* [Xen-devel] [PATCH v5 0/4] purge free_shared_domheap_page()
@ 2020-01-29 10:16 Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 1/4] x86 / vmx: move teardown from domain_destroy() Paul Durrant
` (3 more replies)
0 siblings, 4 replies; 8+ messages in thread
From: Paul Durrant @ 2020-01-29 10:16 UTC (permalink / raw)
To: xen-devel; +Cc: Paul Durrant
Paul Durrant (4):
x86 / vmx: move teardown from domain_destroy()...
mm: modify domain_adjust_tot_pages() to better handle a zero
adjustment
mm: make MEMF_no_refcount pages safe to assign
x86 / vmx: use a MEMF_no_refcount domheap page for
APIC_DEFAULT_PHYS_BASE
xen/arch/x86/hvm/vmx/vmx.c | 25 ++++++++++++++++++++-----
xen/arch/x86/mm.c | 10 ----------
xen/common/page_alloc.c | 38 ++++++++++++++++++++++++++------------
xen/include/asm-arm/mm.h | 5 ++++-
xen/include/asm-x86/mm.h | 9 +++++----
5 files changed, 55 insertions(+), 32 deletions(-)
--
2.20.1
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^ permalink raw reply [flat|nested] 8+ messages in thread
* [Xen-devel] [PATCH v5 1/4] x86 / vmx: move teardown from domain_destroy()...
2020-01-29 10:16 [Xen-devel] [PATCH v5 0/4] purge free_shared_domheap_page() Paul Durrant
@ 2020-01-29 10:16 ` Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment Paul Durrant
` (2 subsequent siblings)
3 siblings, 0 replies; 8+ messages in thread
From: Paul Durrant @ 2020-01-29 10:16 UTC (permalink / raw)
To: xen-devel
Cc: Kevin Tian, Jun Nakajima, Wei Liu, Andrew Cooper, Paul Durrant,
George Dunlap, Roger Pau Monné
... to domain_relinquish_resources().
The teardown code frees the APICv page. This does not need to be done late
so do it in domain_relinquish_resources() rather than domain_destroy().
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Wei Liu <wl@xen.org>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: George Dunlap <george.dunlap@citrix.com>
v4:
- New in v4 (disaggregated from v3 patch #3)
---
xen/arch/x86/hvm/vmx/vmx.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index b262d38a7c..606f3dc2eb 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -419,7 +419,7 @@ static int vmx_domain_initialise(struct domain *d)
return 0;
}
-static void vmx_domain_destroy(struct domain *d)
+static void vmx_domain_relinquish_resources(struct domain *d)
{
if ( !has_vlapic(d) )
return;
@@ -2240,7 +2240,7 @@ static struct hvm_function_table __initdata vmx_function_table = {
.cpu_up_prepare = vmx_cpu_up_prepare,
.cpu_dead = vmx_cpu_dead,
.domain_initialise = vmx_domain_initialise,
- .domain_destroy = vmx_domain_destroy,
+ .domain_relinquish_resources = vmx_domain_relinquish_resources,
.vcpu_initialise = vmx_vcpu_initialise,
.vcpu_destroy = vmx_vcpu_destroy,
.save_cpu_ctxt = vmx_save_vmcs_ctxt,
--
2.20.1
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment
2020-01-29 10:16 [Xen-devel] [PATCH v5 0/4] purge free_shared_domheap_page() Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 1/4] x86 / vmx: move teardown from domain_destroy() Paul Durrant
@ 2020-01-29 10:16 ` Paul Durrant
2020-01-29 11:12 ` Jan Beulich
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 3/4] mm: make MEMF_no_refcount pages safe to assign Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 4/4] x86 / vmx: use a MEMF_no_refcount domheap page for APIC_DEFAULT_PHYS_BASE Paul Durrant
3 siblings, 1 reply; 8+ messages in thread
From: Paul Durrant @ 2020-01-29 10:16 UTC (permalink / raw)
To: xen-devel
Cc: Stefano Stabellini, Julien Grall, Wei Liu, Konrad Rzeszutek Wilk,
George Dunlap, Andrew Cooper, Paul Durrant, Ian Jackson
Currently the function will pointlessly acquire and release the global
'heap_lock' in this case.
