Re: [PATCH V3] x86/ioreq_server: Make p2m_finish_type_change actually work

[George Dunlap <george.dunlap@citrix.com>]

On 10/05/17 23:57, Xiong Zhang wrote:
> Commit 6d774a951696 ("x86/ioreq server: synchronously reset outstanding
> p2m_ioreq_server entries when an ioreq server unmaps") introduced
> p2m_finish_type_change(), which was meant to synchronously finish a
> previously initiated type change over a gpfn range.  It did this by
> calling get_entry(), checking if it was the appropriate type, and then
> calling set_entry().
> 
> Unfortunately, a previous commit (1679e0df3df6 "x86/ioreq server:
> asynchronously reset outstanding p2m_ioreq_server entries") modified
> get_entry() to always return the new type after the type change, meaning
> that p2m_finish_type_change() never changed any entries.  Which means
> when an ioreq server was detached and then re-attached (as happens in
> XenGT on reboot) the re-attach failed.
> 
> Fix this by using the existing p2m-specific recalculation logic instead
> of doing a read-check-write loop.
> 
> Fix: 'commit 6d774a951696 ("x86/ioreq server: synchronously reset
>       outstanding p2m_ioreq_server entries when an ioreq server unmaps")'
> 
> v1: Add ioreq_pre_recalc query flag to get the old p2m_type.(Jan)
> v2: Add p2m->recalc() hook to change gfn p2m_type. (George)
> v3: Make commit message clearer. (George)

These changes should be put like this....

> 
> Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
> Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>

---
v1: Add ioreq_pre_recalc query flag to get the old p2m_type.(Jan)
v2: Add p2m->recalc() hook to change gfn p2m_type. (George)
v3: Make commit message clearer. (George)

That is, below the S-o-B, you should add a line with '---', and then
after that add any comments that you want to aim at the reviewers (such
as changes between the versions) but not to end up checked into the tree.

This can be fixed up on check-in.

Other than that:

Reviewed-by: George Dunlap <george.dunlap@citrix.com>


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