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x86: Remove return value from UPDATE_ENTRY

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UPDATE_ENTRY/update_intpte always returns true since 1bc30c076a
"x86/mm: {paging, sh}_{cmpxchg, write}_guest_entry() cannot fault"

Signed-off-by: Kevin Lampis <kevin.lampis@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
This commit is contained in:
Kevin Lampis authored and Andrew Cooper committed 2026-09-30 15:37:24 +01:00
1 parent 861e44a3ba
commit 5ec86c22b4
4 files changed
+45 -89
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xen/arch/x86/mm.c
+20 -54
View File
@@ -2215,11 +2215,10 @@ static int mod_l1_entry(l1_pgentry_t *pl1e, l1_pgentry_t nl1e,
/* Fast path for sufficiently-similar mappings. */
if ( !l1e_has_changed(ol1e, nl1e, ~FASTPATH_FLAG_WHITELIST) )
{
rc = UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu,
update_flags);
UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, update_flags);
if ( page )
put_page(page);
return rc ? 0 : -EBUSY;
return 0;
}
switch ( rc = get_page_from_l1e(nl1e, pt_dom, pg_dom) )
@@ -2239,20 +2238,12 @@ static int mod_l1_entry(l1_pgentry_t *pl1e, l1_pgentry_t nl1e,
if ( page )
put_page(page);
if ( unlikely(!UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu,
update_flags)) )
{
ol1e = nl1e;
rc = -EBUSY;
}
UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, update_flags);
}
else if ( pv_l1tf_check_l1e(pt_dom, nl1e) )
return -ERESTART;
else if ( unlikely(!UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu,
update_flags)) )
{
return -EBUSY;
}
else
UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, pt_vcpu, update_flags);
put_page_from_l1e(ol1e, pt_dom);
return rc;
@@ -2295,28 +2286,19 @@ static int mod_l2_entry(l2_pgentry_t *pl2e,
/* Fast path for sufficiently-similar mappings. */
if ( !l2e_has_changed(ol2e, nl2e, ~FASTPATH_PDE_FLAG_WHITELIST) )
{
if ( UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, mfn, vcpu, update_flags) )
return 0;
return -EBUSY;
UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, mfn, vcpu, update_flags);
return 0;
}
if ( unlikely((rc = get_page_from_l2e(nl2e, mfn, d, 0)) < 0) )
return rc;
if ( unlikely(!UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, mfn, vcpu,
update_flags)) )
{
ol2e = nl2e;
rc = -EBUSY;
}
UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, mfn, vcpu, update_flags);
}
else if ( pv_l1tf_check_l2e(d, nl2e) )
return -ERESTART;
else if ( unlikely(!UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, mfn, vcpu,
update_flags)) )
{
return -EBUSY;
}
else
UPDATE_ENTRY(l2, pl2e, ol2e, nl2e, mfn, vcpu, update_flags);
put_page_from_l2e(ol2e, mfn, PTF_defer);
@@ -2357,8 +2339,8 @@ static int mod_l3_entry(l3_pgentry_t *pl3e,
/* Fast path for sufficiently-similar mappings. */
if ( !l3e_has_changed(ol3e, nl3e, ~FASTPATH_PDE_FLAG_WHITELIST) )
{
rc = UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, mfn, vcpu, update_flags);
return rc ? 0 : -EFAULT;
UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, mfn, vcpu, update_flags);
return 0;
}
rc = get_page_from_l3e(nl3e, mfn, d, 0);
@@ -2366,20 +2348,12 @@ static int mod_l3_entry(l3_pgentry_t *pl3e,
return rc;
rc = 0;
if ( unlikely(!UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, mfn, vcpu,
update_flags)) )
{
ol3e = nl3e;
rc = -EFAULT;
}
UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, mfn, vcpu, update_flags);
}
else if ( pv_l1tf_check_l3e(d, nl3e) )
return -ERESTART;
else if ( unlikely(!UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, mfn, vcpu,
update_flags)) )
{
return -EFAULT;
}
else
UPDATE_ENTRY(l3, pl3e, ol3e, nl3e, mfn, vcpu, update_flags);
put_page_from_l3e(ol3e, mfn, PTF_defer);
return rc;
@@ -2419,8 +2393,8 @@ static int mod_l4_entry(l4_pgentry_t *pl4e,
/* Fast path for sufficiently-similar mappings. */
if ( !l4e_has_changed(ol4e, nl4e, ~FASTPATH_PDE_FLAG_WHITELIST) )
{
rc = UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, mfn, vcpu, update_flags);
return rc ? 0 : -EFAULT;
UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, mfn, vcpu, update_flags);
return 0;
}
rc = get_page_from_l4e(nl4e, mfn, d, 0);
@@ -2428,20 +2402,12 @@ static int mod_l4_entry(l4_pgentry_t *pl4e,
return rc;
rc = 0;
if ( unlikely(!UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, mfn, vcpu,
update_flags)) )
{
ol4e = nl4e;
rc = -EFAULT;
}
UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, mfn, vcpu, update_flags);
}
else if ( pv_l1tf_check_l4e(d, nl4e) )
return -ERESTART;
else if ( unlikely(!UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, mfn, vcpu,
update_flags)) )
{
return -EFAULT;
}
else
UPDATE_ENTRY(l4, pl4e, ol4e, nl4e, mfn, vcpu, update_flags);
put_page_from_l4e(ol4e, mfn, PTF_defer);
return rc;
xen/arch/x86/pv/grant_table.c
+23 -28
View File
@@ -98,18 +98,16 @@ int create_grant_pv_mapping(uint64_t addr, mfn_t frame,
goto out_unlock;
ol1e = *pl1e;
if ( UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, curr, 0) )
{
/*
* We always create mappings in this path. However, our caller,
* map_grant_ref(), only passes potentially non-zero cache_flags for
* MMIO frames, so this path doesn't create non-coherent mappings of
* RAM frames and there's no need to calculate PGT_non_coherent.
