Messages in this thread | | | Date | Thu, 17 Apr 2008 02:44:16 -0700 | From | "Yinghai Lu" <> | Subject | Re: [PATCH] x86_64: restore mask_bits in msi shutdown |
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On Thu, Apr 17, 2008 at 2:19 AM, Eric W. Biederman <ebiederm@xmission.com> wrote: > > Yinghai Lu <yhlu.kernel.send@gmail.com> writes: > > > I can not kexec RHEL 5.1 from 2.6.25-rc3 later > > > > caused by: > > commit 89d694b9dbe769ca1004e01db0ca43964806a611 > > Author: Thomas Gleixner <tglx@linutronix.de> > > Date: Mon Feb 18 18:25:17 2008 +0100 > > > > genirq: do not leave interupts enabled on free_irq > > > > The default_disable() function was changed in commit: > > > > 76d2160147f43f982dfe881404cfde9fd0a9da21 > > genirq: do not mask interrupts by default > > > > It removed the mask function in favour of the default delayed > > interrupt disabling. Unfortunately this also broke the shutdown in > > free_irq() when the last handler is removed from the interrupt for > > those architectures which rely on the default implementations. Now we > > can end up with a enabled interrupt line after the last handler was > > removed, which can result in spurious interrupts. > > > > Fix this by adding a default_shutdown function, which is only > > installed, when the irqchip implementation does provide neither a > > shutdown nor a disable function. > > > > [@stable: affected versions: .21 - .24 ] > > > > > > > > for MSI, default_shutdown will call mask_bit for msi device. so all mask bits > > will > > left disabled after free_irq. > > then if kexec next kernel that only can use msi_enable bit. > > all device's MSI can not be used. > > > > So try to restore MSI mask bits that is saved before using msi in first kernel. > > > > Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> > > Ouch! In the case of MSI-X this is horrible. Reenabling an interrupt > line when we are not using it. That is likely to cause even stranger > things than kexec to fail.
only does save and restore with msi and doesn't do anything with MSIX
+void msi_restore_mask_bits(unsigned int irq) +{ + struct msi_desc *entry; + + entry = get_irq_msi(irq); + BUG_ON(!entry || !entry->dev); + switch (entry->msi_attrib.type) { + case PCI_CAP_ID_MSI: + if (entry->msi_attrib.maskbit) { + int pos; + u32 mask_bits; + + pos = (long)entry->mask_base; + mask_bits = entry->orig_mask_bits; + pci_write_config_dword(entry->dev, pos, mask_bits); + } + break; + case PCI_CAP_ID_MSIX: + break; ======================> does not restore that for MSIX + default: + BUG(); + break; + } +}
YH
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