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 X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 D7AB1C433B4 for ; Thu, 22 Apr 2021 14:47:10 +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 76F9B61435 for ; Thu, 22 Apr 2021 14:47:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76F9B61435 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.115482.220343 (Exim 4.92) (envelope-from ) id 1lZabX-0003kJ-9g; Thu, 22 Apr 2021 14:46:55 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 115482.220343; Thu, 22 Apr 2021 14:46:55 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZabX-0003kC-6d; Thu, 22 Apr 2021 14:46:55 +0000 Received: by outflank-mailman (input) for mailman id 115482; Thu, 22 Apr 2021 14:46:54 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lZabW-0003k6-68 for xen-devel@lists.xenproject.org; Thu, 22 Apr 2021 14:46:54 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id d14ef3f0-857d-4ae3-a2c0-94599c164533; Thu, 22 Apr 2021 14:46:53 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E835FB19B; Thu, 22 Apr 2021 14:46:51 +0000 (UTC) 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: d14ef3f0-857d-4ae3-a2c0-94599c164533 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1619102812; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=So2JgmrzhvB3sGCo9ejN1SRRrQtA5dudILEINyAz1T8=; b=YwDOqv4vy7B5IwVbyljw7TzZZEkZx+1jgHX8IhteJF5muTMLF8x3iSCFydCNY3pDzr991i BnnIGkf0TMMC/EIJukqT6PJLbWIskJWp/oCxMYmwTcF9IOQFO5KELXbpHvP2JdyC2cEevy Ku7iVdtwRwrtNm0Q0lIOTGJFP5Rkn7U= Subject: [PATCH v3 06/22] x86/xstate: replace xsave_cntxt_size and drop XCNTXT_MASK From: Jan Beulich To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , George Dunlap , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <322de6db-e01f-0b57-5777-5d94a13c441a@suse.com> Message-ID: Date: Thu, 22 Apr 2021 16:46:47 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <322de6db-e01f-0b57-5777-5d94a13c441a@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit XCNTXT_MASK is effectively embedded in recalculate_xstate(), and xsave_cntxt_size was redundant with the host CPUID policy's xstate.max_size field. Use the host CPUID policy as input (requiring it to be calculated earlier), thus allowing e.g. "cpuid=no-avx512f" to also result in avoiding allocation of space for ZMM and mask register state. Also drop a stale part of an adjacent comment. Signed-off-by: Jan Beulich --- a/xen/arch/x86/xstate.c +++ b/xen/arch/x86/xstate.c @@ -20,9 +20,10 @@ /* * Maximum size (in byte) of the XSAVE/XRSTOR save area required by all * the supported and enabled features on the processor, including the - * XSAVE.HEADER. We only enable XCNTXT_MASK that we have known. + * XSAVE.HEADER. We only enable cpuid_policy_xcr0_max(&host_cpuid_policy). + * Note that this identifier should not be usable as an lvalue. */ -static u32 __read_mostly xsave_cntxt_size; +#define xsave_cntxt_size (host_cpuid_policy.xstate.max_size | 0) /* A 64-bit bitmask of the XSAVE/XRSTOR features supported by processor. */ u64 __read_mostly xfeature_mask; @@ -575,8 +576,23 @@ static unsigned int _xstate_ctxt_size(u6 ASSERT(ok); cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); ASSERT(ebx <= ecx); - ok = set_xcr0(act_xcr0); - ASSERT(ok); + + /* + * When called the very first time from xstate_init(), act_xcr0 (as read + * from per-CPU data) is still zero. xstate_init() wants this function to + * leave xfeature_mask in place, so avoid restoration in this case (which + * would fail anyway). + */ + if ( act_xcr0 ) + { + ok = set_xcr0(act_xcr0); + ASSERT(ok); + } + else + { + BUG_ON(!ok); + ASSERT(xcr0 == xfeature_mask); + } return ebx; } @@ -648,42 +664,35 @@ void xstate_init(struct cpuinfo_x86 *c) return; if ( (bsp && !use_xsave) || - boot_cpu_data.cpuid_level < XSTATE_CPUID ) + c->cpuid_level < XSTATE_CPUID ) { BUG_ON(!bsp); setup_clear_cpu_cap(X86_FEATURE_XSAVE); return; } - cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); - feature_mask = (((u64)edx << 32) | eax) & XCNTXT_MASK; - BUG_ON(!valid_xcr0(feature_mask)); - BUG_ON(!(feature_mask & X86_XCR0_SSE)); - - /* - * Set CR4_OSXSAVE and run "cpuid" to get xsave_cntxt_size. - */ - set_in_cr4(X86_CR4_OSXSAVE); - if ( !set_xcr0(feature_mask) ) - BUG(); - if ( bsp ) { + feature_mask = cpuid_policy_xcr0_max(&host_cpuid_policy); + BUG_ON(!valid_xcr0(feature_mask)); + BUG_ON(!(feature_mask & X86_XCR0_SSE)); + xfeature_mask = feature_mask; - /* - * xsave_cntxt_size is the max size required by enabled features. - * We know FP/SSE and YMM about eax, and nothing about edx at present. - */ - xsave_cntxt_size = _xstate_ctxt_size(feature_mask); + /* xsave_cntxt_size is the max size required by enabled features. */ printk("xstate: size: %#x and states: %#"PRIx64"\n", - xsave_cntxt_size, xfeature_mask); - } - else - { - BUG_ON(xfeature_mask != feature_mask); - BUG_ON(xsave_cntxt_size != _xstate_ctxt_size(feature_mask)); + xsave_cntxt_size, feature_mask); + + set_in_cr4(X86_CR4_OSXSAVE); } + cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx); + feature_mask = (((uint64_t)edx << 32) | eax) & xfeature_mask; + BUG_ON(xfeature_mask != feature_mask); + + /* This has the side effect of set_xcr0(feature_mask). */ + if ( xsave_cntxt_size != _xstate_ctxt_size(feature_mask) ) + BUG(); + if ( setup_xstate_features(bsp) && bsp ) BUG(); } --- a/xen/include/asm-x86/xstate.h +++ b/xen/include/asm-x86/xstate.h @@ -30,9 +30,6 @@ extern uint32_t mxcsr_mask; #define XSTATE_AREA_MIN_SIZE (FXSAVE_SIZE + XSAVE_HDR_SIZE) #define XSTATE_FP_SSE (X86_XCR0_FP | X86_XCR0_SSE) -#define XCNTXT_MASK (X86_XCR0_FP | X86_XCR0_SSE | X86_XCR0_YMM | \ - X86_XCR0_OPMASK | X86_XCR0_ZMM | X86_XCR0_HI_ZMM | \ - XSTATE_NONLAZY) #define XSTATE_ALL (~(1ULL << 63)) #define XSTATE_NONLAZY (X86_XCR0_BNDREGS | X86_XCR0_BNDCSR | X86_XCR0_PKRU)