From nobody Mon Feb 9 17:37:06 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=reject dis=none) header.from=citrix.com ARC-Seal: i=1; a=rsa-sha256; t=1661338818; cv=none; d=zohomail.com; s=zohoarc; b=WloZD/g2iI0ZCFPJGjZnePzOTwYeJvEuYBSicXAqSAM2CuGwEczZa/xEzv+jUTeOoLSuayUrwydWF2iSMa6JAZdoGaR1aGWR8/JpaXlDOMoJ83qx9a1z0jWiwszZJXc3FkgVbHMRkecGjJIDjmDBDkEXJW+YGNr/rBeB2bsyGVw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1661338818; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=n+b+GlPhxE+OZEkdEEAi+Qtv4cAEYyGyzls/+mjXrC4=; b=Y5dx8ggtO/nRS5rWIhFEsQxof/VIDubDBFvHR54qKQrY00f/xpEJqrZ1NYVArcVGFsPjhsG30y23DWn2L7e+IvuRQQA4OGX/o8Wie4HPsWj6tm/Qku6PoHB8lbBPDY2fIJTENp0TKpPBT/rPA0aop8QakAbj4EgA+NRx5sjmeQE= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=reject dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1661338818673350.5934892959882; Wed, 24 Aug 2022 04:00:18 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.392408.630758 (Exim 4.92) (envelope-from ) id 1oQo6w-0001m2-Bl; Wed, 24 Aug 2022 10:59:50 +0000 Received: by outflank-mailman (output) from mailman id 392408.630758; Wed, 24 Aug 2022 10:59:50 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oQo6w-0001lv-8L; Wed, 24 Aug 2022 10:59:50 +0000 Received: by outflank-mailman (input) for mailman id 392408; Wed, 24 Aug 2022 10:59:49 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1oQo6v-0001Gd-F5 for xen-devel@lists.xenproject.org; Wed, 24 Aug 2022 10:59:49 +0000 Received: from esa4.hc3370-68.iphmx.com (esa4.hc3370-68.iphmx.com [216.71.155.144]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id ddf38264-239b-11ed-bd2e-47488cf2e6aa; Wed, 24 Aug 2022 12:59:48 +0200 (CEST) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: ddf38264-239b-11ed-bd2e-47488cf2e6aa DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1661338788; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Ea/jZybnglsFeEUUogUtQhSeX6C4gXqXHZmw0VungnM=; b=HtyCeLI6lV2V58EgSV5c5dRbDNw4ZHHnMAh7hqufekUwqER9cN6mqlTr 0OLWhd9O020mIeEEWYBiKKwSx5yaHE+1V1XD9PerCHCntVAHdf9wsyJca 4O552hogsL+H4P1cNmoeS8nRu/g6fK1ELvEjehOiq/Cu1EhWXKRmvPyYQ M=; Authentication-Results: esa4.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none X-SBRS: 2.7 X-MesageID: 81343715 X-Ironport-Server: esa4.hc3370-68.iphmx.com X-Remote-IP: 162.221.156.83 X-Policy: $RELAYED IronPort-Data: A9a23:znvxNq8b1l343a/kqLatDrUD436TJUtcMsCJ2f8bNWPcYEJGY0x3n GMWWj3XOKrZMTD2c9p2bdzjoE8Eu5LVmoMwGgBoryk8E34SpcT7XtnIdU2Y0wF+jyHgoOCLy +1EN7Es+ehtFie0Si+Fa+Sn9z8kvU2xbuKUIPbePSxsThNTRi4kiBZy88Y0mYctitWia++3k YqaT/b3ZRn0gFaYDkpOs/jZ8EM14Kyr0N8llgdWic5j7Qe2e0Y9VPrzFYnpR1PkT49dGPKNR uqr5NlVKUuAon/Bovv8+lrKWhViroz6ZGBiuVIPM0SWuTBQpzRa70oOHKF0hXG7Kdm+t4sZJ N1l7fRcQOqyV0HGsLx1vxJwS0mSMUDakVNuzLfWXcG7liX7n3XQL/pGFwJmMaIy0f9LGCJEp dYHaz0KP0vEiLfjqF67YrEEasULKcDqOMUUu216zCGfBvEjKXzBa/yUv5kChm52350QW6aFD yYaQWMHgBDoShtDIFoITrk5m/+lnCLXeDxEslOF46Ew5gA/ySQhieOxa4WMJ7RmQ+0MpU+yl mnE/l2gGzUnKPiuw2Gv0y2F07qncSTTB9tJSezQGuRRqEKX7nweDlsRT1TTiduTh1O6WtlfA 1cJ4Sdopq83nGS7Q9+4UxCmrXqsuh8HR8EWA+A88BuKyKff/0CeHGdsc9JaQIV47olsH2Vsj wLX2YOybdByjFGLYWnepru7hxirBTFWJz8oemwJSlpepNa29enfkSnzosZf/L+d14OrQGupk mDW8UDSlJ1I05dVivzTEUTvxmv1+8OXFlNdChD/BDrN0+9vWGKyi2VEA3D/5O0IEouWR0LpU JMsy5nHt7Bm4X1geUWwrAQx8FKBva/t3MX02wIHInXY323FF4SfVY5R+ipiA0xiL9wJfzTkC GeK510IvsACbSH0Nv8nC25UNyjN5fmIKDgYfqqMMoomjmZZLmdrAx2ClWbPhjuwwSDAYIk0O