From patchwork Sat Jan 28 08:10:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: David Woodhouse X-Patchwork-Id: 1733255 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b=GXo1BPvD; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4P3nTM6sQWz23hm for ; Sat, 28 Jan 2023 19:21:11 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pLgKI-0007HK-E2; Sat, 28 Jan 2023 03:12:43 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pLgJU-0005vG-77 for qemu-devel@nongnu.org; Sat, 28 Jan 2023 03:11:53 -0500 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pLgJL-0007qr-L3 for qemu-devel@nongnu.org; Sat, 28 Jan 2023 03:11:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Reply-To:Content-ID:Content-Description; bh=DINLcqzDpjJ+jYPK0UPqB5o+PryVmxGz5q2ImNu0Gck=; b=GXo1BPvDmm/3Sp0cPPna6Toviv 0a0SWLtxQinF3u69e1g7pgLF5uLVl79+b6QMyXGjFMx33+Lv9PBwgH0OxGK5wbJdpsxACtFr0LLx3 OGF/QqlyD9dNd9Oq1LJ5P0E5VuiVPKmR7rYJYUDv6zH0RP2HMnn305CCnX+X10Ew7PRws3JGDx3Uj aV9ADSMFyEWS0bc34As0ul3hz2QKmPqhpqCKL5o+BNKKPBbjNFgGWx2gTwe5wVh6GLSfgp8zk2N0N X/AlDebwWw9ZMvyGzWp+t1gOamU60VPAmewbotPKNxEp3YqVpbXn2P4PY0ev1gehn+ZOHxjDCkwpB fmvh2pcQ==; Received: from i7.infradead.org ([2001:8b0:10b:1:21e:67ff:fecb:7a92]) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1pLgIS-0039wV-2M; Sat, 28 Jan 2023 08:10:54 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1pLgIy-006mKT-0F; Sat, 28 Jan 2023 08:11:20 +0000 From: David Woodhouse To: Peter Maydell , qemu-devel@nongnu.org Cc: Paolo Bonzini , Paul Durrant , Joao Martins , Ankur Arora , =?utf-8?q?Philippe_Mathieu-Daud?= =?utf-8?q?=C3=A9?= , Thomas Huth , =?utf-8?q?Alex_Benn=C3=A9e?= , Juan Quintela , "Dr . David Alan Gilbert" , Claudio Fontana , Julien Grall , "Michael S. Tsirkin" , Marcel Apfelbaum , armbru@redhat.com Subject: [PATCH v9 40/58] hw/xen: Support HVM_PARAM_CALLBACK_TYPE_PCI_INTX callback Date: Sat, 28 Jan 2023 08:10:55 +0000 Message-Id: <20230128081113.1615111-41-dwmw2@infradead.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230128081113.1615111-1-dwmw2@infradead.org> References: <20230128081113.1615111-1-dwmw2@infradead.org> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by desiato.infradead.org. See http://www.infradead.org/rpr.html Received-SPF: none client-ip=2001:8b0:10b:1:d65d:64ff:fe57:4e05; envelope-from=BATV+e8fc867402dd322853dc+7097+infradead.org+dwmw2@desiato.srs.infradead.org; helo=desiato.infradead.org X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: David Woodhouse The guest is permitted to specify an arbitrary domain/bus/device/function and INTX pin from which the callback IRQ shall appear to have come. In QEMU we can only easily do this for devices that actually exist, and even that requires us "knowing" that it's a PCMachine in order to find the PCI root bus — although that's OK really because it's always true. We also don't get to get notified of INTX routing changes, because we can't do that as a passive observer; if we try to register a notifier it will overwrite any existing notifier callback on the device. But in practice, guests using PCI_INTX will only ever use pin A on the Xen platform device, and won't swizzle the INTX routing after they set it up. So this is just fine. Signed-off-by: David Woodhouse --- hw/i386/kvm/xen_evtchn.c | 80 ++++++++++++++++++++++++++++++++------- target/i386/kvm/xen-emu.c | 34 +++++++++++++++++ 2 files changed, 100 insertions(+), 14 deletions(-) diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c index 758ba54f69..301a28264f 100644 --- a/hw/i386/kvm/xen_evtchn.c +++ b/hw/i386/kvm/xen_evtchn.c @@ -27,6 +27,8 @@ #include "hw/sysbus.h" #include "hw/xen/xen.h" #include "hw/i386/x86.h" +#include "hw/i386/pc.h" +#include "hw/pci/pci.h" #include "hw/irq.h" #include "xen_evtchn.h" @@ -100,6 +102,7 @@ struct XenEvtchnState { uint64_t callback_param; bool evtchn_in_kernel; + uint32_t callback_gsi; QEMUBH *gsi_bh; @@ -216,11 +219,41 @@ static void xen_evtchn_register_types(void) type_init(xen_evtchn_register_types) +static int set_callback_pci_intx(XenEvtchnState *s, uint64_t param) +{ + PCMachineState *pcms = PC_MACHINE(qdev_get_machine()); + uint8_t pin = param & 3; + uint8_t devfn = (param >> 8) & 0xff; + uint16_t bus = (param >> 16) & 0xffff; + uint16_t domain = (param >> 32) & 0xffff; + PCIDevice *pdev; + PCIINTxRoute r; + + if (domain || !pcms) { + return 0; + } + + pdev = pci_find_device(pcms->bus, bus, devfn); + if (!pdev) { + return 0; + } + + r = pci_device_route_intx_to_irq(pdev, pin); + if (r.mode != PCI_INTX_ENABLED) { + return 0; + } + + /* + * Hm, can we be notified of INTX routing changes? Not without + * *owning* the device and being allowed to overwrite its own + * ->intx_routing_notifier, AFAICT. So let's not. + */ + return r.irq; +} + void xen_evtchn_set_callback_level(int level) { XenEvtchnState *s = xen_evtchn_singleton; - uint32_t param; - if (!s) { return; } @@ -259,18 +292,12 @@ void xen_evtchn_set_callback_level(int level) return; } - param = (uint32_t)s->callback_param; - - switch (s->callback_param >> CALLBACK_VIA_TYPE_SHIFT) { - case HVM_PARAM_CALLBACK_TYPE_GSI: - if (param < GSI_NUM_PINS) { - qemu_set_irq(s->gsis[param], level); - if (level) { - /* Ensure the vCPU polls for deassertion */ - kvm_xen_set_callback_asserted(); - } + if (s->callback_gsi && s->callback_gsi < GSI_NUM_PINS) { + qemu_set_irq(s->gsis[s->callback_gsi], level); + if (level) { + /* Ensure the vCPU polls for deassertion */ + kvm_xen_set_callback_asserted(); } - break; } } @@ -282,15 +309,22 @@ int xen_evtchn_set_callback_param(uint64_t param) .u.vector = 0, }; bool in_kernel = false; + uint32_t gsi = 0; + int type = param >> CALLBACK_VIA_TYPE_SHIFT; int ret; if (!s) { return -ENOTSUP; } + /* + * We need the BQL because set_callback_pci_intx() may call into PCI code, + * and because we may need to manipulate the old and new GSI levels. + */ + assert(qemu_mutex_iothread_locked()); qemu_mutex_lock(&s->port_lock); - switch (param >> CALLBACK_VIA_TYPE_SHIFT) { + switch (type) { case HVM_PARAM_CALLBACK_TYPE_VECTOR: { xa.u.vector = (uint8_t)param, @@ -298,10 +332,17 @@ int xen_evtchn_set_callback_param(uint64_t param) if (!ret && kvm_xen_has_cap(EVTCHN_SEND)) { in_kernel = true; } + gsi = 0; break; } + case HVM_PARAM_CALLBACK_TYPE_PCI_INTX: + gsi = set_callback_pci_intx(s, param); + ret = gsi ? 0 : -EINVAL; + break; + case HVM_PARAM_CALLBACK_TYPE_GSI: + gsi = (uint32_t)param; ret = 0; break; @@ -319,6 +360,17 @@ int xen_evtchn_set_callback_param(uint64_t param) } s->callback_param = param; s->evtchn_in_kernel = in_kernel; + + if (gsi != s->callback_gsi) { + struct vcpu_info *vi = kvm_xen_get_vcpu_info_hva(0); + + xen_evtchn_set_callback_level(0); + s->callback_gsi = gsi; + + if (gsi && vi && vi->evtchn_upcall_pending) { + kvm_xen_inject_vcpu_callback_vector(0, type); + } + } } qemu_mutex_unlock(&s->port_lock); diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c index c0dff1d501..ba83b45b62 100644 --- a/target/i386/kvm/xen-emu.c +++ b/target/i386/kvm/xen-emu.c @@ -131,6 +131,38 @@ int kvm_xen_init(KVMState *s, uint32_t hypercall_msr) return ret; } + /* If called a second time, don't repeat the rest of the setup. */ + if (s->xen_caps) { + return 0; + } + + /* + * Event channel delivery via GSI/PCI_INTX needs to poll the vcpu_info + * of vCPU0 to deassert the IRQ when ->evtchn_upcall_pending is cleared. + * + * In the kernel, there's a notifier hook on the PIC/IOAPIC which allows + * such things to be polled at precisely the right time. We *could* do + * it nicely in the kernel: check vcpu_info[0]->evtchn_upcall_pending at + * the moment the IRQ is acked, and see if it should be reasserted. + * + * But the in-kernel irqchip is deprecated, so we're unlikely to add + * that support in the kernel. Insist on using the split irqchip mode + * instead. + * + * This leaves us polling for the level going low in QEMU, which lacks + * the appropriate hooks in its PIC/IOAPIC code. Even VFIO is sending a + * spurious 'ack' to an INTX IRQ every time there's any MMIO access to + * the device (for which it has to unmap the device and trap access, for + * some period after an IRQ!!). In the Xen case, we do it on exit from + * KVM_RUN, if the flag is set to say that the GSI is currently asserted. + * Which is kind of icky, but less so than the VFIO one. I may fix them + * both later... + */ + if (!kvm_kernel_irqchip_split()) { + error_report("kvm: Xen support requires kernel-irqchip=split"); + return -EINVAL; + } + s->xen_caps = xen_caps; return 0; } @@ -681,7 +713,9 @@ static bool handle_set_param(struct kvm_xen_exit *exit, X86CPU *cpu, switch (hp.index) { case HVM_PARAM_CALLBACK_IRQ: + qemu_mutex_lock_iothread(); err = xen_evtchn_set_callback_param(hp.value); + qemu_mutex_unlock_iothread(); xen_set_long_mode(exit->u.hcall.longmode); break; default: