On PVH dom0, the gsis don't get registered, but
the gsi of a passthrough device must be configured for it to
be able to be mapped into a hvm domU.
On Linux kernel side, it calles PHYSDEVOP_setup_gsi for
passthrough devices to register gsi when dom0 is PVH.
So, add PHYSDEVOP_setup_gsi for above purpose.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
---
The code link that will call this hypercall on linux kernel side is as follows
https://lore.kernel.org/lkml/20240607075109.126277-3-Jiqian.Chen@amd.com/T/#u
---
 xen/arch/x86/hvm/hypercall.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index fa5d50a0dd22..164f4eefa043 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -86,6 +86,7 @@ long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
             return -ENOSYS;
         break;
 
+    case PHYSDEVOP_setup_gsi:
     case PHYSDEVOP_pci_mmcfg_reserved:
     case PHYSDEVOP_pci_device_add:
     case PHYSDEVOP_pci_device_remove:
-- 
2.34.1

On Fri, 7 Jun 2024, Jiqian Chen wrote:
> On PVH dom0, the gsis don't get registered, but
> the gsi of a passthrough device must be configured for it to
> be able to be mapped into a hvm domU.
> On Linux kernel side, it calles PHYSDEVOP_setup_gsi for
> passthrough devices to register gsi when dom0 is PVH.
> So, add PHYSDEVOP_setup_gsi for above purpose.
> 
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

On 07.06.2024 10:11, Jiqian Chen wrote:
> On PVH dom0, the gsis don't get registered, but
> the gsi of a passthrough device must be configured for it to
> be able to be mapped into a hvm domU.
> On Linux kernel side, it calles PHYSDEVOP_setup_gsi for
> passthrough devices to register gsi when dom0 is PVH.

"it calls" implies that ...

> So, add PHYSDEVOP_setup_gsi for above purpose.
> 
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
> ---
> The code link that will call this hypercall on linux kernel side is as follows
> https://lore.kernel.org/lkml/20240607075109.126277-3-Jiqian.Chen@amd.com/T/#u

... the code only to be added there would already be upstream. As I think the
hypervisor change wants to come first, this part of the description will want
re-wording to along the lines of "will need to" or some such.

As to GSIs not being registered: If that's not a problem for Dom0's own
operation, I think it'll also want/need explaining why what is sufficient for
Dom0 alone isn't sufficient when pass-through comes into play.

Jan

On 2024/6/11 00:04, Jan Beulich wrote:
> On 07.06.2024 10:11, Jiqian Chen wrote:
>> On PVH dom0, the gsis don't get registered, but
>> the gsi of a passthrough device must be configured for it to
>> be able to be mapped into a hvm domU.
>> On Linux kernel side, it calles PHYSDEVOP_setup_gsi for
>> passthrough devices to register gsi when dom0 is PVH.
> 
> "it calls" implies that ...
> 
>> So, add PHYSDEVOP_setup_gsi for above purpose.
>>
>> Signed-off-by: Huang Rui <ray.huang@amd.com>
>> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
>> ---
>> The code link that will call this hypercall on linux kernel side is as follows
>> https://lore.kernel.org/lkml/20240607075109.126277-3-Jiqian.Chen@amd.com/T/#u
> 
> ... the code only to be added there would already be upstream. As I think the
> hypervisor change wants to come first, this part of the description will want
> re-wording to along the lines of "will need to" or some such.
Thanks, I will change in next version.

> 
> As to GSIs not being registered: If that's not a problem for Dom0's own
> operation, I think it'll also want/need explaining why what is sufficient for
> Dom0 alone isn't sufficient when pass-through comes into play.
OK, I will add in next version.

> 
> Jan

-- 
Best regards,
Jiqian Chen.