From nobody Thu Feb 12 20:30:28 2026 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 298F517C8 for ; Sat, 8 Jun 2024 00:06:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717805213; cv=none; b=JAe+SQDpN6IPX/nyYUXPClh4IoEpz9/uq9FZ38dpz87+cuLYFmSU9CIoYzO3TqBxslLsc+cKk6boZjPs5yUK3PQM8KdQUbAtOONb7EFZwFntAxFMrzH1460AiEcz4GaJCTQtA3FYeAogkz2hfGQnnL9DHUj4ef60RGRdDwvQWTc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717805213; c=relaxed/simple; bh=CQMK/h9eb5oR6ViVQX4U3uFGNRM5CkCgrRNqS7xc64k=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=N9mCKw+92JWwS95g8z9pO5rOxrTZm7mVXbZjaB31rkrsvH2PSt4qHc9Vx4VK37/ISr8RebDvzu+IIASCUyxPhvZgEbCz7anxtrVDBFgfQwXzByNGbmGk1ZEtxAvstwD8dnr5Bt96js4Q7quuxQ6yEPB2iyKgxw+FqYA14Uvjz6I= 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=TKnyr3DM; arc=none smtp.client-ip=209.85.215.202 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="TKnyr3DM" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-6e4381588c8so1169334a12.2 for ; Fri, 07 Jun 2024 17:06:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1717805211; x=1718410011; 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=hcN62n3eAvJ+wQBQZ24js4P4o2/e149QwTHEtQT2vY4=; b=TKnyr3DMIrUaxY21uPkzmiRNOlkXMfQzAPvk5ka/SWee2REQNZVmqzEaAaFdgROC2e 8bGZKv4B7ASktF2st8uxd5O+ydEKaOpDh1+cz0fLIrFb8KcMQWcKPXBSVxgrCfiT/H3x gz5eAdKZ2JC4zXlNAQgA4/yeoOZASvgVH38DI4sXR6cDEQjq+hoXBtpG9IKbdN3eJNRF cZkigvl9OpzVSS9WGpks1CpmLirVEMS46+ollyYr9E2X9HdJfjB26U3ruw934vMhHeuQ 7dqYJJ98spkuTBoElXfKnCk8aeR9AMuolGHo63TA/HOaYZ/GEBxV/WkPVoyQ3RW1zg/k sSvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1717805211; x=1718410011; 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=hcN62n3eAvJ+wQBQZ24js4P4o2/e149QwTHEtQT2vY4=; b=IqqB2PZlKn/1wTNa5i93Mgm6xOj2L4FD5EY+lIbxm+Ltevrd0FqczqJGbOMocCHnWR GRGw87dlzzEhYronaOBCcvdiiCctGF3xV+Mg/IdZMgs6uwaQQgFdmeyKL5hlKHnU9wzQ HbxgHtE57ZfVbmzvdusu8wfhSRCbFeSHa4lxI6V94UBi4JA3lOo2rJdSOXRYS2FQfuJo PUOJ9xa68o9YO1LIbHU8gnHCjslO68MImwWY7bx/e03H7xvv/vE+gT6ym1fLdpbwdnos 2uO59kFIcUoQSnMV18DTHQkdgd66PEFiO0LEPx4eEtPLix3TSvaLAseZENFxsBstPNJE vIVg== X-Forwarded-Encrypted: i=1; AJvYcCW8QZD0HLMv7Uc95SQKbJYJIUzNnN59JJjo5GaptYOOLShJw1d649Gvjw8vHRQzzXXJ2ZRwewKSMmMaHcnaMKIMwRzoun2apcXmsEOb X-Gm-Message-State: AOJu0Yx3DcIC8FFjGc7ShJso5SWVSdbMwAM9HkOwVk6MmW7k2pq0f97K yX344GxrflcO9DA2Y/burK3ismCel5D+1P3aLdOLF4LFXLgQPJ8MrTJkq6XxPAyXwLfuFq0Uzfr ZBA== X-Google-Smtp-Source: AGHT+IGqgoQIgsdgjc/QsCSr0LlLIFd2eln/NUclIt/hIDKFvlhwEYksb1GJZEUAX2hQBnqbPh5Y3juuvUA= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a63:4e03:0:b0:659:23db:a4b2 with SMTP id 41be03b00d2f7-6e15eaaf307mr8542a12.8.1717805211114; Fri, 07 Jun 2024 17:06:51 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 7 Jun 2024 17:06:36 -0700 In-Reply-To: <20240608000639.3295768-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240608000639.3295768-1-seanjc@google.com> X-Mailer: git-send-email 2.45.2.505.gda0bf45e8d-goog Message-ID: <20240608000639.3295768-6-seanjc@google.com> Subject: [PATCH v3 5/8] KVM: Add arch hooks for enabling/disabling virtualization From: Sean Christopherson To: Paolo Bonzini , Sean Christopherson Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Gao , Kai