From patchwork Thu May 23 11:16:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 13671641 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5D070C25B75 for ; Thu, 23 May 2024 11:17:06 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.728366.1133276 (Exim 4.92) (envelope-from ) id 1sA6RD-0006Xd-LJ; Thu, 23 May 2024 11:16:47 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 728366.1133276; Thu, 23 May 2024 11:16:47 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1sA6RD-0006XT-Ih; Thu, 23 May 2024 11:16:47 +0000 Received: by outflank-mailman (input) for mailman id 728366; Thu, 23 May 2024 11:16:46 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1sA6RC-0006Hv-Np for xen-devel@lists.xenproject.org; Thu, 23 May 2024 11:16:46 +0000 Received: from mail-qt1-x82d.google.com (mail-qt1-x82d.google.com [2607:f8b0:4864:20::82d]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id efcc8158-18f5-11ef-b4bb-af5377834399; Thu, 23 May 2024 13:16:44 +0200 (CEST) Received: by mail-qt1-x82d.google.com with SMTP id d75a77b69052e-43fa6d92b4eso5467811cf.1 for ; Thu, 23 May 2024 04:16:44 -0700 (PDT) Received: from andrew-laptop.citrite.net ([217.156.233.157]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6a15f179cebsm142194236d6.3.2024.05.23.04.16.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 May 2024 04:16:40 -0700 (PDT) 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: efcc8158-18f5-11ef-b4bb-af5377834399 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1716463002; x=1717067802; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=9lVBemlknG/SLrNwwy57y6cT2xHvDd19zUouoa8Th7Q=; b=iqXVxyiQOw5wrq2w+PQ4Yk93emKEY8leXPK8mDy01Erwpcg0Xpgp2mdZND+sULPKI3 060NcvmB8YLDAx+vqxNJ3+L74tl8U+b44GXyA9iSDWYt159iAO+zj2NqxzGdZlFdGDPu PCcPaBTQ1sXinPZh4mA76NT8tBaP1wFuhJu+4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716463002; x=1717067802; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9lVBemlknG/SLrNwwy57y6cT2xHvDd19zUouoa8Th7Q=; b=h6bCZlmgdAU8VixVMRbdQxMPwStMBygcHHR7PcVU49tnaOyXLmnDT5u5ZTCfaL84nQ f8CWlDZHA9QBQc7LFhZqPfCpMgc+1ey2PP+ag1VbfxObbziPkTwxBqtiTTG6RPKTm5AG ZyfE6+p19K9JzEA12c36hqTj8OjBD5WbqLNnyTRJTxvA3qaklZR94ZRNEaaLI6CD2U5i /d2ekiQ2KOCrnD25Y66rqAAf4BR8I2R9vTa+w7UUPhF7nX6BtZn64QX82ICkb8m8RYPx SZYUms6goQwb4eUyKsInjsNyvLpn657UeVRqHc0SY/i4tddXYqvdFyhLcdiY862T8Ca7 17+g== X-Gm-Message-State: AOJu0YwZ1C1JulkUTcwLWHx2JsIBsU45JFsUJoZ2DK2HnafVT2Xxirki 5WRo76IeoTAKUCh2gZq1MAiZDVLqbZc2kiTfXHVv4rUqHD8b82I4f74mAZdYQizXalrCbjTg52J B35E= X-Google-Smtp-Source: AGHT+IH8NEooV914qM081ZP9jeUslFGVNkKno/knvhMmAz3WHl1hGmGhcv0lu/itA9GoeLdPVcJ3Qw== X-Received: by 2002:a05:622a:164e:b0:43b:173e:ce1b with SMTP id d75a77b69052e-43fa74df0a0mr31155171cf.32.1716463001887; Thu, 23 May 2024 04:16:41 -0700 (PDT) From: Andrew Cooper To: Xen-devel Cc: Andrew Cooper , Jan Beulich , =?utf-8?q?Roger_Pau_Monn=C3=A9?= Subject: [PATCH 2/7] x86/xstate: Cross-check dynamic XSTATE sizes at boot Date: Thu, 23 May 2024 12:16:22 +0100 Message-Id: <20240523111627.28896-3-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240523111627.28896-1-andrew.cooper3@citrix.com> References: <20240523111627.28896-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 Right now, xstate_ctxt_size() performs a cross-check of size with CPUID in for every call. This is expensive, being used for domain create/migrate, as well as to service certain guest CPUID instructions. Instead, arrange to