[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH] x86/domain: Drop the only-written smap_check_policy infrastructure


On 08/05/18 17:20, Andrew Cooper wrote:
On 08/05/18 17:10, Roger Pau Monné wrote:
On Tue, May 08, 2018 at 02:03:04PM +0100, Andrew Cooper wrote:
c/s 4c5d78a10d "x86/pagewalk: Re-implement the pagetable walker" dropped the
consumer of smap_policy.  Looking at c/s 31ae587e6f which introduced the
smap_check logic, it exists only to work around a bug in guest_walk_tables()
was resolved by the aformentioned commit.

Remove the unused variables and associated infrastructure.

Reported-by: Jason Andryuk <jandryuk@xxxxxxxxx>
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 8b66096..197f8d6 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -595,7 +583,6 @@ struct arch_vcpu
struct guest_memory_policy
-    smap_check_policy_t smap_policy;
      bool nested_guest_mode;
Maybe guest_memory_policy could be dropped and
update_guest_memory_policy updated to take a bool nested_mode

update_guest_memory_policy() stores the old value in the passed
structure, and would more accurately be toggle_guest_memory_policy()
when it came to guest mode.

Or the function can be dropped altogether likely.

Sadly not yet.  This exists because of Xen's virtual-address based API
for the shared info and time mappings.  This API is bad and wrong and
wants fixing.  ISTR Juergen and Julien having plans to deal with this?

This should indeed be fixed properly, I was waiting some answer on my questions before attempting to go further on a fix (see [1] and [2]). I didn't have bandwidth so far to ping on the subject.


[1] https://www.mail-archive.com/xen-devel@xxxxxxxxxxxxxxxxxxxx/msg08836.html [2] https://www.mail-archive.com/xen-devel@xxxxxxxxxxxxxxxxxxxx/msg08835.html

Julien Grall

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.