Hi Jan,
On 25/03/2020 15:27, Jan Beulich wrote:
On 22.03.2020 17:14, jul...@xen.org wrote:
@@ -785,21 +781,21 @@ bool is_iomem_page(mfn_t mfn)
return (page_get_owner(page) == dom_io);
}
-static int update_xen_mappings(unsigned long mfn, unsigned int cacheattr)
+static int update_xen_mappings(mfn_t mfn, unsigned int cacheattr)
{
int err = 0;
- bool alias = mfn >= PFN_DOWN(xen_phys_start) &&
- mfn < PFN_UP(xen_phys_start + xen_virt_end - XEN_VIRT_START);
+ bool alias = mfn_x(mfn) >= PFN_DOWN(xen_phys_start) &&
+ mfn_x(mfn) < PFN_UP(xen_phys_start + xen_virt_end - XEN_VIRT_START);
unsigned long xen_va =
- XEN_VIRT_START + ((mfn - PFN_DOWN(xen_phys_start)) << PAGE_SHIFT);
+ XEN_VIRT_START + mfn_to_maddr(mfn_add(mfn, -PFN_DOWN(xen_phys_start)));
Depending on the types involved (e.g. in PFN_DOWN()) this may
or may not be safe, so I consider such a transformation at
least fragile. I think we either want to gain mfn_sub() or
keep this as a "real" subtraction.
I want to avoid mfn_x() as much as possible when everything can be done
using typesafe operation. But i am not sure how mfn_sub() would solve
the problem. Do you mind providing more information?
@@ -584,21 +584,21 @@ static unsigned long init_node_heap(int node, unsigned
long mfn,
needed = 0;
}
else if ( *use_tail && nr >= needed &&
- arch_mfn_in_directmap(mfn + nr) &&
+ arch_mfn_in_directmap(mfn_x(mfn_add(mfn, nr))) &&
(!xenheap_bits ||
- !((mfn + nr - 1) >> (xenheap_bits - PAGE_SHIFT))) )
+ !((mfn_x(mfn) + nr - 1) >> (xenheap_bits - PAGE_SHIFT))) )
May I suggest consistency here: This one uses +, while ...
{
- _heap[node] = mfn_to_virt(mfn + nr - needed);
- avail[node] = mfn_to_virt(mfn + nr - 1) +
+ _heap[node] = mfn_to_virt(mfn_add(mfn, nr - needed));
+ avail[node] = mfn_to_virt(mfn_add(mfn, nr - 1)) +
PAGE_SIZE - sizeof(**avail) * NR_ZONES;
}
else if ( nr >= needed &&
- arch_mfn_in_directmap(mfn + needed) &&
+ arch_mfn_in_directmap(mfn_x(mfn_add(mfn, needed))) &&
... this one uses mfn_add() despite the mfn_x() around it, and ...
So the reason I used mfn_x(mfn_add(mfn, needed)) here is I plan to
convert arch_mfn_in_directmap() to use typesafe soon. In the two others
cases...
(!xenheap_bits ||
- !((mfn + needed - 1) >> (xenheap_bits - PAGE_SHIFT))) )
+ !((mfn_x(mfn) + needed - 1) >> (xenheap_bits - PAGE_SHIFT))) )
... here you use + again. My personal preference would be to avoid
constructs like mfn_x(mfn_add()).
... I am still unsure how to avoid mfn_x(). Do you have any ideas?
@@ -269,10 +270,10 @@ out_dealloc:
continue;
for ( i = 0; i < pages; i++ )
{
- uint32_t mfn = t_info_mfn_list[offset + i];
- if ( !mfn )
+ mfn_t mfn = _mfn(t_info_mfn_list[offset + i]);
+ if ( mfn_eq(mfn, _mfn(0)) )
Please could you take the opportunity and add the missing blank line
between these two?
Sure.
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -667,7 +667,7 @@ static inline bool arch_mfn_in_directmap(unsigned long mfn)
{
unsigned long eva = min(DIRECTMAP_VIRT_END, HYPERVISOR_VIRT_END);
- return mfn <= (virt_to_mfn(eva - 1) + 1);
+ return mfn <= mfn_x(mfn_add(virt_to_mfn(eva - 1), 1));
Even if you wanted to stick to using mfn_add() here, there's one
blank too many after the comma.
I will remove the extra blank. Regarding the construction, I have been
wondering for a couple of years now whether we should introduce mfn_{lt,
gt}. What do you think?
With these taken care of
Reviewed-by: Jan Beulich <jbeul...@suse.com>
Thank you for the review.
Cheers,
--
Julien Grall