IuBcNbEMEv2/Z9PlWPuL9rxJJdxmUjSM0uPGs2gp/lmuJLCDEOopUAtagLVMbtktvvd+W04M b93bqO39vmWa8WmCgG/zGLZBQliwaQTbXwul/FqSw== IronPort-HdrOrdr: A9a23:F4VgE67QtppRJbWfUwPXwPLXdLJyesId70hD6qhwISY1TiX+rb HXoB17726MtN9/YgBCpTntAsa9qDbnhPpICOoqTNGftWvdyQmVxehZhOOIqVCNJ8S9zJ876U 4JSdkENDSaNzhHZKjBjjVQa+xQpeW6zA== X-IronPort-AV: E=Sophos;i="5.93,260,1654574400"; d="scan'208";a="81343715" From: Andrew Cooper To: Xen-devel CC: Andrew Cooper , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= , Wei Liu Subject: [PATCH 1/4] x86/hvmloader: SMP improvements Date: Wed, 24 Aug 2022 11:59:12 +0100 Message-ID: <20220824105915.32127-2-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20220824105915.32127-1-andrew.cooper3@citrix.com> References: <20220824105915.32127-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @citrix.com) X-ZM-MESSAGEID: 1661338820018100005 * Use MOV CR instead of LMSW. LMSW has no decode assist at all on AMD CPU= s, forcing us to fully emulate the instruction. * Use __attribute__((used)) to fix the comment about ap_start(). * Have ap_start() perform a self-INIT for APs, rather than having boot_cpu= () do it. This is marginally more parallel, and reduces the amount of remo= te vCPU management that Xen has to do on behalf of the guest. Signed-off-by: Andrew Cooper --- CC: Jan Beulich CC: Roger Pau Monn=C3=A9 CC: Wei Liu --- tools/firmware/hvmloader/smp.c | 46 ++++++++++++++++++++++++++++----------= ---- 1 file changed, 31 insertions(+), 15 deletions(-) diff --git a/tools/firmware/hvmloader/smp.c b/tools/firmware/hvmloader/smp.c index 082b17f13818..80154950ac32 100644 --- a/tools/firmware/hvmloader/smp.c +++ b/tools/firmware/hvmloader/smp.c @@ -35,9 +35,9 @@ asm ( " mov %cs,%ax \n" " mov %ax,%ds \n" " lgdt gdt_desr-ap_boot_start\n" - " xor %ax, %ax \n" - " inc %ax \n" - " lmsw %ax \n" + " mov %cr0, %eax \n" + " or $1, %al \n" + " mov %eax, %cr0 \n" " ljmpl $0x08,$1f \n" "gdt_desr: \n" " .word gdt_end - gdt - 1 \n" @@ -50,8 +50,6 @@ asm ( " movl $stack_top,%esp \n" " movl %esp,%ebp \n" " call ap_start \n" - "1: hlt \n" - " jmp 1b \n" " \n" " .align 8 \n" "gdt: \n" @@ -68,14 +66,37 @@ asm ( " .text \n" ); =20 -void ap_start(void); /* non-static avoids unused-function compiler warning= */ -/*static*/ void ap_start(void) +static void __attribute__((used)) ap_start(void) { - printf(" - CPU%d ... ", ap_cpuid); + unsigned int cpu =3D ap_cpuid; + + printf(" - CPU%d ... ", cpu); cacheattr_init(); printf("done.\n"); - wmb(); - ap_callin =3D 1; + + /* + * Call in to the BSP. For APs, take ourselves offline. + * + * We must not use the stack after calling in to the BSP. + */ + asm volatile ( + " movb $1, ap_callin \n" + + " test %[icr2], %[icr2] \n" + " jz .Lbsp \n" + + " movl %[icr2], %[ICR2] \n" + " movl %[init], %[ICR1] \n" + "1: hlt \n" + " jmp 1b \n" + + ".Lbsp: \n" + : + : [icr2] "r" (SET_APIC_DEST_FIELD(LAPIC_ID(cpu))), + [init] "i" (APIC_DM_INIT), + [ICR1] "m" (*(uint32_t *)(LAPIC_BASE_ADDRESS + APIC_ICR)), + [ICR2] "m" (*(uint32_t *)(LAPIC_BASE_ADDRESS + APIC_ICR2)) + : "memory" ); } =20 static void lapic_wait_ready(void) @@ -111,11 +132,6 @@ static void boot_cpu(unsigned int cpu) */ while ( !ap_callin ) cpu_relax(); - - /* Take the secondary processor offline. */ - lapic_write(APIC_ICR2, icr2); - lapic_write(APIC_ICR, APIC_DM_INIT); - lapic_wait_ready(); =20 } =20 void smp_initialise(void) --=20 2.11.0