check the sizes once at boot. See the code comments for details. Right now, it just checks hardware against the algorithm expectations. Later patches will add further cross-checking. Introduce the missing X86_XCR0_* and X86_XSS_* constants, and a couple of missing CPUID bits. This is to maximise coverage in the sanity check, even if we don't expect to use/virtualise some of these features any time soon. Leave HDC and HWP alone for now. We don't have CPUID bits from them stored nicely. Only perform the cross-checks in debug builds. It's only developers or new hardware liable to trip these checks, and Xen at least tracks "maximum value ever seen in xcr0" for the lifetime of the VM, which we don't want to be tickling in the general case. Signed-off-by: Andrew Cooper --- CC: Jan Beulich CC: Roger Pau Monné v3: * New On Sapphire Rapids with the whole series inc diagnostics, we get this pattern: (XEN) *** check_new_xstate(, 0x00000003) (XEN) *** check_new_xstate(, 0x00000004) (XEN) *** check_new_xstate(, 0x000000e0) (XEN) *** check_new_xstate(, 0x00000200) (XEN) *** check_new_xstate(, 0x00060000) (XEN) *** check_new_xstate(, 0x00000100) (XEN) *** check_new_xstate(, 0x00000400) (XEN) *** check_new_xstate(, 0x00000800) (XEN) *** check_new_xstate(, 0x00001000) (XEN) *** check_new_xstate(, 0x00004000) (XEN) *** check_new_xstate(, 0x00008000) and on Genoa, this pattern: (XEN) *** check_new_xstate(, 0x00000003) (XEN) *** check_new_xstate(, 0x00000004) (XEN) *** check_new_xstate(, 0x000000e0) (XEN) *** check_new_xstate(, 0x00000200) (XEN) *** check_new_xstate(, 0x00000800) (XEN) *** check_new_xstate(, 0x00001000) --- xen/arch/x86/include/asm/x86-defns.h | 25 +++- xen/arch/x86/xstate.c | 150 ++++++++++++++++++++ xen/include/public/arch-x86/cpufeatureset.h | 3 + 3 files changed, 177 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/include/asm/x86-defns.h b/xen/arch/x86/include/asm/x86-defns.h index 48d7a3b7af45..d7602ab225c4 100644 --- a/xen/arch/x86/include/asm/x86-defns.h +++ b/xen/arch/x86/include/asm/x86-defns.h @@ -77,7 +77,7 @@ #define X86_CR4_PKS 0x01000000 /* Protection Key Supervisor */ /* - * XSTATE component flags in XCR0 + * XSTATE component flags in XCR0 | MSR_XSS */ #define X86_XCR0_FP_POS 0 #define X86_XCR0_FP (1ULL << X86_XCR0_FP_POS) @@ -95,11 +95,34 @@ #define X86_XCR0_ZMM (1ULL << X86_XCR0_ZMM_POS) #define X86_XCR0_HI_ZMM_POS 7 #define X86_XCR0_HI_ZMM (1ULL << X86_XCR0_HI_ZMM_POS) +#define X86_XSS_PROC_TRACE (_AC(1, ULL) << 8) #define X86_XCR0_PKRU_POS 9 #define X86_XCR0_PKRU (1ULL << X86_XCR0_PKRU_POS) +#define X86_XSS_PASID (_AC(1, ULL) << 10) +#define X86_XSS_CET_U (_AC(1, ULL) << 11) +#define X86_XSS_CET_S (_AC(1, ULL) << 12) +#define X86_XSS_HDC (_AC(1, ULL) << 13) +#define X86_XSS_UINTR (_AC(1, ULL) << 14) +#define X86_XSS_LBR (_AC(1, ULL) << 15) +#define X86_XSS_HWP (_AC(1, ULL) << 16) +#define X86_XCR0_TILE_CFG (_AC(1, ULL) << 17) +#define X86_XCR0_TILE_DATA (_AC(1, ULL) << 18) #define X86_XCR0_LWP_POS 62 #define X86_XCR0_LWP (1ULL << X86_XCR0_LWP_POS) +#define X86_XCR0_STATES \ + (X86_XCR0_FP | X86_XCR0_SSE | X86_XCR0_YMM | X86_XCR0_BNDREGS | \ + X86_XCR0_BNDCSR | X86_XCR0_OPMASK | X86_XCR0_ZMM | \ + X86_XCR0_HI_ZMM | X86_XCR0_PKRU | X86_XCR0_TILE_CFG | \ + X86_XCR0_TILE_DATA | \ + X86_XCR0_LWP) + +#define X86_XSS_STATES \ + (X86_XSS_PROC_TRACE | X86_XSS_PASID | X86_XSS_CET_U | \ + X86_XSS_CET_S | X86_XSS_HDC | X86_XSS_UINTR | X86_XSS_LBR | \ + X86_XSS_HWP | \ + 0) + /* * Debug status flags in DR6. * diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c index 75788147966a..33a5a89719ef 100644 --- a/xen/arch/x86/xstate.c +++ b/xen/arch/x86/xstate.c @@ -604,9 +604,156 @@ static bool valid_xcr0(uint64_t xcr0) if ( !