From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (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 00CA23BFACA; Thu, 16 Jul 2026 10:04:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784196287; cv=none; b=FuMksDWvmXkL/Nv9x7pYj/jixrunIYHKbsEVdCmNeVLB8TUlnvGWV2ScEtn5yToguG8eRgM/bDEvLgOH/f8O53+5FF5hZWKnaszgYH/sd2IaR9MWCFvRR76Vvg6Wr0CLK2+b7bCirSycw2j9ibh37zHuubA4UaDJa/0+yacdUwU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784196287; c=relaxed/simple; bh=ce/RRqUddOgw7zkNrkSmqdOltk3lABI9Oq+oRLglth8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=W64I1eDJa5zHrg7CZqXaQRa4ZH3TWG8OfOtSavbeAhdOGyzLN8rF7SMqDskZqmBgw8HSM7PxL+CmAqXoZXddcUG+TBMfga36mwG5J7hEV30dT8/BxwottTaV+isU1dHh9Kqara6vaTym5XdKG1gMb7a7M/uhtEkrWYg2fUtOIG4= 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=SYSXSidT; arc=none smtp.client-ip=198.175.65.12 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="SYSXSidT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1784196287; x=1815732287; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ce/RRqUddOgw7zkNrkSmqdOltk3lABI9Oq+oRLglth8=; b=SYSXSidT+BTFfsKriPp24oxXUIl4I1fz1PytMpPqY7O2ECzv8ixF2muf iybgm7aXscSoEtT8zT3A80OiIIMRBtmMZgDrKdAeKzcx+Fn0Qp2dyF8m9 TfklWrooMu1fZDXTHj11Eut7ZCJxyopJTTBHVzRTnFU9lnNlfTSsBFP/c //DP2+EReLzCPJLLvkDCcYiHNL9MCPA0DgDm0nvZv1SzAn4SzVDaI8stk 9VrRlI4/tZ71igSxy63OgGVSnR1wtETeaLcvXZ/YMPYnmCg+9oCheKDug 56IX46TRgTM0efr9NzamZ6rpY6f4ARjV7aEyF0VEU93+rHUfoCESTrW9n Q==; X-CSE-ConnectionGUID: ZPwem7ieQ7SIiZqUalCZ7A== X-CSE-MsgGUID: 8wPrkAfcT4yDYcumQsI6tA== X-IronPort-AV: E=McAfee;i="6800,10657,11847"; a="96365518" X-IronPort-AV: E=Sophos;i="6.25,167,1779174000"; d="scan'208";a="96365518" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2026 03:04:46 -0700 X-CSE-ConnectionGUID: xHqs0uEPQaGplfbjiSVJcg== X-CSE-MsgGUID: xJ5ZSSxuQraz6pm38KQemQ== X-ExtLoop1: 1 Received: from xiaoyaol-hp-g830.ccr.corp.intel.com (HELO [10.124.240.232]) ([10.124.240.232]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2026 03:04:43 -0700 Message-ID: Date: Thu, 16 Jul 2026 18:04:39 +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: [PATCH v5 2/7] KVM: guest_memfd: Rename invalidate() arch hook to reclaim() and isolate it To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Fuad Tabba , Ackerley Tng References: <20260714231015.3337831-1-seanjc@google.com> <20260714231015.3337831-3-seanjc@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20260714231015.3337831-3-seanjc@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/15/2026 7:10 AM, Sean Christopherson wrote: > Rename guest_memfd's invalidate() hook to reclaim() and isolate it via its > own RECLAIM Kconfig, as the hook is called when a folio is freed, which is > far too late and lacks sufficient information for KVM to actually > invalidate its usage of the memory. E.g. SNP uses the hook to convert > memory back to SHARED so that it can be safely accessed by the host, there > is no invalidation of guest mappings anywhere. Isolating the hook will > also allow pKVM on arm64 to opt-in to reclaim() without also having to > differentiate between reclaim and conversions to shared for active VMs. > > Keep guest_memfd's trampoline, even though it would be trivial to wire up > .free_folio() directly to an arch callback, to avoid bleeding guest_memfd > internals into arch code (specifically, avoid referencing folios in arch > code). > > Leave the kvm_x86_ops hook as-is for the moment, as the hook can be dropped > entirely ("reclaim" on SNP is the same as convert-to-shared). > > Cc: Fuad Tabba > Cc: Ackerley Tng > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/Kconfig | 1 + > arch/x86/kvm/x86.c | 7 +++++-- > include/linux/kvm_host.h | 5 ++++- > virt/kvm/Kconfig | 4 ++++ > virt/kvm/guest_memfd.c | 8 ++++---- > 5 files changed, 18 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig > index 801bf9e520db..e0e7ad015839 100644 > --- a/arch/x86/kvm/Kconfig > +++ b/arch/x86/kvm/Kconfig > @@ -161,6 +161,7 @@ config KVM_AMD_SEV > select ARCH_HAS_CC_PLATFORM > select KVM_GENERIC_MEMORY_ATTRIBUTES > select HAVE_KVM_ARCH_GMEM_PREPARE > + select HAVE_KVM_ARCH_GMEM_RECLAIM > select HAVE_KVM_ARCH_GMEM_INVALIDATE > select HAVE_KVM_ARCH_GMEM_POPULATE > help > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index a2cbf6fae118..08d24c6fffa4 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -10626,11 +10626,14 @@ int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_ord > } > #endif > > -#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE > -void kvm_arch_gmem_invalidate(kvm_pfn_t pfn, kvm_pfn_t nr_pages, int max_order) > +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_RECLAIM > +void kvm_arch_gmem_reclaim(kvm_pfn_t pfn, kvm_pfn_t nr_pages, int max_order) The kvm_pfn_t for nr_pages still catches my eye, but it's not the business of this patch. Reviewed-by: Xiaoyao Li