From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>,
"Tim Deegan" <tim@xen.org>,
"George Dunlap" <george.dunlap@citrix.com>
Subject: [PATCH 06/11] x86/shadow: drop a few uses of mfn_valid()
Date: Thu, 5 Jan 2023 17:04:36 +0100 [thread overview]
Message-ID: <ca3e0c70-ae80-4c21-97f7-36525229074b@suse.com> (raw)
In-Reply-To: <074dc3bb-6057-4f61-d516-d0fe3551165c@suse.com>
v->arch.paging.shadow.shadow_table[], v->arch.paging.shadow.oos[],
v->arch.paging.shadow.oos_{snapshot[],fixup[].smfn[]} as well as the
hash table are all only ever written with valid MFNs or INVALID_MFN.
Avoid the somewhat expensive mfn_valid() when checking MFNs coming from
these arrays.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
There are many more uses which can likely be replaced, but I think we're
better off doing this in piecemeal fashion.
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -171,7 +171,7 @@ static void sh_oos_audit(struct domain *
for ( idx = 0; idx < SHADOW_OOS_PAGES; idx++ )
{
mfn_t *oos = v->arch.paging.shadow.oos;
- if ( !mfn_valid(oos[idx]) )
+ if ( mfn_eq(oos[idx], INVALID_MFN) )
continue;
expected_idx = mfn_x(oos[idx]) % SHADOW_OOS_PAGES;
@@ -327,8 +327,7 @@ void oos_fixup_add(struct domain *d, mfn
int i;
for ( i = 0; i < SHADOW_OOS_FIXUPS; i++ )
{
- if ( mfn_valid(oos_fixup[idx].smfn[i])
- && mfn_eq(oos_fixup[idx].smfn[i], smfn)
+ if ( mfn_eq(oos_fixup[idx].smfn[i], smfn)
&& (oos_fixup[idx].off[i] == off) )
return;
}
@@ -461,7 +460,7 @@ static void oos_hash_add(struct vcpu *v,
idx = mfn_x(gmfn) % SHADOW_OOS_PAGES;
oidx = idx;
- if ( mfn_valid(oos[idx])
+ if ( !mfn_eq(oos[idx], INVALID_MFN)
&& (mfn_x(oos[idx]) % SHADOW_OOS_PAGES) == idx )
{
/* Punt the current occupant into the next slot */
@@ -470,8 +469,8 @@ static void oos_hash_add(struct vcpu *v,
swap = 1;
idx = (idx + 1) % SHADOW_OOS_PAGES;
}
- if ( mfn_valid(oos[idx]) )
- {
+ if ( !mfn_eq(oos[idx], INVALID_MFN) )
+ {
/* Crush the current occupant. */
_sh_resync(v, oos[idx], &oos_fixup[idx], oos_snapshot[idx]);
perfc_incr(shadow_unsync_evict);
@@ -607,7 +606,7 @@ void sh_resync_all(struct vcpu *v, int s
/* First: resync all of this vcpu's oos pages */
for ( idx = 0; idx < SHADOW_OOS_PAGES; idx++ )
- if ( mfn_valid(oos[idx]) )
+ if ( !mfn_eq(oos[idx], INVALID_MFN) )
{
/* Write-protect and sync contents */
_sh_resync(v, oos[idx], &oos_fixup[idx], oos_snapshot[idx]);
@@ -630,7 +629,7 @@ void sh_resync_all(struct vcpu *v, int s
for ( idx = 0; idx < SHADOW_OOS_PAGES; idx++ )
{
- if ( !mfn_valid(oos[idx]) )
+ if ( mfn_eq(oos[idx], INVALID_MFN) )
continue;
if ( skip )
@@ -2187,7 +2186,7 @@ void sh_remove_shadows(struct domain *d,
!(pg->shadow_flags & (1 << t)) ) \
break; \
smfn = shadow_hash_lookup(d, mfn_x(gmfn), t); \
- if ( unlikely(!mfn_valid(smfn)) ) \
+ if ( unlikely(mfn_eq(smfn, INVALID_MFN)) ) \
{ \
printk(XENLOG_G_ERR "gmfn %"PRI_mfn" has flags %#x" \
" but no type-%#x shadow\n", \
@@ -2755,7 +2754,7 @@ void shadow_teardown(struct domain *d, b
int i;
mfn_t *oos_snapshot = v->arch.paging.shadow.oos_snapshot;
for ( i = 0; i < SHADOW_OOS_PAGES; i++ )
- if ( mfn_valid(oos_snapshot[i]) )
+ if ( !mfn_eq(oos_snapshot[i], INVALID_MFN) )
{
shadow_free(d, oos_snapshot[i]);
oos_snapshot[i] = INVALID_MFN;
@@ -2938,7 +2937,7 @@ static int shadow_one_bit_disable(struct
int i;
mfn_t *oos_snapshot = v->arch.paging.shadow.oos_snapshot;
for ( i = 0; i < SHADOW_OOS_PAGES; i++ )
