From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 613D93D6689 for ; Wed, 8 Apr 2026 18:22:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672547; cv=none; b=T2UeakCOuGVpJgWZL7XfobaUhthAADu8Uv4iBQHP7YbETJcpba5+v1I8hGepFyp7wwLE8h+5xNz3A17YDtpwyFIWB6bhJad1x2uZmXaST1lR+bljuAzYojJhQpmfc4cpaUwFeIOleOm9VP8rYSqYr+EX/7H9ljiOoa7X+lvczfI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775672547; c=relaxed/simple; bh=nUqrBWeXfG9HLCddqvAosufgQMY5yXV/dnUFQRz3KUQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QldPc930dyz0dRnwPcsdIeKQN9tc7eyRYf4QX/nw7LoORLPzJkpIGyReUqjTXfPJn45iPQGl+Vx3ryzeR9mNeJ/n61qF5C1IKzg391rofzg5VvrDPdKQ+7hHOg7YxxKc0A9P5dpzmYLgT9925WOXTItC1T4FfGexHzLdoZMDEGw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=e7JyATWs; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="e7JyATWs" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1775672545; h=from:from:reply-to:subject:subject: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=utRJDEDUt40XYoA1dmLdZdoz1BpbTCbac6tFrHskUNg=; b=e7JyATWslb+SdpXR3Sczz4AVrPJB3H5lU/t+B/p7lCFGunkH5n3Dp2huDC9EhnObcpqi9W H94TSd5p6XmMZH3aX/Q5qEJyCmGAtp7pXgNc1ZJ8E0UDzUYiCL/UX94K2vGaLHeC/mqN6n tJ4j2YWxq5UlGcRLxx2io5hi3GZwbNU= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-260-1_wbkni1PXm0sS_WpeI5bw-1; Wed, 08 Apr 2026 14:22:21 -0400 X-MC-Unique: 1_wbkni1PXm0sS_WpeI5bw-1 X-Mimecast-MFC-AGG-ID: 1_wbkni1PXm0sS_WpeI5bw_1775672539 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F04EA1955DE3; Wed, 8 Apr 2026 18:22:18 +0000 (UTC) Received: from virtlab1023.lab.eng.rdu2.redhat.lab.eng.rdu2.redhat.com (virtlab1023.lab.eng.rdu2.redhat.com [10.8.1.187]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 697231955D6C; Wed, 8 Apr 2026 18:22:18 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: seanjc@google.com, chang.seok.bae@intel.com Subject: [PATCH 5/7] KVM: SVM: extract RESTORE_*_SPEC_CTRL_BODY out of svm/vmenter.S Date: Wed, 8 Apr 2026 14:22:11 -0400 Message-ID: <20260408182213.522713-6-pbonzini@redhat.com> In-Reply-To: <20260408182213.522713-1-pbonzini@redhat.com> References: <20260408182213.522713-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Pure code movement, in preparation for using these macros for VMX as well. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/vmenter.S | 62 ---------------------------------- arch/x86/kvm/vmenter.h | 68 +++++++++++++++++++++++++++++++++++++- 2 files changed, 67 insertions(+), 63 deletions(-) diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S index 545dc55582bf..67a05fe9827e 100644 --- a/arch/x86/kvm/svm/vmenter.S +++ b/arch/x86/kvm/svm/vmenter.S @@ -41,35 +41,6 @@ "jmp 800f", X86_FEATURE_MSR_SPEC_CTRL, \ "", X86_FEATURE_V_SPEC_CTRL .endm -.macro RESTORE_GUEST_SPEC_CTRL_BODY guest_spec_ctrl:req, label:req - /* - * SPEC_CTRL handling: if the guest's SPEC_CTRL value differs from the - * host's, write the MSR. This is kept out-of-line so that the common - * case does not have to jump. - * - * IMPORTANT: To avoid RSB underflow attacks and any other nastiness, - * there must not be any returns or indirect branches between this code - * and vmentry. - */ -#ifdef CONFIG_X86_64 - mov \guest_spec_ctrl, %rdx - cmp PER_CPU_VAR(x86_spec_ctrl_current), %rdx - je \label - movl %edx, %eax - shr $32, %rdx -#else - mov \guest_spec_ctrl, %eax - mov PER_CPU_VAR(x86_spec_ctrl_current), %ecx - xor %eax, %ecx - mov 4 + \guest_spec_ctrl, %edx - mov PER_CPU_VAR(x86_spec_ctrl_current + 