From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) (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 ED9613546FA for ; Wed, 30 Sep 2026 01:13:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790730818; cv=none; b=ugWvn2Ef9ju+2REDeBbpalSJR55KLK4ZkwRFB6GG1CgA3E5EDGEHvB/9Fdo7IZur2PUOdbuqmfqskZYBMumdOVmHu1qHt0J9ZMdIM+BX4REWL7x0tXGwmOCRvw+5fwDNIHuSuprBASWDUk6alZ64MdNHXTy3HhFNAA7B5Fk+a/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790730818; c=relaxed/simple; bh=qNaxT1lfEbT1LPSsEVh5+AezcCglRx9kPOdT2poCI4Y=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Isk2sc2xs108/bD/AB4Bode8v8p7bLkaWoHCZgeLhohKDHZL5ve00y8cDxreDTjPYAuQESr6PtuB0Q/IKOVK4s6epjcBu08fCRb9NHwMZuLaHAo2SmJ4DEDQPcbApKnQqCH7Vo7+4W8be81P+aynAfPhYNMy3Fl8eKak8hfN7AI= 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=Hxt/4maw; arc=none smtp.client-ip=209.85.214.199 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="Hxt/4maw" Received: by mail-pl1-f199.google.com with SMTP id d9443c01a7336-2dc7337e2a7so45755645ad.0 for ; Tue, 29 Sep 2026 18:13:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790730805; x=1791335605; 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=vlcl2f6ewwzrBjcQFC4aq+Z9uRrmySkT+V2ro3tMTk0=; b=Hxt/4mawJYjl3cUtn9/4R7/pV8adjVj12k9hjy/nnH3kQXwxnvrbhtrrbNqc1poZpb 1Tzhhi9p4rXFC3xxUFBMy0uUxfjhvFvvmP7DZyzmiPizBhS8r6eRgdqJ8kNHrI9BGzzC a02FzqwsychuqMHWPuMtNyJWFEUNEch2TuuVGm3FCE6woHQkhp9hoQWyDJpp+GsgBuSZ jzqFekOhP3tADLohTxtC2faAtJDlm/hVProkACiQGREKJNQt56gZZ+OUFnGxnAn1hkTI ZRcGJXdwTQqbizXMkcBIVHBpsBRiYSB9C7RIQd//el2vZ0XyYMLiv/4NM56jtaqOlh8i E5lQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790730805; x=1791335605; 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=vlcl2f6ewwzrBjcQFC4aq+Z9uRrmySkT+V2ro3tMTk0=; b=rft3lkSRF4mz4v8lb958mbMubYOKy8ORb6NLe6BuPQADdt8/L1Vcmxzz1cRmoAgwV6 7eTYXLvK35k4AFPm+Hic3XoxQs9d29olnAfn4REU1aiemb1yLVZ9sG/3o9X4Lpe4S5Mo GV/9rGtShfM1/gIS7/dyQ7oDQFqua18fDgLYOI1Afq10pggbZx0JuZeaKjeNpX9XZZif spa4u1oais5rc5EaPp9de3UYoy5k3bPNWxv7fwMVw/tUASWBHcUu7YdPpiEGch2SzC4G VjHEa/5Y/2Qh4DsX+Kz3XRZTY6PJZ5O8L11bP6uV+iB7l5TQcLEZzde/dkgvBX5d9SaB n7dA== X-Gm-Message-State: AFq9FYIyW7HmE7OzkzQy0nwMALqlsbMYrYd3H3cYEgKALBqn61G3Ekak eyNP/Yk4R4C6iuRJtmi8I4i7R4gv87vakA//ttICZzBIaIoiqurZxPyRuL/OYaavsjaIhU2rVlp YH4dswA== X-Received: from pldu15.prod.google.com ([2002:a17:903:108f:b0:2e1:2a71:d15b]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:37cd:b0:2e2:de62:2b22 with SMTP id d9443c01a7336-2e2de622b87mr6202935ad.49.1790730804937; Tue, 29 Sep 2026 18:13:24 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 29 Sep 2026 18:13:09 -0700 In-Reply-To: <20260930011313.3197688-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260930011313.3197688-1-seanjc@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20260930011313.3197688-9-seanjc@google.com> Subject: [PATCH v5 08/12] KVM: nSVM: Disable LBRV in nested control cache when unsupported 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: Shivansh Dhiman Clear SVM_MISC2_ENABLE_V_LBR in __nested_copy_vmcb_control_to_cache() when the vCPU does not support LBR Virtualization. This lets the cached value be consumed directly instead of re-checking X86_FEATURE_LBRV on every access. Suggested-by: Yosry Ahmed Signed-off-by: Shivansh Dhiman Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/nested.c | 8 +++++--- arch/x86/kvm/svm/svm.c | 2 +- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index b61149814acc..aca2bbc66f47 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -527,12 +527,16 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu, /* Always clear misc_ctl bits that the guest cannot use */ to->misc_ctl = from->misc_ctl; + to->misc_ctl2 = from->misc_ctl2; if (!guest_cpu_cap_has(vcpu, X86_FEATURE_NPT)) to->misc_ctl &= ~SVM_MISC_ENABLE_NP; if (!gmet_enabled || !guest_cpu_cap_has(vcpu, X86_FEATURE_GMET)) to->misc_ctl &= ~SVM_MISC_ENABLE_GMET; + if (!guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV)) + to->misc_ctl2 &= ~SVM_MISC2_ENABLE_V_LBR; + to->iopm_base_pa = from->iopm_base_pa & PAGE_MASK; to->msrpm_base_pa = from->msrpm_base_pa & PAGE_MASK; to->tsc_offset = from->tsc_offset; @@ -550,7 +554,6 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu, to->event_inj_err = from->event_inj_err; to->next_rip = from->next_rip; to->nested_cr3 = from->nested_cr3; - to->misc_ctl2 = from->misc_ctl2; to->pause_filter_count = from->pause_filter_count; to->pause_filter_thresh = from->pause_filter_thresh; @@ -737,8 +740,7 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, static bool nested_vmcb12_has_lbrv(struct kvm_vcpu *vcpu) { - return guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && - (to_svm(vcpu)->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR); + return to_svm(vcpu)->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR; } static void nested_vmcb02_prepare_save(struct vcpu_svm *svm) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 775eccfb7b24..5253c0143666 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -882,7 +882,7 @@ static bool svm_need_lbr_virtualization(struct kvm_vcpu *vcpu) if (svm->vmcb->save.dbgctl & DEBUGCTLMSR_LBR) return true; - return is_guest_mode(vcpu) && guest_cpu_cap_has(vcpu, X86_FEATURE_LBRV) && + return is_guest_mode(vcpu) && (svm->nested.ctl.misc_ctl2 & SVM_MISC2_ENABLE_V_LBR); } -- 2.56.0.rc1.315.gc6ed9934b7-goog