*/
ASSERT(!cache_flags || is_iomem_page(frame));
UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, curr, 0);
/*
* We always create mappings in this path. However, our caller,
* map_grant_ref(), only passes potentially non-zero cache_flags for
* MMIO frames, so this path doesn't create non-coherent mappings of
* RAM frames and there's no need to calculate PGT_non_coherent.
*/
ASSERT(!cache_flags || is_iomem_page(frame));
rc = GNTST_okay;
}
rc = GNTST_okay;
out_unlock:
page_unlock(page);
@@ -165,10 +163,9 @@ static bool steal_linear_address(unsigned long linear, l1_pgentry_t *out)
goto out_unlock;
ol1e = *pl1e;
okay = UPDATE_ENTRY(l1, pl1e, ol1e, l1e_empty(), gl1mfn, curr, 0);
if ( okay )
*out = ol1e;
UPDATE_ENTRY(l1, pl1e, ol1e, l1e_empty(), gl1mfn, curr, 0);
*out = ol1e;
okay = true;
out_unlock:
page_unlock(page);
@@ -293,19 +290,17 @@ int replace_grant_pv_mapping(uint64_t addr, mfn_t frame,
"PTE flags %x for %"PRIx64" don't match grant (%x)\n",
l1e_get_flags(ol1e), addr, grant_pte_flags);
if ( UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, curr, 0) )
{
/*
* Generally, replace_grant_pv_mapping() is used to destroy mappings
* (n1le = l1e_empty()), but it can be a present mapping on the
* GNTABOP_unmap_and_replace path.
*
* In such cases, the PTE is fully transplanted from its old location
* via steal_linear_addr(), so we need not perform PGT_non_coherent
* checking here.
*/
rc = GNTST_okay;
}
UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, gl1mfn, curr, 0);
/*
* Generally, replace_grant_pv_mapping() is used to destroy mappings
* (n1le = l1e_empty()), but it can be a present mapping on the
* GNTABOP_unmap_and_replace path.
*
* In such cases, the PTE is fully transplanted from its old location
* via steal_linear_addr(), so we need not perform PGT_non_coherent
* checking here.
*/
rc = GNTST_okay;
out_unlock:
page_unlock(page);
xen/arch/x86/pv/mm.h
+1 -5
View File
@@ -67,13 +67,10 @@ static inline intpte_t paging_cmpxchg_guest_entry(
/*
* How to write an entry to the guest pagetables.
* Returns false for failure (pointer not valid), true for success.
*/
static inline bool update_intpte(intpte_t *p, intpte_t old, intpte_t new,
static inline void update_intpte(intpte_t *p, intpte_t old, intpte_t new,
mfn_t mfn, struct vcpu *v, unsigned int flags)
{
bool rv = true;
#ifndef PTE_UPDATE_WITH_CMPXCHG
if ( !(flags & PTE_UPDATE_PRESERVE_AD) )
paging_write_guest_entry(v, p, new, mfn);
@@ -98,7 +95,6 @@ static inline bool update_intpte(intpte_t *p, intpte_t old, intpte_t new,
old = t;
}
}
return rv;
}
/*
xen/arch/x86/pv/ro-page-fault.c
+1 -2
View File
@@ -200,8 +200,7 @@ static int ptwr_emulated_update(unsigned long addr, intpte_t *p_old,
else
{
ol1e = *pl1e;
if ( !UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, mfn, v, 0) )
BUG();
UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, mfn, v, 0);
}
trace_ptwr_emulation(addr, nl1e);
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