From patchwork Thu Mar 19 15:47:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Roger_Pau_Monn=C3=A9?= X-Patchwork-Id: 11447603 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8BA236CA for ; Thu, 19 Mar 2020 15:49:16 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 680622072D for ; Thu, 19 Mar 2020 15:49:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="d7q325Vb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 680622072D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jExOe-0005y9-TN; Thu, 19 Mar 2020 15:47:48 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jExOe-0005xz-6O for xen-devel@lists.xenproject.org; Thu, 19 Mar 2020 15:47:48 +0000 X-Inumbo-ID: faafe1b6-69f8-11ea-b34e-bc764e2007e4 Received: from esa2.hc3370-68.iphmx.com (unknown [216.71.145.153]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id faafe1b6-69f8-11ea-b34e-bc764e2007e4; Thu, 19 Mar 2020 15:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1584632868; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=W9UNjxztVxtieJiPpRXnyo2aVKIiY15sG3BlUG99yOs=; b=d7q325VbU5gRrto1FV8ehIAUxidjIVF8K7C3+QXVJFrGCaJXpVjoeBGD YVO6+ALgt+XT9elorzKsGGdgCJcKiwWOaBfaTQ7kJ594KmKTUCxzPBG6+ 14rQk9PnPxLB0GW9a+tRsRKvZvZV1RaJRmEyBm7/kUOae04XZpePWNVbg A=; Authentication-Results: esa2.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=roger.pau@citrix.com; spf=Pass smtp.mailfrom=roger.pau@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of roger.pau@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="roger.pau@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa2.hc3370-68.iphmx.com: domain of roger.pau@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="roger.pau@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ip4:168.245.78.127 ~all" Received-SPF: None (esa2.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa2.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: 6XTlyTS2FxeM4kHoEAMh4O7tPSScOAqSFJGnOsvIjx70to4CP+wUzthw1kUVIsFwuV/q6LZtdb EHoi3MNZ4vfYOFUomqcHqwRZVwK/If9K4VwK1RmgvjqWYg8qUk08AcPRkBCGysJ6RLMFCuMfnc kpvr3kDX4RHDvCSpkVQPtFEt2UMjcomwQ36BEfhd5x6Ax/7DymbF2O2HoxW9+PIy7jXthUStJ4 /R1zG2BjyBofhIFep6/Bz7WP7YLXr+EbvRlEzaKye+yKw5EJWlY7/NcIJUPh8akb+NwhKuzqsw t38= X-SBRS: 2.7 X-MesageID: 14287882 X-Ironport-Server: esa2.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.70,572,1574139600"; d="scan'208";a="14287882" From: Roger Pau Monne To: Date: Thu, 19 Mar 2020 16:47:16 +0100 Message-ID: <20200319154716.34556-4-roger.pau@citrix.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200319154716.34556-1-roger.pau@citrix.com> References: <20200319154716.34556-1-roger.pau@citrix.com> MIME-Version: 1.0 Subject: [Xen-devel] [PATCH v7 3/3] x86/tlb: use Xen L0 assisted TLB flush when available X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Wei Liu , Jan Beulich , Roger Pau Monne Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Use Xen's L0 HVMOP_flush_tlbs hypercall in order to perform flushes. This greatly increases the performance of TLB flushes when running with a high amount of vCPUs as a Xen guest, and is specially important when running in shim mode. The following figures are from a PV guest running `make -j32 xen` in shim mode with 32 vCPUs and HAP. Using x2APIC and ALLBUT shorthand: real 4m35.973s user 4m35.110s sys 36m24.117s Using L0 assisted flush: real 1m2.596s user 4m34.818s sys 5m16.374s The implementation adds a new hook to hypervisor_ops so other enlightenments can also implement such assisted flush just by filling the hook. Note that the Xen implementation completely ignores the dirty CPU mask and the linear address passed in, and always performs a global TLB flush on all vCPUs. This is a limitation of the hypercall provided by Xen. Also note that local TLB flushes are not performed using the assisted TLB flush, only remote ones. Signed-off-by: Roger Pau Monné Reviewed-by: Wei Liu Reviewed-by: Jan Beulich --- Changes since v5: - Clarify commit message. - Test for assisted flush at setup, do this for all hypervisors. - Return EOPNOTSUPP if assisted flush is not available. Changes since v4: - Adjust order