On 2015/6/11 17:23, Jan Beulich wrote:
On 11.06.15 at 10:23, <tiejun.c...@intel.com> wrote:
On 2015/6/11 15:33, Jan Beulich wrote:
On 11.06.15 at 03:15, <tiejun.c...@intel.com> wrote:
We will create this sort of identity mapping as follows:
If the gfn space is unoccupied, we just set the mapping. If the space
is already occupied by 1:1 mappings, do nothing. Failed for any
other cases.
Signed-off-by: Tiejun Chen <tiejun.c...@intel.com>
First of all you continue to be copying each patch to every
maintainer involved in some part of the series. Please limit the
I just hope all involved guys can see this series on the whole to
review. But,
Cc list of each patch to the actual list of people needing to be
Cc-ed on it (or you know explicitly wanting a copy).
Next, I will just send them to each associated maintainer.
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -898,6 +898,41 @@ int set_mmio_p2m_entry(struct domain *d, unsigned long
gfn, mfn_t mfn,
return set_typed_p2m_entry(d, gfn, mfn, p2m_mmio_direct, access);
}
+int set_identity_p2m_entry(struct domain *d, unsigned long gfn,
+ p2m_access_t p2ma)
+{
+ p2m_type_t p2mt;
+ p2m_access_t a;
+ mfn_t mfn;
+ struct p2m_domain *p2m = p2m_get_hostp2m(d);
+ int ret;
+
+ if ( paging_mode_translate(p2m->domain) )
+ {
+ gfn_lock(p2m, gfn, 0);
+
+ mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL);
+
+ if ( p2mt == p2m_invalid || mfn_x(mfn) == INVALID_MFN )
I'm not fundamentally opposed to this extra INVALID_MFN check, but
could you please clarify for which P2M type you saw INVALID_MFN
coming back here, and for which p2m_invalid cases you didn't also
see INVALID_MFN? I.e. I'd really prefer a single check to be used
when that can cover all cases.
Actually, I initially adopted "!mfn_valid(mfn)" in our previous version.
But Tim issued one comment about this,
"I don't think this check is quite right -- for example, this p2m entry
might be an MMIO mapping or a PoD entry. "if ( p2mt == p2m_invalid )"
would be better."
Ah, I right, I now remember. In which case checking against
INVALID_MFN would cover the MMIO case, but not the PoD one.
But if I just keep his recommended check, you can see the following when
I pass through IGD,
(XEN) Cannot identity map d1:ad800, already mapped to ffffffffffffffff
with p2mt:4.
Looks "4" indicates p2m_mmio_dm, right?
And it seems to me that this particular combination would need
special treatment, i.e. you'd need
if ( p2mt == p2m_invalid ||
(p2mt == p2m_mmio_dm && mfn_x(mfn) == INVALID_MFN) )
as long as p2m_invalid isn't the default type lookups return. But
I'd recommend waiting for Tim to confirm or further adjust that.
Sure.
Thanks
Tiejun
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