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 12B061917ED; Tue, 26 Aug 2025 13:16:27 +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=1756214187; cv=none; b=MsGIBFCrgDVw1EsKg5RwYmgBTcm2jhN8hloFTU4+PePPR4PfxNpqeA1/Kv/G4ZDNdy0lLqqI480KDNVebpwUjXIjkH8R/VpmjekOWgjZrT3RoCT0xqWyzNUwNTpQ4WtmqoV9UWwOjPQSo2hoAJ6MUouTYbOULt57xOc676RruWU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756214187; c=relaxed/simple; bh=GDK3TDB6gILvVBzDxBV9zMbInztVnkUMIG6c2aR+1pM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bN5kqKOUymFwM7H8agRyvO9yvMWUotOUo8QhywjPesvQePGZmNnOe4552C1KYgv0s7ADxc4h5XFa09e+fuOGyvLlV6LRvWWvjIZYl7qKnyBOcZG+FXhyZAmpnPeVcvkvGHmoIZW8xzmjayxZPF9kJ7yGBkS8rXrS8axNIOXnwjI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=k2kn8Acx; 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="k2kn8Acx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 969ABC113CF; Tue, 26 Aug 2025 13:16:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756214186; bh=GDK3TDB6gILvVBzDxBV9zMbInztVnkUMIG6c2aR+1pM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k2kn8AcxZS1gVIjz1+IthwH5wGTyQdrMnS+Raf6ObWljW3oyhFl8FBs3oNBx7a7Jj YdTmLr/fxQzUKl198DPZ2u64nKuYsBaVacrfbQNOuAckDM1fmoNe6wXtyn09VCdAet wGfFU58CWFJXP/r9K1llci2qP5m1uGhCjzOCoDVk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sasha Levin , Sean Christopherson Subject: [PATCH 6.1 042/482] KVM: VMX: Allow guest to set DEBUGCTL.RTM_DEBUG if RTM is supported Date: Tue, 26 Aug 2025 13:04:55 +0200 Message-ID: <20250826110931.851788411@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110930.769259449@linuxfoundation.org> References: <20250826110930.769259449@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson [ Upstream commit 17ec2f965344ee3fd6620bef7ef68792f4ac3af0 ] Let the guest set DEBUGCTL.RTM_DEBUG if RTM is supported according to the guest CPUID model, as debug support is supposed to be available if RTM is supported, and there are no known downsides to letting the guest debug RTM aborts. Note, there are no known bug reports related to RTM_DEBUG, the primary motivation is to reduce the probability of breaking existing guests when a future change adds a missing consistency check on vmcs12.GUEST_DEBUGCTL (KVM currently lets L2 run with whatever hardware supports; whoops). Note #2, KVM already emulates DR6.RTM, and doesn't restrict access to DR7.RTM. Fixes: 83c529151ab0 ("KVM: x86: expose Intel cpu new features (HLE, RTM) to guest") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250610232010.162191-5-seanjc@google.com Signed-off-by: Sasha Levin Signed-off-by: Sean Christopherson Signed-off-by: Sasha Levin --- arch/x86/include/asm/msr-index.h | 1 + arch/x86/kvm/vmx/vmx.c | 4 ++++ 2 files changed, 5 insertions(+) diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 727947ed5e5e..afd65c815043 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -379,6 +379,7 @@ #define DEBUGCTLMSR_FREEZE_PERFMON_ON_PMI (1UL << 12) #define DEBUGCTLMSR_FREEZE_IN_SMM_BIT 14 #define DEBUGCTLMSR_FREEZE_IN_SMM (1UL << DEBUGCTLMSR_FREEZE_IN_SMM_BIT) +#define DEBUGCTLMSR_RTM_DEBUG BIT(15) #define MSR_PEBS_FRONTEND 0x000003f7 diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 60d1ff3fca45..9445def2b3d2 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2064,6 +2064,10 @@ static u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated (host_initiated || intel_pmu_lbr_is_enabled(vcpu))) debugctl |= DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI; + if (boot_cpu_has(X86_FEATURE_RTM) && + (host_initiated || guest_cpuid_has(vcpu, X86_FEATURE_RTM))) + debugctl |= DEBUGCTLMSR_RTM_DEBUG; + return debugctl; } -- 2.50.1