From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org, Jim Mattson <jmattson@google.com>,
Liran Alon <liran.alon@oracle.com>
Subject: [PATCH 6/7] KVM: nVMX: Add helpers to identify shadowed VMCS fields
Date: Tue, 7 May 2019 08:36:28 -0700 [thread overview]
Message-ID: <20190507153629.3681-7-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190507153629.3681-1-sean.j.christopherson@intel.com>
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>
---
arch/x86/kvm/vmx/nested.c | 71 +++++++++++++++------------
arch/x86/kvm/vmx/vmcs_shadow_fields.h | 4 ++
2 files changed, 44 insertions(+), 31 deletions(-)
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 632e7e4324f3..279961a63db2 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -4415,6 +4415,29 @@ 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)
{
@@ -4497,41 +4520,27 @@ 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;
+ 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 && is_shadow_field_ro(field)) {
+ preempt_disable();
+ vmcs_load(vmx->vmcs01.shadow_vmcs);
-#define SHADOW_FIELD_RO(x, y) case x:
-#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_writel(field, field_value);
-
- vmcs_clear(vmx->vmcs01.shadow_vmcs);
- vmcs_load(vmx->loaded_vmcs->vmcs);
- preempt_enable();
- }
- /* fall through */
- default:
- vmx->nested.dirty_vmcs12 = true;
- break;
+ vmcs_clear(vmx->vmcs01.shadow_vmcs);
+ vmcs_load(vmx->loaded_vmcs->vmcs);
+ preempt_enable();
}
+ vmx->nested.dirty_vmcs12 = true;
}
return nested_vmx_succeed(vcpu);
diff --git a/arch/x86/kvm/vmx/vmcs_shadow_fields.h b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
index 2cfa19ca158e..4cea018ba285 100644
--- a/arch/x86/kvm/vmx/vmcs_shadow_fields.h
+++ b/arch/x86/kvm/vmx/vmcs_shadow_fields.h
@@ -1,3 +1,7 @@
+#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
--
2.21.0
next prev parent reply other threads:[~2019-05-07 15:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 15:36 [PATCH 0/7] KVM: nVMX: Optimize VMCS data copying Sean Christopherson
2019-05-07 15:36 ` [PATCH 1/7] KVM: nVMX: Intercept VMWRITEs to read-only shadow VMCS fields Sean Christopherson
2019-06-06 13:26 ` Paolo Bonzini
2019-06-13 17:02 ` Jim Mattson
2019-06-13 17:18 ` Paolo Bonzini
2019-06-13 17:36 ` Jim Mattson
2019-06-13 17:59 ` Paolo Bonzini
2019-05-07 15:36 ` [PATCH 2/7] KVM: nVMX: Intercept VMWRITEs to GUEST_{CS,SS}_AR_BYTES Sean Christopherson
2019-06-06 13:31 ` Paolo Bonzini
2019-05-07 15:36 ` [PATCH 3/7] KVM: nVMX: Track vmcs12 offsets for shadowed VMCS fields Sean Christopherson
2019-05-07 15:36 ` [PATCH 4/7] KVM: nVMX: Lift sync_vmcs12() out of prepare_vmcs12() Sean Christopherson
2019-05-07 15:36 ` [PATCH 5/7] KVM: nVMX: Use descriptive names for VMCS sync functions and flags Sean Christopherson
2019-05-07 15:36 ` Sean Christopherson [this message]
2019-05-07 15:36 ` [PATCH 7/7] KVM: nVMX: Sync rarely accessed guest fields only when needed Sean Christopherson
2019-06-06 15:29 ` Paolo Bonzini
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