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Message-Id: <20210415222106.1643837-9-seanjc@google.com>
Date: Thu, 15 Apr 2021 15:21:05 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
Michael Tokarev <mjt@....msk.ru>,
Christian Borntraeger <borntraeger@...ibm.com>
Subject: [PATCH v3 8/9] KVM: x86: Consolidate guest enter/exit logic to common helpers
Move the enter/exit logic in {svm,vmx}_vcpu_enter_exit() to common
helpers. Opportunistically update the somewhat stale comment about the
updates needing to occur immediately after VM-Exit.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kvm/svm/svm.c | 46 ++-----------------------------------
arch/x86/kvm/vmx/vmx.c | 46 ++-----------------------------------
arch/x86/kvm/x86.h | 52 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 56 insertions(+), 88 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index bb2aa0dde7c5..0677595d07e5 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3713,25 +3713,7 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
- /*
- * VMENTER enables interrupts (host state), but the kernel state is
- * interrupts disabled when this is invoked. Also tell RCU about
- * it. This is the same logic as for exit_to_user_mode().
- *
- * This ensures that e.g. latency analysis on the host observes
- * guest mode as interrupt enabled.
- *
- * guest_enter_irqoff() informs context tracking about the
- * transition to guest mode and if enabled adjusts RCU state
- * accordingly.
- */
- instrumentation_begin();
- trace_hardirqs_on_prepare();
- lockdep_hardirqs_on_prepare(CALLER_ADDR0);
- instrumentation_end();
-
- guest_enter_irqoff();
- lockdep_hardirqs_on(CALLER_ADDR0);
+ kvm_guest_enter_irqoff();
if (sev_es_guest(vcpu->kvm)) {
__svm_sev_es_vcpu_run(svm->vmcb_pa);
@@ -3745,31 +3727,7 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu)
vmload(__sme_page_pa(sd->save_area));
}
- /*
- * VMEXIT disables interrupts (host state), but tracing and lockdep
- * have them in state 'on' as recorded before entering guest mode.
- * Same as enter_from_user_mode().
- *
- * context_tracking_guest_exit_irqoff() restores host context and
- * reinstates RCU if enabled and required.
- *
- * This needs to be done before the below as native_read_msr()
- * contains a tracepoint and x86_spec_ctrl_restore_host() calls
- * into world and some more.
- */
- lockdep_hardirqs_off(CALLER_ADDR0);
- context_tracking_guest_exit_irqoff();
-
- instrumentation_begin();
- /*
- * Account guest time when precise accounting based on context tracking
- * is enabled. Tick based accounting is deferred until after IRQs that
- * occurred within the VM-Enter/VM-Exit "window" are handled.
- */
- if (vtime_accounting_enabled_this_cpu())
- vtime_account_guest_exit();
- trace_hardirqs_off_finish();
- instrumentation_end();
+ kvm_guest_exit_irqoff();
}
static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 5ae9dc197048..19b0e25bf598 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6600,25 +6600,7 @@ static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu)
static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
struct vcpu_vmx *vmx)
{
- /*
- * VMENTER enables interrupts (host state), but the kernel state is
- * interrupts disabled when this is invoked. Also tell RCU about
- * it. This is the same logic as for exit_to_user_mode().
- *
- * This ensures that e.g. latency analysis on the host observes
- * guest mode as interrupt enabled.
- *
- * guest_enter_irqoff() informs context tracking about the
- * transition to guest mode and if enabled adjusts RCU state
- * accordingly.
- */
- instrumentation_begin();
- trace_hardirqs_on_prepare();
- lockdep_hardirqs_on_prepare(CALLER_ADDR0);
- instrumentation_end();
-
- guest_enter_irqoff();
- lockdep_hardirqs_on(CALLER_ADDR0);
+ kvm_guest_enter_irqoff();
/* L1D Flush includes CPU buffer clear to mitigate MDS */
if (static_branch_unlikely(&vmx_l1d_should_flush))
@@ -6634,31 +6616,7 @@ static noinstr void vmx_vcpu_enter_exit(struct kvm_vcpu *vcpu,
vcpu->arch.cr2 = native_read_cr2();
- /*
- * VMEXIT disables interrupts (host state), but tracing and lockdep
- * have them in state 'on' as recorded before entering guest mode.
- * Same as enter_from_user_mode().
- *
- * context_tracking_guest_exit_irqoff() restores host context and
- * reinstates RCU if enabled and required.
- *
- * This needs to be done before the below as native_read_msr()
- * contains a tracepoint and x86_spec_ctrl_restore_host() calls
- * into world and some more.
- */
- lockdep_hardirqs_off(CALLER_ADDR0);
- context_tracking_guest_exit_irqoff();
-
- instrumentation_begin();
- /*
- * Account guest time when precise accounting based on context tracking
- * is enabled. Tick based accounting is deferred until after IRQs that
- * occurred within the VM-Enter/VM-Exit "window" are handled.
- */
- if (vtime_accounting_enabled_this_cpu())
- vtime_account_guest_exit();
- trace_hardirqs_off_finish();
- instrumentation_end();
+ kvm_guest_exit_irqoff();
}
static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index daccf20fbcd5..285953e81777 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -8,6 +8,58 @@
#include "kvm_cache_regs.h"
#include "kvm_emulate.h"
+static __always_inline void kvm_guest_enter_irqoff(void)
+{
+ /*
+ * VMENTER enables interrupts (host state), but the kernel state is
+ * interrupts disabled when this is invoked. Also tell RCU about
+ * it. This is the same logic as for exit_to_user_mode().
+ *
+ * This ensures that e.g. latency analysis on the host observes
+ * guest mode as interrupt enabled.
+ *
+ * guest_enter_irqoff() informs context tracking about the
+ * transition to guest mode and if enabled adjusts RCU state
+ * accordingly.
+ */
+ instrumentation_begin();
+ trace_hardirqs_on_prepare();
+ lockdep_hardirqs_on_prepare(CALLER_ADDR0);
+ instrumentation_end();
+
+ guest_enter_irqoff();
+ lockdep_hardirqs_on(CALLER_ADDR0);
+}
+
+static __always_inline void kvm_guest_exit_irqoff(void)
+{
+ /*
+ * VMEXIT disables interrupts (host state), but tracing and lockdep
+ * have them in state 'on' as recorded before entering guest mode.
+ * Same as enter_from_user_mode().
+ *
+ * context_tracking_guest_exit_irqoff() restores host context and
+ * reinstates RCU if enabled and required.
+ *
+ * This needs to be done immediately after VM-Exit, before any code
+ * that might contain tracepoints or call out to the greater world,
+ * e.g. before x86_spec_ctrl_restore_host().
+ */
+ lockdep_hardirqs_off(CALLER_ADDR0);
+ context_tracking_guest_exit_irqoff();
+
+ instrumentation_begin();
+ /*
+ * Account guest time when precise accounting based on context tracking
+ * is enabled. Tick based accounting is deferred until after IRQs that
+ * occurred within the VM-Enter/VM-Exit "window" are handled.
+ */
+ if (vtime_accounting_enabled_this_cpu())
+ vtime_account_guest_exit();
+ trace_hardirqs_off_finish();
+ instrumentation_end();
+}
+
#define KVM_NESTED_VMENTER_CONSISTENCY_CHECK(consistency_check) \
({ \
bool failed = (consistency_check); \
--
2.31.1.368.gbe11c130af-goog
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