From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 287C1242D6A for ; Thu, 15 Jan 2026 01:13:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768439625; cv=none; b=d1kNKPKKDGjB5wd4ud3MDNYQ7QfGNy2vi21Q/0PC+fwUDgp8exciB44ViaAVJwoPW5wnQFwkgSYcAA/32xa96/kCIFVsiXoNfqgeOpW33t05F1ZjNW3e/IBhja03ucqH9F0BdBNB65ZaUvq1+BeNwHgTXxDqvi4ToptUoIR7lsI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768439625; c=relaxed/simple; bh=fQqA2Bi7beoaqKROaXncLZ1Lzr3jWy523lQs0sPZ5GY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=Ho6gsRl41DEJzB7UdLN8luegH2R7ZnvTnaN+E4hz0VwgszASzXOGO8Kn3z9gYafMSho/xqHXt0maG6P+MJj3xqAmN0wW7LsnDvr+0mIdVzfQfV1La6/JmrxyqcrDC7SR4//pYnqVt45msVuyxcSsvzq3Sb9Be/Pvcuuo5Yzb2+4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=NjDHYfqL; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="NjDHYfqL" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1768439607; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=kOQ4VzmQ9V/wQV3/Huk+MrK5n+USrgmzREJM0lZRg+c=; b=NjDHYfqLR0B6SrO2YhWbQEqDAntPjXXRa6J6FizyD2wALz007bhpA0/95d0dI1YLjDE4hT ruTAN7d+YK/Z/wP+hDtc2XrVSaodadCQaqA7U/rk6xOqMasd7/xP8Q7gU/skTfH0K1C+oe /UBuEKfLiWwgYWymrVuZbQwZknvqrB0= From: Yosry Ahmed To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Subject: [PATCH v4 00/26] Nested SVM fixes, cleanups, and hardening Date: Thu, 15 Jan 2026 01:12:46 +0000 Message-ID: <20260115011312.3675857-1-yosry.ahmed@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT A group of semi-related fixes, cleanups, and hardening patches for nSVM. This series doubled in size between v2 and v3, but it's Sean's fault for finding more bugs that needed fixing. The series is essentially a group of related mini-series stitched together for syntactic and semantic dependencies. The first 19 patches (except patch 3) are all optimistically CC'd to stable as they are fixes or refactoring leading up to bug fixes. Although I am not sure how much of that will actually apply to stable trees. Patches 1-3 here are v2 of the last 3 patches in the LBRV fixes series [1]. The first 3 patches of [1] are already upstream. Patches 4-14 are fixes for failure handling in the nested VMRUN and #VMEXIT code paths, ending with a nice unified code path for handling VMRUN failures as suggested by Sean. Within this block, patches 7-12 are refactoring needed for patches 13-14. Patches 15-19 are fixes for missing or made-up consistency checks. Patches 20-22 are renames and cleanups. Patches 23-26 add hardening to reading the VMCB12, caching all used fields in the save area to prevent theoritical TOC-TOU bugs, sanitizing used fields in the control area, and restricting accesses to the VMCB12 through guest memory. v3 -> v4: - Proerply leave guest mode on failed VMRUN [2]. - Fixed baseline and rebased on top of kvm-x86/next. v3: https://lore.kernel.org/kvm/20251215192722.3654335-1-yosry.ahmed@linux.dev/ [1]https://lore.kernel.org/kvm/20251108004524.1600006-1-yosry.ahmed@linux.dev/ [2]https://lore.kernel.org/kvm/timpvklyyl5juo5ajjzuxwazc5w2t6ffcx7llnv6f2a5qzot3b@hnj3wqwtla6c/ Yosry Ahmed (26): KVM: SVM: Switch svm_copy_lbrs() to a macro KVM: SVM: Add missing save/restore handling of LBR MSRs KVM: selftests: Add a test for LBR save/restore (ft. nested) KVM: nSVM: Always inject a #GP if mapping VMCB12 fails on nested VMRUN KVM: nSVM: Triple fault if mapping VMCB12 fails on nested #VMEXIT KVM: nSVM: Triple fault if restore host CR3 fails on nested #VMEXIT KVM: nSVM: Drop nested_vmcb_check_{save/control}() wrappers KVM: nSVM: Call enter_guest_mode() before switching to VMCB02 KVM: nSVM: Make nested_svm_merge_msrpm() return an errno KVM: nSVM: Call nested_svm_merge_msrpm() from enter_svm_guest_mode() KVM: nSVM: Call nested_svm_init_mmu_context() before switching to VMCB02 KVM: nSVM: Refactor minimal #VMEXIT handling out of nested_svm_vmexit() KVM: nSVM: Unify handling of VMRUN failures with proper cleanup KVM: nSVM: Clear EVENTINJ field in VMCB12 on nested #VMEXIT KVM: nSVM: Drop the non-architectural consistency check for NP_ENABLE KVM: nSVM: Add missing consistency check for nCR3 validity KVM: nSVM: Add missing consistency check for hCR0.PG and NP_ENABLE KVM: nSVM: Add missing consistency check for EFER, CR0, CR4, and CS KVM: nSVM: Add missing consistency check for event_inj KVM: SVM: Rename vmcb->nested_ctl to vmcb->misc_ctl KVM: SVM: Rename vmcb->virt_ext to vmcb->misc_ctl2 KVM: SVM: Use BIT() and GENMASK() for definitions in svm.h KVM: nSVM: Cache all used fields from VMCB12 KVM: nSVM: Restrict mapping VMCB12 on nested VMRUN KVM: nSVM: Sanitize control fields copied from VMCB12 KVM: nSVM: Only copy NP_ENABLE from VMCB01's misc_ctl arch/x86/include/asm/svm.h | 96 ++-- arch/x86/kvm/svm/nested.c | 540 +++++++++++------- arch/x86/kvm/svm/sev.c | 4 +- arch/x86/kvm/svm/svm.c | 68 +-- arch/x86/kvm/svm/svm.h | 51 +- arch/x86/kvm/x86.c | 3 + tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/include/x86/processor.h | 5 + tools/testing/selftests/kvm/include/x86/svm.h | 14 +- tools/testing/selftests/kvm/lib/x86/svm.c | 2 +- .../selftests/kvm/x86/svm_lbr_nested_state.c | 155 +++++ 11 files changed, 636 insertions(+), 303 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86/svm_lbr_nested_state.c base-commit: f62b64b970570c92fe22503b0cdc65be7ce7fc7c -- 2.52.0.457.g6b5491de43-goog