NOTE: No caller yet calls domain_adjust_tot_pages() with a zero 'pages'
argument, but a subsequent patch will make this possible.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Julien Grall <julien@xen.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wl@xen.org>
v5:
- Split out from the subsequent 'make MEMF_no_refcount pages safe to
assign' patch as requested by Jan
---
xen/common/page_alloc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 919a270587..135e15bae0 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -460,6 +460,9 @@ unsigned long domain_adjust_tot_pages(struct domain *d, long pages)
{
long dom_before, dom_after, dom_claimed, sys_before, sys_after;
+ if ( !pages )
+ goto out;
+
ASSERT(spin_is_locked(&d->page_alloc_lock));
d->tot_pages += pages;
--
2.20.1
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Xen-devel] [PATCH v5 3/4] mm: make MEMF_no_refcount pages safe to assign
2020-01-29 10:16 [Xen-devel] [PATCH v5 0/4] purge free_shared_domheap_page() Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 1/4] x86 / vmx: move teardown from domain_destroy() Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment Paul Durrant
@ 2020-01-29 10:16 ` Paul Durrant
2020-01-29 11:20 ` Jan Beulich
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 4/4] x86 / vmx: use a MEMF_no_refcount domheap page for APIC_DEFAULT_PHYS_BASE Paul Durrant
3 siblings, 1 reply; 8+ messages in thread
From: Paul Durrant @ 2020-01-29 10:16 UTC (permalink / raw)
To: xen-devel
Cc: Stefano Stabellini, Julien Grall, Wei Liu, Konrad Rzeszutek Wilk,
George Dunlap, Andrew Cooper, Paul Durrant, Ian Jackson,
Volodymyr Babchuk, Roger Pau Monné
Currently it is unsafe to assign a domheap page allocated with
MEMF_no_refcount to a domain because the domain't 'tot_pages' will not
be incremented, but will be decrement when the page is freed (since
free_domheap_pages() has no way of telling that the increment was skipped).
This patch allocates a new 'count_info' bit for a PGC_no_refcount flag
which is then used to mark domheap pages allocated with MEMF_no_refcount.
This then allows free_domheap_pages() to skip decrementing tot_pages when
appropriate and hence makes the pages safe to assign.
NOTE: The patch sets MEMF_no_refcount directly in alloc_domheap_pages()
rather than in assign_pages() because the latter is called with
MEMF_no_refcount by memory_exchange().
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Julien Grall <julien@xen.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wl@xen.org>
Cc: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
v5:
- Make sure PGC_no_refcount is set before assign_pages() is called
- Don't bother to clear PGC_no_refcount in free_domheap_pages() and
drop ASSERT in free_heap_pages()
- Don't latch count_info in free_heap_pages()
v4:
- New in v4
---
xen/common/page_alloc.c | 35 +++++++++++++++++++++++------------
xen/include/asm-arm/mm.h | 5 ++++-
xen/include/asm-x86/mm.h | 7 +++++--
3 files changed, 32 insertions(+), 15 deletions(-)
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 135e15bae0..984296c687 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -2287,11 +2287,14 @@ int assign_pages(
for ( i = 0; i < (1 << order); i++ )
{
+ unsigned long count_info = pg[i].count_info;
+
ASSERT(page_get_owner(&pg[i]) == NULL);
- ASSERT(!pg[i].count_info);
+ ASSERT(!(count_info & ~PGC_no_refcount));
page_set_owner(&pg[i], d);
smp_wmb(); /* Domain pointer must be visible before updating refcnt. */
- pg[i].count_info = PGC_allocated | 1;
+ count_info &= PGC_no_refcount;
+ pg[i].count_info = count_info | PGC_allocated | 1;
page_list_add_tail(&pg[i], &d->page_list);
}
@@ -2317,11 +2320,6 @@ struct page_info *alloc_domheap_pages(
if ( memflags & MEMF_no_owner )
memflags |= MEMF_no_refcount;
- else if ( (memflags & MEMF_no_refcount) && d )
