From patchwork Mon Feb 19 07:47:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Yang, Weijiang" X-Patchwork-Id: 13562293 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 539DF22F02; Mon, 19 Feb 2024 07:47:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.16 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708328869; cv=none; b=aYYgMqOV+8AKBm1DF3SLvlcRyP28B7yTtcJ9E0OgG9AlMzqG8TIbeAvzpFSu20rj6T6G7aaNEkDm6paS8jmbuShGKJcxhqueSkHBhB6vPv3ToXFvzIRaZGfsojZ1qInX//kNm1tGfApwF6BAAzIn6VmxZeTL6L0lr6h9I1YFK3A= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708328869; c=relaxed/simple; bh=zGkrHzajqrsHUc2oTBuKUFhIGS/Sq5/+bBPPvT6IyEE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=J4UHYD/WNjtDm/13x/iVkrRRPrkzxTm5BrOsFfBnokCV24QKjhbU+YmwmHiUJGqEqmS4Jdu1QZcUdpXabyq8SK9TWVLQCyUqcH39dwSGULrFtgvt0+/JVw6VdsRwXCECRgDd/5kIKN/p2lP85QBOUDyUETKFYUC7f6kg2TVeO+U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=gzhmLEFm; arc=none smtp.client-ip=198.175.65.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="gzhmLEFm" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708328867; x=1739864867; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=zGkrHzajqrsHUc2oTBuKUFhIGS/Sq5/+bBPPvT6IyEE=; b=gzhmLEFmRU1ZftBQ4RJ0/8uN8ghPXp28NIEkAWFuuwFouSdGmmYczDW5 zztO5JofNnxyvnbNgjzyi8kc0g8PZ9UX74BVttcdmuJWeuBVVJ6XutOiO H2xgFalwYJrL1Ymr2BF9hBqSO5SRe4NYBfVxD2mAQTCrxel9/zPTrblLR zNQp4nGcCvhnzlhPNttT5hLaxW0uQzgIYFiX30jmuqhIJw9r4WLI55YWu 9XvN178MYNuGGVPfNxq5SkBb44PmV421wEKNdPnD/Z7wpzbvqdFNvNJGs Uzi0DMLpSRZqoDdMfsw1+phVgwrdlCjpmIUhmAwoa07yYoL5imUvZ35fz g==; X-IronPort-AV: E=McAfee;i="6600,9927,10988"; a="2535023" X-IronPort-AV: E=Sophos;i="6.06,170,1705392000"; d="scan'208";a="2535023" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2024 23:47:43 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10988"; a="826966066" X-IronPort-AV: E=Sophos;i="6.06,170,1705392000"; d="scan'208";a="826966066" Received: from jf.jf.intel.com (HELO jf.intel.com) ([10.165.9.183]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Feb 2024 23:47:43 -0800 From: Yang Weijiang To: seanjc@google.com, pbonzini@redhat.com, dave.hansen@intel.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: peterz@infradead.org, chao.gao@intel.com, rick.p.edgecombe@intel.com, mlevitsk@redhat.com, john.allen@amd.com, weijiang.yang@intel.com Subject: [PATCH v10 03/27] x86/fpu/xstate: Add CET supervisor mode state support Date: Sun, 18 Feb 2024 23:47:09 -0800 Message-ID: <20240219074733.122080-4-weijiang.yang@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240219074733.122080-1-weijiang.yang@intel.com> References: <20240219074733.122080-1-weijiang.yang@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add supervisor mode state support within FPU xstate management framework. Although supervisor shadow stack is not enabled/used today in kernel,KVM requires the support because when KVM advertises shadow stack feature to guest, architecturally it claims the support for both user and supervisor modes for guest OSes(Linux or non-Linux). CET supervisor states not only includes PL{0,1,2}_SSP but also IA32_S_CET MSR, but the latter is not xsave-managed. In virtualization world, guest IA32_S_CET is saved/stored into/from VM control structure. With supervisor xstate support, guest supervisor mode shadow stack state can be properly saved/restored when 1) guest/host FPU context is swapped 2) vCPU thread is sched out/in. The alternative is to enable it in KVM domain, but KVM maintainers NAKed the solution. The external discussion can be found at [*], it ended up with adding the support in kernel instead of KVM domain. Note, in KVM case, guest CET supervisor state i.e., IA32_PL{0,1,2}_MSRs, are preserved after VM-Exit until host/guest fpstates are swapped, but since host supervisor shadow stack is disabled, the preserved MSRs won't hurt host. [*]: https://lore.kernel.org/all/806e26c2-8d21-9cc9-a0b7-7787dd231729@intel.com/ Signed-off-by: Yang Weijiang Reviewed-by: Rick Edgecombe Reviewed-by: Maxim Levitsky --- arch/x86/include/asm/fpu/types.h | 14 ++++++++++++-- arch/x86/include/asm/fpu/xstate.h | 6 +++--- arch/x86/kernel/fpu/xstate.c | 6 +++++- 3 files changed, 20 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index ace9aa3b78a3..fe12724c50cc 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -118,7 +118,7 @@ enum xfeature { XFEATURE_PKRU, XFEATURE_PASID, XFEATURE_CET_USER, - XFEATURE_CET_KERNEL_UNUSED, + XFEATURE_CET_KERNEL, XFEATURE_RSRVD_COMP_13, XFEATURE_RSRVD_COMP_14, XFEATURE_LBR, @@ -141,7 +141,7 @@ enum xfeature { #define XFEATURE_MASK_PKRU (1 << XFEATURE_PKRU) #define XFEATURE_MASK_PASID (1 << XFEATURE_PASID) #define XFEATURE_MASK_CET_USER (1 << XFEATURE_CET_USER) -#define XFEATURE_MASK_CET_KERNEL (1 << XFEATURE_CET_KERNEL_UNUSED) +#define XFEATURE_MASK_CET_KERNEL (1 << XFEATURE_CET_KERNEL) #define XFEATURE_MASK_LBR (1 << XFEATURE_LBR) #define XFEATURE_MASK_XTILE_CFG (1 << XFEATURE_XTILE_CFG) #define XFEATURE_MASK_XTILE_DATA (1 << XFEATURE_XTILE_DATA) @@ -266,6 +266,16 @@ struct cet_user_state { u64 user_ssp; }; +/* + * State component 12 is Control-flow Enforcement supervisor states + */ +struct cet_supervisor_state { + /* supervisor ssp pointers */ + u64 pl0_ssp; + u64 pl1_ssp; + u64 pl2_ssp; +}; + /* * State component 15: Architectural LBR configuration state. * The size of Arch LBR state depends on the number of LBRs (lbr_depth). diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index d4427b88ee12..3b4a038d3c57 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -51,7 +51,8 @@ /* All currently supported supervisor features */ #define XFEATURE_MASK_SUPERVISOR_SUPPORTED (XFEATURE_MASK_PASID | \ - XFEATURE_MASK_CET_USER) + XFEATURE_MASK_CET_USER | \ + XFEATURE_MASK_CET_KERNEL) /* * A supervisor state component may not always contain valuable information, @@ -78,8 +79,7 @@ * Unsupported supervisor features. When a supervisor feature in this mask is * supported in the future, move it to the supported supervisor feature mask. */ -#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT | \ - XFEATURE_MASK_CET_KERNEL) +#define XFEATURE_MASK_SUPERVISOR_UNSUPPORTED (XFEATURE_MASK_PT) /* All supervisor states including supported and unsupported states. */ #define XFEATURE_MASK_SUPERVISOR_ALL (XFEATURE_MASK_SUPERVISOR_SUPPORTED | \ diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index f6b98693da59..03e166a87d61 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -51,7 +51,7 @@ static const char *xfeature_names[] = "Protection Keys User registers", "PASID state", "Control-flow User registers", - "Control-flow Kernel registers (unused)", + "Control-flow Kernel registers", "unknown xstate feature", "unknown xstate feature", "unknown xstate feature", @@ -73,6 +73,7 @@ static unsigned short xsave_cpuid_features[] __initdata = { [XFEATURE_PT_UNIMPLEMENTED_SO_FAR] = X86_FEATURE_INTEL_PT, [XFEATURE_PKRU] = X86_FEATURE_OSPKE, [XFEATURE_PASID] = X86_FEATURE_ENQCMD, + [XFEATURE_CET_KERNEL] = X86_FEATURE_SHSTK, [XFEATURE_XTILE_CFG] = X86_FEATURE_AMX_TILE, [XFEATURE_XTILE_DATA] = X86_FEATURE_AMX_TILE, }; @@ -277,6 +278,7 @@ static void __init print_xstate_features(void) print_xstate_feature(XFEATURE_MASK_PKRU); print_xstate_feature(XFEATURE_MASK_PASID); print_xstate_feature(XFEATURE_MASK_CET_USER); + print_xstate_feature(XFEATURE_MASK_CET_KERNEL); print_xstate_feature(XFEATURE_MASK_XTILE_CFG); print_xstate_feature(XFEATURE_MASK_XTILE_DATA); } @@ -346,6 +348,7 @@ static __init void os_xrstor_booting(struct xregs_state *xstate) XFEATURE_MASK_BNDCSR | \ XFEATURE_MASK_PASID | \ XFEATURE_MASK_CET_USER | \ + XFEATURE_MASK_CET_KERNEL | \ XFEATURE_MASK_XTILE) /* @@ -546,6 +549,7 @@ static bool __init check_xstate_against_struct(int nr) case XFEATURE_PASID: return XCHECK_SZ(sz, nr, struct ia32_pasid_state); case XFEATURE_XTILE_CFG: return XCHECK_SZ(sz, nr, struct xtile_cfg); case XFEATURE_CET_USER: return XCHECK_SZ(sz, nr, struct cet_user_state); + case XFEATURE_CET_KERNEL: return XCHECK_SZ(sz, nr, struct cet_supervisor_state); case XFEATURE_XTILE_DATA: check_xtile_data_against_struct(sz); return true; default: XSTATE_WARN_ON(1, "No structure for xstate: %d\n", nr);