Messages in this thread | | | Subject | Re: [PATCH RFC v2 03/18] irq/dev-msi: Create IR-DEV-MSI irq domain | From | "Dey, Megha" <> | Date | Wed, 22 Jul 2020 10:03:45 -0700 |
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Hi Dan,
On 7/21/2020 9:21 AM, Jason Gunthorpe wrote: > On Tue, Jul 21, 2020 at 09:02:35AM -0700, Dave Jiang wrote: >> From: Megha Dey <megha.dey@intel.com> >> >> When DEV_MSI is enabled, the dev_msi_default_domain is updated to the >> base DEV-MSI irq domain. If interrupt remapping is enabled, we create >> a new IR-DEV-MSI irq domain and update the dev_msi_default domain to >> the same. >> >> For X86, introduce a new irq_alloc_type which will be used by the >> interrupt remapping driver. > > Why? Shouldn't this by symmetrical with normal MSI? Does MSI do this?
Since I am introducing the new dev msi domain for the case when IR_REMAP is turned on, I have introduced the new type in this patch.
MSI/MSIX have their own irq alloc types which are also only used by the intel remapping driver..
> > I would have thought you'd want to switch to this remapping mode as > part of vfio or something like current cases.
Can you let me know what current case you are referring to? > >> +struct irq_domain *create_remap_dev_msi_irq_domain(struct irq_domain *parent, >> + const char *name) >> +{ >> + struct fwnode_handle *fn; >> + struct irq_domain *domain; >> + >> + fn = irq_domain_alloc_named_fwnode(name); >> + if (!fn) >> + return NULL; >> + >> + domain = msi_create_irq_domain(fn, &dev_msi_ir_domain_info, parent); >> + if (!domain) { >> + pr_warn("failed to initialize irqdomain for IR-DEV-MSI.\n"); >> + return ERR_PTR(-ENXIO); >> + } >> + >> + irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI); >> + >> + if (!dev_msi_default_domain) >> + dev_msi_default_domain = domain; >> + >> + return domain; >> +} > > What about this code creates a "remap" ? ie why is the function called > "create_remap" ?
Well, this function creates a new domain for the case when IR_REMAP is enabled, hence I called it create_remap...
> >> diff --git a/include/linux/msi.h b/include/linux/msi.h >> index 1da97f905720..7098ba566bcd 100644 >> +++ b/include/linux/msi.h >> @@ -378,6 +378,9 @@ void *platform_msi_get_host_data(struct irq_domain *domain); >> void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg); >> void platform_msi_unmask_irq(struct irq_data *data); >> void platform_msi_mask_irq(struct irq_data *data); >> + >> +int dev_msi_prepare(struct irq_domain *domain, struct device *dev, >> + int nvec, msi_alloc_info_t *arg); > > I wonder if this should use the popular #ifdef dev_msi_prepare scheme > instead of a weak symbol?
Ok, I will look into the #ifdef option. > > Jason >
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