From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8EA221E2617 for ; Tue, 17 Dec 2024 23:29:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734478147; cv=none; b=YCCjZuNAgdqLCYsl3l3L7pVjMLjGkeVTo6K6T1R96/t/hAZrHKjukto5qjzOTtmqQKuEknKmFGe952n9hj0NNhANtKlvOCcaaiZkxILfZ3OJo/wejQWWRpecALIYeOj2L5/2oxoH2djZwNX3nluWBxgUS2GbQQvbTk/OH8n+F3c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734478147; c=relaxed/simple; bh=ZRW9FS615meeB4cuY9IjMkURWSn1efg/QVqSg7hTwV4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ij9cuG3s+aWQN/Ln9e0gcPNUD63+3AKHKqKCpnQilfwOJecyrQjDOPgo4LDF0b/INF+O1JBPD+NC28uTxNg64DRIBZJNpowiBjZ+G/3SvGdwSyTDrPGVoJPfNIJTXV1mM/xYO6Ri/9aRysNGSs+tKkJdpHa8kgCE1Q3l2I49WUs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=M5VFXZHn; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="M5VFXZHn" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-7fd481e3c0bso3651211a12.0 for ; Tue, 17 Dec 2024 15:29:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1734478145; x=1735082945; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=u+A6OwJrNT6drsvdva0NABswVAfUoqi998cBEN+7hSg=; b=M5VFXZHnLEIygd9ShXtl2BXWk9om7wd7gjd+ykYt6gix1an+05ww8yQMUcMiq5LK9A HPcLp05MES775ftKNpxrM/dVFivcLBIgQTvHKj4H9bue/x5r1TaQROq2pJ8EOOIag/kw JsUYqwPb3cQkF1OImMvKkpswd6DO6gkEx1rUryYMGf3aViVeNnNjG0bXDAZ5oVv8BXwC wtGMv3XvZ2nvdK8/XPZEtYSOPRbEC06lxfnYzseKkkHFi8+u0OCVG5lmlKLxdcAxry5r LNlQnnNMrN48rZASE984q9YNl/Z4QoXym7d3W2134EI6poP68xGaDqk4k9K8SYRaYmp9 R1+w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734478145; x=1735082945; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=u+A6OwJrNT6drsvdva0NABswVAfUoqi998cBEN+7hSg=; b=c1RZt96x1Q/gC2tcifRfJ7iDLL194GNpb0IG37OwXADHQ9YikNS9wkaZQIdJKOzRaV dl33VYzJ8QCI3gwzxQ35pNsNoh5MqqEkbjwQbRPInGqNsLHDJPkaV2k8EIsKV1yh/MyU OqurUOjVrzm6Cmp+l/RxYjYieZKI2c4ep4HW1LYvi2BIiWrurt7ZMUzhnENPdZZ/nYco Y5y5pIKmgvuEJsWsecFyGtIb216EfuQf/mzbUOmjnDLf31wgY45xGsqS9jbssO/WGEZA 0qeOjSNbEB6XK/P+YQQYwL1R6IBVJRp2y0J6aXf/4h7zURSVO/TOjMsB69wq2VrrcBKP qdOA== X-Forwarded-Encrypted: i=1; AJvYcCXV2g15G+wfLbUtplpk33wUZvj25qVluYi3cYeXUV6sTFB/LqTpHq/kFCxMrlAJ5wwqmO4=@vger.kernel.org X-Gm-Message-State: AOJu0YyKmQelhISM/V3fiIMJWY/vXfeyJW+CCPZp9S7OfZI+7bjIFuQG wejYJvgYVIihuCIDDwj6ZIaUCIjQ5+9Zk97daTTeUpQv79Et4wd88SMsGS/aD4/kXQpTKZ449Um 5LA== X-Google-Smtp-Source: AGHT+IG7TM/pjY8G3lM3v4H9HOi2EaCWcjYv/dvMySdb5lytqyhMmiicErLdBSptdE7JNyD0h6ESexhOLvY= X-Received: from pjbqn14.prod.google.com ([2002:a17:90b:3d4e:b0:2ef:82c0:cb8d]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4d10:b0:2ee:a583:e616 with SMTP id 98e67ed59e1d1-2f2e91d93bdmr1138831a91.9.1734478144886; Tue, 17 Dec 2024 15:29:04 -0800 (PST) Date: Tue, 17 Dec 2024 15:29:03 -0800 In-Reply-To: <20241121115703.26381-1-yan.y.zhao@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241121115139.26338-1-yan.y.zhao@intel.com> <20241121115703.26381-1-yan.y.zhao@intel.com> Message-ID: Subject: Re: [RFC PATCH 2/2] KVM: TDX: Kick off vCPUs when SEAMCALL is busy during TD page removal From: Sean Christopherson To: Yan Zhao Cc: pbonzini@redhat.com, kvm@vger.kernel.org, dave.hansen@linux.intel.com, rick.p.edgecombe@intel.com, kai.huang@intel.com, adrian.hunter@intel.com, reinette.chatre@intel.com, xiaoyao.li@intel.com, tony.lindgren@intel.com, binbin.wu@linux.intel.com, dmatlack@google.com, isaku.yamahata@intel.com, isaku.yamahata@gmail.com, nik.borisov@suse.com, linux-kernel@vger.kernel.org, x86@kernel.org Content-Type: text/plain; charset="us-ascii" On Thu, Nov 21, 2024, Yan Zhao wrote: > For tdh_mem_range_block(), tdh_mem_track(), tdh_mem_page_remove(), > > - Upon detection of TDX_OPERAND_BUSY, retry each SEAMCALL only once. > - During the retry, kick off all vCPUs and prevent any vCPU from entering > to avoid potential contentions. > > Signed-off-by: Yan Zhao > --- > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/vmx/tdx.c | 49 +++++++++++++++++++++++++-------- > 2 files changed, 40 insertions(+), 11 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 521c7cf725bc..bb7592110337 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -123,6 +123,8 @@ > #define KVM_REQ_HV_TLB_FLUSH \ > KVM_ARCH_REQ_FLAGS(32, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) > #define KVM_REQ_UPDATE_PROTECTED_GUEST_STATE KVM_ARCH_REQ(34) > +#define KVM_REQ_NO_VCPU_ENTER_INPROGRESS \ > + KVM_ARCH_REQ_FLAGS(33, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) > > #define CR0_RESERVED_BITS \ > (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \ > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index 60d9e9d050ad..ed6b41bbcec6 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -311,6 +311,20 @@ static void tdx_clear_page(unsigned long page_pa) > __mb(); > } > > +static void tdx_no_vcpus_enter_start(struct kvm *kvm) > +{ > + kvm_make_all_cpus_request(kvm, KVM_REQ_NO_VCPU_ENTER_INPROGRESS); I vote for making this a common request with a more succient name, e.g. KVM_REQ_PAUSE. And with appropriate helpers in common code. I could have sworn I floated this idea in the past for something else, but apparently not. The only thing I can find is an old arm64 version for pausing vCPUs to emulated. Hmm, maybe I was thinking of KVM_REQ_OUTSIDE_GUEST_MODE? Anyways, I don't see any reason to make this an arch specific request.