From nobody Wed Oct 8 00:45:54 2025 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 1E1342868A9; Fri, 4 Jul 2025 08:50:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751619040; cv=none; b=Gc6e8nKGfe3CqUp+0syy8yU2PdniidC0Jp1kzII/tybsPu9fuDd70b/XwLcOYYiyR+CW9TA2ynzDKda6lyKh08ebyzum+9XUQkLymzrTKn2a10B/N/8HXRhKeKumET3rBU7TWkh4Y740ne4gbENg5WxlMJUrwVUCVlhzeRjFCLk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751619040; c=relaxed/simple; bh=EmKOsrNzZJJcXfGM/ESPYCS66R+7WBgMhtsNsYmE5/g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FUMutHcu0nzwk90f0H7iUnCh098r3lQPW+9xWXRxUPi8UM0OhGn1SGFR5WXCpUyR4m09vL59vYEf1++eGqpQYV7WS5yoh+AjadMQNlD+WUop7glmpJYnvAeyYGCVOPAo8O9Mxm+Wc2P3J6t3l85ezJ7R8v4Ctfe96Sbe0/65D6I= 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=UwQfjbz6; arc=none smtp.client-ip=192.198.163.7 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="UwQfjbz6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1751619039; x=1783155039; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=EmKOsrNzZJJcXfGM/ESPYCS66R+7WBgMhtsNsYmE5/g=; b=UwQfjbz6h6lbBn5JF56nUoTA1kY/Z5O5yuh5CUKwZu7uvNgAt6SRKttr b31ZlTcEGf22NkonjhqtWpd0IGIA8xh1H7pwWrU549u61BszyXwUwQLat e3KGTYiEx+1irE7hLWCZZLzbuXVJY0Xsrhc8zm/GQhsNw1OCDenmPQ4qA K2rwaRrIwR04m9zdpdnp4U9qdA25seqIWrcRU7VzfbV9vyTssJvX2l9s8 bdL0MSAEDAns2IsDA2GVCELphITjlc81Z/SkxC+h3cWxgRIEclTp2LMRA GkNd8IhQYuxjBf5jGexdEr58QSTJgI2xNVdfn/zZzEJwjTWd9xggWcIv6 w==; X-CSE-ConnectionGUID: m7WhYJ/IRCSqGJHDYlyhHA== X-CSE-MsgGUID: MzIq46PeTaWpu7fCHQ3NLA== X-IronPort-AV: E=McAfee;i="6800,10657,11483"; a="79391596" X-IronPort-AV: E=Sophos;i="6.16,286,1744095600"; d="scan'208";a="79391596" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jul 2025 01:50:36 -0700 X-CSE-ConnectionGUID: d2pwx/CoRyuKh3aTpQqRaw== X-CSE-MsgGUID: jFGbck20RN+mvw7wFDUNEw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,286,1744095600"; d="scan'208";a="154721955" Received: from 984fee019967.jf.intel.com ([10.165.54.94]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jul 2025 01:50:36 -0700 From: Chao Gao To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, seanjc@google.com, pbonzini@redhat.com, dave.hansen@intel.com Cc: rick.p.edgecombe@intel.com, mlevitsk@redhat.com, john.allen@amd.com, weijiang.yang@intel.com, minipli@grsecurity.net, xin@zytor.com, Chao Gao , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: [PATCH v11 04/23] KVM: x86: Zero XSTATE components on INIT by iterating over supported features Date: Fri, 4 Jul 2025 01:49:35 -0700 Message-ID: <20250704085027.182163-5-chao.gao@intel.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250704085027.182163-1-chao.gao@intel.com> References: <20250704085027.182163-1-chao.gao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Tweak the code a bit to facilitate resetting more xstate components in the future, e.g., CET's xstate-managed MSRs. No functional change intended. Suggested-by: Sean Christopherson Signed-off-by: Chao Gao --- arch/x86/kvm/x86.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c956b36314fb..b9d1c84f0794 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12520,6 +12520,8 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) static void kvm_xstate_reset(struct kvm_vcpu *vcpu, bool init_event) { struct fpstate *fpstate =3D vcpu->arch.guest_fpu.fpstate; + u64 xfeatures_mask; + int i; =20 /* * Guest FPU state is zero allocated and so doesn't need to be manually @@ -12533,16 +12535,20 @@ static void kvm_xstate_reset(struct kvm_vcpu *vcp= u, bool init_event) * are unchanged. Currently, the only components that are zeroed and * supported by KVM are MPX related. */ - if (!kvm_mpx_supported()) + xfeatures_mask =3D (kvm_caps.supported_xcr0 | kvm_caps.supported_xss) & + (XFEATURE_MASK_BNDREGS | XFEATURE_MASK_BNDCSR); + if (!xfeatures_mask) return; =20 + BUILD_BUG_ON(sizeof(xfeatures_mask) * BITS_PER_BYTE <=3D XFEATURE_MAX); + /* * All paths that lead to INIT are required to load the guest's FPU * state (because most paths are buried in KVM_RUN). */ kvm_put_guest_fpu(vcpu); - fpstate_clear_xstate_component(fpstate, XFEATURE_BNDREGS); - fpstate_clear_xstate_component(fpstate, XFEATURE_BNDCSR); + for_each_set_bit(i, (unsigned long *)&xfeatures_mask, XFEATURE_MAX) + fpstate_clear_xstate_component(fpstate, i); kvm_load_guest_fpu(vcpu); } =20 --=20 2.47.1