Commit-ID: cf11372949434fc4a6194b1ed9eb861d08032d08 Gitweb: http://git.kernel.org/tip/cf11372949434fc4a6194b1ed9eb861d08032d08 Author: Alexey Makhalov <amakha...@vmware.com> AuthorDate: Wed, 19 Oct 2016 22:02:11 -0700 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 21 Oct 2016 10:12:11 +0200
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 <amakha...@vmware.com> Acked-by: Alok N Kataria <akata...@vmware.com> Cc: virtualizat...@lists.linux-foundation.org Link: http://lkml.kernel.org/r/20161020050211.GA25304@amakhalov-virtual-machine Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- arch/x86/kernel/cpu/vmware.c | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index 8116057..4e34da4b 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;
