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@xxxxxxxxx>
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
