From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752021AbdASLAE (ORCPT ); Thu, 19 Jan 2017 06:00:04 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35702 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751729AbdASLAD (ORCPT ); Thu, 19 Jan 2017 06:00:03 -0500 Date: Thu, 19 Jan 2017 11:58:57 +0100 From: Greg KH To: kys@microsoft.com Cc: linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com, leann.ogasawara@canonical.com Subject: Re: [PATCH V2 05/18] Drivers: hv: vmbus: Consolidate all Hyper-V specific clocksource code Message-ID: <20170119105857.GA24341@kroah.com> References: <1484783072-32286-1-git-send-email-kys@exchange.microsoft.com> <1484783117-32324-5-git-send-email-kys@exchange.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1484783117-32324-5-git-send-email-kys@exchange.microsoft.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2017 at 04:45:04PM -0700, kys@exchange.microsoft.com wrote: > From: K. Y. Srinivasan > > As part of the effort to separate out architecture specific code, > consolidate all Hyper-V specific clocksource code to an architecture > specific code. > > Signed-off-by: K. Y. Srinivasan > --- > arch/x86/hyperv/hv_init.c | 104 +++++++++++++++++++++++++++++++++++++++ > arch/x86/include/asm/mshyperv.h | 12 +++++ > arch/x86/kernel/cpu/mshyperv.c | 23 --------- > drivers/hv/hv.c | 95 ----------------------------------- > drivers/hv/hyperv_vmbus.h | 8 --- > 5 files changed, 116 insertions(+), 126 deletions(-) > > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c > index b5c8e04..691dfaf 100644 > --- a/arch/x86/hyperv/hv_init.c > +++ b/arch/x86/hyperv/hv_init.c > @@ -24,6 +24,79 @@ > #include > #include > #include > +#include > + > + > +#ifdef CONFIG_X86_64 > + > +static struct ms_hyperv_tsc_page *tsc_pg; > + > +static u64 read_hv_clock_tsc(struct clocksource *arg) > +{ > + u64 current_tick; > + > + if (tsc_pg->tsc_sequence != 0) { > + /* > + * Use the tsc page to compute the value. > + */ > + > + while (1) { > + u64 tmp; > + u32 sequence = tsc_pg->tsc_sequence; > + u64 cur_tsc; > + u64 scale = tsc_pg->tsc_scale; > + s64 offset = tsc_pg->tsc_offset; > + > + rdtscll(cur_tsc); > + /* current_tick = ((cur_tsc *scale) >> 64) + offset */ > + asm("mulq %3" > + : "=d" (current_tick), "=a" (tmp) > + : "a" (cur_tsc), "r" (scale)); > + > + current_tick += offset; > + if (tsc_pg->tsc_sequence == sequence) > + return current_tick; > + > + if (tsc_pg->tsc_sequence != 0) > + continue; > + /* > + * Fallback using MSR method. > + */ > + break; > + } > + } > + rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); > + return current_tick; > +} > + > +static struct clocksource hyperv_cs_tsc = { > + .name = "hyperv_clocksource_tsc_page", > + .rating = 400, > + .read = read_hv_clock_tsc, > + .mask = CLOCKSOURCE_MASK(64), > + .flags = CLOCK_SOURCE_IS_CONTINUOUS, > +}; > +#endif > + > +static u64 read_hv_clock_msr(struct clocksource *arg) > +{ > + u64 current_tick; > + /* > + * Read the partition counter to get the current tick count. This count > + * is set to 0 when the partition is created and is incremented in > + * 100 nanosecond units. > + */ > + rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick); > + return current_tick; > +} > + > +static struct clocksource hyperv_cs_msr = { > + .name = "hyperv_clocksource_msr", > + .rating = 400, > + .read = read_hv_clock_msr, > + .mask = CLOCKSOURCE_MASK(64), > + .flags = CLOCK_SOURCE_IS_CONTINUOUS, > +}; > > static void *hypercall_pg; > /* > @@ -31,6 +104,7 @@ > * hypervisor has been detected. > * > * 1. Setup the hypercall page. > + * 2. Register Hyper-V specific clocksource. > */ > void hyperv_init(void) > { > @@ -58,6 +132,36 @@ void hyperv_init(void) > hypercall_msr.enable = 1; > hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg); > wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); > + > + /* > + * Register Hyper-V specific clocksource. > + */ > +#ifdef CONFIG_X86_64 > + if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) { > + union hv_x64_msr_hypercall_contents tsc_msr; > + > + tsc_pg = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL); > + if (!tsc_pg) > + clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100); > + return; There's a reason you always test-build your patches and pay attention to the warnings! How did this pass your tests? I've stopped applying patches here. greg k-h