Huang Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add arch hooks that are invoked when KVM enables/disable virtualization. x86 will use the hooks to register an "emergency disable" callback, which is essentially an x86-specific shutdown notifier that is used when the kernel is doing an emergency reboot/shutdown/kexec. Add comments for the declarations to help arch code understand exactly when the callbacks are invoked. Alternatively, the APIs themselves could communicate most of the same info, but kvm_arch_pre_enable_virtualization() and kvm_arch_post_disable_virtualization() are a bit cumbersome, and make it a bit less obvious that they are intended to be implemented as a pair. Reviewed-by: Chao Gao Reviewed-by: Kai Huang Signed-off-by: Sean Christopherson --- include/linux/kvm_host.h | 14 ++++++++++++++ virt/kvm/kvm_main.c | 14 ++++++++++++++ 2 files changed, 28 insertions(+) diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 96ad3e8b9ddb..12ef3beb4e47 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1514,6 +1514,20 @@ static inline void kvm_create_vcpu_debugfs(struct kv= m_vcpu *vcpu) {} #endif =20 #ifdef CONFIG_KVM_GENERIC_HARDWARE_ENABLING +/* + * kvm_arch_{enable,disable}_virtualization() are called on one CPU, under + * kvm_usage_lock, immediately after/before 0=3D>1 and 1=3D>0 transitions = of + * kvm_usage_count, i.e. at the beginning of the generic hardware enabling + * sequence, and at the end of the generic hardware disabling sequence. + */ +void kvm_arch_enable_virtualization(void); +void kvm_arch_disable_virtualization(void); +/* + * kvm_arch_hardware_{enable,disable}() are called on "every" CPU to do the + * actual twiddling of hardware bits. The hooks are called all online CPUs + * when KVM enables/disabled virtualization. Enabling/disabling is also d= one + * when a CPU is onlined/offlined (or Resumed/Suspended). + */ int kvm_arch_hardware_enable(void); void kvm_arch_hardware_disable(void); #endif diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 7bdd744e4821..e20189a89a64 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -5505,6 +5505,16 @@ static DEFINE_PER_CPU(bool, hardware_enabled); static DEFINE_MUTEX(kvm_usage_lock); static int kvm_usage_count; =20 +__weak void kvm_arch_enable_virtualization(void) +{ + +} + +__weak void kvm_arch_disable_virtualization(void) +{ + +} + static int __kvm_enable_virtualization(void) { if (__this_cpu_read(hardware_enabled)) @@ -5604,6 +5614,8 @@ static int kvm_enable_virtualization(void) if (kvm_usage_count++) return 0; =20 + kvm_arch_enable_virtualization(); + r =3D cpuhp_setup_state(CPUHP_AP_KVM_ONLINE, "kvm/cpu:online", kvm_online_cpu, kvm_offline_cpu); if (r) @@ -5634,6 +5646,7 @@ static int kvm_enable_virtualization(void) unregister_syscore_ops(&kvm_syscore_ops); cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); err_cpuhp: + kvm_arch_disable_virtualization(); --kvm_usage_count; return r; } @@ -5647,6 +5660,7 @@ static void kvm_disable_virtualization(void) =20 unregister_syscore_ops(&kvm_syscore_ops); cpuhp_remove_state(CPUHP_AP_KVM_ONLINE); + kvm_arch_disable_virtualization(); } =20 static int kvm_init_virtualization(void) --=20 2.45.2.505.gda0bf45e8d-goog