Commit 61ada748 authored by Liran Alon's avatar Liran Alon Committed by Paolo Bonzini
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KVM: nVMX: Cache shadow vmcs12 on VMEntry and flush to memory on VMExit 



This is done is done as a preparation to VMCS shadowing emulation.

Signed-off-by: default avatarLiran Alon <liran.alon@oracle.com>
Signed-off-by: default avatarJim Mattson <jmattson@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent f145d90d

arch/x86/kvm/vmx.c

+74 −0
Original line number Diff line number Diff line
@@ -644,6 +644,12 @@ struct nested_vmx { 
	 * memory during VMCLEAR and VMPTRLD.

	 */

	struct vmcs12 *cached_vmcs12;

	/*

	 * Cache of the guest's shadow VMCS, existing outside of guest

	 * memory. Loaded from guest memory during VM entry. Flushed

	 * to guest memory during VM exit.

	 */

	struct vmcs12 *cached_shadow_vmcs12;

	/*

	 * Indicates if the shadow vmcs must be updated with the

	 * data hold by vmcs12
@@ -1076,6 +1082,11 @@ static inline struct vmcs12 *get_vmcs12(struct kvm_vcpu *vcpu) 
	return to_vmx(vcpu)->nested.cached_vmcs12;

}



static inline struct vmcs12 *get_shadow_vmcs12(struct kvm_vcpu *vcpu)

{

	return to_vmx(vcpu)->nested.cached_shadow_vmcs12;

}



static bool nested_ept_ad_enabled(struct kvm_vcpu *vcpu);

static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu);

static u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa);
@@ -7900,6 +7911,10 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu) 
	if (!vmx->nested.cached_vmcs12)

		goto out_cached_vmcs12;



	vmx->nested.cached_shadow_vmcs12 = kmalloc(VMCS12_SIZE, GFP_KERNEL);

	if (!vmx->nested.cached_shadow_vmcs12)

		goto out_cached_shadow_vmcs12;



	if (enable_shadow_vmcs) {

		shadow_vmcs = alloc_vmcs();

		if (!shadow_vmcs)
@@ -7919,6 +7934,9 @@ static int enter_vmx_operation(struct kvm_vcpu *vcpu) 
	return 0;



out_shadow_vmcs:

	kfree(vmx->nested.cached_shadow_vmcs12);



out_cached_shadow_vmcs12:

	kfree(vmx->nested.cached_vmcs12);



out_cached_vmcs12:
@@ -8085,6 +8103,7 @@ static void free_nested(struct vcpu_vmx *vmx) 
		vmx->vmcs01.shadow_vmcs = NULL;

	}

	kfree(vmx->nested.cached_vmcs12);

	kfree(vmx->nested.cached_shadow_vmcs12);

	/* Unpin physical memory we referred to in the vmcs02 */

	if (vmx->nested.apic_access_page) {

		kvm_release_page_dirty(vmx->nested.apic_access_page);
@@ -10926,6 +10945,38 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, 
	return true;

}



static void nested_cache_shadow_vmcs12(struct kvm_vcpu *vcpu,

				       struct vmcs12 *vmcs12)

{

	struct vmcs12 *shadow;

	struct page *page;



	if (!nested_cpu_has_shadow_vmcs(vmcs12) ||

	    vmcs12->vmcs_link_pointer == -1ull)

		return;



	shadow = get_shadow_vmcs12(vcpu);

	page = kvm_vcpu_gpa_to_page(vcpu, vmcs12->vmcs_link_pointer);



	memcpy(shadow, kmap(page), VMCS12_SIZE);



	kunmap(page);

	kvm_release_page_clean(page);

}



static void nested_flush_cached_shadow_vmcs12(struct kvm_vcpu *vcpu,

					      struct vmcs12 *vmcs12)

{

	struct vcpu_vmx *vmx = to_vmx(vcpu);



	if (!nested_cpu_has_shadow_vmcs(vmcs12) ||

	    vmcs12->vmcs_link_pointer == -1ull)

		return;



	kvm_write_guest(vmx->vcpu.kvm, vmcs12->vmcs_link_pointer,

			get_shadow_vmcs12(vcpu), VMCS12_SIZE);

}



static int nested_vmx_check_apic_access_controls(struct kvm_vcpu *vcpu,

					  struct vmcs12 *vmcs12)

{
@@ -11995,6 +12046,18 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) 
		return 1;

	}



	/*

	 * Must happen outside of enter_vmx_non_root_mode() as it will

	 * also be used as part of restoring nVMX state for

	 * snapshot restore (migration).

	 *

	 * In this flow, it is assumed that vmcs12 cache was

	 * trasferred as part of captured nVMX state and should

	 * therefore not be read from guest memory (which may not

	 * exist on destination host yet).

	 */

	nested_cache_shadow_vmcs12(vcpu, vmcs12);



	/*

	 * If we're entering a halted L2 vcpu and the L2 vcpu won't be woken

	 * by event injection, halt vcpu.
@@ -12504,6 +12567,17 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, 
			prepare_vmcs12(vcpu, vmcs12, exit_reason, exit_intr_info,

				       exit_qualification);



		/*

		 * Must happen outside of sync_vmcs12() as it will

		 * also be used to capture vmcs12 cache as part of

		 * capturing nVMX state for snapshot (migration).

		 *

		 * Otherwise, this flush will dirty guest memory at a

		 * point it is already assumed by user-space to be

		 * immutable.

		 */

		nested_flush_cached_shadow_vmcs12(vcpu, vmcs12);



		if (nested_vmx_store_msr(vcpu, vmcs12->vm_exit_msr_store_addr,

					 vmcs12->vm_exit_msr_store_count))

			nested_vmx_abort(vcpu, VMX_ABORT_SAVE_GUEST_MSR_FAIL);