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Date: Wed, 5 Jun 2013 13:50:45 +0100
From: Stefano Stabellini <stefano.stabellini@...citrix.com>
To: Zhenzhong Duan <zhenzhong.duan@...cle.com>
CC: Stefano Stabellini <stefano.stabellini@...citrix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
David Vrabel <david.vrabel@...rix.com>,
"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
Feng Jin <joe.jin@...cle.com>,
Yuval Shaia <yuval.shaia@...cle.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Chien Yen <chien.yen@...cle.com>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [Xen-devel] [PATCH] xen: reuse the same pirq allocated when
driver load first time
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?
--
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