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Diffstat (limited to 'tools/virtio/ringtest/main.h')
| -rw-r--r-- | tools/virtio/ringtest/main.h | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h new file mode 100644 index 000000000..6d1fccd3d --- /dev/null +++ b/tools/virtio/ringtest/main.h @@ -0,0 +1,194 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2016 Red Hat, Inc. + * Author: Michael S. Tsirkin <mst@redhat.com> + * + * Common macros and functions for ring benchmarking. + */ +#ifndef MAIN_H +#define MAIN_H + +#include <stdbool.h> + +extern int param; + +extern bool do_exit; + +#if defined(__x86_64__) || defined(__i386__) +#include "x86intrin.h" + +static inline void wait_cycles(unsigned long long cycles) +{ + unsigned long long t; + + t = __rdtsc(); + while (__rdtsc() - t < cycles) {} +} + +#define VMEXIT_CYCLES 500 +#define VMENTRY_CYCLES 500 + +#elif defined(__s390x__) +static inline void wait_cycles(unsigned long long cycles) +{ + asm volatile("0: brctg %0,0b" : : "d" (cycles)); +} + +/* tweak me */ +#define VMEXIT_CYCLES 200 +#define VMENTRY_CYCLES 200 + +#else +static inline void wait_cycles(unsigned long long cycles) +{ + _Exit(5); +} +#define VMEXIT_CYCLES 0 +#define VMENTRY_CYCLES 0 +#endif + +static inline void vmexit(void) +{ + if (!do_exit) + return; + + wait_cycles(VMEXIT_CYCLES); +} +static inline void vmentry(void) +{ + if (!do_exit) + return; + + wait_cycles(VMENTRY_CYCLES); +} + +/* implemented by ring */ +void alloc_ring(void); +/* guest side */ +int add_inbuf(unsigned, void *, void *); +void *get_buf(unsigned *, void **); +void disable_call(); +bool used_empty(); +bool enable_call(); +void kick_available(); +/* host side */ +void disable_kick(); +bool avail_empty(); +bool enable_kick(); +bool use_buf(unsigned *, void **); +void call_used(); + +/* implemented by main */ +extern bool do_sleep; +void kick(void); +void wait_for_kick(void); +void call(void); +void wait_for_call(void); + +extern unsigned ring_size; + +/* Compiler barrier - similar to what Linux uses */ +#define barrier() asm volatile("" ::: "memory") + +/* Is there a portable way to do this? */ +#if defined(__x86_64__) || defined(__i386__) +#define cpu_relax() asm ("rep; nop" ::: "memory") +#elif defined(__s390x__) +#define cpu_relax() barrier() +#else +#define cpu_relax() assert(0) +#endif + +extern bool do_relax; + +static inline void busy_wait(void) +{ + if (do_relax) + cpu_relax(); + else + /* prevent compiler from removing busy loops */ + barrier(); +} + +#if defined(__x86_64__) || defined(__i386__) +#define smp_mb() asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc") +#else +/* + * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized + * with other __ATOMIC_SEQ_CST calls. + */ +#define smp_mb() __sync_synchronize() +#endif + +/* + * This abuses the atomic builtins for thread fences, and + * adds a compiler barrier. + */ +#define smp_release() do { \ + barrier(); \ + __atomic_thread_fence(__ATOMIC_RELEASE); \ +} while (0) + +#define smp_acquire() do { \ + __atomic_thread_fence(__ATOMIC_ACQUIRE); \ + barrier(); \ +} while (0) + +#if defined(__i386__) || defined(__x86_64__) || defined(__s390x__) +#define smp_wmb() barrier() +#else +#define smp_wmb() smp_release() +#endif + +#ifdef __alpha__ +#define smp_read_barrier_depends() smp_acquire() +#else +#define smp_read_barrier_depends() do {} while(0) +#endif + +static __always_inline +void __read_once_size(const volatile void *p, void *res, int size) +{ + switch (size) { \ + case 1: *(unsigned char *)res = *(volatile unsigned char *)p; break; \ + case 2: *(unsigned short *)res = *(volatile unsigned short *)p; break; \ + case 4: *(unsigned int *)res = *(volatile unsigned int *)p; break; \ + case 8: *(unsigned long long *)res = *(volatile unsigned long long *)p; break; \ + default: \ + barrier(); \ + __builtin_memcpy((void *)res, (const void *)p, size); \ + barrier(); \ + } \ +} + +static __always_inline void __write_once_size(volatile void *p, void *res, int size) +{ + switch (size) { + case 1: *(volatile unsigned char *)p = *(unsigned char *)res; break; + case 2: *(volatile unsigned short *)p = *(unsigned short *)res; break; + case 4: *(volatile unsigned int *)p = *(unsigned int *)res; break; + case 8: *(volatile unsigned long long *)p = *(unsigned long long *)res; break; + default: + barrier(); + __builtin_memcpy((void *)p, (const void *)res, size); + barrier(); + } +} + +#define READ_ONCE(x) \ +({ \ + union { typeof(x) __val; char __c[1]; } __u; \ + __read_once_size(&(x), __u.__c, sizeof(x)); \ + smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ + __u.__val; \ +}) + +#define WRITE_ONCE(x, val) \ +({ \ + union { typeof(x) __val; char __c[1]; } __u = \ + { .__val = (typeof(x)) (val) }; \ + __write_once_size(&(x), __u.__c, sizeof(x)); \ + __u.__val; \ +}) + +#endif |