From nobody Fri Oct 3 19:17:25 2025 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (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 CB48D18DF9D for ; Wed, 27 Aug 2025 00:05:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756253137; cv=none; b=azq+rS0idfVYWGryeXsO+WPvZ4bQr7Q3IcRrqn+tREnIi5a33YxHbkqTL9e3yU6TXCbu1/8Zj58BcWSrFMgY96107c3FgzSsUXAhx3eNKxnGs5FIVCBgR7fCW5TM2ozPNj4aaitncf+9zf9zRxn3Bmzdw5sWA0Kh36zOZXyZZlk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756253137; c=relaxed/simple; bh=I+EU4QhA5nIsOiRwCkJlZRTgDkQkuqLiyShRzJ28eU8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=JxXKi7TaBHQuZNTQM+3OuhWaV6fBFaXRz12kkMbr7tVDX+mEF+95O0uVPNfZjvwLwZaxSGKOYAIIV2f6J0pRAodC3fr48oOoJSdYHJdIJDobrkiJmIbjsrceXflOC+bAzdwjXUCXunG5KkNY56gx0goyHyzlZHV3n69jTxFrsIY= 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=Xr/c0kwy; arc=none smtp.client-ip=209.85.216.74 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="Xr/c0kwy" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-32326e72dfbso9045010a91.3 for ; Tue, 26 Aug 2025 17:05:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1756253133; x=1756857933; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=aoRBu2fbhQAp9J0WDcFWzITHzuyqeUhe62P9ND1eteE=; b=Xr/c0kwy9RzpNh/pIQ89xOgeIUo0Mphha3vzH6N62GT/z2JBioxPs8iuqGWU2TaAxc a1UgoyVJ0ESAVvNSINXvn+x+gsMMRwHkS1jU3nK4Y0YH4bxBFurzgs0R32Cjwlfe+Iny 6RO6omzSnyNVaAYdLaBC2s4qMWa4pplWo2dDFCNlq0CwEkWQEO2s8O4SoTNfphyifo8K StgCftN5jSjS3szA444Puh16R8l+iKzIo+1WOhXA/lxHP+tltHeAH5rVm017bmiVBQKE TYX/7HUPxnNCc+zAwti6f8lAHArPVYbi5sUyJpvT/0r6e5EeJi9xeDKBPjhPmdMbBLd9 0rxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756253133; x=1756857933; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=aoRBu2fbhQAp9J0WDcFWzITHzuyqeUhe62P9ND1eteE=; b=kfv9M3s0Hj7YrGJ1sNJJkOP2UtNCRszvuEY4pXpWP5MPKdvpsJOYNjqfRRRNxaCtTz cUaqaFkEYzL7/NzjE+r0pn/55G9EtMJPA8JJeanzQaOmhUCTVu2cCh/1gtr/bvzDfVY7 ptxyxYFNd2P8GLOzD75z2qS9KtFliNTH4p2IvUyXTUHVM1UgAW/jsGp9r9Av2wZ77c60 tG7lT2sJIYYXnkD5qw0eIsbAHx8LUhnCzFD6PJW5fSB30DZk3qTXr4JHP2kYxDLrXgK8 1wjNn7DQq9hQXRW1EAITQN/WKEoWQqi2MIe3gChzoEBX7fC2EMLJOZsdSEn5Zvp/alJg RVHg== X-Forwarded-Encrypted: i=1; AJvYcCXOOXHi/bCwoh2hkS+3zpaDHg1Gge/+2IXJCOIiSnucDftx+pz4vSVI2T808To9EsFaXJYI3uKXBfCG4uQ=@vger.kernel.org X-Gm-Message-State: AOJu0YzQyPUuHEAw8+bF6PPGz+fQXdyebPvqtDxHq+wyxsAy7VjNzg5f ldwnhVj5fdTDA7GUdWPGeZlz/1RgPEgYdVFoLXjEDez/lzIAV2cJ2gz+Hyrb9tNKSapuMyW2ikT L2iZ6SQ== X-Google-Smtp-Source: AGHT+IHqGAWofh3cMmtYDoc0/YkBsAddd/V2EhhMJBSlpua+zE04DRKyx6kTbjr+RaWkz4HT9l2FGYKmhJE= X-Received: from pjbqb1.prod.google.com ([2002:a17:90b:2801:b0:321:abeb:1d8a]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5445:b0:327:5360:5b1a with SMTP id 98e67ed59e1d1-3275360623bmr3748060a91.37.1756253133098; Tue, 26 Aug 2025 17:05:33 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 26 Aug 2025 17:05:15 -0700 In-Reply-To: <20250827000522.4022426-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250827000522.4022426-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.268.g9569e192d0-goog Message-ID: <20250827000522.4022426-6-seanjc@google.com> Subject: [RFC PATCH 05/12] KVM: TDX: Drop superfluous page pinning in S-EPT management