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

Re: [Xen-devel] [PATCH for-4.11] x86/traps: Fix error handling of the pv %dr7 shadow state



>>> On 01.06.18 at 16:06, <andrew.cooper3@xxxxxxxxxx> wrote:
> c/s "x86/pv: Introduce and use x86emul_write_dr()" fixed a bug with IO shadow
> handling, in that it remained stale and visible until %dr7.L/G got set again.
> 
> However, it neglected the -EPERM return inbetween these two hunks, introducing
> a different bug in which a write to %dr7 which tries to set IO breakpoints
> without %cr4.DE being set clobbers the IO state, rather than leaves it alone.
> 
> Instead, move the zeroing slightly later, which guarentees that the shadow
> gets written exactly once, on a successful update to %dr7.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel

 


Rackspace

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