From patchwork Tue Mar 4 06:06:43 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 13999952 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8BB251F416B for ; Tue, 4 Mar 2025 06:06:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741068419; cv=none; b=D/6w7//HKAhtYDw7pI1xnxVZN49e6QIsWrUg7yXTfJ1er2xAvzZKTgjCoY3SN/xuGDABUff9787gA6NhGjPHg8aRSGFynIHeSuC5ACstnaZfIsvzHuefi8A9wj2/9jPZ4JI3pMEjXT+TYTxNv1JTutUhsCpJKxDkxdnMsk6QuXo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741068419; c=relaxed/simple; bh=zvgqYsvXfHBAbcwouYdhkWdgIpLZPjfAPKvtaSIXKwM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ngjCNVamXWibiRNE1FSDVDYVzsrU26V/6Y3HjMsh0v2IDq4sJQ8Dt1igI+xOsC9wVa8PzYvteQvLeRWP8tyc8tJHQsawx2f+X7ECKVc3b2q2/htA0gkojHBo6+/4SU9zQzmRQdOnhTUP1U2ubIJ4wJjxoAbJJfsBaHQRzs7/WK8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=AGp97W5P; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="AGp97W5P" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741068416; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=meP3mPi7wbZh3Prgz68X3gfGckV8RM5QhsxHPX6Pr9A=; b=AGp97W5PtYdCfzT3ZctTR68JWWTsqAQFw/hNgyYtLiX1cPcm/aTNjiSF0606NLKxiVTesW i1H1A8AOzuBbSxuhxJSlmy76E2cyVBs0W5HWsvou+d5vF7/2VZZXRQRdKbOTBbE++LF7Jn MIrm0HlbzGObE6+IKi7T0pOTaWTSIXs= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-216-kBPcdYSTOk2T7jMM02yEqQ-1; Tue, 04 Mar 2025 01:06:52 -0500 X-MC-Unique: kBPcdYSTOk2T7jMM02yEqQ-1 X-Mimecast-MFC-AGG-ID: kBPcdYSTOk2T7jMM02yEqQ_1741068411 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 661291918165; Tue, 4 Mar 2025 06:06:51 +0000 (UTC) Received: from virtlab1023.lab.eng.rdu2.redhat.com (virtlab1023.lab.eng.rdu2.redhat.com [10.8.1.187]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8633F19560A3; Tue, 4 Mar 2025 06:06:50 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: xiaoyao.li@intel.com, seanjc@google.com, yan.y.zhao@intel.com Subject: [PATCH v3 2/6] KVM: x86: Allow vendor code to disable quirks Date: Tue, 4 Mar 2025 01:06:43 -0500 Message-ID: <20250304060647.2903469-3-pbonzini@redhat.com> In-Reply-To: <20250304060647.2903469-1-pbonzini@redhat.com> References: <20250304060647.2903469-1-pbonzini@redhat.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 In some cases, the handling of quirks is split between platform-specific code and generic code, or it is done entirely in generic code, but the relevant bug does not trigger on some platforms; for example, this will be the case for "ignore guest PAT". Allow unaffected vendor modules to disable handling of a quirk for all VMs via a new entry in kvm_caps. Such quirks remain available in KVM_CAP_DISABLE_QUIRKS2, because that API tells userspace that KVM *knows* that some of its past behavior was bogus or just undesirable. In other words, it's plausible for userspace to refuse to run if a quirk is not listed by KVM_CAP_DISABLE_QUIRKS2, so preserve that and make it part of the API. As an example, mark KVM_X86_QUIRK_CD_NW_CLEARED as auto-disabled on Intel systems. Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/svm/svm.c | 1 + arch/x86/kvm/x86.c | 2 ++ arch/x86/kvm/x86.h | 1 + 4 files changed, 7 insertions(+) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 7ebbedc566ff..a4f213d235dd 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2420,6 +2420,9 @@ int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages); KVM_X86_QUIRK_SLOT_ZAP_ALL | \ KVM_X86_QUIRK_STUFF_FEATURE_MSRS) +#define KVM_X86_CONDITIONAL_QUIRKS \ + KVM_X86_QUIRK_CD_NW_CLEARED + /* * KVM previously used a u32 field in kvm_run to indicate the hypercall was * initiated from long mode. KVM now sets bit 0 to indicate long mode, but the diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ebaa5a41db07..51cfef44b58d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -5426,6 +5426,7 @@ static __init int svm_hardware_setup(void) */ allow_smaller_maxphyaddr = !npt_enabled; + kvm_caps.inapplicable_quirks &= ~KVM_X86_QUIRK_CD_NW_CLEARED; return 0; err: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 35d03fcdb8e9..5abea6c73a38 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9775,6 +9775,7 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops) kvm_host.xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK); kvm_caps.supported_xcr0 = kvm_host.xcr0 & KVM_SUPPORTED_XCR0; } + kvm_caps.inapplicable_quirks = KVM_X86_CONDITIONAL_QUIRKS; rdmsrl_safe(MSR_EFER, &kvm_host.efer); @@ -12754,6 +12755,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) kvm->arch.apic_bus_cycle_ns = APIC_BUS_CYCLE_NS_DEFAULT; kvm->arch.guest_can_read_msr_platform_info = true; kvm->arch.enable_pmu = enable_pmu; + kvm->arch.disabled_quirks = kvm_caps.inapplicable_quirks; #if IS_ENABLED(CONFIG_HYPERV) spin_lock_init(&kvm->arch.hv_root_tdp_lock); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 8ce6da98b5a2..221778792c3c 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -34,6 +34,7 @@ struct kvm_caps { u64 supported_xcr0; u64 supported_xss; u64 supported_perf_cap; + u64 inapplicable_quirks; }; struct kvm_host_values {