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 DF5953CFF65 for ; Tue, 25 Aug 2026 08:25:45 +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=1787646348; cv=none; b=ifxaDh4k6j/GYvCD7keOvXOY33akaAhv29as/aZooZKyphSmS4LG3WpknO0aRsbdbOJ8esAGPulNTUn4PmqXTZOALyI2K41Qlr6rA5MRTQ8DDrEL2U72n+clg8FR91lSdOoc/NanpPeKmqhzT7SjS13QgZ1m6N2DHQJ+A8NWbzM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787646348; c=relaxed/simple; bh=gedJs0vtoiKBYvIXCEhQKxHm0BSByi7gwLqVFH+/z/Q=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=j32N7Zx49pxGuhD5LIJRvkuBtoXXMH3PCEzCk2UOLHD+IMgmFyElAsE7Tte4FE2ECSvSU1MmDajbqlqw951B2tFbGDvbA1UOVvCXalVOIA4kRe0vgAvZWwSjPf7StNPpOvSrJPSa7cNuFH6T7otWFPQKAl+nhOKjMJYtX+M1Xx0= 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=GND00vCh; arc=none smtp.client-ip=192.198.163.10 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="GND00vCh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787646346; x=1819182346; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=gedJs0vtoiKBYvIXCEhQKxHm0BSByi7gwLqVFH+/z/Q=; b=GND00vCh4KEHhXaPHUT/B/pIfMUDFgGJcGJt1TULu/iMQcUks9l6MXPx eSeV2IHrQ79ny8uTVJ2qt2gtuI2+4edAb6Bre7E8ljcLxV5fbSTKjB3Dr xw/Qxb1A0EaT4t+FS4hyflFy2fDulmUnrIOEvK101O3An3z2SmDa5BkyQ jukF0H5ynMAexYSs/I3SKJ+b8ru3IIu7hIJRQG/r4y70kD65iK46eMSLW afo2SwtGC3Tl+sgS1B3pDk3UO9deTMRa7wNMCNPHF78XjddpIONli/RUN jOhyNwYiHH5LOQCoKgW6b1QHHiInljSubHTOlQf/YGb3FSXyF9UhLE/8P A==; X-CSE-ConnectionGUID: O9F3oIu6Q/+Iqz/AJQLf+A== X-CSE-MsgGUID: DMHZAiF+TfK3KLpkGxpOWA== X-IronPort-AV: E=McAfee;i="6800,10657,11885"; a="99454705" X-IronPort-AV: E=Sophos;i="6.25,242,1779174000"; d="scan'208";a="99454705" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2026 01:25:45 -0700 X-CSE-ConnectionGUID: dbEuODyNSE2d0o/gDaizJg== X-CSE-MsgGUID: 4cGhqpINTNCvR1Dnz+3ULw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,242,1779174000"; d="scan'208";a="270695629" Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.240.119]) ([10.124.240.119]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2026 01:25:29 -0700 Message-ID: Date: Tue, 25 Aug 2026 16:25:26 +0800 Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 13/41] KVM: guest_memfd: Return early if range already has requested attributes To: ackerleytng@google.com, aik@amd.com, andrew.jones@linux.dev, binbin.wu@linux.intel.com, brauner@kernel.org, chao.p.peng@linux.intel.com, david@kernel.org, jmattson@google.com, jthoughton@google.com, michael.roth@amd.com, oupton@kernel.org, pankaj.gupta@amd.com, qperret@google.com, rick.p.edgecombe@intel.com, rientjes@google.com, shivankg@amd.com, steven.price@arm.com, tabba@google.com, willy@infradead.org, wyihan@google.com, yan.y.zhao@intel.com, forkloop@google.com, pratyush@kernel.org, suzuki.poulose@arm.com, aneesh.kumar@kernel.org, liam@infradead.org, Paolo Bonzini , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jonathan Corbet , Shuah Khan , Shuah Khan , Vishal Annapurve , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Youngjun Park , Qi Zheng , Shakeel Butt , Kiryl Shutsemau , Baoquan He , Jason Gunthorpe , John Hubbard , Peter Xu , tarunsahu@google.com, Vlastimil Babka Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev References: <20260807-gmem-inplace-conversion-v10-0-2fc18ee6d3ba@google.com> <20260807-gmem-inplace-conversion-v10-13-2fc18ee6d3ba@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20260807-gmem-inplace-conversion-v10-13-2fc18ee6d3ba@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 8/8/2026 5:52 AM, Ackerley Tng via B4 Relay wrote: > From: Ackerley Tng > > Provide function to check that a range has given attributes. > > Optimize setting memory attributes by returning early if all pages in the > requested range already has the requested attributes. > > Reviewed-by: Fuad Tabba > Tested-by: Shivank Garg > Signed-off-by: Ackerley Tng Reviewed-by: Xiaoyao Li > --- > virt/kvm/guest_memfd.c | 23 ++++++++++++++++++++++- > 1 file changed, 22 insertions(+), 1 deletion(-) > > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > index c9874bd85c5d8..896699afcad9d 100644 > --- a/virt/kvm/guest_memfd.c > +++ b/virt/kvm/guest_memfd.c > @@ -95,6 +95,24 @@ static bool kvm_gmem_is_shared_mem(struct inode *inode, pgoff_t index) > return !kvm_gmem_is_private_mem(inode, index); > } > > +static bool kvm_gmem_range_has_attributes(struct inode *inode, > + pgoff_t index, size_t nr_pages, > + u64 attributes) > +{ > + struct maple_tree *mt = &GMEM_I(inode)->attributes; > + pgoff_t end = index + nr_pages - 1; > + void *entry; > + > + lockdep_assert(mt_lock_is_held(mt)); > + > + mt_for_each(mt, entry, index, end) { > + if (kvm_gmem_get_attributes(inode, entry) != attributes) > + return false; > + } > + > + return true; > +} > + > /* > * Returns a locked folio on success. The caller is responsible for > * setting the up-to-date flag before the memory is mapped into the guest. > @@ -605,12 +623,15 @@ static int __kvm_gmem_set_attributes(struct inode *inode, pgoff_t start, > pgoff_t end = start + nr_pages; > struct maple_tree *mt; > struct ma_state mas; > - int r; > + int r = 0; > > mt = &gi->attributes; > > filemap_invalidate_lock(mapping); > > + if (kvm_gmem_range_has_attributes(inode, start, nr_pages, attrs)) > + goto out; > + > mas_init(&mas, mt, start); > r = kvm_gmem_mas_preallocate(&mas, attrs, start, nr_pages); > if (r) { >