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Commit b8b0c871 authored by Jim Mattson's avatar Jim Mattson Committed by Greg Kroah-Hartman
Browse files

kvm: svm: Ensure an IBPB on all affected CPUs when freeing a vmcb 



commit fd65d3142f734bc4376053c8d75670041903134d upstream.

Previously, we only called indirect_branch_prediction_barrier on the
logical CPU that freed a vmcb. This function should be called on all
logical CPUs that last loaded the vmcb in question.

Fixes: 15d45071 ("KVM/x86: Add IBPB support")
Reported-by: default avatarNeel Natu <neelnatu@google.com>
Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 471aca57

arch/x86/kvm/svm.c

+15 −5
Original line number Original line Diff line number Diff line
@@ -2187,21 +2187,31 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 
	return ERR_PTR(err);

	return ERR_PTR(err);

}

}





static void svm_clear_current_vmcb(struct vmcb *vmcb)

{

	int i;



	for_each_online_cpu(i)

		cmpxchg(&per_cpu(svm_data, i)->current_vmcb, vmcb, NULL);

}



static void svm_free_vcpu(struct kvm_vcpu *vcpu)

static void svm_free_vcpu(struct kvm_vcpu *vcpu)

{

{

	struct vcpu_svm *svm = to_svm(vcpu);

	struct vcpu_svm *svm = to_svm(vcpu);





	/*

	 * The vmcb page can be recycled, causing a false negative in

	 * svm_vcpu_load(). So, ensure that no logical CPU has this

	 * vmcb page recorded as its current vmcb.

	 */

	svm_clear_current_vmcb(svm->vmcb);



	__free_page(pfn_to_page(__sme_clr(svm->vmcb_pa) >> PAGE_SHIFT));

	__free_page(pfn_to_page(__sme_clr(svm->vmcb_pa) >> PAGE_SHIFT));

	__free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER);

	__free_pages(virt_to_page(svm->msrpm), MSRPM_ALLOC_ORDER);

	__free_page(virt_to_page(svm->nested.hsave));

	__free_page(virt_to_page(svm->nested.hsave));

	__free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);

	__free_pages(virt_to_page(svm->nested.msrpm), MSRPM_ALLOC_ORDER);

	kvm_vcpu_uninit(vcpu);

	kvm_vcpu_uninit(vcpu);

	kmem_cache_free(kvm_vcpu_cache, svm);

	kmem_cache_free(kvm_vcpu_cache, svm);

	/*

	 * The vmcb page can be recycled, causing a false negative in

	 * svm_vcpu_load(). So do a full IBPB now.

	 */

	indirect_branch_prediction_barrier();

}

}





static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)