From patchwork Thu Feb 27 02:18:41 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13993570 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 3459822C35C for ; Thu, 27 Feb 2025 02:19:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740622788; cv=none; b=CBybHZzqN5QUurMjOQBP2VZNCbkS2VFneQgXaG8NNMZNha+BFLHrPkw441mShqces+UqSpzPny9VN5HdopGYenlzaGuYa94Lar9mFLqx2cB2nErdi4BAoqT+7iec5PtGHNopKkvMe3Uj7Rwmf28gQLIe4/d5uwG/Fp2z1HALguM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740622788; c=relaxed/simple; bh=zjjnD8AWfMJS2/xbCkWD8FS8YCODvYXqFbARM/Ts+/s=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=PnQB6AdRplWUqMgMjwhQ34oyYDDYrKkZnCEJylOTo5tBOCgsNaMdDkSH0CpwTdthbvh9kMfdxyv4dIOV/3dV8Biw6KqeXXX9Y7m+naDb8Lk1ZSz9acBZmiwV7Bvu8rsIGWj/zHz4AXUq8xEcaByegdjytkr++7I1Qq2qT4mycmc= 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=LGdP3V47; arc=none smtp.client-ip=209.85.214.202 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="LGdP3V47" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-22107b29ac3so7797505ad.1 for ; Wed, 26 Feb 2025 18:19:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1740622786; x=1741227586; 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=3WIlT5dxc8eqreSuMAUxshuXGBEM8C/NLPwcD1zy3Y0=; b=LGdP3V47zvBfuYhkNIl11AV1RfpjpLs+4ZoASXY5qRpzH0BbueuSYw41Iptz3ijd3v gtic5rc9c0YEZMvGsRCQDIrMPaDUL6uHWG5KOUwXvJmOOM58H//frQlF7FnmwGuft8Or xaAz8D6Spnx/Hx5xUKEmQxvRMvI8fliZDw55LCSQoM7Kni64zuQkGKnAziTtiFGFhtn/ KvjEcTKJbxSuG8OwRnkKPlkFJgyV2pOU5B4vJSVbGRBy2R64Zek5I9LgxpP61GR4lU8C gVLzI6H3fBqw/0SYdFT+kjqujcFYkM1DN+IkAhUFv3/B+J2ud4G8Jf48/cEHpguSI2sF L1HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740622786; x=1741227586; 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=3WIlT5dxc8eqreSuMAUxshuXGBEM8C/NLPwcD1zy3Y0=; b=bonGZEtjusMbTgAElOlli4+3gUK18eVY1En+xIYHmTDqogiSMrn3EjMRIxtjwYVEbQ 9NtEOkmbiygZhXN0LFiM5RTrMTmoCOFVA/n5yXrRF8JSkKA3wX8F6w70OyVmezqygYJb 4cr1oKsqoQI7gWJg+mEkACKgaj/WGMVKD76LAieYJYgxrNNMXHGaLLSRbgkV+Xv9W9iN nENGks1z1up4KFlBTfg6MBxsQBBAGRrGyrqY38hyZGVLJSx9HeLlU8iCIPTwW+Uo9LGF 9bArr/rrrL3Uq5RcordkTlBBBPs1HKOenHojOlL2ZsWOcoP+obxp8NxjalpH3E4rBDj5 lEyQ== X-Forwarded-Encrypted: i=1; AJvYcCUT7INh7y1KCTY8tWUiaMuC+L6lg8vxkut86aK/0JQs5edT9sjkihwhrcm836z74UIaxdM=@vger.kernel.org X-Gm-Message-State: AOJu0Yx8HAc44b21XaYzrVR3+lWB6WoeopTdHcd3mZAeAwo9zEz2ALSk tFratt3+XK7bWzZL+y1czuvswF5AOW0CkxUQeJ1rIC1UcNrMZnuiY6B8HAsElMD15SysitpLKKs yhw== X-Google-Smtp-Source: AGHT+IEKa+U3XmhHVLGnMc9mY3OxJMjJ1pR3+E2erpOOt4xnyyZwND9G3ZoTVgYNZ7eny0ZZLwJ5fe0HKa8= X-Received: from pjvf4.prod.google.com ([2002:a17:90a:da84:b0:2ea:3a1b:f493]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:e80e:b0:21f:3d0d:2408 with SMTP id d9443c01a7336-2234a28af91mr27386885ad.10.1740622786458; Wed, 26 Feb 2025 18:19:46 -0800 (PST) Reply-To: Sean Christopherson Date: Wed, 26 Feb 2025 18:18:41 -0800 In-Reply-To: <20250227021855.3257188-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250227021855.3257188-1-seanjc@google.com> X-Mailer: git-send-email 2.48.1.711.g2feabab25a-goog Message-ID: <20250227021855.3257188-26-seanjc@google.com> Subject: [PATCH v2 25/38] x86/kvmclock: Hook clocksource.suspend/resume when kvmclock isn't sched_clock From: Sean Christopherson To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "Kirill A. Shutemov" , Paolo Bonzini , Sean Christopherson , Juergen Gross , "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Ajay Kaher , Jan Kiszka , Andy Lutomirski , Peter Zijlstra , Daniel Lezcano , John Stultz Cc: linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev, kvm@vger.kernel.org, virtualization@lists.linux.dev, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, Tom Lendacky , Nikunj A Dadhania Save/restore kvmclock across suspend/resume via clocksource hooks when kvmclock isn't being used for sched_clock. This will allow using kvmclock as a clocksource (or for wallclock!) without also using it for sched_clock. Signed-off-by: Sean Christopherson --- arch/x86/kernel/kvmclock.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 0580fe1aefa0..319f8b2d0702 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -130,7 +130,17 @@ static void kvm_setup_secondary_clock(void) static void kvm_restore_sched_clock_state(void) { - kvm_register_clock("primary cpu clock, resume"); + kvm_register_clock("primary cpu, sched_clock resume"); +} + +static void kvmclock_suspend(struct clocksource *cs) +{ + kvmclock_disable(); +} + +static void kvmclock_resume(struct clocksource *cs) +{ + kvm_register_clock("primary cpu, clocksource resume"); } void kvmclock_cpu_action(enum kvm_guest_cpu_action action) @@ -201,6 +211,8 @@ static struct clocksource kvm_clock = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, .id = CSID_X86_KVM_CLK, .enable = kvm_cs_enable, + .suspend = kvmclock_suspend, + .resume = kvmclock_resume, }; static void __init kvmclock_init_mem(void) @@ -295,6 +307,15 @@ static void __init kvm_sched_clock_init(bool stable) __paravirt_set_sched_clock(kvm_sched_clock_read, stable, kvm_save_sched_clock_state, kvm_restore_sched_clock_state); + /* + * The BSP's clock is managed via dedicated sched_clock save/restore + * hooks when kvmclock is used as sched_clock, as sched_clock needs to + * be kept alive until the very end of suspend entry, and restored as + * quickly as possible after resume. + */ + kvm_clock.suspend = NULL; + kvm_clock.resume = NULL; + pr_info("kvm-clock: using sched offset of %llu cycles", kvm_sched_clock_offset);