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Commit 9f744c59 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Radim Krčmář
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KVM: nVMX: do not pin the VMCS12 



Since the current implementation of VMCS12 does a memcpy in and out
of guest memory, we do not need current_vmcs12 and current_vmcs12_page
anymore.  current_vmptr is enough to read and write the VMCS12.

And David Matlack noted:

  This patch also fixes dirty tracking (memslot->dirty_bitmap) of the
  VMCS12 page by using kvm_write_guest. nested_release_page() only marks
  the struct page dirty.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
[Added David Matlack's note and nested_release_page_clean() fix.]
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent 3898da94

arch/x86/kvm/vmx.c

+7 −17
Original line number Diff line number Diff line
@@ -416,9 +416,6 @@ struct nested_vmx { 


	/* The guest-physical address of the current VMCS L1 keeps for L2 */

	gpa_t current_vmptr;

	/* The host-usable pointer to the above */

	struct page *current_vmcs12_page;

	struct vmcs12 *current_vmcs12;

	/*

	 * Cache of the guest's VMCS, existing outside of guest memory.

	 * Loaded from guest memory during VMPTRLD. Flushed to guest
@@ -7182,10 +7179,6 @@ static inline void nested_release_vmcs12(struct vcpu_vmx *vmx) 
	if (vmx->nested.current_vmptr == -1ull)

		return;



	/* current_vmptr and current_vmcs12 are always set/reset together */

	if (WARN_ON(vmx->nested.current_vmcs12 == NULL))

		return;



	if (enable_shadow_vmcs) {

		/* copy to memory all shadowed fields in case

		   they were modified */
@@ -7198,13 +7191,11 @@ static inline void nested_release_vmcs12(struct vcpu_vmx *vmx) 
	vmx->nested.posted_intr_nv = -1;



	/* Flush VMCS12 to guest memory */

	memcpy(vmx->nested.current_vmcs12, vmx->nested.cached_vmcs12,

	       VMCS12_SIZE);

	kvm_vcpu_write_guest_page(&vmx->vcpu,

				  vmx->nested.current_vmptr >> PAGE_SHIFT,

				  vmx->nested.cached_vmcs12, 0, VMCS12_SIZE);



	kunmap(vmx->nested.current_vmcs12_page);

	nested_release_page(vmx->nested.current_vmcs12_page);

	vmx->nested.current_vmptr = -1ull;

	vmx->nested.current_vmcs12 = NULL;

}



/*
@@ -7622,14 +7613,14 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu) 
		}



		nested_release_vmcs12(vmx);

		vmx->nested.current_vmcs12 = new_vmcs12;

		vmx->nested.current_vmcs12_page = page;

		/*

		 * Load VMCS12 from guest memory since it is not already

		 * cached.

		 */

		memcpy(vmx->nested.cached_vmcs12,

		       vmx->nested.current_vmcs12, VMCS12_SIZE);

		memcpy(vmx->nested.cached_vmcs12, new_vmcs12, VMCS12_SIZE);

		kunmap(page);

		nested_release_page_clean(page);



		set_current_vmptr(vmx, vmptr);

	}
@@ -9284,7 +9275,6 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) 


	vmx->nested.posted_intr_nv = -1;

	vmx->nested.current_vmptr = -1ull;

	vmx->nested.current_vmcs12 = NULL;



	vmx->msr_ia32_feature_control_valid_bits = FEATURE_CONTROL_LOCKED;