From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (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 7888D28CF77 for ; Mon, 25 Aug 2025 20:06:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756152392; cv=none; b=QO1N2bGedynNBMcHkGbbjLwR3OfafohWbnvV/bK/wuIefhUthghHFMFDV6WCj6J9Yj3n1Uc86OnE8SiEZojHiBej5FVqjjRnazJChFLStgVGLU6npkVAEFt5Ydc+YV5vj56nX/7kemFXaNk4IHjlNv5DtzrbszUe0wnLZP/Ph10= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756152392; c=relaxed/simple; bh=CPxGdk0WNt19VUixP2aZz/PEan9gfYpnqsgV+WcH6LI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=nqu8nTsVAwpMv7tEE0qTdIpMtHU6ChY5utz1LIK110FXL64x0Elu5vBb/Yuu20YP3CCCCspeQq1XgJEUmD/8EQpPtYvrN72+JzenhREwxVyVBbzHNWwm+tyd86afHZqUmcM/b3euIX5frmYfJPR+WQToiSL0BuM03TRQ15Buybo= 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=NWmdMSd3; arc=none smtp.client-ip=209.85.215.201 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="NWmdMSd3" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-b4c20148c54so782375a12.2 for ; Mon, 25 Aug 2025 13:06:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1756152389; x=1756757189; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=+oyHFbNT6msf6glrd5KFIdZcOF0+oR5scj5fBrCtJpc=; b=NWmdMSd3Lh10JlmT2fWKv02KZDQWiuEQKdysC/tiz9kaKQ/k4A39kYJnNa2BNLKkM/ VpttUz9ySpgSnao3Bktbskfo+UjH3o+87N8A/tCWclenpElnhwJ/rxC11zWTM/WC5Kl9 VOV/tc2lcMAeDu6jkkFHcmHv0rMmCDlJWgYNPzcKRCMVn+7ywyg7QLfRgjWtmziNPaC9 dq4rkucXgreYX/IiVgJWe048tjvvkJ88x/lrY5JKODFhuLDnU9iFSEtyruFaSdYb6pmx +SdTY5qfATYC9PJyU/uHK9omJ4W368olV7Ml76H2TxsU1+w/cBza7VntthPaigx740Ya 39Hw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756152389; x=1756757189; h=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; bh=+oyHFbNT6msf6glrd5KFIdZcOF0+oR5scj5fBrCtJpc=; b=ny04D5Lyj+W/BJKuf0XnB87v7zy8EfxWQekqqFn/zFajUAKeJq9tDiTvu0Iwckt+7a ky+3H40dnmyrLCbIh0R0HpP7omfx5rBM3txjUnjcoZ9GVmTkDyHHREJOkPYyvBu5GK/2 y85PHEYZBMw1zAu/LxlnZJoK7aITrib76450EaIJP7Ith9Pzrm1sZvFVhUHiYmaFS9O8 sDr3poHrQrLfODZrk1s6Z0StjiW/l9/UCDzHu+fQRwbspgTa9tcAgo++H3FemLJ9qOjP RKXuDEx4bRWlpPm0HGPXhYpmZIuAkuGKZsZWJ0L4aU9eCUUB6BpYlYWrwwll8ZLKAMf9 AKrw== X-Forwarded-Encrypted: i=1; AJvYcCVw+MEExWCVPWb1i13WQwt9AvAhOAHSKubi1Bsqjq6BxVpR4KWbtVnqdRefYruOTqWw25sNieKF6yY9tJw=@vger.kernel.org X-Gm-Message-State: AOJu0Yxem4WUdSkTLY5klzkC0RCLw2KXgP1lBiRdNNnDHAM8JRazshSq VGZfdZS0xUfydx00Nke0jADTkUfMjySHfUrG6A/oauvgjpQT2tVidtmfCTgbjWVzj5g4/uuni/p +vmJ6Sw== X-Google-Smtp-Source: AGHT+IHf2Zj5lnIbPMIr1AZKuHUHSE22v55RmD47MKsgM79RfmKmA7vJz/pJwEChfBNBSyo/bobLCf+GttQ= X-Received: from pjbpq16.prod.google.com ([2002:a17:90b:3d90:b0:325:7fbe:1c64]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:6a0f:b0:243:78a:8289 with SMTP id adf61e73a8af0-24340def606mr21242988637.48.1756152389107; Mon, 25 Aug 2025 13:06:29 -0700 (PDT) Reply-To: Sean Christopherson Date: Mon, 25 Aug 2025 13:06:19 -0700 In-Reply-To: <20250825200622.3759571-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-hyperv@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250825200622.3759571-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.261.g7ce5a0a67e-goog Message-ID: <20250825200622.3759571-3-seanjc@google.com> Subject: [PATCH 2/5] Drivers: hv: Handle NEED_RESCHED_LAZY before transferring to guest From: Sean Christopherson To: Marc Zyngier , Oliver Upton , Catalin Marinas , Will Deacon , Tianrui Zhao , Bibo Mao , Huacai Chen , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Peter Zijlstra , Andy Lutomirski , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-hyperv@vger.kernel.org, rcu@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Check for NEED_RESCHED_LAZY, not just NEED_RESCHED, prior to transferring control to a guest. Failure to check for lazy resched can unnecessarily delay rescheduling until the next tick when using a lazy preemption model. Fixes: 621191d709b1 ("Drivers: hv: Introduce mshv_root module to expose /dev/mshv to VMMs") Signed-off-by: Sean Christopherson --- drivers/hv/mshv_common.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/hv/mshv_common.c b/drivers/hv/mshv_common.c index 1acc47c4be0d..b953b5e21110 100644 --- a/drivers/hv/mshv_common.c +++ b/drivers/hv/mshv_common.c @@ -151,7 +151,7 @@ static int __mshv_do_pre_guest_mode_work(ulong th_flags) if (th_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) return -EINTR; - if (th_flags & _TIF_NEED_RESCHED) + if (th_flags & (_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)) schedule(); if (th_flags & _TIF_NOTIFY_RESUME) @@ -163,7 +163,8 @@ static int __mshv_do_pre_guest_mode_work(ulong th_flags) int mshv_do_pre_guest_mode_work(void) { const ulong work_flags = _TIF_NOTIFY_SIGNAL | _TIF_SIGPENDING | - _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME; + _TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY | + _TIF_NOTIFY_RESUME; ulong th_flags; th_flags = read_thread_flags(); -- 2.51.0.261.g7ce5a0a67e-goog