From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (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 33D6D27A476; Wed, 3 Sep 2025 11:19:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756898385; cv=none; b=Ybr1WhxsseKn5avspQTPui/xQP8o+IQJKETNhoqaz+P6Pb50rs/2oinLW0OKRXNcOUwZg47RajgMeftrnT0FTfoJ4aCg9o46DJlFl5Ziy0zjSP1zMquHBgP/Svf5QIPZAZhdGTOvIMlJ0Lwy3L5IW9fqraMgY5iyQRVgE3841W4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756898385; c=relaxed/simple; bh=Hhu23ZKM03iRMG9GrOYxaRgeFHhng4bMn3jUd+Yr/Tw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Q/u3OsWobrP4NwK+2Un9iG6UHt9mnICm5D/grxq//DleQp66nCB+HCLkwk1yaFE4pVD1UibHJXJWvzojmjBm3I1EU/hzVgrNYWKRlqe9Kk+6GZAjOE5XIFzPJmrXBaZJBgGz2wiPvtBEpGPhGr2ZRIDQqpAqaKqpBTy2QqTLVdI= 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=nHqnw+LI; arc=none smtp.client-ip=192.198.163.10 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="nHqnw+LI" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1756898383; x=1788434383; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Hhu23ZKM03iRMG9GrOYxaRgeFHhng4bMn3jUd+Yr/Tw=; b=nHqnw+LIp0AuCFmPClCrgjyid5lAVVNmO/Hqw8JHqgyQRP05npY8Ivsb exeopVgf5yrpp1tiKr4/JsxgN5vw8C72EkGfmIBYt4dhljqaoTT1B9qTv BeugwK1Qpqn1+445do48LcyHX5h6yEVGdGGhdTr5qmUjvA0YYvj/bp8bi LtATwKDJvoQiVwbj+L3nk3Tgum8MSjDyBQWxM6ysq/k5DFsoAZEWNogOG x0kI1YUdcKL/itsFcfkI6C/fZw+w9gMy2evmh4Wl3hv8erYMu4/ob4zVm i2dE6T8o7dkNAts00vP7DFpRjcHOuz272DI0zuWAhxMGxU94cNWh813SH Q==; X-CSE-ConnectionGUID: VHmHla/PQui+K/CiWSbSQQ== X-CSE-MsgGUID: TZFlqZO1QmWMl3z98S1jjg== X-IronPort-AV: E=McAfee;i="6800,10657,11541"; a="70585862" X-IronPort-AV: E=Sophos;i="6.18,235,1751266800"; d="scan'208";a="70585862" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2025 04:19:42 -0700 X-CSE-ConnectionGUID: oI7RqsbTRlOg+UjuWab8Jg== X-CSE-MsgGUID: VVJ9CYNzT2G8Jl44rq7Shw== X-ExtLoop1: 1 Received: from junyubia-mobl1.ccr.corp.intel.com (HELO [10.124.233.111]) ([10.124.233.111]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2025 04:19:36 -0700 Message-ID: Date: Wed, 3 Sep 2025 19:19:32 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v2 04/23] KVM: TDX: Introduce tdx_clear_folio() to clear huge pages To: Yan Zhao Cc: pbonzini@redhat.com, seanjc@google.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org, rick.p.edgecombe@intel.com, dave.hansen@intel.com, kas@kernel.org, tabba@google.com, ackerleytng@google.com, quic_eberman@quicinc.com, michael.roth@amd.com, david@redhat.com, vannapurve@google.com, vbabka@suse.cz, thomas.lendacky@amd.com, pgonda@google.com, zhiquan1.li@intel.com, fan.du@intel.com, jun.miao@intel.com, ira.weiny@intel.com, isaku.yamahata@intel.com, xiaoyao.li@intel.com, chao.p.peng@intel.com References: <20250807093950.4395-1-yan.y.zhao@intel.com> <20250807094214.4495-1-yan.y.zhao@intel.com> <04d6d306-b495-428f-ac3a-44057fd6ccfc@linux.intel.com> Content-Language: en-US From: Binbin Wu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/3/2025 5:51 PM, Yan Zhao wrote: > On Tue, Sep 02, 2025 at 10:56:25AM +0800, Binbin Wu wrote: >> >> On 8/7/2025 5:42 PM, Yan Zhao wrote: >>> After removing or reclaiming a guest private page or a control page from a >>> TD, zero the physical page using movdir64b(), enabling the kernel to reuse >>> the pages. >>> >>> Introduce the function tdx_clear_folio() to zero out physical memory using >>> movdir64b(), starting from the page at "start_idx" within a "folio" and >>> spanning "npages" contiguous PFNs. >>> >>> Convert tdx_clear_page() to be a helper function to facilitate the >>> zeroing of 4KB pages. >> I think this sentence is outdated? > No? tdx_clear_page() is still invoked to clear tdr_page. I didn't get the word "Convert". > >>> Signed-off-by: Xiaoyao Li >>> Signed-off-by: Isaku Yamahata >>> Signed-off-by: Yan Zhao >>> --- >>> RFC v2: >>> - Add tdx_clear_folio(). >>> - Drop inner loop _tdx_clear_page() and move __mb() outside of the loop. >>> (Rick) >>> - Use C99-style definition of variables inside a for loop. >>> - Note: [1] also changes tdx_clear_page(). RFC v2 is not based on [1] now. >>> >>> [1] https://lore.kernel.org/all/20250724130354.79392-2-adrian.hunter@intel.com >>> >>> RFC v1: >>> - split out, let tdx_clear_page() accept level. >>> --- >>> arch/x86/kvm/vmx/tdx.c | 22 ++++++++++++++++------ >>> 1 file changed, 16 insertions(+), 6 deletions(-) >>> >>> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c >>> index 8eaf8431c5f1..4fabefb27135 100644 >>> --- a/arch/x86/kvm/vmx/tdx.c >>> +++ b/arch/x86/kvm/vmx/tdx.c >>> @@ -277,18 +277,21 @@ static inline void tdx_disassociate_vp(struct kvm_vcpu *vcpu) >>> vcpu->cpu = -1; >>> } >>> -static void tdx_clear_page(struct page *page) >>> +static void tdx_clear_folio(struct folio *folio, unsigned long start_idx, >>> + unsigned long npages) >>> { >>> const void *zero_page = (const void *) page_to_virt(ZERO_PAGE(0)); >>> - void *dest = page_to_virt(page); >>> - unsigned long i; >>> /* >>> * The page could have been poisoned. MOVDIR64B also clears >>> * the poison bit so the kernel can safely use the page again. >>> */ >>> - for (i = 0; i < PAGE_SIZE; i += 64) >>> - movdir64b(dest + i, zero_page); >>> + for (unsigned long j = 0; j < npages; j++) { >>> + void *dest = page_to_virt(folio_page(folio, start_idx + j)); >>> + >>> + for (unsigned long i = 0; i < PAGE_SIZE; i += 64) >>> + movdir64b(dest + i, zero_page); >>> + } >>> /* >>> * MOVDIR64B store uses WC buffer. Prevent following memory reads >>> * from seeing potentially poisoned cache. >>> @@ -296,6 +299,13 @@ static void tdx_clear_page(struct page *page) >>> __mb(); >>> } >>> +static inline void tdx_clear_page(struct page *page) >> No need to tag a local static function with "inline". > Ok. >