[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen: reuse the same pirq allocated when driver load first time
On Wed, 26 Jun 2013, Zhenzhong Duan wrote: > On 2013-06-26 01:51, Stefano Stabellini wrote: > > On Tue, 25 Jun 2013, DuanZhenzhong wrote: > > > Stefano Stabellini wrote: > > > > Trimming some of the people in CC > > > > > > > > On Mon, 24 Jun 2013, Zhenzhong Duan wrote: > > > > > > > > > On 2013-06-20 22:21, Stefano Stabellini wrote: > > > > > > > > > > > On Thu, 20 Jun 2013, Zhenzhong Duan wrote: > > > > > > > > > > > > > On 2013-06-05 20:50, Stefano Stabellini wrote: > > > > > > > > > > > > > > > On Wed, 5 Jun 2013, Zhenzhong Duan wrote: > > > > > > > > > > > > > > > > > Stefano Stabellini wrote: > > > > > > > > > > > > > > > > > > On Tue, 21 May 2013, Stefano Stabellini wrote: > > > > > > > > > On Tue, 21 May 2013, Konrad Rzeszutek Wilk wrote: > > > > > > > > > Looking at the hypervisor code I couldn't see anything > > > > > > > > > obviously > > > > > > > > > wrong. > > > > > > > > > I think the culprit is "physdev_unmap_pirq": > > > > > > > > > > > > > > > > > > if ( is_hvm_domain(d) ) > > > > > > > > > { > > > > > > > > > spin_lock(&d->event_lock); > > > > > > > > > gdprintk(XENLOG_WARNING,"d%d, pirq: %d is %x %s, > > > > > > > > > irq: > > > > > > > > > %d\n", > > > > > > > > > d->domain_id, pirq, domain_pirq_to_emuirq(d, > > > > > > > > > pirq), > > > > > > > > > domain_pirq_to_emuirq(d, pirq) == IRQ_UNBOUND ? > > > > > > > > > "unbound" : > > > > > > > > > "", > > > > > > > > > domain_pirq_to_irq(d, pirq)); > > > > > > > > > > > > > > > > > > if > > > > > > > > > ( domain_pirq_to_emuirq(d, pirq) != IRQ_UNBOUND ) > > > > > > > > > ret = unmap_domain_pirq_emuirq(d, pirq); > > > > > > > > > spin_unlock(&d->event_lock); > > > > > > > > > if ( domid == DOMID_SELF || ret ) > > > > > > > > > goto free_domain; > > > > > > > > > > > > > > > > > > It always tells me unbound: > > > > > > > > > > > > > > > > > > (XEN) physdev.c:237:d14 14, pirq: 54 is ffffffff > > > > > > > > > (XEN) irq.c:1873:d14 14, nr_pirqs: 56 > > > > > > > > > (XEN) physdev.c:237:d14 14, pirq: 53 is ffffffff > > > > > > > > > (XEN) irq.c:1873:d14 14, nr_pirqs: 56 > > > > > > > > > (XEN) physdev.c:237:d14 14, pirq: 52 is ffffffff > > > > > > > > > (XEN) irq.c:1873:d14 14, nr_pirqs: 56 > > > > > > > > > (XEN) physdev.c:237:d14 14, pirq: 51 is ffffffff > > > > > > > > > (XEN) irq.c:1873:d14 14, nr_pirqs: 56 > > > > > > > > > (XEN) physdev.c:237:d14 14, pirq: 50 is ffffffff > > > > > > > > > (XEN) irq.c:1873:d14 14, nr_pirqs: 56 > > > > > > > > > (a bit older debug code, so the 'unbound' does not show up > > > > > > > > > here). > > > > > > > > > > > > > > > > > > Which means that the call to unmap_domain_pirq_emuirq does not > > > > > > > > > happen. > > > > > > > > > The checks in unmap_domain_pirq_emuirq also look to be depend > > > > > > > > > on the code being IRQ_UNBOUND. > > > > > > > > > > > > > > > > > > In other words, all of that code looks to only clear things > > > > > > > > > when > > > > > > > > > they are !IRQ_UNBOUND. > > > > > > > > > > > > > > > > > > But the other logic (IRQ_UNBOUND) looks to be missing a > > > > > > > > > removal > > > > > > > > > in the radix tree: > > > > > > > > > > > > > > > > > > if ( emuirq != IRQ_PT ) > > > > > > > > > radix_tree_delete(&d->arch.hvm_domain.emuirq_pirq, > > > > > > > > > emuirq); > > > > > > > > > > > > > > > > > > And > > > > > > > > > I think that is what is causing the leak - the radix tree > > > > > > > > > needs to be pruned? Or perhaps the allocate_pirq should check > > > > > > > > > the radix tree for IRQ_UNBOUND ones and re-use them? > > > > > > > > > I think that you are looking in the wrong place. > > > > > > > > > The issue is that QEMU doesn't call pt_msi_disable in > > > > > > > > > pt_msgctrl_reg_write if (!val & PCI_MSI_FLAGS_ENABLE). > > > > > > > > > > > > > > > > > > The code above is correct as is because it is trying to handle > > > > > > > > > emulated > > > > > > > > > IRQs