On 2024/6/20 18:42, Jan Beulich wrote:
> On 20.06.2024 11:40, Chen, Jiqian wrote:
>> On 2024/6/18 17:23, Jan Beulich wrote:
>>> On 18.06.2024 10:23, Chen, Jiqian wrote:
>>>> On 2024/6/17 23:32, Jan Beulich wrote:
>>>>> On 17.06.2024 11:00, Jiqian Chen wrote:
>>>>>> @@ -1516,14 +1519,39 @@ static void pci_add_dm_done(libxl__egc *egc,
>>>>>> rc = ERROR_FAIL;
>>>>>> goto out;
>>>>>> }
>>>>>> - r = xc_domain_irq_permission(ctx->xch, domid, irq, 1);
>>>>>> +#ifdef CONFIG_X86
>>>>>> + /* If dom0 doesn't have PIRQs, need to use
>>>>>> xc_domain_gsi_permission */
>>>>>> + r = xc_domain_getinfo_single(ctx->xch, 0, &info);
>>>>>
>>>>> Hard-coded 0 is imposing limitations. Ideally you would use DOMID_SELF,
>>>>> but
>>>>> I didn't check if that can be used with the underlying hypercall(s).
>>>>> Otherwise
>> From the commit 10ef7a91b5a8cb8c58903c60e2dd16ed490b3bcf, DOMID_SELF is not
>> allowed for XEN_DOMCTL_getdomaininfo.
>> And now XEN_DOMCTL_getdomaininfo gets domain through rcu_lock_domain_by_id.
>>
>>>>> you want to pass the actual domid of the local domain here.
>> What is the local domain here?
>
> The domain your code is running in.
>
>> What is method for me to get its domid?
>
> I hope there's an available function in one of the libraries to do that.
I didn't find relate function.
Hi Anthony, do you know?
> But I wouldn't even know what to look for; that's a question to (primarily)
> Anthony then, who sadly continues to be our only tool stack maintainer.
>
> Alternatively we could maybe enable XEN_DOMCTL_getdomaininfo to permit
> DOMID_SELF.
It didn't permit DOMID_SELF since below commit. Does it still have the same
problem if permit DOMID_SELF?
commit 10ef7a91b5a8cb8c58903c60e2dd16ed490b3bcf
Author: kfraser@localhost.localdomain <kfraser@localhost.localdomain>
Date: Tue Aug 14 09:56:46 2007 +0100
xen: Do not accept DOMID_SELF as input to DOMCTL_getdomaininfo.
This was screwing up callers that loop on getdomaininfo(), if there
was a domain with domid DOMID_FIRST_RESERVED-1 (== DOMID_SELF-1).
They would see DOMID_SELF-1, then look up DOMID_SELF, which has domid
0 of course, and then start their domain-finding loop all over again!
Found by Kouya Shimura <ko...@jp.fujitsu.com>. Thanks!
Signed-off-by: Keir Fraser <k...@xensource.com>
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 09a1e84d98e0..5d29667b7c3d 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -463,19 +463,13 @@ long do_domctl(XEN_GUEST_HANDLE(xen_domctl_t) u_domctl)
case XEN_DOMCTL_getdomaininfo:
{
struct domain *d;
- domid_t dom;
-
- dom = op->domain;
- if ( dom == DOMID_SELF )
- dom = current->domain->domain_id;
+ domid_t dom = op->domain;
rcu_read_lock(&domlist_read_lock);
for_each_domain ( d )
- {
if ( d->domain_id >= dom )
break;
- }
if ( d == NULL )
{
>
>>>> But the action of granting permission is from dom0 to domU, what I need to
>>>> get is the infomation of dom0,
>>>> The actual domid here is domU's id I think, it is not useful.
>>>
>>> Note how I said DOMID_SELF and "local domain". There's no talk of using the
>>> DomU's domid. But what you apparently neglect is the fact that the hardware
>>> domain isn't necessarily Dom0 (see CONFIG_LATE_HWDOM in the hypervisor).
>>> While benign in most cases, this is relevant when it comes to referencing
>>> the hardware domain by domid. And it is the hardware domain which is going
>>> to drive the device re-assignment, as that domain is who's in possession of
>>> all the devices not yet assigned to any DomU.
>> OK, I need to get the information of hardware domain here?
>
> Right, with (for this purpose) "hardware domain" == "local domain".
>
> Jan
--
Best regards,
Jiqian Chen.
