@@ -678,10 +678,9 @@ static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
if (!pcifront_dev) {
dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
pcifront_dev = pdev;
- } else {
- dev_err(&pdev->xdev->dev, "PCI frontend already installed!\n");
+ } else
err = -EEXIST;
- }
+
spin_unlock(&pcifront_dev_lock);
if (!err && !swiotlb_nr_tbl()) {
@@ -848,7 +847,7 @@ static int pcifront_try_connect(struct pcifront_device *pdev)
goto out;
err = pcifront_connect_and_init_dma(pdev);
- if (err) {
+ if (err && err != -EEXIST) {
xenbus_dev_fatal(pdev->xdev, err,
"Error setting up PCI Frontend");
goto out;
This is a note to let you know that I have just added a patch titled xen/pcifront: Deal with toolstack missing to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From f38e00dc2b9d24dce95f39b490561f262b03e714 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Date: Mon, 10 Jun 2013 16:48:09 -0400 Subject: [PATCH] xen/pcifront: Deal with toolstack missing 'XenbusStateClosing' state. commit 098b1aeaf4d6149953b8f1f8d55c21d85536fbff upstream. There are two tool-stack that can instruct the Xen PCI frontend and backend to change states: 'xm' (Python code with a daemon), and 'xl' (C library - does not keep state changes). With the 'xm', the path to disconnect a single PCI device (xm pci-detach <guest> <BDF>) is: 4(Connected)->7(Reconfiguring*)-> 8(Reconfigured)-> 4(Connected)->5(Closing*). The * is for states that the tool-stack sets. For 'xl', it is similar: 4(Connected)->7(Reconfiguring*)-> 8(Reconfigured)-> 4(Connected) Both of them also tear down the XenBus structure, so the backend state ends up going in the 3(Initialised) and calls pcifront_xenbus_remove. When a PCI device is plugged back in (xm pci-attach <guest> <BDF>) both of them follow the same pattern: 2(InitWait*), 3(Initialized*), 4(Connected*)->4(Connected). [xen-pcifront ignores the 2,3 state changes and only acts when 4 (Connected) has been reached] Note that this is for a _single_ PCI device. If there were two PCI devices and only one was disconnected 'xm' would show the same state changes. The problem is that git commit 3d925320e9e2de162bd138bf97816bda8c3f71be ("xen/pcifront: Use Xen-SWIOTLB when initting if required") introduced a mechanism to initialize the SWIOTLB when the Xen PCI front moves to Connected state. It also had some aggressive seatbelt code check that would warn the user if one tried to change to Connected state without hitting first the Closing state: pcifront pci-0: PCI frontend already installed! However, that code can be relaxed and we can continue on working even if the frontend is instructed to be the 'Connected' state with no devices and then gets tickled to be in 'Connected' state again. In other words, this 4(Connected)->5(Closing)->4(Connected) state was expected, while 4(Connected)->.... anything but 5(Closing)->4(Connected) was not. This patch removes that aggressive check and allows Xen pcifront to work with the 'xl' toolstack (for one or more PCI devices) and with 'xm' toolstack (for more than two PCI devices). Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org [v2: Added in the description about two PCI devices] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/pci/xen-pcifront.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) -- 1.8.1.2