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 DA6CE3F20E3 for ; Tue, 28 Apr 2026 11:05:19 +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=1777374322; cv=none; b=KrfvQzr1odeAjA3xEZSugq2HvB/oq9kSgW2ubBQKdn0pQek+sZfPCKcXWJPwlqlhflZpAKBV5NiENB61MtrJXmEmvITXo6HF340vmJOsiHBieWEW4EgbMBRQyn9iQpWTqptKd8mr1LmT819zDqIrbUIKYYqAdTliZ1Yan7s2gyk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777374322; c=relaxed/simple; bh=wOxgwsGcM6yALGqi2DIbw5uLad7lQI31kkgbWrcCcsw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kNLz+/ZJpOzKS6j3nrTHExhwqxYKVDCggDLaRLYlsSXYkRBcQgwb2EPVMXOxqrnWkKKLoKYr29624VmMHSgz/aW6m38mWz8kDabLxrSzXk2NPOAniLVgBm8upQEIDK5JFEoIwfGqWLytKfjA4XFuScGh3Oy4Y1l/OnMt1H+DwSQ= 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=RMj8vXL0; 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="RMj8vXL0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777374319; 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=na9NIgRBc1v+C2rQ8Vz2B7eHy+7VwDVJw14Y1qRv1Sk=; b=RMj8vXL00sEJ2JY5I9CtSuNZA3AtcE52D+LhDhTcgtjmtBgl49q6IC4EPZ+IO4Mz8UqMZ7 uyS03uiG6jv/7QXucfkMH/jgx/vtsW9CnOLE/xJhfZcfkKTbKzKgBKXzVTO1IGZoIC4UqW wCmhleVFBhD83HfhUcHJJJYmc+JwNf0= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-508-r9qpgNORMhOaPkaoN41jHw-1; Tue, 28 Apr 2026 07:05:17 -0400 X-MC-Unique: r9qpgNORMhOaPkaoN41jHw-1 X-Mimecast-MFC-AGG-ID: r9qpgNORMhOaPkaoN41jHw_1777374315 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A483618005A8; Tue, 28 Apr 2026 11:05:15 +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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E74DC1800370; Tue, 28 Apr 2026 11:05:14 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Binbin Wu , Uros Bizjak , "Chang S. Bae" , Sean Christopherson Subject: [PATCH 7/8] KVM: VMX: switch to RESTORE_GUEST_SPEC_CTRL_BODY Date: Tue, 28 Apr 2026 07:05:06 -0400 Message-ID: <20260428110507.11248-8-pbonzini@redhat.com> In-Reply-To: <20260428110507.11248-1-pbonzini@redhat.com> References: <20260428110507.11248-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: kvm@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 3.4.1 on 10.30.177.93 This has exactly the same expansion, so there is no change. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmenter.S | 31 ++++--------------------------- 1 file changed, 4 insertions(+), 27 deletions(-) diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S index 38915ca16b05..7dd9bac0e454 100644 --- a/arch/x86/kvm/vmx/vmenter.S +++ b/arch/x86/kvm/vmx/vmenter.S @@ -101,35 +101,12 @@ SYM_FUNC_START(__vmx_vcpu_run) /* Reload @vmx, _ASM_ARG1 may be modified by vmx_update_host_rsp(). */ mov WORD_SIZE(%_ASM_SP), %_ASM_DI - ALTERNATIVE "jmp .Lspec_ctrl_done", "", X86_FEATURE_MSR_SPEC_CTRL - /* - * SPEC_CTRL handling: if the guest's SPEC_CTRL value differs from the - * host's, write the MSR. - * - * IMPORTANT: To avoid RSB underflow attacks and any other nastiness, - * there must not be any returns or indirect branches between this code - * and vmentry. + * Unlike AMD there's no V_SPEC_CTRL here, so do not leave the body + * out of line. Clobbers RAX, RCX, RDX, RSI. */ -#ifdef CONFIG_X86_64 - mov VMX_spec_ctrl(%rdi), %rdx - cmp PER_CPU_VAR(x86_spec_ctrl_current), %rdx - je .Lspec_ctrl_done - movl %edx, %eax - shr $32, %rdx -#else - mov VMX_spec_ctrl(%edi), %eax - mov PER_CPU_VAR(x86_spec_ctrl_current), %ecx - xor %eax, %ecx - mov VMX_spec_ctrl + 4(%edi), %edx - mov PER_CPU_VAR(x86_spec_ctrl_current + 4), %esi - xor %edx, %esi - or %esi, %ecx - je .Lspec_ctrl_done -#endif - mov $MSR_IA32_SPEC_CTRL, %ecx - wrmsr - + ALTERNATIVE "jmp .Lspec_ctrl_done", "", X86_FEATURE_MSR_SPEC_CTRL + RESTORE_GUEST_SPEC_CTRL_BODY VMX_spec_ctrl(%_ASM_DI), .Lspec_ctrl_done .Lspec_ctrl_done: /* -- 2.52.0