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 B5E1CEEAB; Tue, 26 Aug 2025 12:50:51 +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=1756212651; cv=none; b=cK/0TWQYDGbOzUrtnEBHmzmZxuQNDmxKapn06wmhK9Cn/O9s/J2lTMoDT86l1iOufxwyDZTwT0d0xbWuv8eGUp3OCRmenaGHyV+pSA2pIIkdNeKuNd8SdC0o1b83FvvceTPkPxv06TN21QGSaTw7FRR9YUfDFqK3xZx42BYdSvg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756212651; c=relaxed/simple; bh=GzpQTu0aO7DtHxNHfBdkAS8Gn3G+BkuS1wprJvPG85g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D99o0RqjW4Nra7gqZiB+DJGYQGG4RJwq+411g05HhgHfh9nJlW2IOZZ0Yn4PnOYy/x4NQZvJuxS7EHxo4340bjhtJeLuSdUz6yvjLNL4NmmXyXb7NJNzDy2wCVuDDTyaleRdEqOrmRwKQDj32jv8kVU5/FibnAOLZnTmDVFrIXo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0HBjIBx0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0HBjIBx0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4B7B5C4CEF1; Tue, 26 Aug 2025 12:50:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756212651; bh=GzpQTu0aO7DtHxNHfBdkAS8Gn3G+BkuS1wprJvPG85g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0HBjIBx0nD8rVjLZ/E/Ii78sXkvdfYQbF+HfoEDvcoi+aToHF6eWeHPt6Clgol3aL /xYd/WKmE6Ty2KjTgVLkD5MEAbLmPvCkVVG56zM7TYCnbsL9vduB3FUwPxHgHAXvSw UeJZg3vbyA6RANLQ6IvIN+eCCvNbShw/KsCyHCPk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dapeng Mi , Sasha Levin , Sean Christopherson Subject: [PATCH 6.6 050/587] KVM: VMX: Extract checking of guests DEBUGCTL into helper Date: Tue, 26 Aug 2025 13:03:19 +0200 Message-ID: <20250826110954.216596694@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110952.942403671@linuxfoundation.org> References: <20250826110952.942403671@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Stable-dep-of: 7d0cce6cbe71 ("KVM: VMX: Wrap all accesses to IA32_DEBUGCTL with getter/setter APIs") Signed-off-by: Sasha Levin Signed-off-by: Sean Christopherson 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 359c3b7f52a1..aaa767ed170e 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2168,6 +2168,19 @@ 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. @@ -2236,19 +2249,12 @@ 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; @@ -2258,7 +2264,6 @@ 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 && -- 2.50.1