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 1C14B17A2E8; Mon, 10 Mar 2025 18:01:56 +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=1741629716; cv=none; b=Gx0PhQoaUsV1nNVDDcoQ9AbjCOxOlfgLnj6KMKXciBlGroYQUjAVfEs37lpjNAIYS/ChdUUYHiRlRalNcFKpRf17br6UJHmaWLuZ5kjYMqpGmEpNZ6VMbTe94EJFgJCAZYF7WOT0YTzaOrr9/oDA+AMnc+sQvl9TThPM93tG2FU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741629716; c=relaxed/simple; bh=iM0ipvsANEnWlHKBVXtJXIqlOJi4iY0J89ja62chnzs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=M2B7VW658VpVi2gh2I0oLSiOKvCPtvXnIfK7a+bePyXLj9SXN9p7t8xfF+Cu+sputnVRhFPHYYXXiF+fXei1sJefKzUNVr0BUVD4jdNcwmAHjScrde5ixlVktInU0r6tMy7UoKjuoGBB3hIeWEBXx6/0oKImEnVfONBuw1I7mgU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NbqtzZMq; 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="NbqtzZMq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97DEAC4CEE5; Mon, 10 Mar 2025 18:01:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741629716; bh=iM0ipvsANEnWlHKBVXtJXIqlOJi4iY0J89ja62chnzs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NbqtzZMq9udYPDrEuTEhFm92E5SVyqsOpalanhAtRuc5ZErERLKQniSltHXW9NaXu IJnwgQiiR5LZtDSgnYLmoVPCSwxbh6QHwxdMFsQ9IHpSZgNMGP9uAcB8UCRYnqeT7D KMrWKOlUQzSyFH3wTNpJMU0FbdhSw92EaZE7LuEE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dongjie Zou , Vitaly Kuznetsov , Sean Christopherson Subject: [PATCH 5.15 358/620] KVM: x86: Reject Hyper-Vs SEND_IPI hypercalls if local APIC isnt in-kernel Date: Mon, 10 Mar 2025 18:03:24 +0100 Message-ID: <20250310170559.740101103@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310170545.553361750@linuxfoundation.org> References: <20250310170545.553361750@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson commit a8de7f100bb5989d9c3627d3a223ee1c863f3b69 upstream. 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/hyperv.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1902,6 +1902,9 @@ static u64 kvm_hv_send_ipi(struct kvm_vc bool all_cpus; int i; + 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, @@ -2507,7 +2510,8 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vc 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;