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| author | Alexey Makhalov <amakhalov@vmware.com> | 2016-10-20 07:02:11 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-10-21 10:12:11 +0200 |
| commit | cf11372949434fc4a6194b1ed9eb861d08032d08 (patch) | |
| tree | 20c5ecbe1186df54f94b6762d17d47f9d9dd8491 /arch/x86 | |
| parent | Merge tag 'for-f2fs-4.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git... (diff) | |
| download | linux-cf11372949434fc4a6194b1ed9eb861d08032d08.tar.xz linux-cf11372949434fc4a6194b1ed9eb861d08032d08.zip | |
x86/vmware: Read tsc_khz only once at boot time
Re-factor the vmware platform setup code to query the hypervisor for tsc
frequency only once during boot. Since the VMware hypervisor guarantees
constant TSC, calibrate_tsc now uses the saved value.
Signed-off-by: Alexey Makhalov <amakhalov@vmware.com>
Acked-by: Alok N Kataria <akataria@vmware.com>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/20161020050211.GA25304@amakhalov-virtual-machine
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/vmware.c | 37 |
1 files changed, 18 insertions, 19 deletions
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index 81160578b91a..4e34da4be297 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -47,6 +47,8 @@ "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \ "memory"); +static unsigned long vmware_tsc_khz __ro_after_init; + static inline int __vmware_platform(void) { uint32_t eax, ebx, ecx, edx; @@ -56,35 +58,32 @@ static inline int __vmware_platform(void) static unsigned long vmware_get_tsc_khz(void) { - uint64_t tsc_hz, lpj; - uint32_t eax, ebx, ecx, edx; - - VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); - - tsc_hz = eax | (((uint64_t)ebx) << 32); - do_div(tsc_hz, 1000); - BUG_ON(tsc_hz >> 32); - pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n", - (unsigned long) tsc_hz / 1000, - (unsigned long) tsc_hz % 1000); - - if (!preset_lpj) { - lpj = ((u64)tsc_hz * 1000); - do_div(lpj, HZ); - preset_lpj = lpj; - } - - return tsc_hz; + return vmware_tsc_khz; } static void __init vmware_platform_setup(void) { uint32_t eax, ebx, ecx, edx; + uint64_t lpj, tsc_khz; VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); if (ebx != UINT_MAX) { + lpj = tsc_khz = eax | (((uint64_t)ebx) << 32); + do_div(tsc_khz, 1000); + WARN_ON(tsc_khz >> 32); + pr_info("TSC freq read from hypervisor : %lu.%03lu MHz\n", + (unsigned long) tsc_khz / 1000, + (unsigned long) tsc_khz % 1000); + + if (!preset_lpj) { + do_div(lpj, HZ); + preset_lpj = lpj; + } + + vmware_tsc_khz = tsc_khz; x86_platform.calibrate_tsc = vmware_get_tsc_khz; + #ifdef CONFIG_X86_LOCAL_APIC /* Skip lapic calibration since we know the bus frequency. */ lapic_timer_frequency = ecx / HZ; |