From nobody Fri Apr 4 06:37:27 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1742019695839291.8908066864474; Fri, 14 Mar 2025 23:21:35 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ttKtS-00073j-3M; Sat, 15 Mar 2025 02:21:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ttKsQ-0004fk-Lx; Sat, 15 Mar 2025 02:20:09 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ttKsM-0003MY-S1; Sat, 15 Mar 2025 02:20:06 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id B310AFF9E0; Sat, 15 Mar 2025 09:17:07 +0300 (MSK) Received: from gandalf.tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with ESMTP id 8A7671CAC49; Sat, 15 Mar 2025 09:18:01 +0300 (MSK) Received: by gandalf.tls.msk.ru (Postfix, from userid 1000) id 5B9DC558D7; Sat, 15 Mar 2025 09:18:01 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Paolo Bonzini , Xiaoyao Li , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , David Hildenbrand , Pankaj Gupta , Michael Tokarev Subject: [Stable-9.2.3 20/51] physmem: replace assertion with error Date: Sat, 15 Mar 2025 09:17:26 +0300 Message-Id: <20250315061801.622606-20-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1742019697814019100 From: Paolo Bonzini It is possible to start QEMU with a confidential-guest-support object even in TCG mode. While there is already a check in qemu_machine_creation_= done: if (machine->cgs && !machine->cgs->ready) { error_setg(errp, "accelerator does not support confidential guest %= s", object_get_typename(OBJECT(machine->cgs))); exit(1); } the creation of RAMBlocks happens earlier, in qemu_init_board(), if the command line does not override the default memory backend with -M memdev. Then the RAMBlock will try to use guest_memfd (because machine_require_guest_memfd correctly returns true; at least correctly according to the current implementation) and trigger the assertion failure for kvm_enabled(). This happend with a command line as simple as the following: qemu-system-x86_64 -m 512 -nographic -object sev-snp-guest,reduced-phys= -bits=3D48,id=3Dsev0 \ -M q35,kernel-irqchip=3Dsplit,confidential-guest-support=3Dsev0 qemu-system-x86_64: ../system/physmem.c:1871: ram_block_add: Assertion = `kvm_enabled()' failed. Cc: Xiaoyao Li Cc: qemu-stable@nongnu.org Signed-off-by: Paolo Bonzini Reviewed-by: Daniel P. Berrang=C3=A9 Reviewed-by: David Hildenbrand Reviewed-by: Pankaj Gupta Reviewed-by: Xiaoyao Li Link: https://lore.kernel.org/r/20250217120812.396522-1-pbonzini@redhat.com Signed-off-by: Paolo Bonzini (cherry picked from commit 6debfb2cb1795427d2dc6a741c7430a233c76695) Signed-off-by: Michael Tokarev diff --git a/system/physmem.c b/system/physmem.c index 75389064a8..83013b59f7 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -1868,7 +1868,11 @@ static void ram_block_add(RAMBlock *new_block, Error= **errp) if (new_block->flags & RAM_GUEST_MEMFD) { int ret; =20 - assert(kvm_enabled()); + if (!kvm_enabled()) { + error_setg(errp, "cannot set up private guest memory for %s: K= VM required", + object_get_typename(OBJECT(current_machine->cgs))); + goto out_free; + } assert(new_block->guest_memfd < 0); =20 ret =3D ram_block_discard_require(true); --=20 2.39.5