From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.18]) (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 EA2C038E121; Sat, 9 May 2026 08:36:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778315804; cv=none; b=IG8kqa62y1JMdCzCZqYXNvYYLfvh2uUZbyVQMv3E93+rplhwb9+K1vTAVRlgEkzr+2wI1izTN791n7MpeBdWY/k2PTJ7P8ELJP+C6vbMjOwnajA+0tSb+AREu5tsxICHbrru7UN5DcwwMBEciIID7JnCZqrXmfSICnBwMQWOX6w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778315804; c=relaxed/simple; bh=CWVlTJ2fw9Hr14bsGHbzw8g4DedxcZzL9H4u85xMyA4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZTfMwUI+CsUDX69aTLQbcerezsL9NEGPsSmTvL6gM7wI52jKQ5un4kQTtYTNdWDoJrWTLDD207qDoBAF2lJ6Gclr9vFYjl5ig56kg3cNEwYwBoVsczRm5sR8CzDWJ4UZHgAcLg1MeDJWc19rpo/n/5k4NHg2HDLIofGM3OnXK2U= 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=krZgTNyf; arc=none smtp.client-ip=198.175.65.18 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="krZgTNyf" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1778315803; x=1809851803; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=CWVlTJ2fw9Hr14bsGHbzw8g4DedxcZzL9H4u85xMyA4=; b=krZgTNyfDbPeO70b/53mcGNyBlsIoNOcqEzdoYHG3WK4HHymTSfFTck7 SiOL+4LWn0dcLJHVRLBjQR+ICZFG/f8AT08TTWSTj6n6pNbiinsM2cTs5 ilFG+/G7rG/IGaehL8tgYLSmtqYSQPbKHTBiorBd0zfvTjCwrt9SHd8u8 VIebKIKqgpw4OftaVMpui/C5YM+N0OinbE90iRfqFhAAi8DRCsyhbvQJx 2N1VXaXEOSdgyW9j/JctHFyuKAbdTuOO6Ykn2YsaNg6yLN6mXIc3vj+hf R70O51Hi6WgOooorQqe/mJlr4NSjVYdb51uDYCh2Y2zj4EqbvgBGSlqFZ Q==; X-CSE-ConnectionGUID: miNfV0QnQ0S2pACrlkRQFQ== X-CSE-MsgGUID: rBm8L1pJRoCeIPFmkAAwUA== X-IronPort-AV: E=McAfee;i="6800,10657,11780"; a="79306587" X-IronPort-AV: E=Sophos;i="6.23,225,1770624000"; d="scan'208";a="79306587" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa110.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 May 2026 01:36:42 -0700 X-CSE-ConnectionGUID: W/jDTjevRq68nRpsrIxX8w== X-CSE-MsgGUID: 35Tecm0uSbiHNKNABG6h+Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,225,1770624000"; d="scan'208";a="230584765" Received: from yzhao56-desk.sh.intel.com ([10.239.47.19]) by fmviesa009-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 May 2026 01:36:39 -0700 From: Yan Zhao To: seanjc@google.com, pbonzini@redhat.com, kvm@vger.kernel.org, rick.p.edgecombe@intel.com, kas@kernel.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, dave.hansen@intel.com, kai.huang@intel.com, binbin.wu@linux.intel.com, xiaoyao.li@intel.com, yan.y.zhao@intel.com Subject: [PATCH v2 10/15] KVM: x86/mmu: Drop KVM_BUG_ON() on shared lock to zap child external PTEs Date: Sat, 9 May 2026 15:56:47 +0800 Message-ID: <20260509075647.4290-1-yan.y.zhao@intel.com> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20260509075201.4077-1-yan.y.zhao@intel.com> References: <20260509075201.4077-1-yan.y.zhao@intel.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Rick Edgecombe Drop the KVM_BUG_ON() in the KVM MMU core before zapping child external PTEs, since requiring zapping PTEs to be protected by exclusive mmu_lock is TDX's specific requirement. No need to plumb the shared/exclusive info into the remove_external_spte() op or move the KVM_BUG_ON() to TDX, because - There's already an assertion of exclusive mmu_lock protection in TDX. - The KVM_BUG_ON() is a bit redundant given that if there's any bug causing zapping of leaf PTEs in S-EPT under shared mmu_lock, SEAMCALL failures due to contention would result in TDX_BUG_ON() in TDX. Link: https://lore.kernel.org/kvm/aYUarHf3KEwHGuJe@google.com/ Suggested-by: Sean Christopherson Signed-off-by: Rick Edgecombe Signed-off-by: Yan Zhao --- MMU_refactors v2: - Updated commit log and title. (Yan) --- arch/x86/kvm/mmu/tdp_mmu.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index ada4a0837298..553a30628960 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -473,10 +473,8 @@ static void handle_removed_pt(struct kvm *kvm, tdp_ptep_t pt, bool shared) } handle_changed_spte(kvm, sp, gfn, old_spte, FROZEN_SPTE, level, shared); - if (is_mirror_sp(sp)) { - KVM_BUG_ON(shared, kvm); + if (is_mirror_sp(sp)) remove_external_spte(kvm, gfn, old_spte, level); - } } if (is_mirror_sp(sp) && -- 2.43.2