From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.93]) (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 0DE875676C; Tue, 23 Jan 2024 08:32:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.55.52.93 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705998754; cv=none; b=ql/GmwL2QiOxtxyhBC75/Tg8zeeRq+9Pl/fjGN+CPYq5f9gqQh4TSSODxd5/frWopR5H8EVjii/DwIsHP4p6MxuYEnzAR4Y9oNg3Cd3JeGeFH+EAbGq/QvigjWagZ3iby8Gx3O/yiwCL3/fvaOBZ6dRt8iLJdiHsLs5B+GjnuOY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705998754; c=relaxed/simple; bh=4MYkW78c04363Tb5/aRRLw1xwUWwRKc1h7leOKSHZbQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IEDkKInuN2JFks1h4bBZ1hfBB6xh0ajdfqh2u/1lP+HCMe2NYbFGfcM5Au0NErxj1/eqRKc8HrbSM9y6Wx8Gr+2yAoPYNp78ym1u8HXXdDCyxeu0vlXRcNSoJh8tviFhno6gV8zNLbbS2WWfXUBb6Oi+HRHN5io8f4EG/b/E49o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=TdhLtcEX; arc=none smtp.client-ip=192.55.52.93 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="TdhLtcEX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1705998753; x=1737534753; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=4MYkW78c04363Tb5/aRRLw1xwUWwRKc1h7leOKSHZbQ=; b=TdhLtcEXlWOAWnYOr5m7AoeSBwhVPZBHLEw6FekXUpApDECwMAfRpFz9 lZrYXbgoVr3xMz8dMs8A0BVr43E9P29T2fbeGc+DQlMhFiE+8/jY7ASvC ZhTFa5xyNZUbUFV6ANfPy52OK6L+MIalWa9+7Lnfi14hiU+25dwjAyAiP 4uHZp2kcOHsDCpqENKDg7lu9HNdPY+OcWclf0hnng3/zN6gZXZOvUHjwR N7aGIzDqKJbPUrhAziMj/XUjk0s5WpUWL37RXsPuo8lFDZetGUZon6LBb c9tpgvffd46VIFWV+cYZ+69+HL8CFlDya7Y5NfbQbYoTBX3e8bGfKKTnX g==; X-IronPort-AV: E=McAfee;i="6600,9927,10961"; a="398603870" X-IronPort-AV: E=Sophos;i="6.05,213,1701158400"; d="scan'208";a="398603870" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jan 2024 00:32:30 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10961"; a="909222387" X-IronPort-AV: E=Sophos;i="6.05,213,1701158400"; d="scan'208";a="909222387" Received: from binbinwu-mobl.ccr.corp.intel.com (HELO [10.93.8.92]) ([10.93.8.92]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jan 2024 00:32:27 -0800 Message-ID: <03e3eb4c-1d7e-4f24-8d5c-1f48f1d6f81f@linux.intel.com> Date: Tue, 23 Jan 2024 16:32:24 +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 v18 015/121] KVM: TDX: Retry SEAMCALL on the lack of entropy error To: isaku.yamahata@intel.com, Kai Huang Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, isaku.yamahata@gmail.com, Paolo Bonzini , erdemaktas@google.com, Sean Christopherson , Sagi Shahar , chen.bo@intel.com, hang.yuan@intel.com, tina.zhang@intel.com References: From: Binbin Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/23/2024 7:52 AM, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata > > Some SEAMCALL may return TDX_RND_NO_ENTROPY error when the entropy is > lacking. Retry SEAMCALL on the error following rdrand_long() to retry > RDRAND_RETRY_LOOPS times. > > Signed-off-by: Isaku Yamahata > --- > v18: > - update to use struct tdx_modules_args for inputs. > --- > arch/x86/kvm/vmx/tdx_errno.h | 1 + > arch/x86/kvm/vmx/tdx_ops.h | 15 +++++++++++---- > 2 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/vmx/tdx_errno.h b/arch/x86/kvm/vmx/tdx_errno.h > index 7f96696b8e7c..bb093e292fef 100644 > --- a/arch/x86/kvm/vmx/tdx_errno.h > +++ b/arch/x86/kvm/vmx/tdx_errno.h > @@ -14,6 +14,7 @@ > #define TDX_OPERAND_INVALID 0xC000010000000000ULL > #define TDX_OPERAND_BUSY 0x8000020000000000ULL > #define TDX_PREVIOUS_TLB_EPOCH_BUSY 0x8000020100000000ULL > +#define TDX_RND_NO_ENTROPY 0x8000020300000000ULL > #define TDX_VCPU_NOT_ASSOCIATED 0x8000070200000000ULL > #define TDX_KEY_GENERATION_FAILED 0x8000080000000000ULL > #define TDX_KEY_STATE_INCORRECT 0xC000081100000000ULL > diff --git a/arch/x86/kvm/vmx/tdx_ops.h b/arch/x86/kvm/vmx/tdx_ops.h > index 0e26cf22240e..f4c16e5265f0 100644 > --- a/arch/x86/kvm/vmx/tdx_ops.h > +++ b/arch/x86/kvm/vmx/tdx_ops.h > @@ -6,6 +6,7 @@ > > #include > > +#include > #include > #include > #include > @@ -17,14 +18,20 @@ > static inline u64 tdx_seamcall(u64 op, struct tdx_module_args *in, > struct tdx_module_args *out) > { > + struct tdx_module_args args; > + int retry; > u64 ret; > > - if (out) { > + if (!out) > + out = &args; > + > + /* Mimic the existing rdrand_long() to retry RDRAND_RETRY_LOOPS times. */ > + retry = RDRAND_RETRY_LOOPS; > + do { > + /* As __seamcall_ret() overwrites out, init out on each loop. */ > *out = *in; > ret = __seamcall_ret(op, out); > - } else > - ret = __seamcall(op, in); > - > + } while (unlikely(ret == TDX_RND_NO_ENTROPY) && --retry); > if (unlikely(ret == TDX_SEAMCALL_UD)) { > /* > * SEAMCALLs fail with TDX_SEAMCALL_UD returned when VMX is off. One question is when the return code is TDX_RND_NO_ENTROPY, does the input tdx_module_args value will be modified or not? As mentioned by Kai in previous review, there are seamcall*() variants which handle TDX_RND_NO_ENTROPY already. If the input tdx_module_args is not modified by a seamcall when the return code is TDX_RND_NO_ENTROPY, the seamcall_ret() can be used directly. But if the input tdx_module_args could be modified by a seamcall when the return code is TDX_RND_NO_ENTROPY, the implementations of seamcall_ret() and seamcall_saved_ret() have problem then, because the input tdx_module_args is not re-initialized when retry. They need to be fixed or deleted (no one is using them currently).