From patchwork Tue Mar 25 04:13:48 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suleiman Souhlal X-Patchwork-Id: 14028020 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 33A7353365 for ; Tue, 25 Mar 2025 04:13:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742876041; cv=none; b=j8Qn//2N5KIyFatJSwCLEtcG/q++3iKjChR3kM5HoUucgvaGV82tP3vysrfgS5G2tvMHGjSpwtuyiy4WD6vBZYCVdq1l8kGn5JRYclIS72peuQNz5UsTnZ4hYBAgR4BVbLUfhnjfe9lZnCU2aToKiPmoGE8AQKjmIt9zIPPJys4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742876041; c=relaxed/simple; bh=3TAwYkMl/7Jrwu+foCwYFjf4/ZKYpnei3D4Wl9VvD1A=; h=Date:Message-Id:Mime-Version:Subject:From:To:Cc:Content-Type; b=Y+kaelzWfQmFtT/LsotD/BC5DttBtzJgOUERy7WcEVQDa2I0OlJjqsdSnsyA6Q2yTryFrQZCuUlgNMYjHVBsN7udG9B+bYpnHz/xS5l1TaOKkC+qekwPh+Xdrobdyfrpe88U5KMp4menm0hL0n1zgB8fTvMW5rokm4lSzUC3DXw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--suleiman.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=bTSvGoW2; arc=none smtp.client-ip=209.85.219.202 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--suleiman.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bTSvGoW2" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-e582bfcada6so8139386276.1 for ; Mon, 24 Mar 2025 21:13:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1742876039; x=1743480839; darn=vger.kernel.org; h=cc:to:from:subject:mime-version:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=EJASGRGmrPcwpU7CqSRwJwZcThKb/XyXZK/AkLrGpAk=; b=bTSvGoW2tcKUFol305j8zVwTqtJBPxwgMsiZ1O9M3/gj/0eG+pJ0eO+42EJNTIYkDj VJUdpk8zyIWkT9RXKickVnaRPogW0bHMT6kuyjKOa6Nd3LXWWD3Rz3v9eJDMTMITsNCB nuIQlff3Lf3EXwwkvBJL44aqlfeyEFy8qZDlWq87szTkkJdDhgBDZo6rjHPsyGnS562m YK6/2xsux1BRWqmzWEtPFp01TVd9vi3kuQz5y01XZRl7i6OsuQFLsRkuetx3TUzzc+h5 1diN6d4W5ltYMNSbquVfC1ASBrDSEwda2vGn+ZdP5kGO9tYOtWwjc+C110ZlIWwyz53j D3Ew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742876039; x=1743480839; h=cc:to:from:subject:mime-version:message-id:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=EJASGRGmrPcwpU7CqSRwJwZcThKb/XyXZK/AkLrGpAk=; b=wwlEvkQsQRvgWAb0u/+eNmRZdyG7FLzeGtDVKOdMAGsR6C3zKw3JVKpyo6Miag/owp RjkzJAMd1vHAQBeXRBHgNwcfFLTXqfEu6U86Zzqu+W1UEw8ImE4NMjLE52YCD/hjjabZ ee474+jvdQ46hmjuQCOLhUoKRjUK/GIWrcLNnSQRNDjn7HSxLMFB+htHCUgYehBk4+ut GS46lSRx+8Gayx2UwRnpSv+yhWdGrWGACfDJTWCygn0Mt3C0A00eO1iWOQWb3v/2d+Kv /vzyCgncYD0z4i62bSrRLpqJrnRHsocLkJcrV6zrrxQiHpbe6vgO4j4TpkIiQ3ih5J8d 8kkA== X-Forwarded-Encrypted: i=1; AJvYcCU90xql0UAFSE3fq6zzMyUCDLFecuTPbAC6rSo6g+/dzFoTyfJFdYZ9lUzGHga6g2Aj64Y=@vger.kernel.org X-Gm-Message-State: AOJu0YxjH/TqCGLg49D/lHNS+Xlih6mrMB8IHaJRLvVGzy1vGWCQ7tV+ cOsKtHX9lEgB56Mu/GLc96y/c3Kr9oYbU64u552OI4+cDtf+KMnPdh0b52CvcNaJC72WC0ivz3z W23Fsj9U7lA== X-Google-Smtp-Source: AGHT+IFRXyADSH1VG1iqof3ddCopTGj+wUY0S7x/42w9GR77Lq+bRsylsnD/Z9GFSuEUsXLsmUb1Qkhap5kX8Q== X-Received: from suleiman1.tok.corp.google.com ([2401:fa00:8f:203:858a:76d0:aa73:eec8]) (user=suleiman job=sendgmr) by 2002:a25:b582:0:b0:e63:65c4:798a with SMTP id 3f1490d57ef6-e66a4fd11a3mr11205276.7.1742876038884; Mon, 24 Mar 2025 21:13:58 -0700 (PDT) Date: Tue, 25 Mar 2025 13:13:48 +0900 Message-Id: <20250325041350.1728373-1-suleiman@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.49.0.395.g12beb8f557-goog Subject: [PATCH v5 0/2] KVM: x86: Include host suspended time in steal time From: Suleiman Souhlal To: Paolo Bonzini , Sean Christopherson Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Chao Gao , David Woodhouse , Sergey Senozhatsky , Konrad Rzeszutek Wilk , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, ssouhlal@freebsd.org, Suleiman Souhlal This series makes it so that the time that the host is suspended is included in guests' steal time. When the host resumes from a suspend, the guest thinks any task that was running during the suspend ran for a long time, even though the effective run time was much shorter, which can end up having negative effects with scheduling. To mitigate this issue, we include the time that the host was suspended in steal time, which lets the guest can subtract the duration from the tasks' runtime. In addition, we make the guest TSC behavior consistent whether the host TSC went backwards or not. v5: - Fix grammar mistakes in commit message. v4: https://lore.kernel.org/kvm/20250221053927.486476-1-suleiman@google.com/T/ - Advance guest TSC on suspends where host TSC goes backwards. - Block vCPUs from running until resume notifier. - Move suspend duration accounting out of machine-independent kvm to x86. - Merge code and documentation patches. - Reworded documentation. v3: https://lore.kernel.org/kvm/Z5AB-6bLRNLle27G@google.com/T/ - Use PM notifier instead of syscore ops (kvm_suspend()/kvm_resume()), because the latter doesn't get called on shallow suspend. - Don't call function under UACCESS. - Whitespace. v2: https://lore.kernel.org/lkml/20241118043745.1857272-1-suleiman@google.com/ - Accumulate suspend time at machine-independent kvm layer and track per-VCPU instead of per-VM. - Document changes. v1: https://lore.kernel.org/kvm/20240710074410.770409-1-suleiman@google.com/ Suleiman Souhlal (2): KVM: x86: Advance guest TSC after deep suspend. KVM: x86: Include host suspended time in steal time Documentation/virt/kvm/x86/msr.rst | 10 +++- arch/x86/include/asm/kvm_host.h | 7 +++ arch/x86/kvm/x86.c | 84 +++++++++++++++++++++++++++++- 3 files changed, 98 insertions(+), 3 deletions(-)