From patchwork Tue Feb 19 15:20:57 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 221714 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id F139A2C0089 for ; Wed, 20 Feb 2013 02:22:36 +1100 (EST) Received: from localhost ([::1]:34459 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7p1f-0001UL-5F for incoming@patchwork.ozlabs.org; Tue, 19 Feb 2013 10:22:35 -0500 Received: from eggs.gnu.org ([208.118.235.92]:47591) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7p1K-0000nt-HP for qemu-devel@nongnu.org; Tue, 19 Feb 2013 10:22:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U7p1A-0006XA-Rr for qemu-devel@nongnu.org; Tue, 19 Feb 2013 10:22:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:6726) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7p1A-0006X1-Je for qemu-devel@nongnu.org; Tue, 19 Feb 2013 10:22:04 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r1JFKv4J007652 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 19 Feb 2013 10:20:57 -0500 Received: from redhat.com (dhcp-4-130.tlv.redhat.com [10.35.4.130]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with SMTP id r1JFKsFo019385; Tue, 19 Feb 2013 10:20:55 -0500 Date: Tue, 19 Feb 2013 17:20:57 +0200 From: "Michael S. Tsirkin" To: Alexey Korolev Message-ID: <20130219152057.GA30086@redhat.com> References: <511B1F5D.4060906@endace.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <511B1F5D.4060906@endace.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Peter Maydell , gleb@redhat.com, jan.kiszka@siemens.com, "qemu-devel@nongnu.org" , Gerd Hoffmann , alexey.korolev@endace.com Subject: [Qemu-devel] [PATCH for-1.4] pc: tag apic as overlap region X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 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 apic overlaps PCI space. On real hardware it has higher priority, emulate this correctly. This should addresses the following issue: > Subject: Re: [BUG] Guest OS hangs on boot when 64bit BAR present (kvm-apic-msi resource conflict) > Sometime ago I reported an issue about guest OS hang when 64bit BAR present. > http://lists.gnu.org/archive/html/qemu-devel/2012-01/msg03189.html > http://lists.gnu.org/archive/html/qemu-devel/2012-12/msg00413.html > > Some more investigation has been done, so in this post I'll try to explain why it happens and offer possible solutions: > > *When the issue happens* > The issue occurs on Linux guest OS if kernel version <2.6.36 > A Guest OS hangs on boot when a 64bit PCI BAR is present in a system (if we use ivshmem driver for example) and occupies range within first > 4 GB. > > *How to reproduce* > I used the following qemu command to reproduce the case: > /usr/local/bin/qemu-system-x86_64 -M pc-1.3 -enable-kvm -m 2000 -smp 1,sockets=1,cores=1,threads=1 -name Rh5332 -chardev > socket,id=charmonitor,path=/var/lib/libvirt/qemu/Rh5332.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=readline -rtc > base=utc -boot cd -drive file=/home/akorolev/rh5332.img,if=none,id=drive-ide0-0-0,format=raw -device > ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -chardev file,id=charserial0,path=/home/akorolev/serial.log -device > isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:0 -k en-us -vga cirrus -device ivshmem,shm,size=32M-device > virtio-balloon-pci,id=balloon0 > > Tried different guests: Centos 5.8 64bit, RHEL 5.3 32bit, FC 12 64bit on all machines hang occurs in 100% cases > > *Why it happens* > The issue basically comes from Linux PCI enumeration code. > > The OS enumerates 64BIT bars when device is enabled using the following procedure. > 1. Write all FF's to lower half of 64bit BAR > 2. Write address back to lower half of 64bit BAR > 3. Write all FF's to higher half of 64bit BAR > 4. Write address back to higher half of 64bit BAR > > For qemu it means that qemu pci_default_write_config() recevies all FFs for lower part of the 64bit BAR. > Then it applies the mask and converts the value to "All FF's - size + 1" (FE000000 if size is 32MB). > > So for short period of time the range [0xFE000000 - 0xFFFFFFFF] will be occupied by ivshmem resource. > For some reason it is lethal for further boot process. > > We have found that boot process screws up completely if kvm-apic-msi range is overlapped even for short period of time. (We still don't > know why it happens, hope that the qemu maintainers can answer?) > > If we look at kvm-apic-msi memory region it is a non-overlapable memory region with hardcoded address range [0xFEE00000 - 0xFEF00000]. > > Here is a log we collected from render_memory_regions: > > system overlap 0 pri 0 [0x0 - 0x7fffffffffffffff] > kvmvapic-rom overlap 1 pri 1000 [0xca000 - 0xcd000] > pc.ram overlap 0 pri 0 [0xca000 - 0xcd000] > ++ pc.ram [0xca000 - 0xcd000] is added to view > .................... > smram-region overlap 1 pri 1 [0xa0000 - 0xc0000] > pci overlap 0 pri 0 [0xa0000 - 0xc0000] > cirrus-lowmem-container overlap 1 pri 1 [0xa0000 - 0xc0000] > cirrus-low-memory overlap 0 pri 0 [0xa0000 - 0xc0000] > ++cirrus-low-memory [0xa0000 - 0xc0000] is added to view > kvm-ioapic overlap 0 pri 0 [0xfec00000 - 0xfec01000] > ++kvm-ioapic [0xfec00000 - 0xfec01000] is added to view > pci-hole64 overlap 0 pri 0 [0x100000000 - 0x4000000100000000] > pci overlap 0 pri 0 [0x100000000 - 0x4000000100000000] > pci-hole overlap 0 pri 0 [0x7d000000 - 0x100000000] > pci overlap 0 pri 0 [0x7d000000 - 0x100000000] > ivshmem-bar2-container overlap 1 pri 1 [0xfe000000 - 0x100000000] > ivshmem.bar2 overlap 0 pri 0 [0xfe000000 - 0x100000000] > ++ivshmem.bar2 [0xfe000000 - 0xfec00000] is added to view > ++ivshmem.bar2 [0xfec01000 - 0x100000000] is added to view > ivshmem-mmio overlap 1 pri 1 [0xfebf1000 - 0xfebf1100] > e1000-mmio overlap 1 pri 1 [0xfeba0000 - 0xfebc0000] > cirrus-mmio overlap 1 pri 1 [0xfebf0000 - 0xfebf1000] > cirrus-pci-bar0 overlap 1 pri 1 [0xfa000000 - 0xfc000000] > vga.vram overlap 1 pri 1 [0xfa000000 - 0xfa800000] > ++vga.vram [0xfa000000 - 0xfa800000] is added to view > cirrus-bitblt-mmio overlap 0 pri 0 [0xfb000000 - 0xfb400000] > ++cirrus-bitblt-mmio [0xfb000000 - 0xfb400000] is added to view > cirrus-linear-io overlap 0 pri 0 [0xfa000000 - 0xfa800000] > pc.bios overlap 0 pri 0 [0xfffe0000 - 0x100000000] > ram-below-4g overlap 0 pri 0 [0x0 - 0x7d000000] > pc.ram overlap 0 pri 0 [0x0 - 0x7d000000] > ++pc.ram [0x0 - 0xa0000] is added to view > ++pc.ram [0x100000 - 0x7d000000] is added to view > kvm-apic-msi overlap 0 pri 0 [0xfee00000 - 0xfef00000] > > As you can see from log the kvm-apic-msi is enumarated last when range [0xfee00000 - 0xfef00000] is already occupied by ivshmem.bar2 > [0xfec01000 - 0x100000000]. > > > *Possible solutions* > Solution 1. Probably the best would be adding the rule that regions which may not be overlapped are added to view first (In in other words > regions which must not be overlapped have the highest priority). Please find patch in the following message. > > Solution 2. Raise priority of kvm-apic-msi resource. This is a bit misleading solution, as priority is only applicable for overlap-able > regions, but this region must not be overlapped. > > Solution 3. Fix the issue at PCI level. Track if the resource is 64bit and apply changes if both parts of 64bit BAR are programmed. (It > appears that real PCI bus controllers are smart enough to track 64bit BAR writes on PC, so qemu could do the same? Drawbacks are that > tracking PCI writes is bit cumbersome, and such tracking may appear to somebody as a hack) --- The following patch is under test ATM. Alexey, does it address the crash for you? diff --git a/hw/pc.c b/hw/pc.c index 53cc173..745c89d 100644 --- a/hw/pc.c +++ b/hw/pc.c @@ -1154,7 +1154,8 @@ void ioapic_init_gsi(GSIState *gsi_state, const char *parent_name) } qdev_init_nofail(dev); d = SYS_BUS_DEVICE(dev); - sysbus_mmio_map(d, 0, 0xfec00000); + /* APIC overlaps the PCI window. */ + sysbus_mmio_map_overlap(d, 0, 0xfec00000, 1000); for (i = 0; i < IOAPIC_NUM_PINS; i++) { gsi_state->ioapic_irq[i] = qdev_get_gpio_in(dev, i); diff --git a/hw/sysbus.c b/hw/sysbus.c index 6d9d1df..40bf352 100644 --- a/hw/sysbus.c +++ b/hw/sysbus.c @@ -66,6 +66,26 @@ void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr) dev->mmio[n].memory); } +void sysbus_mmio_map_overlap(SysBusDevice *dev, int n, hwaddr addr, + unsigned priority) +{ + assert(n >= 0 && n < dev->num_mmio); + + if (dev->mmio[n].addr == addr) { + /* ??? region already mapped here. */ + return; + } + if (dev->mmio[n].addr != (hwaddr)-1) { + /* Unregister previous mapping. */ + memory_region_del_subregion(get_system_memory(), dev->mmio[n].memory); + } + dev->mmio[n].addr = addr; + memory_region_add_subregion_overlap(get_system_memory(), + addr, + dev->mmio[n].memory, + priority); +} + /* Request an IRQ source. The actual IRQ object may be populated later. */ void sysbus_init_irq(SysBusDevice *dev, qemu_irq *p) diff --git a/hw/sysbus.h b/hw/sysbus.h index a7fcded..2100bd7 100644 --- a/hw/sysbus.h +++ b/hw/sysbus.h @@ -56,6 +56,8 @@ void sysbus_init_ioports(SysBusDevice *dev, pio_addr_t ioport, pio_addr_t size); void sysbus_connect_irq(SysBusDevice *dev, int n, qemu_irq irq); void sysbus_mmio_map(SysBusDevice *dev, int n, hwaddr addr); +void sysbus_mmio_map_overlap(SysBusDevice *dev, int n, hwaddr addr, + unsigned priority); void sysbus_add_memory(SysBusDevice *dev, hwaddr addr, MemoryRegion *mem); void sysbus_add_memory_overlap(SysBusDevice *dev, hwaddr addr,