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    SubjectRe: [PATCH v3 02/27] x86/xen/MSI: Eliminate arch_msix_mask_irq() and arch_msi_mask_irq()
    On Wed, Oct 15, 2014 at 11:06:50AM +0800, Yijing Wang wrote:
    > Commit 0e4ccb1505a9 ("PCI: Add x86_msi.msi_mask_irq() and msix_mask_irq()")
    > introduced two __weak arch functions arch_msix_mask_irq() and
    > arch_msi_mask_irq() to work around a bug when running xen in x86.
    > These two functions made msi code more complex. This patch reverts
    > the commit and introduces a global flag to control msi mask action to
    > avoid the bug. The patch is also preparation for using MSI chip framework
    > instead of weak arch MSI functions in all platforms. Keep default_msi_mask_irq()
    > and default_msix_mask_irq() in linux/msi.h to make s390 MSI code compile
    > happy, they will be removed in the later patch.

    This patch is basically a revert of 0e4ccb1505a9 intermingled with the
    addition of the new pci_msi_ignore_mask technique.

    Can you please split this into two patches:

    - Add the pci_msi_ignore_mask stuff (alongside the existing way)
    - Revert 0e4ccb1505a9

    I think that will make it easier to see what's going on.

    > Signed-off-by: Yijing Wang <wangyijing@huawei.com>
    > CC: David Vrabel <david.vrabel@citrix.com>
    > CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    > ---
    > Hi David and Konrad,
    > I dropped the Acked-by and tested-by, because this version has a
    > lot changes compared to last. So, I guess you may want to check it again.
    > ---
    > arch/x86/include/asm/x86_init.h | 3 ---
    > arch/x86/kernel/x86_init.c | 10 ----------
    > arch/x86/pci/xen.c | 14 ++------------
    > drivers/pci/msi.c | 29 ++++++++++++-----------------
    > include/linux/msi.h | 8 ++++++--
    > 5 files changed, 20 insertions(+), 44 deletions(-)
    >
    > diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
    > index e45e4da..f58a9c7 100644
    > --- a/arch/x86/include/asm/x86_init.h
    > +++ b/arch/x86/include/asm/x86_init.h
    > @@ -172,7 +172,6 @@ struct x86_platform_ops {
    >
    > struct pci_dev;
    > struct msi_msg;
    > -struct msi_desc;
    >
    > struct x86_msi_ops {
    > int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
    > @@ -183,8 +182,6 @@ struct x86_msi_ops {
    > void (*teardown_msi_irqs)(struct pci_dev *dev);
    > void (*restore_msi_irqs)(struct pci_dev *dev);
    > int (*setup_hpet_msi)(unsigned int irq, unsigned int id);
    > - u32 (*msi_mask_irq)(struct msi_desc *desc, u32 mask, u32 flag);
    > - u32 (*msix_mask_irq)(struct msi_desc *desc, u32 flag);
    > };
    >
    > struct IO_APIC_route_entry;
    > diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
    > index e48b674..234b072 100644
    > --- a/arch/x86/kernel/x86_init.c
    > +++ b/arch/x86/kernel/x86_init.c
    > @@ -116,8 +116,6 @@ struct x86_msi_ops x86_msi = {
    > .teardown_msi_irqs = default_teardown_msi_irqs,
    > .restore_msi_irqs = default_restore_msi_irqs,
    > .setup_hpet_msi = default_setup_hpet_msi,
    > - .msi_mask_irq = default_msi_mask_irq,
    > - .msix_mask_irq = default_msix_mask_irq,
    > };
    >
    > /* MSI arch specific hooks */
    > @@ -140,14 +138,6 @@ void arch_restore_msi_irqs(struct pci_dev *dev)
    > {
    > x86_msi.restore_msi_irqs(dev);
    > }
    > -u32 arch_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > -{
    > - return x86_msi.msi_mask_irq(desc, mask, flag);
    > -}
    > -u32 arch_msix_mask_irq(struct msi_desc *desc, u32 flag)
    > -{
    > - return x86_msi.msix_mask_irq(desc, flag);
    > -}
    > #endif
    >
    > struct x86_io_apic_ops x86_io_apic_ops = {
    > diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
    > index 093f5f4..e5b8b78 100644
    > --- a/arch/x86/pci/xen.c
    > +++ b/arch/x86/pci/xen.c
    > @@ -394,14 +394,6 @@ static void xen_teardown_msi_irq(unsigned int irq)
    > {
    > xen_destroy_irq(irq);
    > }
    > -static u32 xen_nop_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > -{
    > - return 0;
    > -}
    > -static u32 xen_nop_msix_mask_irq(struct msi_desc *desc, u32 flag)
    > -{
    > - return 0;
    > -}
    > #endif
    >
    > int __init pci_xen_init(void)
    > @@ -425,8 +417,7 @@ int __init pci_xen_init(void)
    > x86_msi.setup_msi_irqs = xen_setup_msi_irqs;
    > x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
    > x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
    > - x86_msi.msi_mask_irq = xen_nop_msi_mask_irq;
    > - x86_msi.msix_mask_irq = xen_nop_msix_mask_irq;
    > + pci_msi_ignore_mask = 1;
    > #endif
    > return 0;
    > }
    > @@ -506,8 +497,7 @@ int __init pci_xen_initial_domain(void)
    > x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
    > x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
    > x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
    > - x86_msi.msi_mask_irq = xen_nop_msi_mask_irq;
