From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) (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 ED2B248033E for ; Tue, 25 Aug 2026 13:31:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.72 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787664684; cv=none; b=WjFTY9w5AxtlZZ2uY9KppX0KVNKddTcSBUHVaMKZFOufX+03u2l25NIl6BT1Wp51wHdwsHe4DkbcFwi/l/e/d6EllLJ00aOVOJy4DOA6Uj6E0fZH1JyuwyBnPcmTs4YlYo/OSh0muREy3bQKzF2tyHPEZCAgZsN02zD+5K4x5M8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787664684; c=relaxed/simple; bh=6FzKXwp+dR8NiionnviS33tPSKmxD/OLjwV6jirP7lU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=JuESAEWNxDnt76TsqILV1CkJxH8pfyeKfG2pOPAWkU6skmwOFvaTXu2mzUbN50F8KJ+Ykk5TqtXfGivYGBhKwhjSF/LIGs2nELtM/yMRYPxvNux0XaaPay0GZEmPGoD8MhSEs9NGv/tflRNBM2MwJa8NoCOM7dQmV3yw0YShPIk= 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=nys99VQe; arc=none smtp.client-ip=209.85.216.72 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="nys99VQe" Received: by mail-pj1-f72.google.com with SMTP id 98e67ed59e1d1-39512608fb1so11751686a91.1 for ; Tue, 25 Aug 2026 06:31:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787664681; x=1788269481; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=MKSXRuaVLFrzkymJkeDqbMbN6zJt7kGbPsTEn0x+kNo=; b=nys99VQeSqRz2LN0htvS3f77KqvNXgiMIXgEM5h0mIaWZa4On1KhcWSLk/LZfSxKL6 IxiI36nm4mP9zk+dPN1+ZQN1ExkWp53R7Dt66ChygDe4r1KvrEvrixDDuzOGsZWNYrIr FDLYK/GUIM00K+hj6Fxg11mVdf7P5pySO6Zc/G7/xckYGWgUNYFhgQZyPmGuCwqiF3uj YPQYTYiod1VlLx6btgYb/jxqIBJC12OrLj+KnClMf/y+2+YC0AVDDhS1RPSdnkgkmCvy BtqhNWSfsScSElzCgrICZl9nj3s2pVuITQFBAug/3Qzwhq2boyL1uG/IJuqDeu+w99vz zUbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787664681; x=1788269481; h=content-type: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:content-type; bh=MKSXRuaVLFrzkymJkeDqbMbN6zJt7kGbPsTEn0x+kNo=; b=QeFm67s9kCX8MrXC1aJUhESpJxQEPrt11ltwuzjFS9pWkqs2l7PNdCr2A3Enwy7Wah EFpAg1vyyW0lddEw7TlQ7Z2sAeETusFeY8rl3oPn/RHvFrV2T9UDkFcGj5OehgtvPfsK ZeSQoG00BIpG2FoaAo7Yw0O8VhUfTl5YSMex+Rl3jbwWKzO5boIdY+kHgDQWDa9lOI9K YPxukMaK582cCRLAeklPwyiSiaqb2KHPXqrhCAEe5YpvfKLu7rGJkVotmQA3lHtsSIy9 7/ZvzN2zlAbvtl+zAS/bXEwkhZZGogTSg6j1NuSeIVIqIdE/cO8ImekTzceVR3X57oi8 Zcag== X-Forwarded-Encrypted: i=1; AHgh+RoKspJ8V3y+N8QRD5I12RrByosOXUgd7+Xr7lhiAFNgrTitWlJZWdLd5ws57hklamXqt3TInKVOkL0msZw=@vger.kernel.org X-Gm-Message-State: AFuF++lEulpA+8uJaJUV0V7C4XDQbGv7pf5QGq0qcIeeDIhOMSdShDny d9Uhthlv+MOtBv4f19BFI8kOE2sBmLm2odhPBnNKX1qYKH0O1e4XoQ2NZM9A9NmX6l9ZQ3zfWFv hX1APeA== X-Received: from pgch31.prod.google.com ([2002:a05:6a02:509f:b0:c9e:3c0b:5818]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:134b:b0:3c4:396d:4a6c with SMTP id adf61e73a8af0-3cd910a2c53mr15074204637.5.1787664680841; Tue, 25 Aug 2026 06:31:20 -0700 (PDT) Date: Tue, 25 Aug 2026 06:31:11 -0700 In-Reply-To: <20260825025533.25663-1-yan.y.zhao@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260825025533.25663-1-yan.y.zhao@intel.com> Message-ID: Subject: Re: [PATCH] x86/virt/tdx: Warn on !4K level in tdh_mem_page_aug() From: Sean Christopherson To: Yan Zhao Cc: kas@kernel.org, dave.hansen@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-coco@lists.linux.dev, rick.p.edgecombe@intel.com, pbonzini@redhat.com, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, kai.huang@intel.com, yilun.xu@linux.intel.com, vannapurve@google.com, ackerleytng@google.com, sagis@google.com, binbin.wu@linux.intel.com, xiaoyao.li@intel.com, Dave Hansen Content-Type: text/plain; charset="us-ascii" On Tue, Aug 25, 2026, Yan Zhao wrote: > Add a warning on a !4K level to loudly flag the unexpected condition when > callers pass in a level > 4K before tdh_mem_page_aug() supports huge pages. > > The warning makes the unexpected condition more obvious since the SEAMCALL > TDH_MEM_PAGE_AUG does not necessarily fail when the level is above 4K, > while tdh_mem_page_aug() only flushes the cache for a 4K page before huge > page support is added. If the only problem is the lack of CLFLUSH coverage, why not simply fix the bug? The changelog spends more effort justifying not fixing a bug than it would take to fix the bug. diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index 42df8ea464c4..1a83857eb7e6 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -1628,9 +1628,9 @@ static void tdx_clflush_page(struct page *page) clflush_cache_range(page_to_virt(page), PAGE_SIZE); } -static void tdx_clflush_pfn(kvm_pfn_t pfn) +static void tdx_clflush_pfn(kvm_pfn_t pfn, enum pg_level level) { - clflush_cache_range(__va(PFN_PHYS(pfn)), PAGE_SIZE); + clflush_cache_range(__va(PFN_PHYS(pfn)), page_level_size(level)); } static int pg_level_to_tdx_sept_level(enum pg_level level) @@ -1670,7 +1670,7 @@ u64 tdh_mem_page_add(struct tdx_td *td, u64 gpa, kvm_pfn_t pfn, struct page *sou }; u64 ret; - tdx_clflush_pfn(pfn); + tdx_clflush_pfn(pfn, PG_LEVEL_4K); ret = seamcall_ret(TDH_MEM_PAGE_ADD, &args); *ext_err1 = args.rcx; @@ -1722,7 +1722,7 @@ u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, enum pg_level level, }; u64 ret; - tdx_clflush_pfn(pfn); + tdx_clflush_pfn(pfn, level); ret = seamcall_ret(TDH_MEM_PAGE_AUG, &args); *ext_err1 = args.rcx;