- {
- ASSERT(!(memflags & MEMF_no_refcount));
- return NULL;
- }
if ( !dma_bitsize )
memflags &= ~MEMF_no_dma;
@@ -2334,11 +2332,20 @@ struct page_info *alloc_domheap_pages(
memflags, d)) == NULL)) )
return NULL;
- if ( d && !(memflags & MEMF_no_owner) &&
- assign_pages(d, pg, order, memflags) )
+ if ( d && !(memflags & MEMF_no_owner) )
{
- free_heap_pages(pg, order, memflags & MEMF_no_scrub);
- return NULL;
+ if ( memflags & MEMF_no_refcount )
+ {
+ unsigned long i;
+
+ for ( i = 0; i < (1 << order); i++ )
+ pg[i].count_info |= PGC_no_refcount;
+ }
+ if ( assign_pages(d, pg, order, memflags) )
+ {
+ free_heap_pages(pg, order, memflags & MEMF_no_scrub);
+ return NULL;
+ }
}
return pg;
@@ -2371,6 +2378,8 @@ void free_domheap_pages(struct page_info *pg, unsigned int order)
if ( likely(d) && likely(d != dom_cow) )
{
+ long pages = 0;
+
/* NB. May recursively lock from relinquish_memory(). */
spin_lock_recursive(&d->page_alloc_lock);
@@ -2386,9 +2395,11 @@ void free_domheap_pages(struct page_info *pg, unsigned int order)
BUG();
}
arch_free_heap_page(d, &pg[i]);
+ if ( !(pg[i].count_info & PGC_no_refcount) )
+ pages--;
}
- drop_dom_ref = !domain_adjust_tot_pages(d, -(1 << order));
+ drop_dom_ref = !domain_adjust_tot_pages(d, pages);
spin_unlock_recursive(&d->page_alloc_lock);
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index 333efd3a60..1076cc9713 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -119,9 +119,12 @@ struct page_info
#define PGC_state_offlined PG_mask(2, 9)
#define PGC_state_free PG_mask(3, 9)
#define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st)
+/* Page is not reference counted */
+#define _PGC_no_refcount PG_shift(10)
+#define PGC_no_refcount PG_mask(1, 10)
/* Count of references to this frame. */
-#define PGC_count_width PG_shift(9)
+#define PGC_count_width PG_shift(10)
#define PGC_count_mask ((1UL<<PGC_count_width)-1)
/*
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 2ca8882ad0..e75feea15e 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -77,9 +77,12 @@
#define PGC_state_offlined PG_mask(2, 9)
#define PGC_state_free PG_mask(3, 9)
#define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st)
+/* Page is not reference counted */
+#define _PGC_no_refcount PG_shift(10)
+#define PGC_no_refcount PG_mask(1, 10)
- /* Count of references to this frame. */
-#define PGC_count_width PG_shift(9)
+/* Count of references to this frame. */
+#define PGC_count_width PG_shift(10)
#define PGC_count_mask ((1UL<<PGC_count_width)-1)
/*
--
2.20.1
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Xen-devel] [PATCH v5 4/4] x86 / vmx: use a MEMF_no_refcount domheap page for APIC_DEFAULT_PHYS_BASE
2020-01-29 10:16 [Xen-devel] [PATCH v5 0/4] purge free_shared_domheap_page() Paul Durrant
` (2 preceding siblings ...)
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 3/4] mm: make MEMF_no_refcount pages safe to assign Paul Durrant
@ 2020-01-29 10:16 ` Paul Durrant
3 siblings, 0 replies; 8+ messages in thread
From: Paul Durrant @ 2020-01-29 10:16 UTC (permalink / raw)
To: xen-devel
Cc: Kevin Tian, Wei Liu, Andrew Cooper, Paul Durrant, Jun Nakajima,
Roger Pau Monné
vmx_alloc_vlapic_mapping() currently contains some very odd looking code
that allocates a MEMF_no_owner domheap page and then shares with the guest
as if it were a xenheap page. This then requires vmx_free_vlapic_mapping()
to call a special function in the mm code: free_shared_domheap_page().
By using a MEMF_no_refcount domheap page instead, the odd looking code in
vmx_alloc_vlapic_mapping() can simply use get_page_and_type() to set up a
writable mapping before insertion in the P2M and vmx_free_vlapic_mapping()
can simply release the page using put_page_alloc_ref() followed by
put_page_and_type(). This then allows free_shared_domheap_page() to be
purged.
Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
Cc: Jun Nakajima <jun.nakajima@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Wei Liu <wl@xen.org>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
v4:
- Use a MEMF_no_refcount page rather than a 'normal' page
v2:
- Set an initial value for max_pages rather than avoiding the check in
assign_pages()
- Make domain_destroy() optional
---
xen/arch/x86/hvm/vmx/vmx.c | 21 ++++++++++++++++++---
xen/arch/x86/mm.c | 10 ----------
xen/include/asm-x86/mm.h | 2 --
3 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 606f3dc2eb..7423d2421b 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3028,12 +3028,22 @@ static int vmx_alloc_vlapic_mapping(struct domain *d)
if ( !cpu_has_vmx_virtualize_apic_accesses )
return 0;
- pg = alloc_domheap_page(d, MEMF_no_owner);
+ pg = alloc_domheap_page(d, MEMF_no_refcount);
if ( !pg )
return -ENOMEM;
+
+ if ( !get_page_and_type(pg, d, PGT_writable_page) )
+ {
+ /*
+ * The domain can't possibly know about this page yet, so failure
+ * here is a clear indication of something fishy going on.
+ */
+ domain_crash(d);
+ return -ENODATA;
+ }
+
mfn = page_to_mfn(pg);
clear_domain_page(mfn);
- share_xen_page_with_guest(pg, d, SHARE_rw);
d->arch.hvm.vmx.apic_access_mfn = mfn;
return set_mmio_p2m_entry(d, paddr_to_pfn(APIC_DEFAULT_PHYS_BASE), mfn,
@@ -3047,7 +3057,12 @@ static void vmx_free_vlapic_mapping(struct domain *d)
d->arch.hvm.vmx.apic_access_mfn = _mfn(0);
if ( !mfn_eq(mfn, _mfn(0)) )
- free_shared_domheap_page(mfn_to_page(mfn));
+ {
+ struct page_info *pg = mfn_to_page(mfn);
+
+ put_page_alloc_ref(pg);
+ put_page_and_type(pg);
+ }
}
static void vmx_install_vlapic_mapping(struct vcpu *v)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index f50c065af3..67351798c7 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -496,16 +496,6 @@ void share_xen_page_with_guest(struct page_info *page, struct domain *d,
spin_unlock(&d->page_alloc_lock);
}
-void free_shared_domheap_page(struct page_info *page)
-{
- put_page_alloc_ref(page);
- if ( !test_and_clear_bit(_PGC_xen_heap, &page->count_info) )
- ASSERT_UNREACHABLE();
- page->u.inuse.type_info = 0;
- page_set_owner(page, NULL);
- free_domheap_page(page);
-}
-
void make_cr3(struct vcpu *v, mfn_t mfn)
{
struct domain *d = v->domain;
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index e75feea15e..036d7ac22f 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -320,8 +320,6 @@ struct page_info
#define maddr_get_owner(ma) (page_get_owner(maddr_to_page((ma))))
-extern void free_shared_domheap_page(struct page_info *page);
-
#define frame_table ((struct page_info *)FRAMETABLE_VIRT_START)
extern unsigned long max_page;
extern unsigned long total_pages;
--
2.20.1
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment Paul Durrant
@ 2020-01-29 11:12 ` Jan Beulich
2020-01-29 11:15 ` Durrant, Paul
0 siblings, 1 reply; 8+ messages in thread
From: Jan Beulich @ 2020-01-29 11:12 UTC (permalink / raw)
To: Paul Durrant
Cc: Stefano Stabellini, Julien Grall, Wei Liu, Konrad Rzeszutek Wilk,
George Dunlap, Andrew Cooper, Ian Jackson, xen-devel
On 29.01.2020 11:16, Paul Durrant wrote:
> Currently the function will pointlessly acquire and release the global
> 'heap_lock' in this case.
>
> NOTE: No caller yet calls domain_adjust_tot_pages() with a zero 'pages'
> argument, but a subsequent patch will make this possible.
With this memory_exchange(), as previously indicated, now needlessly
prevents the call when !dec_count. I do think, as said there, that
together with the addition here then redundant checks in callers
should be dropped (and as it looks the named one is the only one).