(xcr0 & X86_XCR0_BNDREGS) != !(xcr0 & X86_XCR0_BNDCSR) ) return false; + /* TILE_CFG and TILE_DATA must be the same. */ + if ( !(xcr0 & X86_XCR0_TILE_CFG) != !(xcr0 & X86_XCR0_TILE_DATA) ) + return false; + return true; } +struct xcheck_state { + uint64_t states; + uint32_t uncomp_size; + uint32_t comp_size; +}; + +static void __init check_new_xstate(struct xcheck_state *s, uint64_t new) +{ + uint32_t hw_size; + + BUILD_BUG_ON(X86_XCR0_STATES & X86_XSS_STATES); + + BUG_ON(s->states & new); /* States only increase. */ + BUG_ON(!valid_xcr0(s->states | new)); /* Xen thinks it's a good value. */ + BUG_ON(new & ~(X86_XCR0_STATES | X86_XSS_STATES)); /* Known state. */ + BUG_ON((new & X86_XCR0_STATES) && + (new & X86_XSS_STATES)); /* User or supervisor, not both. */ + + s->states |= new; + if ( new & X86_XCR0_STATES ) + { + if ( !set_xcr0(s->states & X86_XCR0_STATES) ) + BUG(); + } + else + set_msr_xss(s->states & X86_XSS_STATES); + + /* + * Check the uncompressed size. Some XSTATEs are out-of-order and fill in + * prior holes in the state area, so we check that the size doesn't + * decrease. + */ + hw_size = cpuid_count_ebx(0xd, 0); + + if ( hw_size < s->uncomp_size ) + panic("XSTATE 0x%016"PRIx64", new bits {%63pbl}, uncompressed hw size %#x < prev size %#x\n", + s->states, &new, hw_size, s->uncomp_size); + + s->uncomp_size = hw_size; + + /* + * Check the compressed size, if available. All components strictly + * appear in index order. In principle there are no holes, but some + * components have their base address 64-byte aligned for efficiency + * reasons (e.g. AMX-TILE) and there are other components small enough to + * fit in the gap (e.g. PKRU) without increasing the overall length. + */ + hw_size = cpuid_count_ebx(0xd, 1); + + if ( cpu_has_xsavec ) + { + if ( hw_size < s->comp_size ) + panic("XSTATE 0x%016"PRIx64", new bits {%63pbl}, compressed hw size %#x < prev size %#x\n", + s->states, &new, hw_size, s->comp_size); + + s->comp_size = hw_size; + } + else + BUG_ON(hw_size); /* Compressed size reported, but no XSAVEC ? */ +} + +/* + * The {un,}compressed XSTATE sizes are reported by dynamic CPUID value, based + * on the current %XCR0 and MSR_XSS values. The exact layout is also feature + * and vendor specific. Cross-check Xen's understanding against real hardware + * on boot. + * + * Testing every combination is prohibitive, so we use a partial approach. + * Starting with nothing active, we add new XSTATEs and check that the CPUID + * dynamic values never decreases. + */ +static void __init noinline xstate_check_sizes(void) +{ + uint64_t old_xcr0 = get_xcr0(); + uint64_t old_xss = get_msr_xss(); + struct xcheck_state s = {}; + + /* + * User XSTATEs, increasing by index. + * + * Chronologically, Intel and AMD had identical layouts for AVX (YMM). + * AMD introduced LWP in Fam15h, following immediately on from YMM. Intel + * left an LWP-shaped hole when adding MPX (BND{CSR,REGS}) in Skylake. + * AMD removed LWP in Fam17h, putting PKRU in the same space, breaking + * layout compatibility with Intel and having a knock-on effect on all + * subsequent states. + */ + check_new_xstate(&s, X86_XCR0_SSE | X86_XCR0_FP); + + if ( cpu_has_avx ) + check_new_xstate(&s, X86_XCR0_YMM); + + if ( cpu_has_mpx ) + check_new_xstate(&s, X86_XCR0_BNDCSR | X86_XCR0_BNDREGS); + + if ( cpu_has_avx512f ) + check_new_xstate(&s, X86_XCR0_HI_ZMM | X86_XCR0_ZMM | X86_XCR0_OPMASK); + + if ( cpu_has_pku ) + check_new_xstate(&s, X86_XCR0_PKRU); + + if ( boot_cpu_has(X86_FEATURE_AMX_TILE) ) + check_new_xstate(&s, X86_XCR0_TILE_DATA | X86_XCR0_TILE_CFG); + + if ( boot_cpu_has(X86_FEATURE_LWP) ) + check_new_xstate(&s, X86_XCR0_LWP); + + /* + * Supervisor XSTATEs, increasing by index. + * + * Intel Broadwell in particular had Processor Trace but no XSAVES. There + * doesn't appear to have been a new enumeration when X86_XSS_PROC_TRACE + * was introduced in Skylake. + */ + if ( cpu_has_xsaves ) + { + if ( cpu_has_proc_trace ) + check_new_xstate(&s, X86_XSS_PROC_TRACE); + + if ( boot_cpu_has(X86_FEATURE_ENQCMD) ) + check_new_xstate(&s, X86_XSS_PASID); + + if ( boot_cpu_has(X86_FEATURE_CET_SS) || + boot_cpu_has(X86_FEATURE_CET_IBT) ) + { + check_new_xstate(&s, X86_XSS_CET_U); + check_new_xstate(&s, X86_XSS_CET_S); + } + + if ( boot_cpu_has(X86_FEATURE_UINTR) ) + check_new_xstate(&s, X86_XSS_UINTR); + + if ( boot_cpu_has(X86_FEATURE_ARCH_LBR) ) + check_new_xstate(&s, X86_XSS_LBR); + } + + /* Restore old state now the test is done. */ + if ( !set_xcr0(old_xcr0) ) + BUG(); + if ( cpu_has_xsaves ) + set_msr_xss(old_xss); +} + /* Collect the information of processor's extended state */ void xstate_init(struct cpuinfo_x86 *c) { @@ -683,6 +830,9 @@ void xstate_init(struct cpuinfo_x86 *c) if ( setup_xstate_features(bsp) && bsp ) BUG(); + + if ( IS_ENABLED(CONFIG_DEBUG) && bsp ) + xstate_check_sizes(); } int validate_xstate(const struct domain *d, uint64_t xcr0, uint64_t xcr0_accum, diff --git a/xen/include/public/arch-x86/cpufeatureset.h b/xen/include/public/arch-x86/cpufeatureset.h index 6627453e3985..d9eba5e9a714 100644 --- a/xen/include/public/arch-x86/cpufeatureset.h +++ b/xen/include/public/arch-x86/cpufeatureset.h @@ -266,6 +266,7 @@ XEN_CPUFEATURE(IBPB_RET, 8*32+30) /*A IBPB clears RSB/RAS too. */ XEN_CPUFEATURE(AVX512_4VNNIW, 9*32+ 2) /*A AVX512 Neural Network Instructions */ XEN_CPUFEATURE(AVX512_4FMAPS, 9*32+ 3) /*A AVX512 Multiply Accumulation Single Precision */ XEN_CPUFEATURE(FSRM, 9*32+ 4) /*A Fast Short REP MOVS */ +XEN_CPUFEATURE(UINTR, 9*32+ 5) /* User-mode Interrupts */ XEN_CPUFEATURE(AVX512_VP2INTERSECT, 9*32+8) /*a VP2INTERSECT{D,Q} insns */ XEN_CPUFEATURE(SRBDS_CTRL, 9*32+ 9) /* MSR_MCU_OPT_CTRL and RNGDS_MITG_DIS. */ XEN_CPUFEATURE(MD_CLEAR, 9*32+10) /*!A| VERW clears microarchitectural buffers */ @@ -274,8 +275,10 @@ XEN_CPUFEATURE(TSX_FORCE_ABORT, 9*32+13) /* MSR_TSX_FORCE_ABORT.RTM_ABORT */ XEN_CPUFEATURE(SERIALIZE, 9*32+14) /*A SERIALIZE insn */ XEN_CPUFEATURE(HYBRID, 9*32+15) /* Heterogeneous platform */ XEN_CPUFEATURE(TSXLDTRK, 9*32+16) /*a TSX load tracking suspend/resume insns */ +XEN_CPUFEATURE(ARCH_LBR, 9*32+19) /* Architectural Last Branch Record */ XEN_CPUFEATURE(CET_IBT, 9*32+20) /* CET - Indirect Branch Tracking */ XEN_CPUFEATURE(AVX512_FP16, 9*32+23) /*A AVX512 FP16 instructions */ +XEN_CPUFEATURE(AMX_TILE, 9*32+24) /* AMX Tile architecture */ XEN_CPUFEATURE(IBRSB, 9*32+26) /*A IBRS and IBPB support (used by Intel) */ XEN_CPUFEATURE(STIBP, 9*32+27) /*A STIBP */ XEN_CPUFEATURE(L1D_FLUSH, 9*32+28) /*S MSR_FLUSH_CMD and L1D flush. */