On Wed, May 12, 2021 at 11:32:35AM +0200, Joerg Roedel wrote:
> On Wed, May 12, 2021 at 10:58:20AM +0200, Juergen Gross wrote:
> > No, those were used before, but commit 9da3f2b7405440 broke Xen's use
> > case. That is why I did commit 1457d8cf7664f.
>
> [...]
>
> Having the distinction between
On Wed, May 12, 2021 at 08:57:53AM -0700, Dave Hansen wrote:
> The changelog _helps_, but using a "user" function to handle kernel MMIO
> for its error handling properties seems like it's begging for a comment.
>
> __put_user() also seems to have fun stuff like __chk_user_ptr(). It all
> seems
On 5/12/21 1:37 AM, 'Joerg Roedel' wrote:
> I also thought about adding page_fault_disable()/page_fault_enable()
> calls, but being in atomic context is enough according to the
> faulthandler_disabled() implementation.
That would be nice to add to a comment:
On 5/12/21 12:54 AM, Joerg Roedel wrote:
> The put_user() and get_user() functions do checks on the address which is
> passed to them. They check whether the address is actually a user-space
> address and whether its fine to access it. They also call might_fault()
> to indicate that they could
From: Juergen Gross
> Sent: 12 May 2021 09:58
>
> On 12.05.21 10:50, 'Joerg Roedel' wrote:
> > On Wed, May 12, 2021 at 10:16:12AM +0200, Juergen Gross wrote:
> >> You want something like xen_safe_[read|write]_ulong().
> >
> > From a first glance I can't see it, what is the difference between the
On Wed, May 12, 2021 at 10:58:20AM +0200, Juergen Gross wrote:
> No, those were used before, but commit 9da3f2b7405440 broke Xen's use
> case. That is why I did commit 1457d8cf7664f.
I see, thanks for the heads-up. So here this is not a big issue, because
when an access to kernel space faults
On 12.05.21 10:50, 'Joerg Roedel' wrote:
On Wed, May 12, 2021 at 10:16:12AM +0200, Juergen Gross wrote:
You want something like xen_safe_[read|write]_ulong().
From a first glance I can't see it, what is the difference between the
xen_safe_*_ulong() functions and __get_user()/__put_user()?
On Wed, May 12, 2021 at 10:16:12AM +0200, Juergen Gross wrote:
> You want something like xen_safe_[read|write]_ulong().
>From a first glance I can't see it, what is the difference between the
xen_safe_*_ulong() functions and __get_user()/__put_user()? The only
difference I can see is that
On Wed, May 12, 2021 at 08:04:33AM +, David Laight wrote:
> That can't be right at all.
> __put/get_user() are only valid on user addresses and will try to
> fault in a missing page - so can sleep.
Yes, in general these functions can sleep, but not in this context. They
are called in atomic
On 12.05.21 10:04, David Laight wrote:
From: Joerg
Sent: 12 May 2021 08:55
From: Joerg Roedel
The put_user() and get_user() functions do checks on the address which is
passed to them. They check whether the address is actually a user-space
address and whether its fine to access it. They also
From: Joerg
> Sent: 12 May 2021 08:55
>
> From: Joerg Roedel
>
> The put_user() and get_user() functions do checks on the address which is
> passed to them. They check whether the address is actually a user-space
> address and whether its fine to access it. They also call might_fault()
> to
From: Joerg Roedel
The put_user() and get_user() functions do checks on the address which is
passed to them. They check whether the address is actually a user-space
address and whether its fine to access it. They also call might_fault()
to indicate that they could fault and possibly sleep.
All
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