Its used conveniently to create RMRR mapping in shared EPT case.
Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
---
xen/arch/x86/mm/p2m.c | 29 +++++++++++++++++++++++++++++
xen/include/asm-x86/p2m.h | 3 +++
2 files changed, 32 insertions(+)
v6:
* Refactor set_identity_p2m_entry to make sense
v5:
* Rename this function as set_identity_p2m_entry()
* Get mfn directly inside set_identity_p2m_entry()
v4:
* new patch to combine get and set together to create RMRR mapping.
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 642ec28..06bed7a 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -858,6 +858,35 @@ 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);
}
+int set_identity_p2m_entry(struct domain *d, unsigned long gfn)
+{
+ p2m_type_t p2mt;
+ p2m_access_t a;
+ mfn_t mfn;
+ struct p2m_domain *p2m = p2m_get_hostp2m(d);
+ int ret = -EBUSY;
+
+ gfn_lock(p2m, gfn, 0);
+
+ mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL);
+
+ if ( !mfn_valid(mfn) )
+ ret = p2m_set_entry(p2m, gfn, _mfn(gfn), PAGE_ORDER_4K,
p2m_mmio_direct,
+ p2m_access_rw);
+ else if ( mfn_x(mfn) == gfn &&
+ p2mt == p2m_mmio_direct &&
+ a == p2m_access_rw )
+ ret = 0;
+ else
+ printk(XENLOG_G_WARNING
+ "Cannot identity map d%d:%lx, already mapped to %lx.\n",
+ d->domain_id, gfn, mfn_x(mfn));
+
+ gfn_unlock(p2m, gfn, 0);
+
+ return ret;
+}
+
/* Returns: 0 for success, -errno for failure */
int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn)
{
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 0ddbadb..d130f9a 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -536,6 +536,9 @@ int p2m_is_logdirty_range(struct p2m_domain *, unsigned
long start,
int set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn);
int clear_mmio_p2m_entry(struct domain *d, unsigned long gfn);
+/* Set identity addresses in the p2m table (for pass-through) */
+int set_identity_p2m_entry(struct domain *d, unsigned long gfn);
+
/* Add foreign mapping to the guest's p2m table. */
int p2m_add_foreign(struct domain *tdom, unsigned long fgfn,
unsigned long gpfn, domid_t foreign_domid);
