From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39516) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SSdBU-00007h-Lp for qemu-devel@nongnu.org; Thu, 10 May 2012 19:54:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SSdBS-0004m2-Nx for qemu-devel@nongnu.org; Thu, 10 May 2012 19:54:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51032) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SSdBS-0004lo-FO for qemu-devel@nongnu.org; Thu, 10 May 2012 19:54:10 -0400 Message-ID: <4FAC5518.5060807@redhat.com> Date: Fri, 11 May 2012 07:54:00 +0800 From: Amos Kong MIME-Version: 1.0 References: <1315976141-6684-1-git-send-email-akong@redhat.com> <20120510154423.11306.85353.stgit@t> <4FABF639.4070205@gmail.com> <20120510185516.GI14647@redhat.com> In-Reply-To: <20120510185516.GI14647@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3] pci: clean all funcs when hot-removing multifunc device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: linux-pci@vger.kernel.org, seabios@seabios.org, qemu-devel@nongnu.org, jbarnes@virtuousgeek.org, alex.williamson@redhat.com, kevin@koconnor.net, Jiang Liu On 05/11/2012 02:55 AM, Michael S. Tsirkin wrote: > On Fri, May 11, 2012 at 01:09:13AM +0800, Jiang Liu wrote: >> On 05/10/2012 11:44 PM, Amos Kong wrote: >> >>> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c >>> index 806c44f..a7442d9 100644 >>> --- a/drivers/pci/hotplug/acpiphp_glue.c >>> +++ b/drivers/pci/hotplug/acpiphp_glue.c >>> @@ -885,7 +885,7 @@ static void disable_bridges(struct pci_bus *bus) >>> static int disable_device(struct acpiphp_slot *slot) >>> { >>> struct acpiphp_func *func; >>> - struct pci_dev *pdev; >>> + struct pci_dev *pdev, *tmp; >>> struct pci_bus *bus = slot->bridge->pci_bus; >>> >>> /* The slot will be enabled when func 0 is added, so check >>> @@ -902,9 +902,10 @@ static int disable_device(struct acpiphp_slot *slot) >>> func->bridge = NULL; >>> } >>> >>> - pdev = pci_get_slot(slot->bridge->pci_bus, >>> - PCI_DEVFN(slot->device, func->function)); >>> - if (pdev) { >>> + list_for_each_entry_safe(pdev, tmp, &bus->devices, bus_list) { >>> + if (PCI_SLOT(pdev->devfn) != slot->device) >>> + continue; >>> + >> The pci_bus_sem lock should be acquired when walking the bus->devices list. >> Otherwise it may cause invalid memory access if another thread is modifying >> the bus->devices list concurrently. >> BTW, what's the relationship with "[PATCH v3] hotplug: add device per func >> in ACPI DSDT tables"? Seems they are both solving the same issue. Two work need to be done when we disable a slot, cleaning configuration(in OS) and power off slot. Currently the second part(power off) works fine, all funcs disappear from "(qemu)#info block" after hot-remove slot. The only problem is func 1~7 are not unconfigured, so I NAKed seabios patch, and try to fix this problem in pci driver. (btw, winxp & win7 hotplug works currently) /** * acpiphp_disable_slot - power off slot * @slot: ACPI PHP slot */ int acpiphp_disable_slot(struct acpiphp_slot *slot) { mutex_lock(&slot->crit_sect); /* unconfigure all functions */ retval = disable_device(slot); /* power off all functions */ retval = power_off_slot(slot); .... } > That's a bios patch. It's needed if you want broken linux to work. This > makes linux behave properly on the original bios. > >>> pci_stop_bus_device(pdev); >>> if (pdev->subordinate) { >>> disable_bridges(pdev->subordinate); -- Amos.