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KVM: nVMX: Allocate shadow vmcs

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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: Abel Gordon <abelg@il.ibm.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Abel Gordon 2013-04-18 14:37:25 +03:00 committed by Gleb Natapov
parent 145c28dd19
commit 8de4883370
1 changed files with 12 additions and 0 deletions
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12
arch/x86/kvm/vmx.c
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@ -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;