Commit e2174295 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: nVMX: Add helpers to identify shadowed VMCS fields 



So that future optimizations related to shadowed fields don't need to
define their own switch statement.

Add a BUILD_BUG_ON() to ensure at least one of the types (RW vs RO) is
defined when including vmcs_shadow_fields.h (guess who keeps mistyping
SHADOW_FIELD_RO as SHADOW_FIELD_R0).

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 3731905e

arch/x86/kvm/vmx/nested.c

+40 −31
Original line number Diff line number Diff line
@@ -4420,6 +4420,29 @@ static int handle_vmread(struct kvm_vcpu *vcpu) 
	return nested_vmx_succeed(vcpu);

}



static bool is_shadow_field_rw(unsigned long field)

{

	switch (field) {

#define SHADOW_FIELD_RW(x, y) case x:

#include "vmcs_shadow_fields.h"

		return true;

	default:

		break;

	}

	return false;

}



static bool is_shadow_field_ro(unsigned long field)

{

	switch (field) {

#define SHADOW_FIELD_RO(x, y) case x:

#include "vmcs_shadow_fields.h"

		return true;

	default:

		break;

	}

	return false;

}



static int handle_vmwrite(struct kvm_vcpu *vcpu)

{
@@ -4503,27 +4526,17 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu) 
	vmcs12_write_any(vmcs12, field, offset, field_value);



	/*

	 * Do not track vmcs12 dirty-state if in guest-mode

	 * as we actually dirty shadow vmcs12 instead of vmcs12.

	 * Do not track vmcs12 dirty-state if in guest-mode as we actually

	 * dirty shadow vmcs12 instead of vmcs12.  Fields that can be updated

	 * by L1 without a vmexit are always updated in the vmcs02, i.e. don't

	 * "dirty" vmcs12, all others go down the prepare_vmcs02() slow path.

	 */

	if (!is_guest_mode(vcpu)) {

		switch (field) {

#define SHADOW_FIELD_RW(x, y) case x:

#include "vmcs_shadow_fields.h"

			/*

			 * The fields that can be updated by L1 without a vmexit are

			 * always updated in the vmcs02, the others go down the slow

			 * path of prepare_vmcs02.

			 */

			break;



#define SHADOW_FIELD_RO(x, y) case x:

#include "vmcs_shadow_fields.h"

	if (!is_guest_mode(vcpu) && !is_shadow_field_rw(field)) {

		/*

		 * L1 can read these fields without exiting, ensure the

		 * shadow VMCS is up-to-date.

		 */

			if (enable_shadow_vmcs) {

		if (enable_shadow_vmcs && is_shadow_field_ro(field)) {

			preempt_disable();

			vmcs_load(vmx->vmcs01.shadow_vmcs);
@@ -4533,11 +4546,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu) 
			vmcs_load(vmx->loaded_vmcs->vmcs);

			preempt_enable();

		}

			/* fall through */

		default:

		vmx->nested.dirty_vmcs12 = true;

			break;

		}

	}



	return nested_vmx_succeed(vcpu);

arch/x86/kvm/vmx/vmcs_shadow_fields.h

+4 −0
Original line number Diff line number Diff line 
#if !defined(SHADOW_FIELD_RO) && !defined(SHADOW_FIELD_RW)

BUILD_BUG_ON(1)

#endif



#ifndef SHADOW_FIELD_RO

#define SHADOW_FIELD_RO(x, y)

#endif

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