Commit c74ad08f authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

KVM: nSVM: fix few bugs in the vmcb02 caching logic 



* Define and use an invalid GPA (all ones) for init value of last
  and current nested vmcb physical addresses.

* Reset the current vmcb12 gpa to the invalid value when leaving
  the nested mode, similar to what is done on nested vmexit.

* Reset	the last seen vmcb12 address when disabling the nested SVM,
  as it relies on vmcb02 fields which are freed at that point.

Fixes: 4995a368 ("KVM: SVM: Use a separate vmcb for the nested L2 guest")

Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210503125446.1353307-3-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent deee59ba

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ 
#define VALID_PAGE(x) ((x) != INVALID_PAGE)



#define UNMAPPED_GVA (~(gpa_t)0)

#define INVALID_GPA (~(gpa_t)0)



/* KVM Hugepage definitions for x86 */

#define KVM_MAX_HUGEPAGE_LEVEL	PG_LEVEL_1G

arch/x86/kvm/svm/nested.c

+11 −0
Original line number Diff line number Diff line
@@ -872,6 +872,15 @@ void svm_free_nested(struct vcpu_svm *svm) 
	__free_page(virt_to_page(svm->nested.vmcb02.ptr));

	svm->nested.vmcb02.ptr = NULL;



	/*

	 * When last_vmcb12_gpa matches the current vmcb12 gpa,

	 * some vmcb12 fields are not loaded if they are marked clean

	 * in the vmcb12, since in this case they are up to date already.

	 *

	 * When the vmcb02 is freed, this optimization becomes invalid.

	 */

	svm->nested.last_vmcb12_gpa = INVALID_GPA;



	svm->nested.initialized = false;

}
@@ -884,6 +893,8 @@ void svm_leave_nested(struct vcpu_svm *svm) 


	if (is_guest_mode(vcpu)) {

		svm->nested.nested_run_pending = 0;

		svm->nested.vmcb12_gpa = INVALID_GPA;



		leave_guest_mode(vcpu);



		svm_switch_vmcb(svm, &svm->vmcb01);

arch/x86/kvm/svm/svm.c

+2 −2
Original line number Diff line number Diff line
@@ -1235,8 +1235,8 @@ static void init_vmcb(struct kvm_vcpu *vcpu) 
	svm->current_vmcb->asid_generation = 0;

	svm->asid = 0;



	svm->nested.vmcb12_gpa = 0;

	svm->nested.last_vmcb12_gpa = 0;

	svm->nested.vmcb12_gpa = INVALID_GPA;

	svm->nested.last_vmcb12_gpa = INVALID_GPA;

	vcpu->arch.hflags = 0;



	if (!kvm_pause_in_guest(vcpu->kvm)) {