From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (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 CAB11192B70; Mon, 16 Dec 2024 06:03:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734329013; cv=none; b=h5qAopoEIIoqNa6xrjhRVs/YMbbWgvntWhzaB4ccM3nu5mgVCyUEAo3rDPhkcX6sHRgGOD6SR5bBOSOV1k7YxDT0AiQHt1j0wnpH+F6Sst52Tb7jP85nMGfJt6SKuncWCX0OqzLgNICO75OYlMhP4Ny/JZhKppOSaQR/vpPlOl8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734329013; c=relaxed/simple; bh=Kp3xyFWz/0v88Gf9lCCF/jg6HhyIQ70bMmDlTQNGy34=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=FbmB5M6rsgC6RnTrOaOk1fmjl1Mku95n0y6bCpR4c1WpwUtECof44Z+ChbNGHfLUz9G7RsfXYzKJwwiUneW0eR5LdifX+VgwN+o9lQiG9WUIZqoKRJZAMsdloF29nbbpz4HqCM978jcx/yatK7XSlwNTyxoqv/H+6uLyG3VlFUQ= 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=RqlKUML+; arc=none smtp.client-ip=192.198.163.18 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="RqlKUML+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1734329012; x=1765865012; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Kp3xyFWz/0v88Gf9lCCF/jg6HhyIQ70bMmDlTQNGy34=; b=RqlKUML+lsxOFE3ed/LJo23RQ7NMJmjOB0VRt7guU3hl4m7rkSqaSUem uaof1AljOVFvWZfOKGkg3fVoIahB09xvPUAsmhNnMtTyW1NRp8MKg/rs2 0shIGzqxe3/X3+AubeNJJzFtLRB/kE02JrK3S0V5/Y2qniNC2nRnG63B4 ZPsmOXW6s9Ksv3RMjx1nyvMaAKYy7a/0jkQIb++jCczvysf1MsZppv80v 80XlYrfrQIxPN8ZI44ulo0SdLZOKygXVYCGk8uhPl1/TDiWekpur8MOb0 aKFPzSm+3HpUKKHGNpRXwE++wVTQdIREGUMwz4mx+wAfB1UDEX65Z+LCu Q==; X-CSE-ConnectionGUID: 1ESOfbjXR7WLBmKnV3KmJg== X-CSE-MsgGUID: KMc6HI3CQOq9tZukTycg7A== X-IronPort-AV: E=McAfee;i="6700,10204,11287"; a="34025178" X-IronPort-AV: E=Sophos;i="6.12,237,1728975600"; d="scan'208";a="34025178" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Dec 2024 22:03:30 -0800 X-CSE-ConnectionGUID: pzG4dA16RuKsXXmsY274tA== X-CSE-MsgGUID: /0V0jTxaShS1V4JayPgpGg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="96951397" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.247.1]) ([10.124.247.1]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Dec 2024 22:03:26 -0800 Message-ID: Date: Mon, 16 Dec 2024 14:03:23 +0800 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 4/7] KVM: TDX: Handle TDG.VP.VMCALL To: Binbin Wu Cc: pbonzini@redhat.com, seanjc@google.com, kvm@vger.kernel.org, rick.p.edgecombe@intel.com, kai.huang@intel.com, adrian.hunter@intel.com, reinette.chatre@intel.com, tony.lindgren@linux.intel.com, isaku.yamahata@intel.com, yan.y.zhao@intel.com, chao.gao@intel.com, michael.roth@amd.com, linux-kernel@vger.kernel.org References: <20241201035358.2193078-1-binbin.wu@linux.intel.com> <20241201035358.2193078-5-binbin.wu@linux.intel.com> <692aacc1-809f-449d-8f67-8e8e7ede8c8d@linux.intel.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <692aacc1-809f-449d-8f67-8e8e7ede8c8d@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 12/16/2024 9:08 AM, Binbin Wu wrote: > > > > On 12/13/2024 5:32 PM, Xiaoyao Li wrote: >> On 12/1/2024 11:53 AM, Binbin Wu wrote: >> > [...] >>> + >>> +static int tdx_map_gpa(struct kvm_vcpu *vcpu) >>> +{ >>> +    struct vcpu_tdx * tdx = to_tdx(vcpu); >>> +    u64 gpa = tdvmcall_a0_read(vcpu); >> >> We can use kvm_r12_read() directly, which is more intuitive. And