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 5704324293B for ; Thu, 14 Aug 2025 13:24:34 +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=1755177875; cv=none; b=GeoGmlxvy0vxm/Qz1FSMRnX6RPDqdB08tiNXRIznzc+GQzerQwiHXy1TI51hNHjoMidepxfhR9rVs46o8jyXqe3cZBVMubIejxaPR8hngkonnWPDDXmXMCUNVYVgo/yWN0aS5KxarGOe+la+wa1DAb8ly2hE0eACYJgIW9YRnec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755177875; c=relaxed/simple; bh=pPbc7u65AIffnDxbXGtQybkDqlaUuJ+H7lfOWn/yvVs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Vreh0dkquFKinR3b0hZNyKLJ5xSGkFNhhZJV/7KFztaDK+oqaGcWa03zAL4TIiUhUwUoRC9kzFFy9eGWMAF38RDcuJMMI5lQlugdMmcZjvFVxUP7AQAukSwpZpLJN9TABHHttb40WXTkfYZ1lKqv+nnH6+aYQK85TExJG1jLV7c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eL6dKvEl; 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="eL6dKvEl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BE34C4CEF6; Thu, 14 Aug 2025 13:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755177874; bh=pPbc7u65AIffnDxbXGtQybkDqlaUuJ+H7lfOWn/yvVs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eL6dKvElDVlTCmkQPA3IjHiZ/eUrpOTnSSrSae9BDKUudiSLIohz78yufoOdOSAmm Kn4St+LtGpoicYgHohWJnLwxANrc+787PccgtspLi7H7+EOVBKn0+wpQTUgJGmk4eV 6xu1E4B9F+gTB/mQHLCzTJD3dvRtThGxse6iIzAh0bZvAELyZkjLTT3xjRGOF3dMRf 8XWTDM2VtYP0Okw5i1wgGdlXmb78YbZPuZAJpr4ZtU+p2gPbTdNaHXJCRU3+MwKmJ4 pbho3SGe2V0237XtnEznK6zH3a/GOiReMIJ8gjCSqAYNEmIyot7StOlXRrfgpSLlNX ZheacpB0Wpv4w== From: Sasha Levin To: stable@vger.kernel.org Cc: Sean Christopherson , Dapeng Mi , Sasha Levin Subject: [PATCH 6.1.y 2/3] KVM: VMX: Extract checking of guest's DEBUGCTL into helper Date: Thu, 14 Aug 2025 09:24:30 -0400 Message-Id: <20250814132431.2096835-2-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250814132431.2096835-1-sashal@kernel.org> References: <2025081224-material-dismay-771d@gregkh> <20250814132431.2096835-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sean Christopherson [ Upstream commit 8a4351ac302cd8c19729ba2636acfd0467c22ae8 ] Move VMX's logic to check DEBUGCTL values into a standalone helper so that the code can be used by nested VM-Enter to apply the same logic to the value being loaded from vmcs12. KVM needs to explicitly check vmcs12->guest_ia32_debugctl on nested VM-Enter, as hardware may support features that KVM does not, i.e. relying on hardware to detect invalid guest state will result in false negatives. Unfortunately, that means applying KVM's funky suppression of BTF and LBR to vmcs12 so as not to break existing guests. No functional change intended. Reviewed-by: Dapeng Mi Link: https://lore.kernel.org/r/20250610232010.162191-6-seanjc@google.com Signed-off-by: Sean Christopherson Stable-dep-of: 095686e6fcb4 ("KVM: nVMX: Check vmcs12->guest_ia32_debugctl on nested VM-Enter") Signed-off-by: Sasha Levin --- arch/x86/kvm/vmx/vmx.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index dac7883acdd2..164bbf7959be 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2071,6 +2071,19 @@ static u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated return debugctl; } +static bool vmx_is_valid_debugctl(struct kvm_vcpu *vcpu, u64 data, + bool host_initiated) +{ + u64 invalid; + + invalid = data & ~vmx_get_supported_debugctl(vcpu, host_initiated); + if (invalid & (DEBUGCTLMSR_BTF | DEBUGCTLMSR_LBR)) { + kvm_pr_unimpl_wrmsr(vcpu, MSR_IA32_DEBUGCTLMSR, data); + invalid &= ~(DEBUGCTLMSR_BTF | DEBUGCTLMSR_LBR); + } + return !invalid; +} + /* * Writes msr value into the appropriate "register". * Returns 0 on success, non-0 otherwise. @@ -2139,19 +2152,12 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) } vmcs_writel(GUEST_SYSENTER_ESP, data); break; - case MSR_IA32_DEBUGCTLMSR: { - u64 invalid; - - invalid = data & ~vmx_get_supported_debugctl(vcpu, msr_info->host_initiated); - if (invalid & (DEBUGCTLMSR_BTF|DEBUGCTLMSR_LBR)) { - kvm_pr_unimpl_wrmsr(vcpu, msr_index, data); - data &= ~(DEBUGCTLMSR_BTF|DEBUGCTLMSR_LBR); - invalid &= ~(DEBUGCTLMSR_BTF|DEBUGCTLMSR_LBR); - } - - if (invalid) + case MSR_IA32_DEBUGCTLMSR: + if (!vmx_is_valid_debugctl(vcpu, data, msr_info->host_initiated)) return 1; + data &= vmx_get_supported_debugctl(vcpu, msr_info->host_initiated); + if (is_guest_mode(vcpu) && get_vmcs12(vcpu)->vm_exit_controls & VM_EXIT_SAVE_DEBUG_CONTROLS) get_vmcs12(vcpu)->guest_ia32_debugctl = data; @@ -2161,7 +2167,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) (data & DEBUGCTLMSR_LBR)) intel_pmu_create_guest_lbr_event(vcpu); return 0; - } case MSR_IA32_BNDCFGS: if (!kvm_mpx_supported() || (!msr_info->host_initiated && -- 2.39.5