45 commit 5f8bb00
Showing 1 changed file with 5 additions and 1 deletion.
6 changes: 5 additions & 1 deletion arch/x86/kvm/vmx.c
Original file line number Diff line number Diff line change
Expand Up @@ -1572,8 +1572,12 @@ static int vmx_hv_remote_flush_tlb(struct kvm *kvm)
goto out;
}

/*
* FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE hypercall needs the address of the
* base of EPT PML4 table, strip off EPT configuration information.
*/
ret = hyperv_flush_guest_mapping(
to_vmx(kvm_get_vcpu(kvm, 0))->ept_pointer);
to_vmx(kvm_get_vcpu(kvm, 0))->ept_pointer & PAGE_MASK);

out:
spin_unlock(&to_kvm_vmx(kvm)->ept_pointer_lock);
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