- if ( mfn_valid(oos_snapshot[i]) )
+ if ( !mfn_eq(oos_snapshot[i], INVALID_MFN) )
{
shadow_free(d, oos_snapshot[i]);
oos_snapshot[i] = INVALID_MFN;
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -110,7 +110,7 @@ get_fl1_shadow_status(struct domain *d,
/* Look for FL1 shadows in the hash table */
{
mfn_t smfn = shadow_hash_lookup(d, gfn_x(gfn), SH_type_fl1_shadow);
- ASSERT(!mfn_valid(smfn) || mfn_to_page(smfn)->u.sh.head);
+ ASSERT(mfn_eq(smfn, INVALID_MFN) || mfn_to_page(smfn)->u.sh.head);
return smfn;
}
@@ -2680,7 +2680,7 @@ static int cf_check sh_page_fault(
mfn_t smfn = pagetable_get_mfn(
v->arch.paging.shadow.shadow_table[i]);
- if ( mfn_valid(smfn) && (mfn_x(smfn) != 0) )
+ if ( mfn_x(smfn) )
{
used |= (mfn_to_page(smfn)->v.sh.back == mfn_x(gmfn));
@@ -3824,7 +3824,7 @@ static void cf_check sh_pagetable_dying(
: shadow_hash_lookup(d, mfn_x(gmfn), SH_type_l2_pae_shadow);
}
- if ( mfn_valid(smfn) )
+ if ( !mfn_eq(smfn, INVALID_MFN) )
{
gmfn = _mfn(mfn_to_page(smfn)->v.sh.back);
mfn_to_page(gmfn)->pagetable_dying = true;
@@ -3867,7 +3867,7 @@ static void cf_check sh_pagetable_dying(
smfn = shadow_hash_lookup(d, mfn_x(gmfn), SH_type_l4_64_shadow);
#endif
- if ( mfn_valid(smfn) )
+ if ( !mfn_eq(smfn, INVALID_MFN) )
{
mfn_to_page(gmfn)->pagetable_dying = true;
shadow_unhook_mappings(d, smfn, 1/* user pages only */);
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -770,8 +770,10 @@ get_shadow_status(struct domain *d, mfn_
/* Look for shadows in the hash table */
{
mfn_t smfn = shadow_hash_lookup(d, mfn_x(gmfn), shadow_type);
- ASSERT(!mfn_valid(smfn) || mfn_to_page(smfn)->u.sh.head);
+
+ ASSERT(mfn_eq(smfn, INVALID_MFN) || mfn_to_page(smfn)->u.sh.head);
perfc_incr(shadow_get_shadow_status);
+
return smfn;
}
next prev parent reply other threads:[~2023-01-05 16:04 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-05 15:57 [PATCH 00/11] x86/shadow: misc tidying Jan Beulich
2023-01-05 15:59 ` [PATCH 01/11] x86/shadow: replace sh_reset_l3_up_pointers() Jan Beulich
2023-01-06 0:55 ` Andrew Cooper
2023-01-09 8:35 ` Jan Beulich
2023-01-05 15:59 ` [PATCH 02/11] x86/shadow: convert sh_audit_flags()'es 1st parameter to domain Jan Beulich
2023-01-05 15:59 ` [PATCH 03/11] x86/shadow: drop hash_vcpu_foreach() Jan Beulich
2023-01-05 16:00 ` [PATCH 04/11] x86/shadow: rename hash_domain_foreach() Jan Beulich
2023-01-05 16:04 ` [PATCH 05/11] x86/shadow: move bogus HVM checks in sh_pagetable_dying() Jan Beulich
2023-01-06 1:00 ` Andrew Cooper
2023-01-09 8:39 ` Jan Beulich
2023-01-05 16:04 ` Jan Beulich [this message]
2023-01-06 1:02 ` [PATCH 06/11] x86/shadow: drop a few uses of mfn_valid() Andrew Cooper
2023-01-09 8:42 ` Jan Beulich
2023-01-05 16:05 ` [PATCH 07/11] x86/shadow: L2H shadow type is PV32-only Jan Beulich
2023-01-06 1:31 ` Andrew Cooper
2023-01-09 9:12 ` Jan Beulich
2023-01-05 16:05 ` [PATCH 08/11] x86/shadow: reduce effort of hash calculation Jan Beulich
2023-01-06 2:03 ` Andrew Cooper
2023-01-09 9:48 ` Jan Beulich
2023-01-05 16:06 ` [PATCH 09/11] x86/shadow: simplify conditionals in sh_{get,put}_ref() Jan Beulich
2023-01-05 16:07 ` [PATCH 10/11] x86/shadow: correct shadow type bounds checks Jan Beulich
2023-01-05 16:07 ` [PATCH 11/11] x86/shadow: sh_remove_all_mappings() is HVM-only Jan Beulich
2023-01-06 2:03 ` [PATCH 00/11] x86/shadow: misc tidying Andrew Cooper
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