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 86B68E571 for ; Thu, 14 Aug 2025 12:52:04 +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=1755175924; cv=none; b=d8DPZSg7JFJCykkpKZT1UEEnKLpld9Cr2vijA55mGdAXvivi+9gVgIatr0P0u4vJ17Iyw4ZlXSWVqzEoQDHvL8msActurKndp37NX2uEQbZ9KrNpJKRzK+mXIQpycrEj4Z9PSPsCLGXYp+taEVclw0vont2pnGlGwAE+trFbnqQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755175924; c=relaxed/simple; bh=DX5PyXmvuoram2JCuG0y6yqEhrOdtnLys+r57/ddrMk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Eh+mk29ygzLJMsaZ5MEqzqMfcH8hnNUcSBcGMI6FqWFGen2/QFksj0B3NdVpJHFqHsa9WWzxnjsCUXjjYzlYi4Rt1KD0TUf6/KL8VOxweFFloX8R+msLtlAFjWl/BOtYXLo7vgNgzh7X6J3sXjlZdnO5TXr6QVvH3NTfU1BAlDE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OkTTwZwn; 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="OkTTwZwn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3E27C4CEED; Thu, 14 Aug 2025 12:52:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755175924; bh=DX5PyXmvuoram2JCuG0y6yqEhrOdtnLys+r57/ddrMk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OkTTwZwn7vS2qtKsqC39I8gLDfA/sFdcL9nszb18r3mMQk4AXAeZf6a9du2mvRcXg veajXEVhhGcd9yIYNbjn9Iwqdcy70et2zHaBFYNupcOCtnKtKSc9DBVuxO4h/fpXV9 S8KMm/+3cg5Z1L0bY9aFeveGy5wyedAN+0OtDXVHXkZMRiZsrQpOxMk+aJr/RpBLn5 8Z8N1QmF2qkSwHiAE9PEqoWI/BXYHfS4kGSm134SKNyxfO9iC+Jd3UH9WpdXH/+JWE Z2HRrkkCD8FQ2gkiVZqofzls6X0V2kjtTpPAYDhz3o418FK8g8rOESRG4MzYr9eyJ1 WVspFLafhyl9g== From: Sasha Levin To: stable@vger.kernel.org Cc: Sean Christopherson , Dapeng Mi , Sasha Levin Subject: [PATCH 6.15.y 1/3] KVM: VMX: Extract checking of guest's DEBUGCTL into helper Date: Thu, 14 Aug 2025 08:51:59 -0400 Message-Id: <20250814125201.2090009-1-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <2025081208-petition-barcode-1e2a@gregkh> References: <2025081208-petition-barcode-1e2a@gregkh> 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: 7d0cce6cbe71 ("KVM: VMX: Wrap all accesses to IA32_DEBUGCTL with getter/setter APIs") 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 eec0aa13e002..e812e98b06a8 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2195,6 +2195,19 @@ 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. @@ -2263,19 +2276,12 @@ 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; @@ -2285,7 +2291,6 @@ 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