Jan
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment
2020-01-29 11:12 ` Jan Beulich
@ 2020-01-29 11:15 ` Durrant, Paul
0 siblings, 0 replies; 8+ messages in thread
From: Durrant, Paul @ 2020-01-29 11:15 UTC (permalink / raw)
To: Jan Beulich
Cc: Stefano Stabellini, Julien Grall, Wei Liu, Konrad Rzeszutek Wilk,
George Dunlap, Andrew Cooper, Ian Jackson, xen-devel
> -----Original Message-----
> From: Jan Beulich <jbeulich@suse.com>
> Sent: 29 January 2020 11:13
> To: Durrant, Paul <pdurrant@amazon.co.uk>
> Cc: xen-devel@lists.xenproject.org; Andrew Cooper
> <andrew.cooper3@citrix.com>; George Dunlap <George.Dunlap@eu.citrix.com>;
> Ian Jackson <ian.jackson@eu.citrix.com>; Julien Grall <julien@xen.org>;
> Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>; Stefano Stabellini
> <sstabellini@kernel.org>; Wei Liu <wl@xen.org>
> Subject: Re: [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better
> handle a zero adjustment
>
> On 29.01.2020 11:16, Paul Durrant wrote:
> > Currently the function will pointlessly acquire and release the global
> > 'heap_lock' in this case.
> >
> > NOTE: No caller yet calls domain_adjust_tot_pages() with a zero 'pages'
> > argument, but a subsequent patch will make this possible.
>
> With this memory_exchange(), as previously indicated, now needlessly
> prevents the call when !dec_count. I do think, as said there, that
> together with the addition here then redundant checks in callers
> should be dropped (and as it looks the named one is the only one).
>
Ok, yes I missed that.
Paul
> Jan
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [Xen-devel] [PATCH v5 3/4] mm: make MEMF_no_refcount pages safe to assign
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 3/4] mm: make MEMF_no_refcount pages safe to assign Paul Durrant
@ 2020-01-29 11:20 ` Jan Beulich
0 siblings, 0 replies; 8+ messages in thread
From: Jan Beulich @ 2020-01-29 11:20 UTC (permalink / raw)
To: Paul Durrant
Cc: Stefano Stabellini, Julien Grall, Wei Liu, Konrad Rzeszutek Wilk,
George Dunlap, Andrew Cooper, Ian Jackson, xen-devel,
Volodymyr Babchuk, Roger Pau Monné
On 29.01.2020 11:16, Paul Durrant wrote:
> --- a/xen/common/page_alloc.c
> +++ b/xen/common/page_alloc.c
> @@ -2287,11 +2287,14 @@ int assign_pages(
>
> for ( i = 0; i < (1 << order); i++ )
> {
> + unsigned long count_info = pg[i].count_info;
> +
> ASSERT(page_get_owner(&pg[i]) == NULL);
> - ASSERT(!pg[i].count_info);
> + ASSERT(!(count_info & ~PGC_no_refcount));
I think this would benefit from being more strict: The flag may also
not be set if MEMF_no_refcount is clear in the flags passed in.
> @@ -2334,11 +2332,20 @@ struct page_info *alloc_domheap_pages(
> memflags, d)) == NULL)) )
> return NULL;
>
> - if ( d && !(memflags & MEMF_no_owner) &&
> - assign_pages(d, pg, order, memflags) )
> + if ( d && !(memflags & MEMF_no_owner) )
> {
> - free_heap_pages(pg, order, memflags & MEMF_no_scrub);
> - return NULL;
> + if ( memflags & MEMF_no_refcount )
> + {
> + unsigned long i;
With this you mean ...
> + for ( i = 0; i < (1 << order); i++ )
... 1UL here. Or else "unsigned int" and 1U. The file isn't
very consistent with this, but at least locally to a single
functions things should match up.
Jan
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^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-01-29 11:21 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-29 10:16 [Xen-devel] [PATCH v5 0/4] purge free_shared_domheap_page() Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 1/4] x86 / vmx: move teardown from domain_destroy() Paul Durrant
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 2/4] mm: modify domain_adjust_tot_pages() to better handle a zero adjustment Paul Durrant
2020-01-29 11:12 ` Jan Beulich
2020-01-29 11:15 ` Durrant, Paul
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 3/4] mm: make MEMF_no_refcount pages safe to assign Paul Durrant
2020-01-29 11:20 ` Jan Beulich
2020-01-29 10:16 ` [Xen-devel] [PATCH v5 4/4] x86 / vmx: use a MEMF_no_refcount domheap page for APIC_DEFAULT_PHYS_BASE Paul Durrant
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