From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (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 1C8064C6F for ; Thu, 7 Mar 2024 01:13:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709774029; cv=none; b=cFOVqUdsAy+4Pmkng7f1WVyrE3idJ+umqs9Rk9Yle6dDaqmNHaFol9UkMN8wc2Xvy+zd+lBiHz/gC/KGG6ifJDua9/ckoPx/LY43f9BAKu1vO/YrsZByHYOVUq35z4VxGUArmoc8db8TjnsCPiz1KDDWqD+hK4wusmqovWYuno0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709774029; c=relaxed/simple; bh=hZ5Sn1jSz8DAkNrCHxC3gfo9H5L7otCVEGMyNOPmqyo=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=X4Go5y5sqAyX66WYaolQd6+qi/AKrppqENrnqmvYlzIot7aF9DFzo5S1gctAa5Mx5I89TRc44HRm60H8owVGY/B/eKt1kQPpB1+jb40xGz+VO4OV9nNsBi8enESK/PqloNCNguzPcNIEiMg9sOYcWg67EKpdJ5c4qCs+O9LzMJ4= 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=PKHGNoPu; arc=none smtp.client-ip=209.85.128.202 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="PKHGNoPu" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-608e88ca078so5472357b3.1 for ; Wed, 06 Mar 2024 17:13:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1709774027; x=1710378827; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:reply-to:from:to:cc :subject:date:message-id:reply-to; bh=rt0lW+kiwJbcMwQc46VkiXalXJk5+eKabvSXhIGfvyw=; b=PKHGNoPumI+ZyWWTJJp1Hm9EYyJ1/44OIk65AK6xkd5m6NWOAIy/KTz13KYELFKviV nmYniytveXrg4Xt+VI1znvSH4EcKFEHIuzMc5pnDWeFeIlgnBpI+k7BNzqcEHAJZs83i CAS3CQqGp+X3Qx95rb4GKvZKvbHn/jauLZbq7a0/ohknT82EsCaYMKtbYCLG7nqkjQKR PnRjZ3LGWxE3VwJ0EGBg04+V07oYThqX5RVBPiR8J4A1KKBFY9PHahd0F8kGQTJ3VUBY Pfs9UHWDk7o7FLEwMca2rgkrOJ2dsXLVzGsUSiHlXmfEWU7aaZ8xxQd24TrpotVYiz8g BEQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709774027; x=1710378827; h=cc:to:from:subject:message-id:mime-version:date:reply-to :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=rt0lW+kiwJbcMwQc46VkiXalXJk5+eKabvSXhIGfvyw=; b=eOQ0YVjpgCsEUc39BIAdwgxxmqLIBuIZwhK/1/HejiDNMF2GT9f8wUQTwPTm5X081v AQIjSl4mCt7j24pl1RyUJX614rRH8QNxod1CdRXecqojwpoVQbD9pTwXFxj/v6PC8wh/ Z1AgyfwFAoCbUNFdYUQxPxQFUNRd5NqqUjfmk1MOkC/0ALQiRrllVD7Vj+kaPbAHsl3V 1IBWOIoaJ2U7/8wnUigXyvbl2TGCPGKSlxOGnGbjp8TFaLd3ElLj80XsRk4NQbRVQUeB 5x0XHHfMlw9rbW42GRspha5WcIdQ1ZzuOeVLUa+Tpn/OiHbAU/0CQdS3Va1GPTTcA1iw DIRw== X-Forwarded-Encrypted: i=1; AJvYcCVQpGnEiemHIR8ufDNrJCyX5vv0Wc6ZLZRz2V0WNYIGgnQ+l+mr+cFm3MTLtREE44MfQk+D4OJGLYeFWmY1+Nv/hyKS7WlHsDymNqqF X-Gm-Message-State: AOJu0YxkwPrsA0g5bZxbd10nyZ61Ezt1o+2voTJBaprYXtG0NetHoVSQ I9odyNWW98G2EIlbTXxA1wqLGUKkbte7sHw8Tt1/ojNy3YcqXKBrobTJ19wLWMNov1RYPPzAQYF tIA== X-Google-Smtp-Source: AGHT+IHf2WAdN8sJOEpl8sXRG0fsScQWF4WTan2Mj8l4gnGUdx7FojV+fNOXpKpPaex0EROrURmv1CzhYg0= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a81:9b97:0:b0:609:38d1:2ad9 with SMTP id s145-20020a819b97000000b0060938d12ad9mr4120303ywg.4.1709774027042; Wed, 06 Mar 2024 17:13:47 -0800 (PST) Reply-To: Sean Christopherson Date: Wed, 6 Mar 2024 17:13:41 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.44.0.278.ge034bb2e1d-goog Message-ID: <20240307011344.835640-1-seanjc@google.com> Subject: [PATCH 0/3] KVM: VMX: Disable LBRs if CPU doesn't have callstacks From: Sean Christopherson To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Sean Christopherson , Paolo Bonzini Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Mingwei Zhang , Jim Mattson Content-Type: text/plain; charset="UTF-8" Disable LBR virtualization if the CPU (or I guess perf) doesn't support LBR callstacks, as KVM unconditionally creates the associated perf LBR event with PERF_SAMPLE_BRANCH_CALL_STACK. That results in perf rejecting the event, and cause LBR virtualization to silently fail. This was detected by running vmx_pmu_caps_test on older hardware. I didn't tag it for stable because I can't imagine anyone is trying to use KVM's LBR virtualization on pre-HSW. Sean Christopherson (3): KVM: VMX: Snapshot LBR capabilities during module initialization perf/x86/intel: Expose existence of callback support to KVM KVM: VMX: Disable LBR virtualization if the CPU doesn't support LBR callstacks arch/x86/events/intel/lbr.c | 1 + arch/x86/include/asm/perf_event.h | 1 + arch/x86/kvm/vmx/pmu_intel.c | 2 +- arch/x86/kvm/vmx/vmx.c | 17 +++++++++++++---- arch/x86/kvm/vmx/vmx.h | 2 ++ 5 files changed, 18 insertions(+), 5 deletions(-) base-commit: 0c64952fec3ea01cb5b09f00134200f3e7ab40d5 -- 2.44.0.278.ge034bb2e1d-goog