From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0EA0A1B21B7 for ; Tue, 18 Feb 2025 11:26:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739878015; cv=none; b=pQyaCT4qs42O1GaQdodlvyd+LgJ63T3eZSttLsMWfQvc9Q+hy3vFkqHi9scSrVWu1Ih7xUocgGa6FWPd96fKQ8AXF2EfXx/MgK9Sp7++nDYk7rSlKyFRvcDVIAJsMcQO3OFIUNuSWzUzlAaTJ/p/P3uIKJnWrqnaHqcgUsXorxc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739878015; c=relaxed/simple; bh=uQDt+Z3pfHQePvvOYIO0mkuDBQmG2BMf3/5f4B/rQSU=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=c3WZB7dH/dM1kcWHxt1pq0ptImbj8MiyBWQ7yi5E7mF67wxedyn7d1BUVgGBxEexQmXiy/J8SMtKaZfqZYvK7Y0qCMZWrmf3RcI3LOw7mr0uopYAtpCAd6ejUJQ7WUXzHoiNOZW8QX4fwLwJge0we46g/JAnR7hauDreuyMoPiA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PD7y2iH2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="PD7y2iH2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1989AC4CEE7; Tue, 18 Feb 2025 11:26:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739878013; bh=uQDt+Z3pfHQePvvOYIO0mkuDBQmG2BMf3/5f4B/rQSU=; h=Subject:To:Cc:From:Date:From; b=PD7y2iH23jOUaqcoeoxfPwQ97Kull3nMH2XJJvuRZ/RcIJY9dveGy9L8iMh18pIAs GaiVgkgheGDBLx4/N/YKoKS1DVAFZGVlGhDAZKHaEY0P+wYO6jrVl6D1/vci/lzJDE ICJ3H+2mldzyQLI3DDffIR+uEilVxj/BgkHLhXho= Subject: FAILED: patch "[PATCH] KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC" failed to apply to 5.10-stable tree To: seanjc@google.com,vkuznets@redhat.com,zoudongjie@huawei.com Cc: From: Date: Tue, 18 Feb 2025 12:26:50 +0100 Message-ID: <2025021850-exes-cabana-e868@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x a8de7f100bb5989d9c3627d3a223ee1c863f3b69 # git commit -s git send-email --to '' --in-reply-to '2025021850-exes-cabana-e868@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From a8de7f100bb5989d9c3627d3a223ee1c863f3b69 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 17 Jan 2025 16:34:51 -0800 Subject: [PATCH] KVM: x86: Reject Hyper-V's SEND_IPI hypercalls if local APIC isn't in-kernel Advertise support for Hyper-V's SEND_IPI and SEND_IPI_EX hypercalls if and only if the local API is emulated/virtualized by KVM, and explicitly reject said hypercalls if the local APIC is emulated in userspace, i.e. don't rely on userspace to opt-in to KVM_CAP_HYPERV_ENFORCE_CPUID. Rejecting SEND_IPI and SEND_IPI_EX fixes a NULL-pointer dereference if Hyper-V enlightenments are exposed to the guest without an in-kernel local APIC: dump_stack+0xbe/0xfd __kasan_report.cold+0x34/0x84 kasan_report+0x3a/0x50 __apic_accept_irq+0x3a/0x5c0 kvm_hv_send_ipi.isra.0+0x34e/0x820 kvm_hv_hypercall+0x8d9/0x9d0 kvm_emulate_hypercall+0x506/0x7e0 __vmx_handle_exit+0x283/0xb60 vmx_handle_exit+0x1d/0xd0 vcpu_enter_guest+0x16b0/0x24c0 vcpu_run+0xc0/0x550 kvm_arch_vcpu_ioctl_run+0x170/0x6d0 kvm_vcpu_ioctl+0x413/0xb20 __se_sys_ioctl+0x111/0x160 do_syscal1_64+0x30/0x40 entry_SYSCALL_64_after_hwframe+0x67/0xd1 Note, checking the sending vCPU is sufficient, as the per-VM irqchip_mode can't be modified after vCPUs are created, i.e. if one vCPU has an in-kernel local APIC, then all vCPUs have an in-kernel local APIC. Reported-by: Dongjie Zou Fixes: 214ff83d4473 ("KVM: x86: hyperv: implement PV IPI send hypercalls") Fixes: 2bc39970e932 ("x86/kvm/hyper-v: Introduce KVM_GET_SUPPORTED_HV_CPUID") Cc: stable@vger.kernel.org Reviewed-by: Vitaly Kuznetsov Link: https://lore.kernel.org/r/20250118003454.2619573-2-seanjc@google.com Signed-off-by: Sean Christopherson diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 6a6dd5a84f22..6ebeb6cea6c0 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -2226,6 +2226,9 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) u32 vector; bool all_cpus; + if (!lapic_in_kernel(vcpu)) + return HV_STATUS_INVALID_HYPERCALL_INPUT; + if (hc->code == HVCALL_SEND_IPI) { if (!hc->fast) { if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi, @@ -2852,7 +2855,8 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid, ent->eax |= HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED; ent->eax |= HV_X64_APIC_ACCESS_RECOMMENDED; ent->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED; - ent->eax |= HV_X64_CLUSTER_IPI_RECOMMENDED; + if (!vcpu || lapic_in_kernel(vcpu)) + ent->eax |= HV_X64_CLUSTER_IPI_RECOMMENDED; ent->eax |= HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED; if (evmcs_ver) ent->eax |= HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;