and MSIs, not real passthrough MSIs. They latter are not > > > > > > > > > added to > > > > > > > > > that radix tree, see physdev_hvm_map_pirq and > > > > > > > > > physdev_map_pirq. > > > > > > > > > This patch fixes the issue, I have only tested MSI > > > > > > > > > (MSI-X > > > > > > > > > completely > > > > > > > > > untested). > > > > > > > > > > > > > > > > > > > > > > > > > > > diff --git a/hw/pass-through.c b/hw/pass-through.c > > > > > > > > > index 304c438..079e465 100644 > > > > > > > > > --- a/hw/pass-through.c > > > > > > > > > +++ b/hw/pass-through.c > > > > > > > > > @@ -3866,7 +3866,11 @@ static int pt_msgctrl_reg_write(struct > > > > > > > > > pt_dev > > > > > > > > > *ptdev, > > > > > > > > > ptdev->msi->flags |= PCI_MSI_FLAGS_ENABLE; > > > > > > > > > } > > > > > > > > > else > > > > > > > > > - ptdev->msi->flags &= ~PCI_MSI_FLAGS_ENABLE; > > > > > > > > > + { > > > > > > > > > + if (ptdev->msi->flags & PT_MSI_MAPPED) { > > > > > > > > > + pt_msi_disable(ptdev); > > > > > > > > > + } > > > > > > > > > + } > > > > > > > > > /* pass through MSI_ENABLE bit when no MSI-INTx > > > > > > > > > translation > > > > > > > > > */ > > > > > > > > > if (!ptdev->msi_trans_en) { > > > > > > > > > @@ -4013,6 +4017,8 @@ static int pt_msixctrl_reg_write(struct > > > > > > > > > pt_dev > > > > > > > > > *ptdev, > > > > > > > > > pt_disable_msi_translate(ptdev); > > > > > > > > > } > > > > > > > > > pt_msix_update(ptdev); > > > > > > > > > + } else if (!(*value & PCI_MSIX_ENABLE) && > > > > > > > > > ptdev->msix->enabled) { > > > > > > > > > + pt_msix_delete(ptdev); > > > > > > > > > Hi Stefano, > > > > > > > > > I made a test with this patch, os reboot when driver reload. > > > > > > > > > If > > > > > > > > > use > > > > > > > > > pt_msix_disable > > > > > > > > > instead of pt_msix_delete, driver could be reloaded. > > > > > > > > > But I still see some error in qemu.log and xen console. Seems > > > > > > > > > four > > > > > > > > > IRQs > > > > > > > > > are not freed > > > > > > > > > when unmap. > > > > > > > > > --------------first load--------------------------- > > > > > > > > > pt_msix_update_one: pt_msix_update_one requested pirq = 103 > > > > > > > > > pt_msix_update_one: Update msix entry 0 with pirq 67 gvec 0 > > > > > > > > > pt_msix_update_one: pt_msix_update_one requested pirq = 102 > > > > > > > > > pt_msix_update_one: Update msix entry 1 with pirq 66 gvec 0 > > > > > > > > > pt_msix_update_one: pt_msix_update_one requested pirq = 101 > > > > > > > > > pt_msix_update_one: Update msix entry 2 with pirq 65 gvec 0 > > > > > > > > > pt_msix_update_one: pt_msix_update_one requested pirq = 100 > > > > > > > > > pt_msix_update_one: Update msix entry 3 with pirq 64 gvec 0 > > > > > > > > > ------------- first unload--------------------------- > > > > > > > > > pt_msix_disable: Unbind msix with pirq 67, gvec 0 > > > > > > > > > pt_msix_disable: Unmap msix with pirq 67 > > > > > > > > > pt_msix_disable: Error: Unmapping of MSI-X failed. [00:04.0] > > > > > > > > > pt_msix_disable: Unbind msix with pirq 66, gvec 0 > > > > > > > > > pt_msix_disable: Unmap msix with pirq 66 > > > > > > > > > pt_msix_disable: Error: Unmapping of MSI-X failed. [00:04.0] > > > > > > > > > pt_msix_disable: Unbind msix with pirq 65, gvec 0 > > > > > > > > > pt_msix_disable: Unmap msix with pirq 65 > > > > > > > > > pt_msix_disable: Error: Unmapping of MSI-X failed. [00:04.0] > > > > > > > > > pt_msix_disable: Unbind msix with pirq 64, gvec 0 > > > > > > > > > pt_msix_disable: Unmap msix with pirq 64 > > > > > > > > > pt_msix_disable: Error: Unmapping of MSI-X failed. [00:04.0] > > > > > > > > > > > > > > > > > Can you add some printks in Xen (the hypercall name is > > > > > > > > PHYSDEVOP_unmap_pirq) to figure out exactly why they are > > > > > > > > failing? > > > > > > > > > > > > > > > Did some test, domain_pirq_to_emuirq(d, unmap->pirq) = IRQ_UNBOUND > > > > > > > in > > > > > > > physdev_unmap_pirq. > > > > > > > > > > > > > That means that