diff options
| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2017-03-03 16:21:42 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-03-11 16:47:28 +0300 |
| commit | 90b20432aeb850ef84086a72893cd9411479d896 (patch) | |
| tree | 507f4ef6a4098f8f8919f625d57bc464170cefe7 /arch/x86/entry/vdso/vclock_gettime.c | |
| parent | 0733379b512ce36ba0b10942f9597b74f579f063 (diff) | |
| download | linux-90b20432aeb850ef84086a72893cd9411479d896.tar.xz | |
x86/vdso: Add VCLOCK_HVCLOCK vDSO clock read method
Hyper-V TSC page clocksource is suitable for vDSO, however, the protocol
defined by the hypervisor is different from VCLOCK_PVCLOCK. Implement the
required support by adding hvclock_page VVAR.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: devel@linuxdriverproject.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/20170303132142.25595-4-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/entry/vdso/vclock_gettime.c')
| -rw-r--r-- | arch/x86/entry/vdso/vclock_gettime.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 9d4d6e138311..fa8dbfcf7ed3 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -17,6 +17,7 @@ #include <asm/unistd.h> #include <asm/msr.h> #include <asm/pvclock.h> +#include <asm/mshyperv.h> #include <linux/math64.h> #include <linux/time.h> #include <linux/kernel.h> @@ -32,6 +33,11 @@ extern u8 pvclock_page __attribute__((visibility("hidden"))); #endif +#ifdef CONFIG_HYPERV_TSCPAGE +extern u8 hvclock_page + __attribute__((visibility("hidden"))); +#endif + #ifndef BUILD_VDSO32 notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) @@ -141,6 +147,20 @@ static notrace u64 vread_pvclock(int *mode) return last; } #endif +#ifdef CONFIG_HYPERV_TSCPAGE +static notrace u64 vread_hvclock(int *mode) +{ + const struct ms_hyperv_tsc_page *tsc_pg = + (const struct ms_hyperv_tsc_page *)&hvclock_page; + u64 current_tick = hv_read_tsc_page(tsc_pg); + + if (current_tick != U64_MAX) + return current_tick; + + *mode = VCLOCK_NONE; + return 0; +} +#endif notrace static u64 vread_tsc(void) { @@ -173,6 +193,10 @@ notrace static inline u64 vgetsns(int *mode) else if (gtod->vclock_mode == VCLOCK_PVCLOCK) cycles = vread_pvclock(mode); #endif +#ifdef CONFIG_HYPERV_TSCPAGE + else if (gtod->vclock_mode == VCLOCK_HVCLOCK) + cycles = vread_hvclock(mode); +#endif else return 0; v = (cycles - gtod->cycle_last) & gtod->mask; |