Commit 8de48833 authored by Abel Gordon's avatar Abel Gordon Committed by Gleb Natapov
Browse files

KVM: nVMX: Allocate shadow vmcs 



Allocate a shadow vmcs used by the processor to shadow part of the fields
stored in the software defined VMCS12 (let L1 access fields without causing
exits). Note we keep a shadow vmcs only for the current vmcs12.  Once a vmcs12
becomes non-current, its shadow vmcs is released.

Signed-off-by: default avatarAbel Gordon <abelg@il.ibm.com>
Reviewed-by: default avatarOrit Wasserman <owasserm@redhat.com>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 145c28dd

arch/x86/kvm/vmx.c

+12 −0
Original line number Diff line number Diff line
@@ -355,6 +355,7 @@ struct nested_vmx { 
	/* The host-usable pointer to the above */

	struct page *current_vmcs12_page;

	struct vmcs12 *current_vmcs12;

	struct vmcs *current_shadow_vmcs;



	/* vmcs02_list cache of VMCSs recently used to run L2 guests */

	struct list_head vmcs02_pool;
@@ -5527,6 +5528,7 @@ static int handle_vmon(struct kvm_vcpu *vcpu) 
{

	struct kvm_segment cs;

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	struct vmcs *shadow_vmcs;



	/* The Intel VMX Instruction Reference lists a bunch of bits that

	 * are prerequisite to running VMXON, most notably cr4.VMXE must be
@@ -5555,6 +5557,16 @@ static int handle_vmon(struct kvm_vcpu *vcpu) 
		skip_emulated_instruction(vcpu);

		return 1;

	}

	if (enable_shadow_vmcs) {

		shadow_vmcs = alloc_vmcs();

		if (!shadow_vmcs)

			return -ENOMEM;

		/* mark vmcs as shadow */

		shadow_vmcs->revision_id |= (1u << 31);

		/* init shadow vmcs */

		vmcs_clear(shadow_vmcs);

		vmx->nested.current_shadow_vmcs = shadow_vmcs;

	}



	INIT_LIST_HEAD(&(vmx->nested.vmcs02_pool));

	vmx->nested.vmcs02_num = 0;

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