From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 E66BC24291A for ; Tue, 8 Jul 2025 20:57:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752008267; cv=none; b=cvIrcCggtIOhNckfcbvNi8WDhueQPrg8+enpJQCoFziNm4HDM+y9ty7joYTrHCnDaEc9UZFmkTlkJYmAFNDwwBSqRjz24qWzakbhxrZmtKjmYNpBoPpepDwtuU+Hcape6eDHgQAU3NBHPo1pZqlWj9P/63+iCWzRCEZ4W/gy/6M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752008267; c=relaxed/simple; bh=OJygdgSC/prRJ/2e265vfEgL4IMrls0u7oAx15a9nyU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=EVEa/XFmTahzgv63sxoTlY4cjl1c7IM0LVWzg1KEwDj141gk+Hca9qp6pUM95a8wcOviQk3xGIBCLhf2Y+QHo9QJeLaLY3aUsMRJzutEK7puA92zBBjax9nBO+BxlunTwXmeSaWEapaVk/R047NPaRDrt/SA/4sM9T14VjJsv8U= 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=ZMzWtj4u; arc=none smtp.client-ip=209.85.210.201 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="ZMzWtj4u" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-74b537e8d05so3869807b3a.3 for ; Tue, 08 Jul 2025 13:57:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1752008265; x=1752613065; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:from:to:cc:subject:date:message-id :reply-to; bh=xj/rgIwow7I47txNalOr1f2xg0tOMdekLQmzegO3DyE=; b=ZMzWtj4uab9PPbMAmYwvZBKdsGsVvDr3mQ9DhNCBV1A+XOgK+B2DfwMUur8E3vRai5 Nve/9p2kFuTA5fi53SehWkOE5Tr9zVlbZoSbPni1j9gO7HYhuad9wbMPElSxRb4kx7cj Es+PWp01OkKU0x6wD+s2+p/iLMy6IEIS3zx6m3C2/m7NDTi57eQfM9JK4LNxph1qS5jg zypomph5P+IyjD04/KQyLJWX/7C7RAcXCnQKYBw/kKx9w3RwpsOYGkRvtpeEPrkiD/IM bsfygbohbHn782mYsKH1H5uwAW94hYmv42hms2GVXAlBRiHWhv5ymGsEqOeMpsT/mzHw 8Mhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752008265; x=1752613065; h=content-transfer-encoding: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; bh=xj/rgIwow7I47txNalOr1f2xg0tOMdekLQmzegO3DyE=; b=AMm6MkCq0CVn+n9bfZdilu97VXeAAvtUbpTBhM7uWAFJG1WkONOerdmjB9zJc2ENJ7 eIKd5Eg/2JZ7DcxVEyIMQMnX1caGEYpsGMV31u+9vIgfPqIsaBzLTIp9+w+hmgSqHG4Z QkCA3U+d07/W1S8Dct719J0SI4Krt5tDHk3n8zUZGN3r6dG+BYaaUy2danAevCsBFTWE gHD+vsvzeCe0t4lLPnmjn63Ta+NTUWIBXmqT1M68N6n3XZaXkhLH/F2vpotndq4m18VQ 179EoRrBPwnfWMIVD/XzXJkKmpAZl8iVtZJwX6nvq587jxdMQw3fy/WIwrVcJMaA8W/1 DVIQ== X-Gm-Message-State: AOJu0YwQaoISLCmSoEdxKhDXVXQIuFyKwXgIDg3CwbK5H5zINaGMBfZ8 X/7URhjUAgoxw/2Hvl/SxgSp+nbqvRq0VL67xU4/K73ckqJj+bM43wbiuRg0DOJKlY3enEGnbac tLbVj4Q== X-Google-Smtp-Source: AGHT+IHt3O6gpCRhitlrcX0MVCqOa+15++d+WNMG3zixOkR5O+/tVnP+/zUIylUP45iQshj9EIxXjfZXHzk= X-Received: from pflc19.prod.google.com ([2002:a05:6a00:ad3:b0:748:fc2e:e489]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:ad3:b0:742:a77b:8c3 with SMTP id d2e1a72fcca58-74ea6411205mr95826b3a.4.1752008265114; Tue, 08 Jul 2025 13:57:45 -0700 (PDT) Date: Tue, 8 Jul 2025 13:57:43 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: Message-ID: Subject: Re: KVM Unit Test Suite Regression on AMD EPYC Turin (Zen 5) From: Sean Christopherson To: Srikanth Aithal Cc: KVM Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Tue, Jul 08, 2025, Srikanth Aithal wrote: > Hello all, > KVM unit test suite for SVM is regressing on the AMD EPYC Turin platform > (Zen 5) for a while now, even on latest linux-next[https://git.kernel.org= /pub/scm/linux/kernel/git/next/linux-next.git/tag/?h=3D > next-20250704]. The same seem to work fine with linux-next tag > next-20250505. > The TSC delay test fails intermittently (approximately once in three runs= ) > with an unexpected result (expected: 50, actual: 49). This test passed > consistently on earlier tags (e.g., next-20250505) and on non-Turin > platforms. Stating the obvious to some extent, I suspect it's something to do with Tur= in, not a KVM issue. This fails on our Turin hosts as far back as v6.12, i.e. = long before next-20250505 (I haven't bothered checking earlier builds), and AFAI= CT the KUT test isn't doing anything to actually stress KVM itself. I.e. I wo= uld expect KVM bugs to manifest as blatant, 100% reproducible failures, not ran= dom TSC slop. FAIL: tsc delay (expected: 50, actual: 49) SUMMARY: 13 tests, 1 unexpected failures =E2=9C=98 ~/build/kut/x86 # uname -r 6.12.0-smp--adc218676eef-tsc