From mboxrd@z Thu Jan 1 00:00:00 1970 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 7EA422BDC2A for ; Fri, 17 Oct 2025 00:33:22 +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=1760661205; cv=none; b=ne98G100FZr1H4dmVzbzog63VNr6QoNbJ1Jjy1Q6owSj2TO/HHp9hmob9ZMcLck5ATfdKisL5B5wx5niHl/onDXqnfVp1OWM9Y0Kv+wxr5AyLAHHq8t5BuO2hkJ6bWbi8/jt48/m1fi9lDrkpib7eaUdJDWEGRuXlIm5XzPJiYI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760661205; c=relaxed/simple; bh=yaQKyTxksrTJX2fl14PtTN0UzNHo3LiOiMMysefNVFI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=iz3XgPtWte48TVaW9GthcROmys5TrWrLHi9WXn+d9L1vUQoOBRGsJJNUl6NAqEZIUcfDO2q2fFHsnML4/Patrp57zkEWlYvSF9/GihI+fyvwByam4ehB/BhKH7P3eZg6T/ApsiCIfZnJQ1kYaSAEzuqpLcXhiLLXF3Y8uRlji1g= 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=gn50R/3x; 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="gn50R/3x" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-3307af9b55eso1200444a91.2 for ; Thu, 16 Oct 2025 17:33:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1760661202; x=1761266002; darn=lists.linux.dev; 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=6nFGgJBVWEpkJy+c6A8c/BAOcJuYsJfcEhqI0sTwd+k=; b=gn50R/3xyVgZhj34xX2yZOfBeagnVYksqSRG8/jNcFb065Q1zXmDBrPWEpJzwoJThV TvXn2Prh7OsrmREDnFa+ynKM0yK0dvtqU92AaZG42+mIGYn/hkCFjVEUjwGIQHyrTAOK pJ0guSHJhuzZAHTHkMUb3KhvzLAEgwWR3x5mVvjAUx2Gm2wHWbn3Zo/9A24GdSmg7e7/ i8xEZHhVg7mWXsCWCdotUvYusRBuNM0kdErP1clMC2GtC9wxRvY/HL9iTE2DQxi8/6UJ pOTV9LkVz5W86bmBEYD4rwbiNJCYMZrm+GMEn59a3jaoZe0Fe6jC+e3EUPKP5RqmtlwA yaGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760661202; x=1761266002; 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=6nFGgJBVWEpkJy+c6A8c/BAOcJuYsJfcEhqI0sTwd+k=; b=LNAyypS9FAKIL6TdyjkX50KQSG6/ce2XLRzJJuQ2VM95sweGFqjabnutLUDyOQ6ECY aW7vM55T9nZZ+pcJzuXn73bvjv0FNFYo0AkXjr6dScBK03iSrk/n6Yv344V+8VyGSGIY ztN5Ea1AxofsQSnlsgfeH2eujVSrtYc8z6j9TB82LF6pO2PW9Ia5axBHS9tcaq5vdTvz R/mApYkbGh6w8Hg6LtDOOTFwCBomgjpapphg9Aez4ZiEVnp1tSzJzv1sks3y3NMu6j0q 7YnT+faESjKM861Ap/HWcJdEzlfrA9xeuD/dV747NONVlhbAn9PV/OEjkuyQ2z+iGBXZ uiDA== X-Forwarded-Encrypted: i=1; AJvYcCVOGKo0BEZDvVweJwdN/jF8zNqYwxcf4dIVUKqaXrnSU5AU/FwRL/ylDddCAdhnzL2dsRlhSOlL0+GP@lists.linux.dev X-Gm-Message-State: AOJu0YwfvkmexDihEaQrTEetmzz6jP43VHd/Jr9AXAtEWNg7i5By41p1 6x2wnXqqpjcz0o6BtkKCVFzRlL/KRr7i0uWNAhY3Nsaogk6w5Td2lXKoPtA8nsyG9R9Q4MS3wiO 45gM77Q== X-Google-Smtp-Source: AGHT+IGwUk2DKc/Clop/mYKkbeytMt0iZD/Bzj0bONucI419CZOE9/NPfh2luTSi9dr6fi1GHUAnQKjomOI= X-Received: from pjnu19.prod.google.com ([2002:a17:90a:8913:b0:329:ec3d:72ad]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:4fc6:b0:330:6d5e:f17e with SMTP id 98e67ed59e1d1-33bcf8faaeamr1865014a91.24.1760661201850; Thu, 16 Oct 2025 17:33:21 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 16 Oct 2025 17:32:37 -0700 In-Reply-To: <20251017003244.186495-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251017003244.186495-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.858.gf9c4a03a3a-goog Message-ID: <20251017003244.186495-20-seanjc@google.com> Subject: [PATCH v3 19/25] KVM: TDX: Assert that mmu_lock is held for write when removing S-EPT entries From: Sean Christopherson To: Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Sean Christopherson , Paolo Bonzini , "Kirill A. Shutemov" Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, x86@kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, Ira Weiny , Kai Huang , Michael Roth , Yan Zhao , Vishal Annapurve , Rick Edgecombe , Ackerley Tng , Binbin Wu Content-Type: text/plain; charset="UTF-8" Unconditionally assert that mmu_lock is held for write when removing S-EPT entries, not just when removing S-EPT entries triggers certain conditions, e.g. needs to do TDH_MEM_TRACK or kick vCPUs out of the guest. Conditionally asserting implies that it's safe to hold mmu_lock for read when those paths aren't hit, which is simply not true, as KVM doesn't support removing S-EPT entries under read-lock. Only two paths lead to remove_external_spte(), and both paths asserts that mmu_lock is held for write (tdp_mmu_set_spte() via lockdep, and handle_removed_pt() via KVM_BUG_ON()). Deliberately leave lockdep assertions in the "no vCPUs" helpers to document that wait_for_sept_zap is guarded by holding mmu_lock for write. Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/tdx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index e517ad3d5f4f..f6782b0ffa98 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1711,8 +1711,6 @@ static void tdx_track(struct kvm *kvm) if (unlikely(kvm_tdx->state != TD_STATE_RUNNABLE)) return; - lockdep_assert_held_write(&kvm->mmu_lock); - err = tdh_mem_track(&kvm_tdx->td); if (unlikely(tdx_operand_busy(err))) { /* After no vCPUs enter, the second retry is expected to succeed */ @@ -1758,6 +1756,8 @@ static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn, gpa_t gpa = gfn_to_gpa(gfn); u64 err, entry, level_state; + lockdep_assert_held_write(&kvm->mmu_lock); + /* * HKID is released after all private pages have been removed, and set * before any might be populated. Warn if zapping is attempted when -- 2.51.0.858.gf9c4a03a3a-goog