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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen staging] x86/altp2m: aggregate get entry and populate into common funcs
commit ce65c0226db8d112c28a588802e43a482b210621
Author: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
AuthorDate: Mon May 13 09:55:24 2019 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon May 13 09:55:24 2019 +0200
x86/altp2m: aggregate get entry and populate into common funcs
The code for getting the entry and then populating was repeated in
p2m_change_altp2m_gfn() and in p2m_set_altp2m_mem_access().
The code is now in one place with a bool param that lets the caller choose
if it populates after get_entry().
If remapping is being done then both the old and new gfn's should be
unshared in the hostp2m for keeping things consistent. The page type
of old_gfn was already checked whether it's p2m_ram_rw and bail if it
wasn't so functionality-wise this just simplifies things as a user
doesn't have to request unsharing manually before remapping.
Now, if the new_gfn is invalid it shouldn't query the hostp2m as
that is effectively a request to remove the entry from the altp2m.
But provided that scenario is used only when removing entries that
were previously remapped/copied to the altp2m, those entries already
went through P2M_ALLOC | P2M_UNSHARE before, so it won't have an
affect so the core function get_altp2m_entry() is calling
__get_gfn_type_access() with P2M_ALLOC | P2M_UNSHARE.
altp2m_get_entry_direct() is also called in p2m_set_suppress_ve()
because on a new altp2m view the function will fail with invalid mfn if
p2m->set_entry() was not called before.
Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
Reviewed-by: George Dunlap <george.dunlap@xxxxxxxxxx>
Acked-by: Tamas K Lengyel <tamas@xxxxxxxxxxxxx>
---
xen/arch/x86/mm/mem_access.c | 31 +++-------------
xen/arch/x86/mm/p2m.c | 85 ++++++++++++++++++++++++--------------------
xen/include/asm-x86/p2m.h | 12 +++++++
3 files changed, 63 insertions(+), 65 deletions(-)
diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
index a144bb0ce4..0144f92b98 100644
--- a/xen/arch/x86/mm/mem_access.c
+++ b/xen/arch/x86/mm/mem_access.c
@@ -262,35 +262,12 @@ int p2m_set_altp2m_mem_access(struct domain *d, struct
p2m_domain *hp2m,
mfn_t mfn;
p2m_type_t t;
p2m_access_t old_a;
- unsigned int page_order;
- unsigned long gfn_l = gfn_x(gfn);
int rc;
- mfn = ap2m->get_entry(ap2m, gfn, &t, &old_a, 0, NULL, NULL);
-
- /* Check host p2m if no valid entry in alternate */
- if ( !mfn_valid(mfn) )
- {
-
- mfn = __get_gfn_type_access(hp2m, gfn_l, &t, &old_a,
- P2M_ALLOC | P2M_UNSHARE, &page_order, 0);
-
- rc = -ESRCH;
- if ( !mfn_valid(mfn) || t != p2m_ram_rw )
- return rc;
-
- /* If this is a superpage, copy that first */
- if ( page_order != PAGE_ORDER_4K )
- {
- unsigned long mask = ~((1UL << page_order) - 1);
- gfn_t gfn2 = _gfn(gfn_l & mask);
- mfn_t mfn2 = _mfn(mfn_x(mfn) & mask);
-
- rc = ap2m->set_entry(ap2m, gfn2, mfn2, page_order, t, old_a, 1);
- if ( rc )
- return rc;
- }
- }
+ rc = altp2m_get_effective_entry(ap2m, gfn, &mfn, &t, &old_a,
+ AP2MGET_prepopulate);
+ if ( rc )
+ return rc;
/*
* Inherit the old suppress #VE bit value if it is already set, or set it
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 9e81a30cc4..278e1c114e 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -478,6 +478,42 @@ void p2m_unlock_and_tlb_flush(struct p2m_domain *p2m)
mm_write_unlock(&p2m->lock);
}
+int altp2m_get_effective_entry(struct p2m_domain *ap2m, gfn_t gfn, mfn_t *mfn,
+ p2m_type_t *t, p2m_access_t *a,
+ bool prepopulate)
+{
+ *mfn = ap2m->get_entry(ap2m, gfn, t, a, 0, NULL, NULL);
+
+ /* Check host p2m if no valid entry in alternate */
+ if ( !mfn_valid(*mfn) && !p2m_is_hostp2m(ap2m) )
+ {
