From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CBBFE8F4A; Tue, 24 Feb 2026 22:34:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771972461; cv=none; b=ipc/Su2c+30dBKGBMqjYe67h/zLLai9gckz+yFXZHNSrk8Q2EycsjKiTOKDFwn1fIY7GIvIQdlZ+njBm9zqw8zpmMYkWmOEdPcysLkN7TSTu7JH69A0+4SKAfvlUpJx4NUhv9/xCFOlFYCGltUO6jbh0QUj6MXjlAdB8aKwyHsA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771972461; c=relaxed/simple; bh=Z127UEFMX+xC/GQ4f7BhqeRAlZyC95G5cspFEeYWSAk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=ZkjVx5J76UOol9dL9C2fLNxkWb8qauuMUkH2A2oTQYO29bN4KCWoHUgoNwbetg27qQzd6azz+1cjc0DrBCkJznYuTPs5AvSYTpncN9S4rfH7reYIBE9vekQ7dwH8FPNpek6spzGTKRtNO6/RWozLyFdxDcdJVVmpW3tdAdDAhMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VHUZMGp3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VHUZMGp3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3610BC116D0; Tue, 24 Feb 2026 22:34:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771972461; bh=Z127UEFMX+xC/GQ4f7BhqeRAlZyC95G5cspFEeYWSAk=; h=From:To:Cc:Subject:Date:From; b=VHUZMGp3okznwL8sD3KNancaTMKOU8kZsS0uVC1bJJyYKkb5CD42bfOlbN9c7BaP7 a8+mHVkInCscFi8scvuHEoi+C9CewUjp8TnqlkEvewyjgM77DVUu4x1hBdpy07XhGB OCOukjDFsKuT0uae8ExxEt4h0j++Q1aSgv6L23/wHsfdQzR2TObzZINgKgP4zVkYtE PwCZcqJaezK6YEua7rqutKwdjYDXTWhp2RLM0fMed6Naz32piLD8pYNQcEW0xGJ3Un 1msOkPOkG9J66RaLlKUIqvxidORevelOYjig5mODigok/JwOb1rzLd0pNbMEAHpYMY EKPJ5doJ6Nj1Q== From: Yosry Ahmed To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed Subject: [PATCH 00/31] Nested SVM fixes, cleanups, and hardening Date: Tue, 24 Feb 2026 22:33:34 +0000 Message-ID: <20260224223405.3270433-1-yosry@kernel.org> X-Mailer: git-send-email 2.53.0.414.gf7e9f6c205-goog 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 A group of semi-related fixes, cleanups, and hardening patches for nSVM. The series is essentially a group of related mini-series stitched together for syntactic and semantic dependencies. The first 22 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 4-17 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 18-22 are fixes for missing or made-up consistency checks. Patches 23-24 are renames and cleanups. Patches 25-30 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. Finally, patch 31 is a selftest for nested VMRUN and #VMEXIT failures due to failing to map vmcb12. v5 -> v6: - Set VMCB_LBR dirty when setting LBR registers [Yosry]. - Fix state leakage in LBR save/restore test [Kevin Cheng]. - Do not abort nested #VMEXIT flow if mapping vmcb12 or restoring L1 CR3 fails [Sean]. - Break down the patch sanitizing control fields from vmcb12 and drop the ASID comment change [Sean]. - Add a selftest for VMRUN and #VMEXIT with unmappable vmcb12 [Yosry]. v5: https://lore.kernel.org/kvm/20260206190851.860662-1-yosry.ahmed@linux.dev/ Yosry Ahmed (31): KVM: nSVM: Avoid clearing VMCB_LBR in vmcb12 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: Refactor checking LBRV enablement in vmcb12 into a helper KVM: nSVM: Refactor writing vmcb12 on nested #VMEXIT as a helper 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 EVENTINJ KVM: SVM: Rename vmcb->nested_ctl to vmcb->misc_ctl KVM: SVM: Rename vmcb->virt_ext to vmcb->misc_ctl2 KVM: nSVM: Cache all used fields from VMCB12 KVM: nSVM: Restrict mapping VMCB12 on nested VMRUN KVM: nSVM: Use PAGE_MASK to drop lower bits of bitmap GPAs from vmcb12 KVM: nSVM: Sanitize TLB_CONTROL field when copying from vmcb12 KVM: nSVM: Sanitize INT/EVENTINJ fields when copying from vmcb12 KVM: nSVM: Only copy SVM_MISC_ENABLE_NP from VMCB01's misc_ctl KVM: selftest: Add a selftest for VMRUN/#VMEXIT with unmappable vmcb12 arch/x86/include/asm/svm.h | 20 +- arch/x86/kvm/svm/nested.c | 570 +++++++++++------- arch/x86/kvm/svm/sev.c | 4 +- arch/x86/kvm/svm/svm.c | 68 ++- arch/x86/kvm/svm/svm.h | 50 +- arch/x86/kvm/x86.c | 3 + tools/testing/selftests/kvm/Makefile.kvm | 2 + .../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 +- .../kvm/x86/nested_vmsave_vmload_test.c | 16 +- .../selftests/kvm/x86/svm_lbr_nested_state.c | 145 +++++ .../kvm/x86/svm_nested_invalid_vmcb12_gpa.c | 95 +++ 13 files changed, 711 insertions(+), 283 deletions(-) create mode 100644 tools/testing/selftests/kvm/x86/svm_lbr_nested_state.c create mode 100644 tools/testing/selftests/kvm/x86/svm_nested_invalid_vmcb12_gpa.c base-commit: 183bb0ce8c77b0fd1fb25874112bc8751a461e49 -- 2.53.0.414.gf7e9f6c205-goog