From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Michael Tokarev <mjt@tls.msk.ru>
Subject: [RFC PATCH 3/7] context_tracking: Consolidate guest enter/exit wrappers
Date: Tue, 13 Apr 2021 11:29:29 -0700 [thread overview]
Message-ID: <20210413182933.1046389-4-seanjc@google.com> (raw)
In-Reply-To: <20210413182933.1046389-1-seanjc@google.com>
Consolidate the guest enter/exit wrappers by providing stubs for the
context tracking helpers as necessary. This will allow moving the
wrappers under KVM without having to bleed too many #ifdefs into the
soon-to-be KVM code.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
include/linux/context_tracking.h | 65 ++++++++++++++------------------
1 file changed, 29 insertions(+), 36 deletions(-)
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 89a1a5ccb2ab..ded56aed539a 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -76,18 +76,7 @@ static __always_inline void context_tracking_guest_enter_irqoff(void)
if (context_tracking_enabled())
__context_tracking_enter(CONTEXT_GUEST);
- /* KVM does not hold any references to rcu protected data when it
- * switches CPU into a guest mode. In fact switching to a guest mode
- * is very similar to exiting to userspace from rcu point of view. In
- * addition CPU may stay in a guest mode for quite a long time (up to
- * one time slice). Lets treat guest mode as quiescent state, just like
- * we do with user-mode execution.
- */
- if (!context_tracking_enabled_this_cpu()) {
- instrumentation_begin();
- rcu_virt_note_context_switch(smp_processor_id());
- instrumentation_end();
- }
+ return context_tracking_enabled_this_cpu();
}
static __always_inline void context_tracking_guest_exit_irqoff(void)
@@ -116,6 +105,17 @@ static inline void user_exit_irqoff(void) { }
static inline enum ctx_state exception_enter(void) { return 0; }
static inline void exception_exit(enum ctx_state prev_ctx) { }
static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
+
+static __always_inline bool context_tracking_guest_enter_irqoff(void)
+{
+ return false;
+}
+
+static __always_inline void context_tracking_guest_exit_irqoff(void)
+{
+
+}
+
#endif /* !CONFIG_CONTEXT_TRACKING */
#define CT_WARN_ON(cond) WARN_ON(context_tracking_enabled() && (cond))
@@ -126,48 +126,41 @@ extern void context_tracking_init(void);
static inline void context_tracking_init(void) { }
#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
/* must be called with irqs disabled */
static __always_inline void guest_enter_irqoff(void)
{
+ /*
+ * This is running in ioctl context so its safe to assume that it's the
+ * stime pending cputime to flush.
+ */
instrumentation_begin();
vtime_account_guest_enter();
instrumentation_end();
- context_tracking_guest_enter_irqoff();
+ /*
+ * KVM does not hold any references to rcu protected data when it
+ * switches CPU into a guest mode. In fact switching to a guest mode
+ * is very similar to exiting to userspace from rcu point of view. In
+ * addition CPU may stay in a guest mode for quite a long time (up to
+ * one time slice). Lets treat guest mode as quiescent state, just like
+ * we do with user-mode execution.
+ */
+ if (!context_tracking_guest_enter_irqoff()) {
+ instrumentation_begin();
+ rcu_virt_note_context_switch(smp_processor_id());
+ instrumentation_end();
+ }
}
static __always_inline void guest_exit_irqoff(void)
{
context_tracking_guest_exit_irqoff();
- instrumentation_begin();
- vtime_account_guest_exit();
- instrumentation_end();
-}
-
-#else
-static __always_inline void guest_enter_irqoff(void)
-{
- /*
- * This is running in ioctl context so its safe
- * to assume that it's the stime pending cputime
- * to flush.
- */
- instrumentation_begin();
- vtime_account_guest_enter();
- rcu_virt_note_context_switch(smp_processor_id());
- instrumentation_end();
-}
-
-static __always_inline void guest_exit_irqoff(void)
-{
instrumentation_begin();
/* Flush the guest cputime we spent on the guest */
vtime_account_guest_exit();
instrumentation_end();
}
-#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
static inline void guest_exit(void)
{
--
2.31.1.295.g9ea45b61b8-goog
next prev parent reply other threads:[~2021-04-13 18:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 18:29 [RFC PATCH 0/7] KVM: Fix tick-based vtime accounting on x86 Sean Christopherson
2021-04-13 18:29 ` [RFC PATCH 1/7] sched/vtime: Move guest enter/exit vtime accounting to separate helpers Sean Christopherson
2021-04-13 18:29 ` [RFC PATCH 2/7] context_tracking: Move guest enter/exit logic to standalone helpers Sean Christopherson
2021-04-13 18:29 ` Sean Christopherson [this message]
2021-04-13 18:29 ` [RFC PATCH 4/7] context_tracking: KVM: Move guest enter/exit wrappers to KVM's domain Sean Christopherson
2021-04-13 18:29 ` [RFC PATCH 5/7] KVM: Move vtime accounting of guest exit to separate helper Sean Christopherson
2021-04-13 18:29 ` [RFC PATCH 6/7] KVM: x86: Consolidate guest enter/exit logic to common helpers Sean Christopherson
2021-04-13 18:29 ` [RFC PATCH 7/7] KVM: x86: Defer tick-based accounting 'til after IRQ handling Sean Christopherson
2021-04-14 17:33 ` [RFC PATCH 0/7] KVM: Fix tick-based vtime accounting on x86 Thomas Gleixner
2021-04-14 17:57 ` Sean Christopherson
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