we >> can drop the MACRO for a0/a1/a2/a3 accessors in patch 022. > I am neutral about it. > a0, a1, a2, a3, are the name convention for KVM's hypercall. It makes sense when serving as the parameters to __kvm_emulate_hypercall(). However, now __kvm_emulate_hypercall() is made to a MACRO and we don't need the temp variable like a0 = kvm_xx_read(). For TDVMCALL leafs other than normal KVM hypercalls, they are all TDX specific and defined in TDX GHCI spec, a0/a1/a2/a3 makes no sense for them. > >> >>> +    u64 size = tdvmcall_a1_read(vcpu); >>> +    u64 ret; >>> + >>> +    /* >>> +     * Converting TDVMCALL_MAP_GPA to KVM_HC_MAP_GPA_RANGE requires >>> +     * userspace to enable KVM_CAP_EXIT_HYPERCALL with >>> KVM_HC_MAP_GPA_RANGE >>> +     * bit set.  If not, the error code is not defined in GHCI for >>> TDX, use >>> +     * TDVMCALL_STATUS_INVALID_OPERAND for this case. >>> +     */ >>> +    if (!user_exit_on_hypercall(vcpu->kvm, KVM_HC_MAP_GPA_RANGE)) { >>> +        ret = TDVMCALL_STATUS_INVALID_OPERAND; >>> +        goto error; >>> +    } >>> + >>> +    if (gpa + size <= gpa || !kvm_vcpu_is_legal_gpa(vcpu, gpa) || >>> +        !kvm_vcpu_is_legal_gpa(vcpu, gpa + size -1) || >>> +        (vt_is_tdx_private_gpa(vcpu->kvm, gpa) != >>> +         vt_is_tdx_private_gpa(vcpu->kvm, gpa + size -1))) { >>> +        ret = TDVMCALL_STATUS_INVALID_OPERAND; >>> +        goto error; >>> +    } >>> + >>> +    if (!PAGE_ALIGNED(gpa) || !PAGE_ALIGNED(size)) { >>> +        ret = TDVMCALL_STATUS_ALIGN_ERROR; >>> +        goto error; >>> +    } >>> + >>> +    tdx->map_gpa_end = gpa + size; >>> +    tdx->map_gpa_next = gpa; >>> + >>> +    __tdx_map_gpa(tdx); >>> +    /* Forward request to userspace. */ >>> +    return 0; >> >> Maybe let __tdx_map_gpa() return a int to decide whether it needs to >> return to userspace and >> >>     return __tdx_map_gpa(tdx); >> >> ? > > To save one line of code and the comment? No. Just I found most of the cases that need to exit to usespace, comes with "return 0" after setting up the run->exit_reason and run->(fields). > Because MapGPA always goes to userspace, I don't want to make a function > return > a int that is a fixed value. > And if the multiple comments bother you, I think the comments can be > removed. > >> >> >>> + >>> +error: >>> +    tdvmcall_set_return_code(vcpu, ret); >>> +    kvm_r11_write(vcpu, gpa); >>> +    return 1; >>> +} >>> + >>>   static int handle_tdvmcall(struct kvm_vcpu *vcpu) >>>   { >>>       if (tdvmcall_exit_type(vcpu)) >>>           return tdx_emulate_vmcall(vcpu); >>>         switch (tdvmcall_leaf(vcpu)) { >>> +    case TDVMCALL_MAP_GPA: >>> +        return tdx_map_gpa(vcpu); >>>       default: >>>           break; >>>       } >>> diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h >>> index 1abc94b046a0..bfae70887695 100644 >>> --- a/arch/x86/kvm/vmx/tdx.h >>> +++ b/arch/x86/kvm/vmx/tdx.h >>> @@ -71,6 +71,9 @@ struct vcpu_tdx { >>>         enum tdx_prepare_switch_state prep_switch_state; >>>       u64 msr_host_kernel_gs_base; >>> + >>> +    u64 map_gpa_next; >>> +    u64 map_gpa_end; >>>   }; >>>     void tdh_vp_rd_failed(struct vcpu_tdx *tdx, char *uclass, u32 >>> field, u64 err); >> >