From nobody Fri Oct 3 15:31:39 2025 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 A67B81FBEB1 for ; Fri, 29 Aug 2025 00:06:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756425999; cv=none; b=R4C9pHr6Skbb1+QW3KxRy47tOuyUunvk5BwUG0TvlXPAZD/f0QRSaUcrse3VfzV2zUW6shDogInqT1LZzirFWIONWVPpRk1JjgIpqivWQ0l9/x5WAd2BWhSzGk4NHsDN331avyOkmO2jZ+bCaOI3jpsnyNVvFh9pE7gxK1A9zko= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756425999; c=relaxed/simple; bh=f3WKeCxN8el5k5LrAboMphhH9rXooGmaPRmdkWif71U=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=o9z3/CXvkg9f+ymisSOMbDiFWxzBuMPDv8ZWDyf4ZvrE74JpzcZH8uof4eXQVQHlW3W5ZCQ6So1GOPboXdkeXfZu0aVuswjNQ8MR/N1h6mmNR7Melu67W531fVK8w5SHv74TL/SwYEojGv71ywdrsXO2fEhXDqZzxxTPHu9LKeU= 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=fDvguf3x; arc=none smtp.client-ip=209.85.215.202 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="fDvguf3x" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-b4c746c020cso531948a12.1 for ; Thu, 28 Aug 2025 17:06:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1756425997; x=1757030797; 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=4vFObST+7ZlqgxAzKSnwUtFLpnriAXTWXVO/mc38gG8=; b=fDvguf3xTaXUj/7eMva20CV20zom1ivQbtzX4XSrEczWsbaOvTIu748zZGfQz02Mrv 3om5ov8zdIokmJUghjpJdxQEt+jcq5KZLtcs9ykQC2shCO22vCYIoYAq2ABDVq60lROW ghtBz+BcvWMNZuIRXeaHJxJondQJSRsKqe2/zNs8Nsr3zXtC8/7KoZSW8modSmNzYUFw H3qToRpGuqLV74vHee1ttymDZR1vEw3m5hpt/V5w6j1RXGnkTUOIU+eoNG5XBei5nfUJ 2/I351mtQ9xWBV70129km/2NCtQ38KDt94ieCrF+Uc9yn9czyJ5H1j5XYbgivXFUhies If9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756425997; x=1757030797; 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=4vFObST+7ZlqgxAzKSnwUtFLpnriAXTWXVO/mc38gG8=; b=sP/NO5oMm67JzL5qB3y6JCQOf+AAVw0Y+ozIZW8Ira+8ljN5pvDCK2Asn0LwWVQ0l6 c2tMjux08AaDAV560ntwv9zUdrNPGJxfwm1Mji6HiX58AiCYv+ZmX663aeej5iaLWjLu UGpPSVx9JHOlyyhra2u9caK7pdPZZljyHNgY1wb3yRrDX4hIL0Jz6OUtPXvMu0wz/may qM/Sv+TJUIbnp2bd3Cpu3q85xzEXaDEQS642HwmxoQh5UYgXyUSFxGsxwvCT12vXiKpe cUakl31Gd/gugw8Dic/+DsaEVy0Pm74Qs2Y6wwZ+rmbkbbFp0xKHrxzDOVnJoULIMaaN I+iQ== X-Forwarded-Encrypted: i=1; AJvYcCXUR73qGDgC69oN5ljGZPiQ3iVOObCoiGfTwKsfBs6IpKJdsr4s2iGlmQACAYexgxz8V2FDaurAeukru7c=@vger.kernel.org X-Gm-Message-State: AOJu0YyRU+KC0t7QBnbicFlnyx7sKuGCmCpwmuXJQ9rBTQysDEaY3i5R l6lHw9jeTVtyhcOFGg8tQm+VJPZNXAHhOX43trNkFxLzDI1dkhoftZYocAI2k+DlC2ftVT+MDhX FwF0JdA== X-Google-Smtp-Source: AGHT+IEG9WztooY4bnn6abzlnsjj0dOg/1Kl7H1cw1QcQlPgDxUccZQ1mG0Culs2cO/x0pGpmGMyNJwe/+c= X-Received: from pgww7.prod.google.com ([2002:a05:6a02:2c87:b0:b47:8e6:9c33]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:7488:b0:243:9b05:ac7d with SMTP id adf61e73a8af0-2439b05b008mr14000596637.36.1756425997067; Thu, 28 Aug 2025 17:06:37 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 28 Aug 2025 17:06:09 -0700 In-Reply-To: <20250829000618.351013-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250829000618.351013-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.318.gd7df087d1a-goog Message-ID: <20250829000618.351013-10-seanjc@google.com> Subject: [RFC PATCH v2 09/18] KVM: TDX: Avoid a double-KVM_BUG_ON() in tdx_sept_zap_private_spte() From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Ira Weiny , Kai Huang , Michael Roth , Yan Zhao , Vishal Annapurve , Rick Edgecombe , Ackerley Tng Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Return -EIO immediately from tdx_sept_zap_private_spte() if the number of to-be-added pages underflows, so that the following "KVM_BUG_ON(err, kvm)" isn't also triggered. Isolating the check from the "is premap error" if-statement will also allow adding a lockdep assertion that premap errors are encountered if and only if slots_lock is held. Reviewed-by: Rick Edgecombe Signed-off-by: Sean Christopherson Reviewed-by: Binbin Wu --- arch/x86/kvm/vmx/tdx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 07f9ad1fbfb6..cafd618ca43c 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1724,8 +1724,10 @@ static int tdx_sept_zap_private_spte(struct kvm *kvm= , gfn_t gfn, err =3D tdh_mem_range_block(&kvm_tdx->td, gpa, tdx_level, &entry, &level= _state); tdx_no_vcpus_enter_stop(kvm); } - if (tdx_is_sept_zap_err_due_to_premap(kvm_tdx, err, entry, level) && - !KVM_BUG_ON(!atomic64_read(&kvm_tdx->nr_premapped), kvm)) { + if (tdx_is_sept_zap_err_due_to_premap(kvm_tdx, err, entry, level)) { + if (KVM_BUG_ON(!atomic64_read(&kvm_tdx->nr_premapped), kvm)) + return -EIO; + atomic64_dec(&kvm_tdx->nr_premapped); return 0; } --=20 2.51.0.318.gd7df087d1a-goog