From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (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 27E6B15AAB8; Wed, 29 May 2024 01:16:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716945373; cv=none; b=IzPudMzU8qg3ktgqokkw+2EIgD5nJAn30GU8XgZKCGmD1P6OIndQGO8vrpq2nawcfjloJbkVwWUD0LtPM1adF7gZxIz7MjPidqKQFN9CwjXULpels8yikYoBLH4nDG6Wji9jlQTaUbdlns1e6MCTQWkNJT0lzGpukyHx3Ueh9zk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716945373; c=relaxed/simple; bh=X6eKSJId4PnbR29PlohmOfwdfESIOrzsPzvWL9z8YwA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ovmlSUKkHWCgM9IbZCrdOI/b+X1BnRiiagTdDJLwW2hMWmIAh4SuOU/MXZ1YANggSt2mSvCXECBDZK4ctNmCIBgyO0vYjzo93hmXY/vkJGXajbLVcUgHdEGY9RewQKlJADjlpb+Y9K4TtYjfurBqqPY8E4Ne1hSMu5aLtLHYYCo= 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=NZOBzO3w; arc=none smtp.client-ip=192.198.163.19 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="NZOBzO3w" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1716945371; x=1748481371; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=X6eKSJId4PnbR29PlohmOfwdfESIOrzsPzvWL9z8YwA=; b=NZOBzO3wpabN1awWApwNC7k80rih9Fqgsa0parwPWYGdzFxeTPjBjeN6 YCT9aUVgM6WGVq/5ldmfygmRUbWqhNkXsqlix4+IUt6VpfYwaJLBSSa6y 0Nh9IIHt2M8FSOfuWKwrm2rU3/WO7iD4rlnKfDgbCmCLB1E+JeZgM8MHt fU9KmGE8Kx7Ykjw5iI9wKzFPj4P3EjRfz/GEBEXJKZTDvljuKA7PXXh62 JJ3nBrB37pJL0YOsCSRsbsWZAWlz3LFl1WrO0q/b/6+WYGd/IYkvEda4j npwYUODQGvo1V7OFwLN5uSKoWADJqSvDEezEx3NX857+3/9grcWyq53fw Q==; X-CSE-ConnectionGUID: 5VWDJTspSM6pLVyy3Jm5pQ== X-CSE-MsgGUID: Mz5uUd2QRLWVrA0aDubjrw== X-IronPort-AV: E=McAfee;i="6600,9927,11085"; a="13146363" X-IronPort-AV: E=Sophos;i="6.08,197,1712646000"; d="scan'208";a="13146363" Received: from orviesa002.jf.intel.com ([10.64.159.142]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2024 18:16:10 -0700 X-CSE-ConnectionGUID: HUY80etjTZ6dUxDCo3rhIA== X-CSE-MsgGUID: AcQgqI7FRC61DAX6K7/Bzg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,197,1712646000"; d="scan'208";a="66106689" Received: from ls.sc.intel.com (HELO localhost) ([172.25.112.54]) by orviesa002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2024 18:16:10 -0700 Date: Tue, 28 May 2024 18:16:09 -0700 From: Isaku Yamahata To: "Edgecombe, Rick P" Cc: "Yamahata, Isaku" , "linux-kernel@vger.kernel.org" , "seanjc@google.com" , "sagis@google.com" , "isaku.yamahata@gmail.com" , "Zhao, Yan Y" , "Aktas, Erdem" , "kvm@vger.kernel.org" , "pbonzini@redhat.com" , "dmatlack@google.com" Subject: Re: [PATCH 10/16] KVM: x86/tdp_mmu: Support TDX private mapping for TDP MMU Message-ID: <20240529011609.GD386318@ls.amr.corp.intel.com> References: <20240515005952.3410568-1-rick.p.edgecombe@intel.com> <20240515005952.3410568-11-rick.p.edgecombe@intel.com> <6273a3de68722ddbb453cab83fe8f155eff7009a.camel@intel.com> <20240524082006.GG212599@ls.amr.corp.intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Tue, May 28, 2024 at 09:48:45PM +0000, "Edgecombe, Rick P" wrote: > On Fri, 2024-05-24 at 01:20 -0700, Isaku Yamahata wrote: > > > > > > I don't see why these (zap_private_spte and remove_private_spte) can't be a > > > single op. Was it to prepare for huge pages support or something? In the > > > base > > > series they are both only called once. > > > > That is for large page support. The step to merge or split large page is > > 1. zap_private_spte() > > 2. tlb shoot down > > 3. merge/split_private_spte() > > I think we can simplify it for now. Otherwise we can't justify it without > getting into the huge page support. Ok. Now we don't care large page support, we can combine those hooks into single hook. > Looking at how to create some more explainable code here, I'm also wondering > about the tdx_track() call in tdx_sept_remove_private_spte(). I didn't realize > it will send IPIs to each vcpu for *each* page getting zapped. Another one in > the "to optimize later" bucket I guess. And I guess it won't happen very often. We need it. Without tracking (or TLB shoot down), we'll hit TDX_TLB_TRACKING_NOT_DONE. The TDX module has to guarantee that there is no remaining TLB entries for pages freed by TDH.MEM.PAGE.REMOVE(). -- Isaku Yamahata