4), %esi - xor %edx, %esi - or %esi, %ecx - je \label -#endif - mov $MSR_IA32_SPEC_CTRL, %ecx - wrmsr -.endm .macro RESTORE_HOST_SPEC_CTRL /* No need to do anything if SPEC_CTRL is unset or V_SPEC_CTRL is set */ @@ -77,39 +48,6 @@ "jmp 900f", X86_FEATURE_MSR_SPEC_CTRL, \ "", X86_FEATURE_V_SPEC_CTRL .endm -.macro RESTORE_HOST_SPEC_CTRL_BODY guest_spec_ctrl:req, enter_flags:req, label:req - /* Same for after vmexit. */ - mov $MSR_IA32_SPEC_CTRL, %ecx - - /* - * Load the value that the guest had written into MSR_IA32_SPEC_CTRL, - * if it was not intercepted during guest execution. - */ - testl $KVM_ENTER_SAVE_SPEC_CTRL, \enter_flags - jnz 998f - rdmsr - movl %eax, \guest_spec_ctrl - movl %edx, 4 + \guest_spec_ctrl -998: - /* Now restore the host value of the MSR if different from the guest's. */ -#ifdef CONFIG_X86_64 - mov PER_CPU_VAR(x86_spec_ctrl_current), %rdx - cmp \guest_spec_ctrl, %rdx - je \label - movl %edx, %eax - shr $32, %rdx -#else - mov PER_CPU_VAR(x86_spec_ctrl_current), %eax - mov \guest_spec_ctrl, %esi - xor %eax, %esi - mov PER_CPU_VAR(x86_spec_ctrl_current + 4), %edx - mov 4 + \guest_spec_ctrl, %edi - xor %edx, %edi - or %edi, %esi - je \label -#endif - wrmsr -.endm #define SVM_CLEAR_CPU_BUFFERS \ ALTERNATIVE "", __CLEAR_CPU_BUFFERS, X86_FEATURE_CLEAR_CPU_BUF_VM diff --git a/arch/x86/kvm/vmenter.h b/arch/x86/kvm/vmenter.h index 29cdae650069..e746e1328d3f 100644 --- a/arch/x86/kvm/vmenter.h +++ b/arch/x86/kvm/vmenter.h @@ -6,4 +6,70 @@ #define KVM_ENTER_SAVE_SPEC_CTRL BIT(1) #define KVM_ENTER_CLEAR_CPU_BUFFERS_FOR_MMIO BIT(2) -#endif /* __KVM_X86_VMENTER_H */ +#ifdef __ASSEMBLER__ +.macro RESTORE_GUEST_SPEC_CTRL_BODY guest_spec_ctrl:req, label:req + /* + * SPEC_CTRL handling: if the guest's SPEC_CTRL value differs from the + * host's, write the MSR. This is kept out-of-line so that the common + * case does not have to jump. + * + * IMPORTANT: To avoid RSB underflow attacks and any other nastiness, + * there must not be any returns or indirect branches between this code + * and vmentry. + */ +#ifdef CONFIG_X86_64 + mov \guest_spec_ctrl, %rdx + cmp PER_CPU_VAR(x86_spec_ctrl_current), %rdx + je \label + movl %edx, %eax + shr $32, %rdx +#else + mov \guest_spec_ctrl, %eax + mov PER_CPU_VAR(x86_spec_ctrl_current), %ecx + xor %eax, %ecx + mov 4 + \guest_spec_ctrl, %edx + mov PER_CPU_VAR(x86_spec_ctrl_current + 4), %esi + xor %edx, %esi + or %esi, %ecx + je \label +#endif + mov $MSR_IA32_SPEC_CTRL, %ecx + wrmsr +.endm + +.macro RESTORE_HOST_SPEC_CTRL_BODY guest_spec_ctrl:req, enter_flags:req, label:req + /* Same for after vmexit. */ + mov $MSR_IA32_SPEC_CTRL, %ecx + + /* + * Load the value that the guest had written into MSR_IA32_SPEC_CTRL, + * if it was not intercepted during guest execution. + */ + testl $KVM_ENTER_SAVE_SPEC_CTRL, \enter_flags + jnz 998f + rdmsr + movl %eax, \guest_spec_ctrl + movl %edx, 4 + \guest_spec_ctrl +998: + /* Now restore the host value of the MSR if different from the guest's. */ +#ifdef CONFIG_X86_64 + mov PER_CPU_VAR(x86_spec_ctrl_current), %rdx + cmp \guest_spec_ctrl, %rdx + je \label + movl %edx, %eax + shr $32, %rdx +#else + mov PER_CPU_VAR(x86_spec_ctrl_current), %eax + mov \guest_spec_ctrl, %esi + xor %eax, %esi + mov PER_CPU_VAR(x86_spec_ctrl_current + 4), %edx + mov 4 + \guest_spec_ctrl, %edi + xor %edx, %edi + or %edi, %esi + je \label +#endif + wrmsr +.endm + +#endif /* __ASSEMBLER__ */ +#endif /* __KVM_X86_ENTER_FLAGS_H */ -- 2.52.0