calculation. Changes since v3: - Use an alternative call for the flush hook. Changes since v1: - Add a L0 assisted hook to hypervisor ops. --- xen/arch/x86/guest/hypervisor.c | 14 ++++++++++++++ xen/arch/x86/guest/xen/xen.c | 6 ++++++ xen/arch/x86/smp.c | 7 +++++++ xen/include/asm-x86/guest/hypervisor.h | 17 +++++++++++++++++ 4 files changed, 44 insertions(+) diff --git a/xen/arch/x86/guest/hypervisor.c b/xen/arch/x86/guest/hypervisor.c index 647cdb1367..e46de42ded 100644 --- a/xen/arch/x86/guest/hypervisor.c +++ b/xen/arch/x86/guest/hypervisor.c @@ -18,6 +18,7 @@ * * Copyright (c) 2019 Microsoft. */ +#include #include #include @@ -51,6 +52,10 @@ void __init hypervisor_setup(void) { if ( ops.setup ) ops.setup(); + + /* Check if assisted flush is available and disable the TLB clock if so. */ + if ( !hypervisor_flush_tlb(cpumask_of(smp_processor_id()), NULL, 0) ) + tlb_clk_enabled = false; } int hypervisor_ap_setup(void) @@ -73,6 +78,15 @@ void __init hypervisor_e820_fixup(struct e820map *e820) ops.e820_fixup(e820); } +int hypervisor_flush_tlb(const cpumask_t *mask, const void *va, + unsigned int order) +{ + if ( ops.flush_tlb ) + return alternative_call(ops.flush_tlb, mask, va, order); + + return -EOPNOTSUPP; +} + /* * Local variables: * mode: C diff --git a/xen/arch/x86/guest/xen/xen.c b/xen/arch/x86/guest/xen/xen.c index e74fd1e995..3bc01c8723 100644 --- a/xen/arch/x86/guest/xen/xen.c +++ b/xen/arch/x86/guest/xen/xen.c @@ -324,12 +324,18 @@ static void __init e820_fixup(struct e820map *e820) pv_shim_fixup_e820(e820); } +static int flush_tlb(const cpumask_t *mask, const void *va, unsigned int order) +{ + return xen_hypercall_hvm_op(HVMOP_flush_tlbs, NULL); +} + static const struct hypervisor_ops __initconstrel ops = { .name = "Xen", .setup = setup, .ap_setup = ap_setup, .resume = resume, .e820_fixup = e820_fixup, + .flush_tlb = flush_tlb, }; const struct hypervisor_ops *__init xg_probe(void) diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c index bcead5d01b..1d9fec65de 100644 --- a/xen/arch/x86/smp.c +++ b/xen/arch/x86/smp.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -268,6 +269,12 @@ void flush_area_mask(const cpumask_t *mask, const void *va, unsigned int flags) if ( (flags & ~FLUSH_ORDER_MASK) && !cpumask_subset(mask, cpumask_of(cpu)) ) { + if ( cpu_has_hypervisor && + !(flags & ~(FLUSH_TLB | FLUSH_TLB_GLOBAL | FLUSH_VA_VALID | + FLUSH_ORDER_MASK)) && + !hypervisor_flush_tlb(mask, va, (flags - 1) & FLUSH_ORDER_MASK) ) + return; + spin_lock(&flush_lock); cpumask_and(&flush_cpumask, mask, &cpu_online_map); cpumask_clear_cpu(cpu, &flush_cpumask); diff --git a/xen/include/asm-x86/guest/hypervisor.h b/xen/include/asm-x86/guest/hypervisor.h index ade10e74ea..77a1d21824 100644 --- a/xen/include/asm-x86/guest/hypervisor.h +++ b/xen/include/asm-x86/guest/hypervisor.h @@ -19,6 +19,8 @@ #ifndef __X86_HYPERVISOR_H__ #define __X86_HYPERVISOR_H__ +#include + #include struct hypervisor_ops { @@ -32,6 +34,8 @@ struct hypervisor_ops { void (*resume)(void); /* Fix up e820 map */ void (*e820_fixup)(struct e820map *e820); + /* L0 assisted TLB flush */ + int (*flush_tlb)(const cpumask_t *mask, const void *va, unsigned int order); }; #ifdef CONFIG_GUEST @@ -41,6 +45,14 @@ void hypervisor_setup(void); int hypervisor_ap_setup(void); void hypervisor_resume(void); void hypervisor_e820_fixup(struct e820map *e820); +/* + * L0 assisted TLB flush. + * mask: cpumask of the dirty vCPUs that should be flushed. + * va: linear address to flush, or NULL for global flushes. + * order: order of the linear address pointed by va. + */ +int hypervisor_flush_tlb(const cpumask_t *mask, const void *va, + unsigned int order); #else @@ -52,6 +64,11 @@ static inline void hypervisor_setup(void) { ASSERT_UNREACHABLE(); } static inline int hypervisor_ap_setup(void) { return 0; } static inline void hypervisor_resume(void) { ASSERT_UNREACHABLE(); } static inline void hypervisor_e820_fixup(struct e820map *e820) {} +static inline int hypervisor_flush_tlb(const cpumask_t *mask, const void *va, + unsigned int order) +{ + return -EOPNOTSUPP; +} #endif /* CONFIG_GUEST */