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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: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2019-05-07 08:36:28 -07:00 committed by Paolo Bonzini
parent 3731905ef2
commit e2174295b4
2 changed files with 44 additions and 31 deletions
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71
arch/x86/kvm/vmx/nested.c
View File

@ -4420,6 +4420,29 @@ static int handle_vmread(struct kvm_vcpu *vcpu)
return nested_vmx_succeed(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) static int handle_vmwrite(struct kvm_vcpu *vcpu)
{ {
@ -4503,41 +4526,27 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
vmcs12_write_any(vmcs12, field, offset, field_value); vmcs12_write_any(vmcs12, field, offset, field_value);
/* /*
* Do not track vmcs12 dirty-state if in guest-mode * Do not track vmcs12 dirty-state if in guest-mode as we actually
* as we actually dirty shadow vmcs12 instead of vmcs12. * 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)) { if (!is_guest_mode(vcpu) && !is_shadow_field_rw(field)) {
switch (field) { /*
#define SHADOW_FIELD_RW(x, y) case x: * L1 can read these fields without exiting, ensure the
#include "vmcs_shadow_fields.h" * shadow VMCS is up-to-date.
/* */
* The fields that can be updated by L1 without a vmexit are if (enable_shadow_vmcs && is_shadow_field_ro(field)) {
* always updated in the vmcs02, the others go down the slow preempt_disable();
* path of prepare_vmcs02. vmcs_load(vmx->vmcs01.shadow_vmcs);
*/
break;
#define SHADOW_FIELD_RO(x, y) case x: __vmcs_writel(field, field_value);
#include "vmcs_shadow_fields.h"
/*
* L1 can read these fields without exiting, ensure the
* shadow VMCS is up-to-date.
*/
if (enable_shadow_vmcs) {
preempt_disable();
vmcs_load(vmx->vmcs01.shadow_vmcs);
__vmcs_writel(field, field_value); vmcs_clear(vmx->vmcs01.shadow_vmcs);
vmcs_load(vmx->loaded_vmcs->vmcs);
vmcs_clear(vmx->vmcs01.shadow_vmcs); preempt_enable();
vmcs_load(vmx->loaded_vmcs->vmcs);
preempt_enable();
}
/* fall through */
default:
vmx->nested.dirty_vmcs12 = true;
break;
} }
vmx->nested.dirty_vmcs12 = true;
} }
return nested_vmx_succeed(vcpu); return nested_vmx_succeed(vcpu);

4
arch/x86/kvm/vmx/vmcs_shadow_fields.h
View File

@ -1,3 +1,7 @@
#if !defined(SHADOW_FIELD_RO) && !defined(SHADOW_FIELD_RW)
BUILD_BUG_ON(1)
#endif
#ifndef SHADOW_FIELD_RO #ifndef SHADOW_FIELD_RO
#define SHADOW_FIELD_RO(x, y) #define SHADOW_FIELD_RO(x, y)
#endif #endif