From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 315494C0424 for ; Wed, 30 Sep 2026 19:36:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790797016; cv=none; b=nl/j8zPWyCT1fwLVJK/8zMRcia9+DMzfpeX6bIiIhAfA2bWGtqALqGwZtle8eF3MOBNux4tB1iIDedDaUyUKZzfQMFaBw7vOb6TpodZUUu2p3A/TjYhJJhiZOvIh6lxgYbq6eU4sWVTMyOowZzbIQz7czn/6iIQGa67iJViMlYw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790797016; c=relaxed/simple; bh=Jgndf1FLVPtw1RjeBvHSK/j9YvB+rS6M1T9+7Mb9Hxw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=qOjuyy1gFztBIfyZFrKVzrVqF+y7ayabb02l8/oKj7b/rbkdJ4Y86ovxDYZPfF2X7Lb7rpfNMyCO2+Mb9abf5inRntpntpkn3eLU4pidDxMj6vT6+kg4Ui1kresELlPwbIBAw+222GP2foLMTNBHXNIcyeFZWkMm7VIRz3ibTfM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=vfKuo4hb; arc=none smtp.client-ip=209.85.214.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vfKuo4hb" Received: by mail-pl1-f197.google.com with SMTP id d9443c01a7336-2e2e7d08ab7so6524145ad.1 for ; Wed, 30 Sep 2026 12:36:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790797014; x=1791401814; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=5ZPdaAVKbCuct+Drs4hq/dXnJoZKDoPUJjaVzhPw8KY=; b=vfKuo4hbwNLfmDjS2UikM8pr8u6kt147HBAnmycH1kXJNtn87sMEc/ZGDnE006fHhc h0uhh5H9R8w6au3DB7qd6Sk4eyqc9gUykZHlvMjvr5qFQ0a/6Wl1lB06/+xrvKS9Xyvf 2854Ib1SN9zQT3jXCNS2LlfIMmlI/5mP6fjceUZS+Yegd05ci8blHehgZzhhvrcYQzbP NCXRG7Y0dLQD7jNf1DMsak3UEwxLrGPDxKS2p6pxQ63qatwXWgtv1y/lNd4yfTpJiHQs M9YmE4I0ETPHaaLpXtmg8yBFyVd6nzYebm6zd91ZnD74hq6goqgBckEhtdvd+3+3W8Px X9GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790797014; x=1791401814; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=5ZPdaAVKbCuct+Drs4hq/dXnJoZKDoPUJjaVzhPw8KY=; b=m+x/eNkteTDhATBMf5CbefNqWvIf8ZvqzBWLGuWhZoLkuQxk9sXNIOmKc77OY15tis Oa/38qoKFfPOxZwu4n5jvFEqQAEFvthO9gpX+jngAZAjYdEG8+hkODEa1REhaAT5vvsV GRfl1Revvp0QSuw7AbFIF8lEv1zjTeMfrVR//VoETkS4f3hLotDrDDjbNUQ0cff4C5/Z LEBh8b65tV8i0hNEI1GnpWvbfeJK50ezvF6CpbphJZG2fXda8DeVXY/eFO9c0mcP4G34 Xfa/BcgJJhdHVjvcjKpgXCRGH3IIHPMa26XLY3IwtQcUoOlV6uK7gTZBIw64kSfK9Pn6 eJcQ== X-Forwarded-Encrypted: i=1; AKwUvBw8V0tnqzHQKqvNZ23jeZ5h7IDJWjizkNp2i2s6V0MUNqsZjs5qfjMmVB+YrvTqWxv7sBhr0dsGEZ5LV9U=@vger.kernel.org X-Gm-Message-State: AFq9FYI4eLz5N2pbn6gGDBvbdI+kGxcvsFROvc2ebYBFPLBYXuIURdDK KgfOI0rRrMW47hXOKqQ/J3WhjiPjjPoby+MtJ+yzA4zo9rOlHqAmvgIejwUptOoBfXPjaEFd56p 7P2f8KA== X-Received: from plaw3.prod.google.com ([2002:a17:902:c783:b0:2e2:f0cb:c185]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:228e:b0:2e2:c459:2ed with SMTP id d9443c01a7336-2e2e4b551bfmr18928225ad.42.1790797014291; Wed, 30 Sep 2026 12:36:54 -0700 (PDT) Reply-To: Sean Christopherson Date: Wed, 30 Sep 2026 12:36:34 -0700 In-Reply-To: <20260930193634.3415089-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260930193634.3415089-1-seanjc@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20260930193634.3415089-13-seanjc@google.com> Subject: [PATCH v6 12/12] KVM: SVM: Add support for virtualizating Bus Lock Detect From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , Shivansh Dhiman , Nikunj A Dadhania , Ravi Bangoria , Tom Lendacky Content-Type: text/plain; charset="UTF-8" From: Ravi Bangoria Advertise support for virtualizing Bus Lock Detect and allow the guest to enable BUS_LOCK_DETECT if LBR Virtualization is enabled (Bus Lock Detect is enabled through MSR_IA32_DEBUGCTLMSR, which context-switched if and only if LBR Virtualization is enabled). Signed-off-by: Ravi Bangoria Reviewed-by: Tom Lendacky Co-developed-by: Shivansh Dhiman Signed-off-by: Shivansh Dhiman [sean: massage changelog] Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/svm.c | 12 ++++++++++-- arch/x86/kvm/svm/svm.h | 7 ++++++- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 1e58ad8691e9..e7c296c52591 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -879,7 +879,7 @@ static bool svm_need_lbr_virtualization(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); - if (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) + if (svm->vmcb->save.dbgctl & (DEBUGCTLMSR_LBR | DEBUGCTLMSR_BUS_LOCK_DETECT)) return true; return is_guest_mode(vcpu) && @@ -5712,9 +5712,17 @@ static __init void svm_set_cpu_caps(void) * Clear capabilities that are automatically configured by common code, * but that require explicit SVM support (that isn't yet implemented). */ - kvm_cpu_cap_clear(X86_FEATURE_BUS_LOCK_DETECT); kvm_cpu_cap_clear(X86_FEATURE_MSR_IMM); + /* + * LBR Virtualization must be enabled to support BusLockTrap inside the + * guest, since BusLockTrap is enabled through MSR_IA32_DEBUGCTLMSR and + * MSR_IA32_DEBUGCTLMSR is virtualized only if LBR Virtualization is + * enabled. + */ + if (!lbrv) + kvm_cpu_cap_clear(X86_FEATURE_BUS_LOCK_DETECT); + kvm_setup_xss_caps(); kvm_finalize_cpu_caps(); } diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index c3380d865b75..6d0242966dc8 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -789,7 +789,12 @@ BUILD_SVM_MSR_BITMAP_HELPERS(void, set, __set) static inline u64 svm_get_supported_debugctl(struct kvm_vcpu *vcpu) { - return DEBUGCTLMSR_LBR; + u64 debugctl = DEBUGCTLMSR_LBR; + + if (guest_cpu_cap_has(vcpu, X86_FEATURE_BUS_LOCK_DETECT)) + debugctl |= DEBUGCTLMSR_BUS_LOCK_DETECT; + + return debugctl; } /* svm.c */ -- 2.56.0.rc1.315.gc6ed9934b7-goog