    > - x86_msi.msix_mask_irq = xen_nop_msix_mask_irq;
    > + pci_msi_ignore_mask = 1;
    > #endif
    > xen_setup_acpi_sci();
    > __acpi_register_gsi = acpi_register_gsi_xen;
    > diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
    > index ecb92a5..22e413c 100644
    > --- a/drivers/pci/msi.c
    > +++ b/drivers/pci/msi.c
    > @@ -23,6 +23,7 @@
    > #include "pci.h"
    >
    > static int pci_msi_enable = 1;
    > +int pci_msi_ignore_mask;
    >
    > #define msix_table_size(flags) ((flags & PCI_MSIX_FLAGS_QSIZE) + 1)
    >
    > @@ -162,11 +163,11 @@ static inline __attribute_const__ u32 msi_mask(unsigned x)
    > * reliably as devices without an INTx disable bit will then generate a
    > * level IRQ which will never be cleared.
    > */
    > -u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > +u32 __msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > {
    > u32 mask_bits = desc->masked;
    >
    > - if (!desc->msi_attrib.maskbit)
    > + if (pci_msi_ignore_mask || !desc->msi_attrib.maskbit)
    > return 0;
    >
    > mask_bits &= ~mask;
    > @@ -176,14 +177,9 @@ u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > return mask_bits;
    > }
    >
    > -__weak u32 arch_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > -{
    > - return default_msi_mask_irq(desc, mask, flag);
    > -}
    > -
    > static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > {
    > - desc->masked = arch_msi_mask_irq(desc, mask, flag);
    > + desc->masked = __msi_mask_irq(desc, mask, flag);
    > }
    >
    > /*
    > @@ -193,11 +189,15 @@ static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
    > * file. This saves a few milliseconds when initialising devices with lots
    > * of MSI-X interrupts.
    > */
    > -u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag)
    > +u32 __msix_mask_irq(struct msi_desc *desc, u32 flag)
    > {
    > u32 mask_bits = desc->masked;
    > unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
    > PCI_MSIX_ENTRY_VECTOR_CTRL;
    > +
    > + if (pci_msi_ignore_mask)
    > + return 0;
    > +
    > mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
    > if (flag)
    > mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT;
    > @@ -206,14 +206,9 @@ u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag)
    > return mask_bits;
    > }
    >
    > -__weak u32 arch_msix_mask_irq(struct msi_desc *desc, u32 flag)
    > -{
    > - return default_msix_mask_irq(desc, flag);
    > -}
    > -
    > static void msix_mask_irq(struct msi_desc *desc, u32 flag)
    > {
    > - desc->masked = arch_msix_mask_irq(desc, flag);
    > + desc->masked = __msix_mask_irq(desc, flag);
    > }
    >
    > static void msi_set_mask_bit(struct irq_data *data, u32 flag)
    > @@ -866,7 +861,7 @@ void pci_msi_shutdown(struct pci_dev *dev)
    > /* Return the device with MSI unmasked as initial states */
    > mask = msi_mask(desc->msi_attrib.multi_cap);
    > /* Keep cached state to be restored */
    > - arch_msi_mask_irq(desc, mask, ~mask);
    > + __msi_mask_irq(desc, mask, ~mask);
    >
    > /* Restore dev->irq to its default pin-assertion irq */
    > dev->irq = desc->msi_attrib.default_irq;
    > @@ -964,7 +959,7 @@ void pci_msix_shutdown(struct pci_dev *dev)
    > /* Return the device with MSI-X masked as initial states */
    > list_for_each_entry(entry, &dev->msi_list, list) {
    > /* Keep cached states to be restored */
    > - arch_msix_mask_irq(entry, 1);
    > + __msix_mask_irq(entry, 1);
    > }
    >
    > msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
    > diff --git a/include/linux/msi.h b/include/linux/msi.h
    > index 44f4746..9ac1e3b 100644
    > --- a/include/linux/msi.h
    > +++ b/include/linux/msi.h
    > @@ -10,6 +10,8 @@ struct msi_msg {
    > u32 data; /* 16 bits of msi message data */
    > };
    >
    > +extern int pci_msi_ignore_mask;
    > +
    > /* Helper functions */
    > struct irq_data;
    > struct msi_desc;
    > @@ -21,6 +23,8 @@ void __write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
    > void read_msi_msg(unsigned int irq, struct msi_msg *msg);
    > void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg);
    > void write_msi_msg(unsigned int irq, struct msi_msg *msg);
    > +u32 __msix_mask_irq(struct msi_desc *desc, u32 flag);
    > +u32 __msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag);
    >
    > struct msi_desc {
    > struct {
    > @@ -61,8 +65,8 @@ void arch_restore_msi_irqs(struct pci_dev *dev);
    >
    > void default_teardown_msi_irqs(struct pci_dev *dev);
    > void default_restore_msi_irqs(struct pci_dev *dev);
    > -u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag);
    > -u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag);
    > +#define default_msi_mask_irq __msi_mask_irq
    > +#define default_msix_mask_irq __msix_mask_irq
    >
    > struct msi_chip {
    > struct module *owner;
    > --
    > 1.7.1
    >


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