From patchwork Thu Dec 3 12:18:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yifei Jiang X-Patchwork-Id: 11948617 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 348D3C71156 for ; Thu, 3 Dec 2020 12:21:37 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 544F522244 for ; Thu, 3 Dec 2020 12:21:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 544F522244 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=SJqFisnfm72XofZpDL7eT8Tys0xuXnLyNONekxDMZNc=; b=cJ0nsY0p2wDtIaou3whQ/1a1f BnN25W2arKQae4DMWaVmP45CsgbWXTHG561xFEShc4fAg/TvJd5SMoDTfpwF5j3khDeMx0OJ6Dk9X EDHnaMqZynOmS1THSqhy8vv+rg4c1XC0Eog7kKHwt/HD4SYh6njaoxv09RrS4NeKOkqy9++dIZAF6 LUBfFMp1hQDX9bGL7sSTBzinoH35kdcE5FVKOmbqIp4qGtvD5vx2IolixaZAot2/jYTAps8nzuJZh H7SEnWgy7oRxwH5l0N2xv5HOUs94izH47eZFxYQupcEjnJnrtceaaa/xsGlsYQJHRLoKCTm2UUv2u D58Yzub1A==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kknby-0001rg-2F; Thu, 03 Dec 2020 12:21:26 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kknbt-0001nK-NC; Thu, 03 Dec 2020 12:21:23 +0000 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4Cmw0N6GcxzLywj; Thu, 3 Dec 2020 20:20:36 +0800 (CST) Received: from huawei.com (10.174.186.236) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.487.0; Thu, 3 Dec 2020 20:21:05 +0800 From: Yifei Jiang To: , , , , , Subject: [PATCH RFC 1/3] RISC-V: KVM: Change the method of calculating cycles to nanoseconds Date: Thu, 3 Dec 2020 20:18:37 +0800 Message-ID: <20201203121839.308-2-jiangyifei@huawei.com> X-Mailer: git-send-email 2.26.2.windows.1 In-Reply-To: <20201203121839.308-1-jiangyifei@huawei.com> References: <20201203121839.308-1-jiangyifei@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.186.236] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201203_072122_053892_4CD6173F X-CRM114-Status: UNSURE ( 9.35 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: zhang.zhanghailiang@huawei.com, kvm@vger.kernel.org, yinyipeng1@huawei.com, victor.zhangxiaofeng@huawei.com, linux-kernel@vger.kernel.org, Yifei Jiang , kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, wu.wubin@huawei.com, dengkai1@huawei.com Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Because we will introduce the dynamic guest frequency later, we can't use the fixed mult and shift to calculate nanoseconds. Signed-off-by: Yifei Jiang Signed-off-by: Yipeng Yin --- arch/riscv/include/asm/kvm_vcpu_timer.h | 3 --- arch/riscv/kvm/vcpu_timer.c | 3 +-- 2 files changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/riscv/include/asm/kvm_vcpu_timer.h b/arch/riscv/include/asm/kvm_vcpu_timer.h index 375281eb49e0..87e00d878999 100644 --- a/arch/riscv/include/asm/kvm_vcpu_timer.h +++ b/arch/riscv/include/asm/kvm_vcpu_timer.h @@ -12,9 +12,6 @@ #include struct kvm_guest_timer { - /* Mult & Shift values to get nanoseconds from cycles */ - u32 nsec_mult; - u32 nsec_shift; /* Time delta value */ u64 time_delta; }; diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c index ddd0ce727b83..f6b35180199a 100644 --- a/arch/riscv/kvm/vcpu_timer.c +++ b/arch/riscv/kvm/vcpu_timer.c @@ -33,7 +33,7 @@ static u64 kvm_riscv_delta_cycles2ns(u64 cycles, cycles_delta = cycles - cycles_now; else cycles_delta = 0; - delta_ns = (cycles_delta * gt->nsec_mult) >> gt->nsec_shift; + delta_ns = mul_u64_u64_div_u64(cycles_delta, NSEC_PER_SEC, riscv_timebase); local_irq_restore(flags); return delta_ns; @@ -218,7 +218,6 @@ int kvm_riscv_guest_timer_init(struct kvm *kvm) { struct kvm_guest_timer *gt = &kvm->arch.timer; - riscv_cs_get_mult_shift(>->nsec_mult, >->nsec_shift); gt->time_delta = -get_cycles64(); return 0;