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[2620:137:e000::1:20]) by mx.google.com with ESMTP id r133-20020a632b8b000000b0047007e62032si1646858pgr.791.2022.11.03.11.00.48; Thu, 03 Nov 2022 11:01:02 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.microsoft.com header.s=default header.b=bJcsAsXG; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.microsoft.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231324AbiKCR71 (ORCPT + 99 others); Thu, 3 Nov 2022 13:59:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231935AbiKCR7K (ORCPT ); Thu, 3 Nov 2022 13:59:10 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0E70D264F; Thu, 3 Nov 2022 10:59:05 -0700 (PDT) Received: from skinsburskii-cloud-desktop.internal.cloudapp.net (unknown [20.120.152.163]) by linux.microsoft.com (Postfix) with ESMTPSA id CB3D120C3338; Thu, 3 Nov 2022 10:59:04 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com CB3D120C3338 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1667498344; bh=++SExWSpMkq0Dv7lblZI7lZBKKts6IU3NqmxJpdUgoo=; h=Subject:From:Cc:Date:In-Reply-To:References:From; b=bJcsAsXG7mKa0C51B997E5v1xmj3NZw0x86iDTf8jVX4gDFtfc8GZUBIDCyTJkjJx eyvs8bOHYj0dcHpu4RpJS/EZ5ZR+2cPmWECzeSSxTd6ppWsIsyyqeb9O5Ju9sN6k2p pOh8ETzkwWKr2nZfT9V4iI9vQZh2cErZ4T/njDpo= Subject: [PATCH v3 4/4] drivers/clocksource/hyper-v: Add TSC page support for root partition From: Stanislav Kinsburskii Cc: Stanislav Kinsburskiy , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Daniel Lezcano , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, mikelley@microsoft.com Date: Thu, 03 Nov 2022 17:59:04 +0000 Message-ID: <166749834466.218190.3482871684875422987.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> In-Reply-To: <166749827889.218190.12775118554387271641.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> References: <166749827889.218190.12775118554387271641.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Spam-Status: No, score=-18.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,ENV_AND_HDR_SPF_MATCH,MISSING_HEADERS, RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS,USER_IN_DEF_DKIM_WL, USER_IN_DEF_SPF_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1748498867894540609?= X-GMAIL-MSGID: =?utf-8?q?1748498867894540609?= From: Stanislav Kinsburskiy Microsoft Hypervisor root partition has to map the TSC page specified by the hypervisor, instead of providing the page to the hypervisor like it's done in the guest partitions. However, it's too early to map the page when the clock is initialized, so, the actual mapping is happening later. Signed-off-by: Stanislav Kinsburskiy CC: "K. Y. Srinivasan" CC: Haiyang Zhang CC: Wei Liu CC: Dexuan Cui CC: Thomas Gleixner CC: Ingo Molnar CC: Borislav Petkov CC: Dave Hansen CC: x86@kernel.org CC: "H. Peter Anvin" CC: Daniel Lezcano CC: linux-hyperv@vger.kernel.org CC: linux-kernel@vger.kernel.org --- arch/x86/hyperv/hv_init.c | 2 ++ drivers/clocksource/hyperv_timer.c | 38 +++++++++++++++++++++++++++--------- include/clocksource/hyperv_timer.h | 1 + 3 files changed, 32 insertions(+), 9 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index f49bc3ec76e6..89954490af93 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -464,6 +464,8 @@ void __init hyperv_init(void) BUG_ON(!src); memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE); memunmap(src); + + hv_remap_tsc_clocksource(); } else { hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index 9445a1558fe9..dec7ad3b85ba 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c @@ -509,9 +509,6 @@ static bool __init hv_init_tsc_clocksource(void) if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) return false; - if (hv_root_partition) - return false; - /* * If Hyper-V offers TSC_INVARIANT, then the virtualized TSC correctly * handles frequency and offset changes due to live migration, @@ -529,16 +526,22 @@ static bool __init hv_init_tsc_clocksource(void) } hv_read_reference_counter = read_hv_clock_tsc; - tsc_pfn = HVPFN_DOWN(virt_to_phys(tsc_page)); /* - * The Hyper-V TLFS specifies to preserve the value of reserved - * bits in registers. So read the existing value, preserve the - * low order 12 bits, and add in the guest physical address - * (which already has at least the low 12 bits set to zero since - * it is page aligned). Also set the "enable" bit, which is bit 0. + * TSC page mapping works differently in root compared to guest. + * - In guest partition the guest PFN has to be passed to the + * hypervisor. + * - In root partition it's other way around: it has to map the PFN + * provided by the hypervisor. + * But it can't be mapped right here as it's too early and MMU isn't + * ready yet. So, we only set the enable bit here and will remap the + * page later in hv_remap_tsc_clocksource(). */ tsc_msr.as_uint64 = hv_get_register(HV_REGISTER_REFERENCE_TSC); + if (hv_root_partition) + tsc_pfn = tsc_msr.pfn; + else + tsc_pfn = HVPFN_DOWN(virt_to_phys(tsc_page)); tsc_msr.enable = 1; tsc_msr.pfn = tsc_pfn; hv_set_register(HV_REGISTER_REFERENCE_TSC, tsc_msr.as_uint64); @@ -573,3 +576,20 @@ void __init hv_init_clocksource(void) hv_sched_clock_offset = hv_read_reference_counter(); hv_setup_sched_clock(read_hv_sched_clock_msr); } + +void __init hv_remap_tsc_clocksource(void) +{ + if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE)) + return; + + if (!hv_root_partition) { + WARN(1, "%s: attempt to remap TSC page in guest partition\n", + __func__); + return; + } + + tsc_page = memremap(tsc_pfn << HV_HYP_PAGE_SHIFT, sizeof(tsc_pg), + MEMREMAP_WB); + if (!tsc_page) + pr_err("Failed to remap Hyper-V TSC page.\n"); +} diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h index 3078d23faaea..783701a2102d 100644 --- a/include/clocksource/hyperv_timer.h +++ b/include/clocksource/hyperv_timer.h @@ -31,6 +31,7 @@ extern void hv_stimer_global_cleanup(void); extern void hv_stimer0_isr(void); extern void hv_init_clocksource(void); +extern void hv_remap_tsc_clocksource(void); extern unsigned long hv_get_tsc_pfn(void); extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void);