+ struct p2m_domain *hp2m = p2m_get_hostp2m(ap2m->domain);
+ unsigned int page_order;
+ int rc;
+
+ *mfn = __get_gfn_type_access(hp2m, gfn_x(gfn), t, a,
+ P2M_ALLOC | P2M_UNSHARE, &page_order, 0);
+
+ rc = -ESRCH;
+ if ( !mfn_valid(*mfn) || *t != p2m_ram_rw )
+ return rc;
+
+ /* If this is a superpage, copy that first */
+ if ( prepopulate && page_order != PAGE_ORDER_4K )
+ {
+ unsigned long mask = ~((1UL << page_order) - 1);
+ gfn_t gfn_aligned = _gfn(gfn_x(gfn) & mask);
+ mfn_t mfn_aligned = _mfn(mfn_x(*mfn) & mask);
+
+ rc = ap2m->set_entry(ap2m, gfn_aligned, mfn_aligned, page_order,
*t, *a, 1);
+ if ( rc )
+ return rc;
+ }
+ }
+
+ return 0;
+}
+
mfn_t __get_gfn_type_access(struct p2m_domain *p2m, unsigned long gfn_l,
p2m_type_t *t, p2m_access_t *a, p2m_query_t q,
unsigned int *page_order, bool_t locked)
@@ -2618,7 +2654,6 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned int
idx,
p2m_access_t a;
p2m_type_t t;
mfn_t mfn;
- unsigned int page_order;
int rc = -EINVAL;
if ( idx >= MAX_ALTP2M || d->arch.altp2m_eptp[idx] == mfn_x(INVALID_MFN) )
@@ -2630,47 +2665,23 @@ int p2m_change_altp2m_gfn(struct domain *d, unsigned
int idx,
p2m_lock(hp2m);
p2m_lock(ap2m);
- mfn = ap2m->get_entry(ap2m, old_gfn, &t, &a, 0, NULL, NULL);
-
if ( gfn_eq(new_gfn, INVALID_GFN) )
{
+ mfn = ap2m->get_entry(ap2m, old_gfn, &t, &a, 0, NULL, NULL);
if ( mfn_valid(mfn) )
p2m_remove_page(ap2m, gfn_x(old_gfn), mfn_x(mfn), PAGE_ORDER_4K);
rc = 0;
goto out;
}
- /* Check host p2m if no valid entry in alternate */
- if ( !mfn_valid(mfn) )
- {
- mfn = __get_gfn_type_access(hp2m, gfn_x(old_gfn), &t, &a,
- P2M_ALLOC, &page_order, 0);
-
- if ( !mfn_valid(mfn) || t != p2m_ram_rw )
- goto out;
-
- /* If this is a superpage, copy that first */
- if ( page_order != PAGE_ORDER_4K )
- {
- gfn_t gfn;
- unsigned long mask;
-
- mask = ~((1UL << page_order) - 1);
- gfn = _gfn(gfn_x(old_gfn) & mask);
- mfn = _mfn(mfn_x(mfn) & mask);
-
- if ( ap2m->set_entry(ap2m, gfn, mfn, page_order, t, a, 1) )
- goto out;
- }
- }
-
- mfn = ap2m->get_entry(ap2m, new_gfn, &t, &a, 0, NULL, NULL);
-
- if ( !mfn_valid(mfn) )
- mfn = hp2m->get_entry(hp2m, new_gfn, &t, &a, 0, NULL, NULL);
+ rc = altp2m_get_effective_entry(ap2m, old_gfn, &mfn, &t, &a,
+ AP2MGET_prepopulate);
+ if ( rc )
+ goto out;
- /* Note: currently it is not safe to remap to a shared entry */
- if ( !mfn_valid(mfn) || (t != p2m_ram_rw) )
+ rc = altp2m_get_effective_entry(ap2m, new_gfn, &mfn, &t, &a,
+ AP2MGET_query);
+ if ( rc )
goto out;
if ( !ap2m->set_entry(ap2m, old_gfn, mfn, PAGE_ORDER_4K, t, a,
@@ -3002,12 +3013,10 @@ int p2m_set_suppress_ve(struct domain *d, gfn_t gfn,
bool suppress_ve,
if ( ap2m )
p2m_lock(ap2m);
- mfn = p2m->get_entry(p2m, gfn, &t, &a, 0, NULL, NULL);
- if ( !mfn_valid(mfn) )
- {
- rc = -ESRCH;
+ rc = altp2m_get_effective_entry(p2m, gfn, &mfn, &t, &a, AP2MGET_query);
+
+ if ( rc )
goto out;
- }
rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, t, a, suppress_ve);
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 2801a8ccca..719513f4ba 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -514,6 +514,18 @@ static inline unsigned long mfn_to_gfn(struct domain *d,
mfn_t mfn)
return mfn_x(mfn);
}
+#define AP2MGET_prepopulate true
+#define AP2MGET_query false
+
+/*
+ * Looks up altp2m entry. If the entry is not found it looks up the entry in
+ * hostp2m.
+ * The prepopulate param is used to set the found entry in altp2m.
+ */
+int altp2m_get_effective_entry(struct p2m_domain *ap2m, gfn_t gfn, mfn_t *mfn,
+ p2m_type_t *t, p2m_access_t *a,
+ bool prepopulate);
+
/* Deadlock-avoidance scheme when calling get_gfn on different gfn's */
struct two_gfns {
struct domain *first_domain, *second_domain;
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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