Linux didn't call irq_enable on the MSI-X in > > > > > > question: > > > > > > > > > > > > irq_enable -> __startup_pirq -> EVTCHNOP_bind_pirq > > > > > > > > > > > > EVTCHNOP_bind_pirq is implemented by evtchn_bind_pirq in Xen and > > > > > > calls > > > > > > map_domain_emuirq_pirq, so domain_pirq_to_emuirq(d, unmap->pirq) > > > > > > should > > > > > > be IRQ_PT. > > > > > > > > > > > > I don't know if that's a normal condition, but in any case it should > > > > > > not create any problems to physdev_unmap_pirq, in fact the folloing > > > > > > check: > > > > > > > > > > > > if ( domid == DOMID_SELF || ret ) > > > > > > goto free_domain; > > > > > > > > > > > > should fail so Xen should continue and execute unmap_domain_pirq. > > > > > > That's > > > > > > what we want. > > > > > > > > > > > From linux side, request_irq-> request_threaded_irq-> __setup_irq-> > > > > > irq_startup-> startup_pirq-> EVTCHNOP_bind_pirq > > > > > If irq_enable isn't called, how does the driver receive interrupt, I > > > > > did > > > > > see > > > > > four interrupts in /proc/interrupt and driver works ok. > > > > > > > > > Good to know > > > > > > > > > > > > > Could you have a look if there is something wrong in xen side of > > > > > clearing > > > > > the > > > > > mapping? > > > > > > > > > What I am saying is that the error you are getting: > > > > > > > > pt_msix_disable: Unbind msix with pirq 67, gvec 0 > > > > pt_msix_disable: Unmap msix with pirq 67 > > > > pt_msix_disable: Error: Unmapping of MSI-X failed. [00:04.0] > > > > > > > > cannot be caused by domain_pirq_to_emuirq(d, pirq) returning > > > > IRQ_UNBOUND. > > > > So, why are you getting this error? What is failing? > > > > I am ready to believe the problem is in Xen but Without understanding > > > > why you are getting the error it's hard to find a solution. > > > > > > > I found the reason, you are looking at xen-unstable, I was working with > > > 4.1.30-OVM, it has patch of CVE-2012-4536 / XSA-21. > > > That patch set ret to -EINVAL initially. After remove that line, unmap > > > succeed. > > > But we still need below patch to let driver reload succeed everytime. > > > Without > > > that, 1st reload failed, 2nd succeed, 3 failed, ... > > > > > > diff -up --new-file ./hw/pt-msi.c.old1 ./hw/pt-msi.c > > > --- ./hw/pt-msi.c.old1 2013-06-26 01:36:08.000000000 +0800 > > > +++ ./hw/pt-msi.c 2013-06-26 01:37:41.000000000 +0800 > > > @@ -469,7 +469,7 @@ static void pci_msix_writel(void *opaque > > > return; > > > } > > > > > > - if ( offset != 3 && entry->io_mem[offset] != val ) > > > + if ( offset != 3 && (entry->io_mem[offset] != val || entry->pirq == > > > -1)) > > > entry->flags = 1; > > > entry->io_mem[offset] = val; > > Interesting. I don't think this is the proper fix though. > > Does the appended patch change anything? > > > > diff --git a/hw/pt-msi.c b/hw/pt-msi.c > > index 71fa6f0..cd5d9c7 100644 > > --- a/hw/pt-msi.c > > +++ b/hw/pt-msi.c > > @@ -302,7 +302,7 @@ static int pt_msix_update_one(struct pt_dev *dev, int > > entry_nr) > > uint32_t gflags = __get_msi_gflags(entry->io_mem[2], gaddr); > > int ret; > > - if ( !entry->flags ) > > + if ( !entry->flags && ptdev->msix->enabled ) > > return 0; > > if (!gvec) { > Tested, not work. > If you look at msix_capability_init in kernel, line 707,722, > dev->msix->enabled is already set when pt_msix_update is called. Yeah, but it shouldn't be already set in QEMU. In fact in QEMU dev->msix->enabled is modified in pt_msixctrl_reg_write after calling to pt_msix_update. I was assuming that you needed to add "|| entry->pirq == -1" because you needed to pass the check: if ( !entry->flags ) return 0; at the beginning of pt_msix_update_one. Am I getting it right? If that is case that I thought that we just needed to make sure that when ptdev->msix->enabled is still zero then we go through the test in pt_msix_update_one. Where is the mistake? _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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