From patchwork Fri May 17 17:38:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13667232 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 C0E7B1422D5 for ; Fri, 17 May 2024 17:40:05 +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=1715967607; cv=none; b=k7eZEo27SGbbENdo0N89uTpZJbAxgUIExkftNJAIUN+634uSzFbu8zIAJkKDrJQnro4noQTpnhKjxneU+1zSHUtxUDRES3REDs6wz/FMqhKS9JNPREIJLdrySLpBdc+WNqm0sPUI4wQV2SiBEUAnisdbchYHvc6fMiw5zKSqqUQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715967607; c=relaxed/simple; bh=zzIqDBRAgEIRt3fg5FrSfGxYl1fjerG/V7tHwfIOdIE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=NWVMXAWTv6bfd3+7zaCIK+uuoAtmZtO+pyaVNpI5533i1iRpdt89Wu1+/O0jhK2+7sD3lVhytetbonzNSVbJdAcnUfWQK3SsCRJuNjcFQKcnXQVbXAYnEGSqf/UWuF6eGBCPXs807tq8H1ArLtsUlncE8QwMUaC3XVPAWRG+eLg= 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=ddiUDC9P; 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="ddiUDC9P" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-5e4df21f22dso7570995a12.0 for ; Fri, 17 May 2024 10:40:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1715967605; x=1716572405; 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=/QhdGtxhJBxvqCSUNKLB6DvJjtt7mVPP3auKAb2NG/M=; b=ddiUDC9PuTC84wjc1Fi4CgPrVe29wdneoAG0CLbUjR1SQc7ufVFlm2QSIfBwWBXtQx SF++3fzsjJxZwJFtyNNPtIItaXvkL4NgXiPdOkymfY7jtLHBXTmeKuSN6xQ2vcYFXzGW shYU9jG4GRHOz/qaO8UK+eIuTsGs2Ru1rKV75A9EalLInml4mQWmIDQyD43+rmCfwkkC +JjUy9+daIOm3qnRg4f9ABYaoLuZMpxXfWIg+/pd3yzlsc+obpunYjwn71jxOdMafPV4 zQMwyi+hYQZwVEHVx738VTf7y5ZjyLwVInbXogIjHiGT9jBOUrTkct5v1TDASp8622y9 Vm7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715967605; x=1716572405; 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=/QhdGtxhJBxvqCSUNKLB6DvJjtt7mVPP3auKAb2NG/M=; b=v38qTvuaAKXl3WmzYD53Mh2GN0VQy4oWyZeW6A3vB1o9aH3S0C59KFm6sTu4MX2ECw zdrxGq3C8JKrMPNCNzc6rO5JmcuehICX8MqO6y7S4LDA8iCtMt7+ZPnzJ/kYAfkvIYfz CLRhLIsd0C6DxWZibutk2Jvvys+ndeWqRzD/gCHM/4uZpeqecMCRC1mTE1PMfIvhjG7y e+3rd3gTCE3VzFOhHLsCBWqNCgCE+8JS6GS4Sp3wPDQYVocdOn8HGdNbWKDxXTwuWLiK 4hSIc0CvrNbZpGBgxZg8oBRdB5xtAlpsjv/Cqy+x5J3SghtNbHp75+PJS7QoC9G6zUpW Lm3w== X-Gm-Message-State: AOJu0YxX3TW77df03CHGDmqNmIhoqxA4ezweFZOVlCJzmda05jzh3mF5 glpliUhGNYwD7/z+eo3oHuJCyQdUsDgFXZ3HicAvbJTi6j/fUR7CsXhTDIyZy9sUx7hA0iAU2V3 0Hw== X-Google-Smtp-Source: AGHT+IGXqcyVYyfsrhvREnbdq6WGI4rUGu/X6D5dsKbIh4G7tVICZ2/7A3biOpPmKuH5H/rOeO18jjJySrY= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6a02:69a:b0:5f4:246c:1406 with SMTP id 41be03b00d2f7-6331ae42ab2mr99526a12.3.1715967604889; Fri, 17 May 2024 10:40:04 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 17 May 2024 10:38:48 -0700 In-Reply-To: <20240517173926.965351-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240517173926.965351-1-seanjc@google.com> X-Mailer: git-send-email 2.45.0.215.g3402c0e53f-goog Message-ID: <20240517173926.965351-12-seanjc@google.com> Subject: [PATCH v2 11/49] KVM: x86: Disallow KVM_CAP_X86_DISABLE_EXITS after vCPU creation From: Sean Christopherson To: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Hou Wenlong , Kechen Lu , Oliver Upton , Maxim Levitsky , Binbin Wu , Yang Weijiang , Robert Hoo Reject KVM_CAP_X86_DISABLE_EXITS if vCPUs have been created, as disabling PAUSE/MWAIT/HLT exits after vCPUs have been created is broken and useless, e.g. except for PAUSE on SVM, the relevant intercepts aren't updated after vCPU creation. vCPUs may also end up with an inconsistent configuration if exits are disabled between creation of multiple vCPUs. Cc: Hou Wenlong Link: https://lore.kernel.org/all/9227068821b275ac547eb2ede09ec65d2281fe07.1680179693.git.houwenlong.hwl@antgroup.com Link: https://lore.kernel.org/all/20230121020738.2973-2-kechenl@nvidia.com Signed-off-by: Sean Christopherson Reviewed-by: Maxim Levitsky Reviewed-by: Xiaoyao Li --- Documentation/virt/kvm/api.rst | 1 + arch/x86/kvm/x86.c | 6 ++++++ 2 files changed, 7 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 6ab8b5b7c64e..884846282d06 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7645,6 +7645,7 @@ branch to guests' 0x200 interrupt vector. :Architectures: x86 :Parameters: args[0] defines which exits are disabled :Returns: 0 on success, -EINVAL when args[0] contains invalid exits + or if any vCPUs have already been created Valid bits in args[0] are:: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index bb34891d2f0a..4cb0c150a2f8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6568,6 +6568,10 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->args[0] & ~KVM_X86_DISABLE_VALID_EXITS) break; + mutex_lock(&kvm->lock); + if (kvm->created_vcpus) + goto disable_exits_unlock; + if (cap->args[0] & KVM_X86_DISABLE_EXITS_PAUSE) kvm->arch.pause_in_guest = true; @@ -6589,6 +6593,8 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, } r = 0; +disable_exits_unlock: + mutex_unlock(&kvm->lock); break; case KVM_CAP_MSR_PLATFORM_INFO: kvm->arch.guest_can_read_msr_platform_info = cap->args[0];