| Message ID | 1405690440-32211-1-git-send-email-ian.campbell@citrix.com |
|---|---|
| State | Accepted |
| Commit | 964fd5a99c13c707c0c3355743ed1fadf88fc9d9 |
| Headers | show |
Hi Ian, On 18/07/14 14:33, Ian Campbell wrote: > When we change which PT page we are mapping at a given level then we need to > invalidate any cached mappings further down the tree, otherwise we risk using > them because their offset might match but be based on a different offset > further up the table. > > e.g. when remapping first then cur_first_offset and cur_second_offset (which > indicate the currently mapped second and third tables respectively) both become > invalid > > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Acked-by: Julien Grall <julien.grall@linaro.org> Regards, > --- > v2: Also invalidate cur_first_offset when changing cur_first_page. > Corrected/clarified commit message, this issue isn't really specific to > superpages, they just happen to expose it. > --- > xen/arch/arm/p2m.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c > index 2f855b5..8ffddac 100644 > --- a/xen/arch/arm/p2m.c > +++ b/xen/arch/arm/p2m.c > @@ -743,6 +743,8 @@ static int apply_p2m_changes(struct domain *d, > goto out; > } > cur_first_page = p2m_first_level_index(addr); > + /* Any mapping further down is now invalid */ > + cur_first_offset = cur_second_offset = ~0; > } > > /* We only use a 3 level p2m at the moment, so no level 0, > @@ -765,6 +767,8 @@ static int apply_p2m_changes(struct domain *d, > if (second) unmap_domain_page(second); > second = map_domain_page(first[first_table_offset(addr)].p2m.base); > cur_first_offset = first_table_offset(addr); > + /* Any mapping further down is now invalid */ > + cur_second_offset = ~0; > } > /* else: second already valid */ > >
On Fri, 2014-07-18 at 21:29 +0100, Julien Grall wrote:
> Acked-by: Julien Grall <julien.grall@linaro.org>
Applied thanks.
Ian.
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index 2f855b5..8ffddac 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -743,6 +743,8 @@ static int apply_p2m_changes(struct domain *d, goto out; } cur_first_page = p2m_first_level_index(addr); + /* Any mapping further down is now invalid */ + cur_first_offset = cur_second_offset = ~0; } /* We only use a 3 level p2m at the moment, so no level 0, @@ -765,6 +767,8 @@ static int apply_p2m_changes(struct domain *d, if (second) unmap_domain_page(second); second = map_domain_page(first[first_table_offset(addr)].p2m.base); cur_first_offset = first_table_offset(addr); + /* Any mapping further down is now invalid */ + cur_second_offset = ~0; } /* else: second already valid */
When we change which PT page we are mapping at a given level then we need to invalidate any cached mappings further down the tree, otherwise we risk using them because their offset might match but be based on a different offset further up the table. e.g. when remapping first then cur_first_offset and cur_second_offset (which indicate the currently mapped second and third tables respectively) both become invalid Signed-off-by: Ian Campbell <ian.campbell@citrix.com> --- v2: Also invalidate cur_first_offset when changing cur_first_page. Corrected/clarified commit message, this issue isn't really specific to superpages, they just happen to expose it. --- xen/arch/arm/p2m.c | 4 ++++ 1 file changed, 4 insertions(+)