From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Michael Roth , Yan Zhao , Ira Weiny , Vishal Annapurve , Rick Edgecombe Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Don't explicitly pin pages when mapping pages into the S-EPT, guest_memfd doesn't support page migration in any capacity, i.e. there are no migrate callbacks because guest_memfd pages *can't* be migrated. See the WARN in kvm_gmem_migrate_folio(). Signed-off-by: Sean Christopherson Reviewed-by: Ira Weiny Reviewed-by: Kai Huang --- arch/x86/kvm/vmx/tdx.c | 28 ++++------------------------ 1 file changed, 4 insertions(+), 24 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 1724d82c8512..9fb6e5f02cc9 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1586,29 +1586,22 @@ void tdx_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t = root_hpa, int pgd_level) td_vmcs_write64(to_tdx(vcpu), SHARED_EPT_POINTER, root_hpa); } =20 -static void tdx_unpin(struct kvm *kvm, struct page *page) -{ - put_page(page); -} - static int tdx_mem_page_aug(struct kvm *kvm, gfn_t gfn, - enum pg_level level, struct page *page) + enum pg_level level, kvm_pfn_t pfn) { int tdx_level =3D pg_level_to_tdx_sept_level(level); struct kvm_tdx *kvm_tdx =3D to_kvm_tdx(kvm); + struct page *page =3D pfn_to_page(pfn); gpa_t gpa =3D gfn_to_gpa(gfn); u64 entry, level_state; u64 err; =20 err =3D tdh_mem_page_aug(&kvm_tdx->td, gpa, tdx_level, page, &entry, &lev= el_state); - if (unlikely(tdx_operand_busy(err))) { - tdx_unpin(kvm, page); + if (unlikely(tdx_operand_busy(err))) return -EBUSY; - } =20 if (KVM_BUG_ON(err, kvm)) { pr_tdx_error_2(TDH_MEM_PAGE_AUG, err, entry, level_state); - tdx_unpin(kvm, page); return -EIO; } =20 @@ -1642,29 +1635,18 @@ static int tdx_sept_set_private_spte(struct kvm *kv= m, gfn_t gfn, enum pg_level level, kvm_pfn_t pfn) { struct kvm_tdx *kvm_tdx =3D to_kvm_tdx(kvm); - struct page *page =3D pfn_to_page(pfn); =20 /* TODO: handle large pages. */ if (KVM_BUG_ON(level !=3D PG_LEVEL_4K, kvm)) return -EINVAL; =20 - /* - * Because guest_memfd doesn't support page migration with - * a_ops->migrate_folio (yet), no callback is triggered for KVM on page - * migration. Until guest_memfd supports page migration, prevent page - * migration. - * TODO: Once guest_memfd introduces callback on page migration, - * implement it and remove get_page/put_page(). - */ - get_page(page); - /* * Read 'pre_fault_allowed' before 'kvm_tdx->state'; see matching * barrier in tdx_td_finalize(). */ smp_rmb(); if (likely(kvm_tdx->state =3D=3D TD_STATE_RUNNABLE)) - return tdx_mem_page_aug(kvm, gfn, level, page); + return tdx_mem_page_aug(kvm, gfn, level, pfn); =20 return tdx_mem_page_record_premap_cnt(kvm, gfn, level, pfn); } @@ -1715,7 +1697,6 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm= , gfn_t gfn, return -EIO; } tdx_clear_page(page); - tdx_unpin(kvm, page); return 0; } =20 @@ -1795,7 +1776,6 @@ static int tdx_sept_zap_private_spte(struct kvm *kvm,= gfn_t gfn, if (tdx_is_sept_zap_err_due_to_premap(kvm_tdx, err, entry, level) && !KVM_BUG_ON(!atomic64_read(&kvm_tdx->nr_premapped), kvm)) { atomic64_dec(&kvm_tdx->nr_premapped); - tdx_unpin(kvm, page); return 0; } =20 --=20 2.51.0.268.g9569e192d0-goog