File 5e86fa2a-x86-p2m_remove_page-retval.patch of Package xen.22517
# Commit a6b051a87a586347969bfbaa6925ac0f0c845413
# Date 2020-04-03 10:56:10 +0200
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
x86/p2m: don't ignore p2m_remove_page()'s return value
It's not very nice to return from guest_physmap_add_entry() after
perhaps already having made some changes to the P2M, but this is pre-
existing practice in the function, and imo better than ignoring errors.
Take the liberty and replace an mfn_add() instance with a local variable
already holding the result (as proven by the check immediately ahead).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -772,8 +772,7 @@ void p2m_final_teardown(struct domain *d
p2m_teardown_hostp2m(d);
}
-
-static int
+static int __must_check
p2m_remove_page(struct p2m_domain *p2m, unsigned long gfn_l, unsigned long mfn,
unsigned int page_order)
{
@@ -961,9 +960,9 @@ guest_physmap_add_entry(struct domain *d
ASSERT(mfn_valid(omfn));
P2M_DEBUG("old gfn=%#lx -> mfn %#lx\n",
gfn_x(ogfn) , mfn_x(omfn));
- if ( mfn_eq(omfn, mfn_add(mfn, i)) )
- p2m_remove_page(p2m, gfn_x(ogfn), mfn_x(mfn_add(mfn, i)),
- 0);
+ if ( mfn_eq(omfn, mfn_add(mfn, i)) &&
+ (rc = p2m_remove_page(p2m, gfn_x(ogfn), mfn_x(omfn), 0)) )
+ goto out;
}
}
}
@@ -987,6 +986,7 @@ guest_physmap_add_entry(struct domain *d
}
}
+ out:
p2m_unlock(p2m);
return rc;
@@ -2646,9 +2646,9 @@ int p2m_change_altp2m_gfn(struct domain
if ( gfn_eq(new_gfn, INVALID_GFN) )
{
- if ( mfn_valid(mfn) )
- p2m_remove_page(ap2m, gfn_x(old_gfn), mfn_x(mfn), PAGE_ORDER_4K);
- rc = 0;
+ rc = mfn_valid(mfn)
+ ? p2m_remove_page(ap2m, gfn_x(old_gfn), mfn_x(mfn), PAGE_ORDER_4K)
+ : 0;
goto out;
}