Jan Beulich
2011-Mar-09 10:58 UTC
[Xen-devel] [PATCH 5/5] x86: make mod_l2_entry() return a proper error code
... so that finally all mod_lN_entry() functions behave identically,
allowing some cleanup in do_mmu_update() (which no longer needs to
track both an okay status and an error code).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- 2011-03-09.orig/xen/arch/x86/mm.c
+++ 2011-03-09/xen/arch/x86/mm.c
@@ -1845,16 +1845,16 @@ static int mod_l2_entry(l2_pgentry_t *pl
struct domain *d = vcpu->domain;
struct page_info *l2pg = mfn_to_page(pfn);
unsigned long type = l2pg->u.inuse.type_info;
- int rc = 1;
+ int rc = 0;
if ( unlikely(!is_guest_l2_slot(d, type, pgentry_ptr_to_slot(pl2e))) )
{
MEM_LOG("Illegal L2 update attempt in Xen-private area %p",
pl2e);
- return 0;
+ return -EPERM;
}
if ( unlikely(__copy_from_user(&ol2e, pl2e, sizeof(ol2e)) != 0) )
- return 0;
+ return -EFAULT;
if ( l2e_get_flags(nl2e) & _PAGE_PRESENT )
{
@@ -1862,32 +1862,33 @@ static int mod_l2_entry(l2_pgentry_t *pl
{
MEM_LOG("Bad L2 flags %x",
l2e_get_flags(nl2e) & L2_DISALLOW_MASK);
- return 0;
+ return -EINVAL;
}
/* Fast path for identical mapping and presence. */
if ( !l2e_has_changed(ol2e, nl2e, _PAGE_PRESENT) )
{
adjust_guest_l2e(nl2e, d);
- rc = UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, pfn, vcpu, preserve_ad);
- return rc;
+ if ( UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, pfn, vcpu, preserve_ad) )
+ return 0;
+ return -EBUSY;
}
- if ( unlikely(get_page_from_l2e(nl2e, pfn, d) < 0) )
- return 0;
+ if ( unlikely((rc = get_page_from_l2e(nl2e, pfn, d)) < 0) )
+ return rc;
adjust_guest_l2e(nl2e, d);
if ( unlikely(!UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, pfn, vcpu,
preserve_ad)) )
{
ol2e = nl2e;
- rc = 0;
+ rc = -EBUSY;
}
}
else if ( unlikely(!UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, pfn, vcpu,
preserve_ad)) )
{
- return 0;
+ return -EBUSY;
}
put_page_from_l2e(ol2e, pfn);
@@ -3367,7 +3368,7 @@ int do_mmu_update(
void *va;
unsigned long gpfn, gmfn, mfn;
struct page_info *page;
- int rc = 0, okay = 1, i = 0;
+ int rc = 0, i = 0;
unsigned int cmd, done = 0, pt_dom;
struct vcpu *v = current;
struct domain *d = v->domain, *pt_owner = d, *pg_owner;
@@ -3434,7 +3435,6 @@ int do_mmu_update(
}
cmd = req.ptr & (sizeof(l1_pgentry_t)-1);
- okay = 0;
switch ( cmd )
{
@@ -3451,6 +3451,7 @@ int do_mmu_update(
rc = xsm_mmu_normal_update(d, pg_owner, req.val);
if ( rc )
break;
+ rc = -EINVAL;
req.ptr -= cmd;
gmfn = req.ptr >> PAGE_SHIFT;
@@ -3521,7 +3522,6 @@ int do_mmu_update(
rc = mod_l1_entry(va, l1e, mfn,
cmd == MMU_PT_UPDATE_PRESERVE_AD, v,
pg_owner);
- okay = !rc;
}
break;
case PGT_l2_page_table:
@@ -3545,13 +3545,12 @@ int do_mmu_update(
else if ( p2m_ram_shared == l2e_p2mt )
{
MEM_LOG("Unexpected attempt to map shared
page.\n");
- rc = -EINVAL;
break;
}
- okay = mod_l2_entry(va, l2e, mfn,
- cmd == MMU_PT_UPDATE_PRESERVE_AD, v);
+ rc = mod_l2_entry(va, l2e, mfn,
+ cmd == MMU_PT_UPDATE_PRESERVE_AD, v);
}
break;
case PGT_l3_page_table:
@@ -3575,13 +3574,11 @@ int do_mmu_update(
else if ( p2m_ram_shared == l3e_p2mt )
{
MEM_LOG("Unexpected attempt to map shared
page.\n");
- rc = -EINVAL;
break;
}
rc = mod_l3_entry(va, l3e, mfn,
cmd == MMU_PT_UPDATE_PRESERVE_AD, 1, v);
- okay = !rc;
}
break;
#if CONFIG_PAGING_LEVELS >= 4
@@ -3607,20 +3604,18 @@ int do_mmu_update(
else if ( p2m_ram_shared == l4e_p2mt )
{
MEM_LOG("Unexpected attempt to map shared
page.\n");
- rc = -EINVAL;
break;
}
rc = mod_l4_entry(va, l4e, mfn,
cmd == MMU_PT_UPDATE_PRESERVE_AD, 1, v);
- okay = !rc;
}
break;
#endif
case PGT_writable_page:
perfc_incr(writable_mmu_updates);
- okay = paging_write_guest_entry(
- v, va, req.val, _mfn(mfn));
+ if ( paging_write_guest_entry(v, va, req.val, _mfn(mfn)) )
+ rc = 0;
break;
}
page_unlock(page);
@@ -3630,8 +3625,8 @@ int do_mmu_update(
else if ( get_page_type(page, PGT_writable_page) )
{
perfc_incr(writable_mmu_updates);
- okay = paging_write_guest_entry(
- v, va, req.val, _mfn(mfn));
+ if ( paging_write_guest_entry(v, va, req.val, _mfn(mfn)) )
+ rc = 0;
put_page_type(page);
}
@@ -3652,17 +3647,18 @@ int do_mmu_update(
if ( unlikely(!get_page_from_pagenr(mfn, pg_owner)) )
{
MEM_LOG("Could not get page for mach->phys
update");
+ rc = -EINVAL;
break;
}
if ( unlikely(paging_mode_translate(pg_owner)) )
{
MEM_LOG("Mach-phys update on auto-translate guest");
+ rc = -EINVAL;
break;
}
set_gpfn_from_mfn(mfn, gpfn);
- okay = 1;
paging_mark_dirty(pg_owner, mfn);
@@ -3672,15 +3668,11 @@ int do_mmu_update(
default:
MEM_LOG("Invalid page update command %x", cmd);
rc = -ENOSYS;
- okay = 0;
break;
}
- if ( unlikely(!okay) )
- {
- rc = rc ? rc : -EINVAL;
+ if ( unlikely(rc) )
break;
- }
guest_handle_add_offset(ureqs, 1);
}
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