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d0e536d893
guest_enter and guest_exit must be called with interrupts disabled,
since they take the vtime_seqlock with write_seq{lock,unlock}.
Therefore, it is not necessary to check for exceptions, nor to
save/restore the IRQ state, when context tracking functions are
called by guest_enter and guest_exit.
Split the body of context_tracking_entry and context_tracking_exit
out to __-prefixed functions, and use them from KVM.
Rik van Riel has measured this to speed up a tight vmentry/vmexit
loop by about 2%.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Tested-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
130 lines
3.2 KiB
C
130 lines
3.2 KiB
C
#ifndef _LINUX_CONTEXT_TRACKING_H
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#define _LINUX_CONTEXT_TRACKING_H
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#include <linux/sched.h>
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#include <linux/vtime.h>
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#include <linux/context_tracking_state.h>
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#include <asm/ptrace.h>
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#ifdef CONFIG_CONTEXT_TRACKING
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extern void context_tracking_cpu_set(int cpu);
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/* Called with interrupts disabled. */
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extern void __context_tracking_enter(enum ctx_state state);
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extern void __context_tracking_exit(enum ctx_state state);
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extern void context_tracking_enter(enum ctx_state state);
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extern void context_tracking_exit(enum ctx_state state);
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extern void context_tracking_user_enter(void);
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extern void context_tracking_user_exit(void);
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static inline void user_enter(void)
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{
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if (context_tracking_is_enabled())
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context_tracking_enter(CONTEXT_USER);
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}
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static inline void user_exit(void)
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{
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if (context_tracking_is_enabled())
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context_tracking_exit(CONTEXT_USER);
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}
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static inline enum ctx_state exception_enter(void)
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{
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enum ctx_state prev_ctx;
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if (!context_tracking_is_enabled())
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return 0;
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prev_ctx = this_cpu_read(context_tracking.state);
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if (prev_ctx != CONTEXT_KERNEL)
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context_tracking_exit(prev_ctx);
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return prev_ctx;
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}
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static inline void exception_exit(enum ctx_state prev_ctx)
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{
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if (context_tracking_is_enabled()) {
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if (prev_ctx != CONTEXT_KERNEL)
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context_tracking_enter(prev_ctx);
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}
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}
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/**
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* ct_state() - return the current context tracking state if known
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*
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* Returns the current cpu's context tracking state if context tracking
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* is enabled. If context tracking is disabled, returns
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* CONTEXT_DISABLED. This should be used primarily for debugging.
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*/
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static inline enum ctx_state ct_state(void)
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{
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return context_tracking_is_enabled() ?
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this_cpu_read(context_tracking.state) : CONTEXT_DISABLED;
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}
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#else
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static inline void user_enter(void) { }
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static inline void user_exit(void) { }
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static inline enum ctx_state exception_enter(void) { return 0; }
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static inline void exception_exit(enum ctx_state prev_ctx) { }
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static inline enum ctx_state ct_state(void) { return CONTEXT_DISABLED; }
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#endif /* !CONFIG_CONTEXT_TRACKING */
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#define CT_WARN_ON(cond) WARN_ON(context_tracking_is_enabled() && (cond))
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#ifdef CONFIG_CONTEXT_TRACKING_FORCE
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extern void context_tracking_init(void);
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#else
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static inline void context_tracking_init(void) { }
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#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
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static inline void guest_enter(void)
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{
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if (vtime_accounting_enabled())
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vtime_guest_enter(current);
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else
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current->flags |= PF_VCPU;
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if (context_tracking_is_enabled())
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__context_tracking_enter(CONTEXT_GUEST);
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}
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static inline void guest_exit(void)
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{
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if (context_tracking_is_enabled())
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__context_tracking_exit(CONTEXT_GUEST);
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if (vtime_accounting_enabled())
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vtime_guest_exit(current);
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else
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current->flags &= ~PF_VCPU;
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}
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#else
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static inline void guest_enter(void)
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{
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/*
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* This is running in ioctl context so its safe
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* to assume that it's the stime pending cputime
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* to flush.
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*/
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vtime_account_system(current);
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current->flags |= PF_VCPU;
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}
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static inline void guest_exit(void)
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{
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/* Flush the guest cputime we spent on the guest */
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vtime_account_system(current);
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current->flags &= ~PF_VCPU;
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}
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#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
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#endif
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