Re: [PATCH v2] xen/pci: Refactor PCI MSI interrupts related code

[Rahul Singh <Rahul.Singh@arm.com>]

Hi Jan,

> On 20 Apr 2021, at 4:36 pm, Jan Beulich <jbeulich@suse.com> wrote:
> 
> On 20.04.2021 15:45, Rahul Singh wrote:
>>> On 19 Apr 2021, at 1:33 pm, Jan Beulich <jbeulich@suse.com> wrote:
>>> On 19.04.2021 13:54, Julien Grall wrote:
>>>> For the time being, I think move this code in x86 is a lot better than 
>>>> #ifdef or keep the code in common code.
>>> 
>>> Well, I would perhaps agree if it ended up being #ifdef CONFIG_X86.
>>> I would perhaps not agree if there was a new CONFIG_* which other
>>> (future) arch-es could select if desired.
>> 
>> I agree with Julien moving the code to x86 file as currently it is referenced only in x86 code
>> and as of now we are not sure how other architecture will implement the Interrupt remapping
>> (via IOMMU or any other means).  
>> 
>> Let me know if you are ok with moving the code to x86.
> 
> I can't answer this with "yes" or "no" without knowing what the alternative
> would be. As said, if the alternative is CONFIG_X86 #ifdef-ary, then yes.
> If a separate CONFIG_* gets introduced (and selected by X86), then a
> separate file (getting built only when that new setting is y) would seem
> better to me.

I just made a quick patch. Please let me know if below patch is ok. I move the definition to  "passthrough/x86/iommu.c” file.

diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 705137f8be..199ce08612 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -1303,13 +1303,6 @@ static int __init setup_dump_pcidevs(void)
 }
 __initcall(setup_dump_pcidevs);
 
-int iommu_update_ire_from_msi(
-    struct msi_desc *msi_desc, struct msi_msg *msg)
-{
-    return iommu_intremap
-           ? iommu_call(&iommu_ops, update_ire_from_msi, msi_desc, msg) : 0;
-}
-
 static int iommu_add_device(struct pci_dev *pdev)
 {
     const struct domain_iommu *hd;
diff --git a/xen/drivers/passthrough/x86/iommu.c b/xen/drivers/passthrough/x86/iommu.c
index b90bb31bfe..cf51dec564 100644
--- a/xen/drivers/passthrough/x86/iommu.c
+++ b/xen/drivers/passthrough/x86/iommu.c
@@ -340,6 +340,13 @@ bool arch_iommu_use_permitted(const struct domain *d)
             likely(!p2m_get_hostp2m(d)->global_logdirty));
 }
 
+int iommu_update_ire_from_msi(
+    struct msi_desc *msi_desc, struct msi_msg *msg)
+{
+    return iommu_intremap
+           ? iommu_call(&iommu_ops, update_ire_from_msi, msi_desc, msg) : 0;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/include/xen/iommu.h b/xen/include/xen/iommu.h
index ea0cd0f1a2..bd42d87b72 100644
--- a/xen/include/xen/iommu.h
+++ b/xen/include/xen/iommu.h
@@ -243,7 +243,6 @@ struct iommu_ops {
                            u8 devfn, device_t *dev);
 #ifdef CONFIG_HAS_PCI
     int (*get_device_group_id)(u16 seg, u8 bus, u8 devfn);
-    int (*update_ire_from_msi)(struct msi_desc *msi_desc, struct msi_msg *msg);
 #endif /* HAS_PCI */
 
     void (*teardown)(struct domain *d);
@@ -272,6 +271,7 @@ struct iommu_ops {
     int (*adjust_irq_affinities)(void);
     void (*sync_cache)(const void *addr, unsigned int size);
     void (*clear_root_pgtable)(struct domain *d);
+    int (*update_ire_from_msi)(struct msi_desc *msi_desc, struct msi_msg *msg);
 #endif /* CONFIG_X86 */
 
     int __must_check (*suspend)(void)

Regards,
Rahul
> 
> Jan