From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F663C4332F for ; Thu, 3 Nov 2022 15:31:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232176AbiKCPbR (ORCPT ); Thu, 3 Nov 2022 11:31:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232202AbiKCPao (ORCPT ); Thu, 3 Nov 2022 11:30:44 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B8E151CB3C; Thu, 3 Nov 2022 08:30:25 -0700 (PDT) Received: from anrayabh-desk (unknown [167.220.238.193]) by linux.microsoft.com (Postfix) with ESMTPSA id A3C65205DA30; Thu, 3 Nov 2022 08:30:20 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com A3C65205DA30 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1667489425; bh=LVBwdOCgh5S6moCYBOoLpAcgiJqiRXPqQN4nBFQUFc4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EKj6uG4ALhiUoBACqTyMJgoglFkzdtbwaHbNPafkQqBy8VihwsnkHXpXGBqq/BEVU +XbhLL+Jd3q/81THSkWW0JFeg1/0S5/cmK/uiA59yi9HCD5xyw7OYEAWlR38ysRRU5 N897vK30B2PQdT0BPVi5a5sfNc/n/SMoqoR4VhAQ= Date: Thu, 3 Nov 2022 21:00:15 +0530 From: Anirudh Rayabharam To: Wei Liu Cc: "Michael Kelley (LINUX)" , KY Srinivasan , Haiyang Zhang , Stephen Hemminger , Dexuan Cui , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "daniel.lezcano@linaro.org" , Arnd Bergmann , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "stanislav.kinsburskiy@gmail.com" , "kumarpraveen@linux.microsoft.com" , "mail@anirudhrb.com" Subject: Re: [PATCH v2 1/2] clocksource/drivers/hyperv: add data structure for reference TSC MSR Message-ID: References: <20221027095729.1676394-1-anrayabh@linux.microsoft.com> <20221027095729.1676394-2-anrayabh@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Thu, Nov 03, 2022 at 02:24:05PM +0000, Wei Liu wrote: > On Wed, Nov 02, 2022 at 08:33:31PM +0000, Michael Kelley (LINUX) wrote: > > From: Michael Kelley (LINUX) Sent: Thursday, October 27, 2022 6:43 AM > > > From: Anirudh Rayabharam Sent: Thursday, > > > October 27, 2022 2:57 AM > > > > > > > > Add a data structure to represent the reference TSC MSR similar to > > > > other MSRs. This simplifies the code for updating the MSR. > > > > > > > > Signed-off-by: Anirudh Rayabharam > > > > --- > > > > drivers/clocksource/hyperv_timer.c | 28 ++++++++++++++-------------- > > > > include/asm-generic/hyperv-tlfs.h | 9 +++++++++ > > > > 2 files changed, 23 insertions(+), 14 deletions(-) > > > > > > > > diff --git a/drivers/clocksource/hyperv_timer.c > > > b/drivers/clocksource/hyperv_timer.c > > > > index bb47610bbd1c..11332c82d1af 100644 > > > > --- a/drivers/clocksource/hyperv_timer.c > > > > +++ b/drivers/clocksource/hyperv_timer.c > > > > @@ -395,25 +395,25 @@ static u64 notrace read_hv_sched_clock_tsc(void) > > > > > > > > static void suspend_hv_clock_tsc(struct clocksource *arg) > > > > { > > > > - u64 tsc_msr; > > > > + union hv_reference_tsc_msr tsc_msr; > > > > > > > > /* Disable the TSC page */ > > > > - tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC); > > > > - tsc_msr &= ~BIT_ULL(0); > > > > - hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr); > > > > + tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); > > > > + tsc_msr.enable = 0; > > > > + hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64); > > > > } > > > > > > > > > > > > static void resume_hv_clock_tsc(struct clocksource *arg) > > > > { > > > > phys_addr_t phys_addr = virt_to_phys(&tsc_pg); > > > > - u64 tsc_msr; > > > > + union hv_reference_tsc_msr tsc_msr; > > > > > > > > /* Re-enable the TSC page */ > > > > - tsc_msr = hv_get_register(HV_REGISTER_REFERENCE_TSC); > > > > - tsc_msr &= GENMASK_ULL(11, 0); > > > > - tsc_msr |= BIT_ULL(0) | (u64)phys_addr; > > > > - hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr); > > > > + tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); > > > > + tsc_msr.enable = 1; > > > > + tsc_msr.pfn = __phys_to_pfn(phys_addr); > > > > My previous review missed a problem here (and in the similar line below). > > __phys_to_pfn() will return a PFN based on the guest page size, which might > > be different from Hyper-V's page size that is always 4K. This needs to be a > > Hyper-V PFN, and we have virt_to_hvpfn() available to do just that, assuming > > that function is safe to use here and in the case below. > > Anirudh, please take a look. Just sent a fix for this using HVPFN_DOWN() which looks safe to use here. Thanks, Anirudh. > > I'm holding off sending hyperv-fixes to Linus for now. > > Thanks, > Wei.