From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (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 815053B8934 for ; Tue, 28 Jul 2026 19:33:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785267221; cv=none; b=qZWhF9ufmYb5jrc6WK4BCYucV7CmQ9YzWwv7vusiWMHgeB/SiF1P+gsM68LkuRGTMWdCSl0euXJZ2tBt3ItLE0DzHugkLaqRsLqnd1e0UEg1JZB2Ee6bXj/y5bd2fzDOm6kE0NQhUQVxV7QPbEdnKkY4YMLhj/5MmEw8owUv9II= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785267221; c=relaxed/simple; bh=aL2CxHVIvF3NgG8BrwDcCR08x+oXQFHFk9QKoI+P+Ro=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=gtNF/xDiVDHeh+vV6Hga2ungb7anmHlmNeDcyC3A67PvPhwlcqa4H9mLqUvTis8gySC2VBhWLFRNT8gwdzC4MrFOyUsETN9s5eyhfT+xKco2E1u9lRIJV9wFIx09PinxZ7YZwaCH001/d4cK2xA1I+jG8sRegm7m6WlpLlzFqkM= 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=u7mqI7Ma; arc=none smtp.client-ip=209.85.210.200 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="u7mqI7Ma" Received: by mail-pf1-f200.google.com with SMTP id d2e1a72fcca58-84859a64079so205244b3a.3 for ; Tue, 28 Jul 2026 12:33:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1785267220; x=1785872020; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=aL2CxHVIvF3NgG8BrwDcCR08x+oXQFHFk9QKoI+P+Ro=; b=u7mqI7Ma2cs3Adh5kOcCgtxTxhjoso7Zac0jLvevDBYqkXGCyadY/UrYuygDgvMITd tr2McuqgdZPojnwRV5vO3NaSc7iBqqcjXTVG/Qhp5ozrWjYJpYHjVIHKCnZWbxAhZ+Tr WlREOPcfebbfuU7KmSYHri4G4hsocBKrET/yDb0buQBPwbAIz4Q/sM1NMJNmgrtjhtHf UU99t+tPSFnOUQX8E7A3RKO4y51Ol6nNLBE5FIT+nJX3rMiMFI2KlXi9PVnSTcJ2BN49 P7Ne4olwb7b4E6VXyY8oIj1IPHzfmTR7mcU5Snoucmg4KklSkk+41Mkip/BVzcDg6sry cZQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1785267220; x=1785872020; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=aL2CxHVIvF3NgG8BrwDcCR08x+oXQFHFk9QKoI+P+Ro=; b=USZn+X3zt4kGkGddl+mMJd0Q9ZaOqMtu6Nju21as529xbGgtTae7GY0DHW4x0roDUs EiNYg9kspkePZ4/IuUyF9AeEL2+6FBhGXrfoHxeLBuxfwgNAK5X2T45HF4E9W3fTNMzX QxvfsDUGoFBfA7PQd2MItlHVoRRIUT5hJ2/eeDWgJrWBGjBkF6uLYXEQZYMCYHu1d8YU p5i6F9wG4MXmoBmChqKw5lqQynIyAszKvFUSS5db+i8odgvaMU6wlK8jRRTrjDKfZWAI Lb09OBiF9IzTJKCk9KGEpODa5GNq2cp1wQ88Lu+bGBq5VacH7oFhOXoA8d5ohJ44Waa5 /IJQ== X-Forwarded-Encrypted: i=1; AHgh+Ro0MwZXowJ8kyTunspu5Snlp47ONP+evimGHpEcqyLMq0znYiH6M8mVHe5QZXcV2uubGCTtVFmbkBRi6Fo=@vger.kernel.org X-Gm-Message-State: AOJu0Yy2GRB6g19OBeoG7rwfWrW4h48NQcyf0b7hThA38yWwhILtdGGz SUcVbZbKE5i99WlEL4V8ap9la5GVWEVoNogUdO4/woiTA/RgEuyl5beRJ313hc9gctOYMbbWu9P Kc4sZQQ== X-Received: from pfay39.prod.google.com ([2002:a05:6a00:1827:b0:84b:6d07:4d38]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:44c9:b0:84c:2b8e:8e06 with SMTP id d2e1a72fcca58-84e93264421mr3915195b3a.40.1785267219515; Tue, 28 Jul 2026 12:33:39 -0700 (PDT) Date: Tue, 28 Jul 2026 12:33:38 -0700 In-Reply-To: <20260707183405.15571-12-zide.chen@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260707183405.15571-1-zide.chen@intel.com> <20260707183405.15571-12-zide.chen@intel.com> Message-ID: Subject: Re: [PATCH 11/15] KVM: x86/pmu: Emulate streamlined Freeze-LBR-on-PMI From: Sean Christopherson To: Zide Chen Cc: Paolo Bonzini , Peter Zijlstra , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson , Mingwei Zhang , Das Sandipan , Shukla Manali , Dapeng Mi , Falcon Thomas , Xudong Hao Content-Type: text/plain; charset="us-ascii" On Tue, Jul 07, 2026, Zide Chen wrote: > PerfMon v4 streamlined the Freeze-LBR-on-PMI mechanism. When > DEBUGCTLMSR_FREEZE_LBRS_ON_PMI is set and a PMI fires, hardware sets > IA32_PERF_GLOBAL_STATUS.LBR_Frz instead of clearing DEBUGCTLMSR_LBR. But KVM doesn't even support LBRs for the mediated PMU?