Hello Sergej,
On 01/08/16 18:10, Sergej Proskurin wrote:
This commit extends the functionality of the function "__p2m_lookup".
The function "__p2m_lookup" performs the necessary steps gathering
information concerning memory attributes and the p2m table level a
specific gfn is mapped to. Thus, we extend the function's prototype so
that the caller can optionally get these information for further
processing.
Also, we extend the function prototype of "__p2m_lookup" to hold an
argument of type "struct p2m_domain*", as we need to distinguish between
the host's p2m and different altp2m views. While doing so, we needed to
extend the function's prototypes of the following functions:
* __p2m_get_mem_access
* p2m_mem_access_and_get_page
Signed-off-by: Sergej Proskurin <prosku...@sec.in.tum.de>
---
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Julien Grall <julien.gr...@arm.com>
---
xen/arch/arm/p2m.c | 59 ++++++++++++++++++++++++++++++++++++------------------
1 file changed, 39 insertions(+), 20 deletions(-)
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 784f8da..326e343 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -168,15 +168,22 @@ void p2m_flush_tlb(struct p2m_domain *p2m)
}
}
+static int __p2m_get_mem_access(struct p2m_domain*, gfn_t, xenmem_access_t*);
+
/*
* Lookup the MFN corresponding to a domain's GFN.
*
* There are no processor functions to do a stage 2 only lookup therefore we
* do a a software walk.
+ *
+ * Optionally, __p2m_lookup takes arguments to provide information about the
+ * p2m type, the p2m table level the paddr is mapped to, associated mem
+ * attributes, and memory access rights.
*/
-static mfn_t __p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
+static mfn_t __p2m_lookup(struct p2m_domain *p2m, gfn_t gfn, p2m_type_t *t,
+ unsigned int *level, unsigned int *mattr,
+ xenmem_access_t *xma)
Please give a look at my series "xen/arm: Rework the P2M code to follow
break-before-make sequence" [1], it will expose a clean interface to
retrieve all the necessary information.
mfn_t p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
{
mfn_t ret;
- struct p2m_domain *p2m = &d->arch.p2m;
+ struct p2m_domain *p2m = p2m_get_hostp2m(d);
p2m_read_lock(p2m);
- ret = __p2m_lookup(d, gfn, t);
+ ret = __p2m_lookup(p2m, gfn, t, NULL, NULL, NULL);
p2m_read_unlock(p2m);
return ret;
@@ -479,10 +499,9 @@ static int p2m_create_table(struct p2m_domain *p2m, lpae_t
*entry,
return 0;
}
-static int __p2m_get_mem_access(struct domain *d, gfn_t gfn,
+static int __p2m_get_mem_access(struct p2m_domain *p2m, gfn_t gfn,
xenmem_access_t *access)
{
- struct p2m_domain *p2m = p2m_get_hostp2m(d);
void *i;
unsigned int index;
@@ -525,7 +544,7 @@ static int __p2m_get_mem_access(struct domain *d, gfn_t gfn,
* No setting was found in the Radix tree. Check if the
* entry exists in the page-tables.
*/
- mfn_t mfn = __p2m_lookup(d, gfn, NULL);
+ mfn_t mfn = __p2m_lookup(p2m, gfn, NULL, NULL, NULL, NULL);
if ( mfn_eq(mfn, INVALID_MFN) )
return -ESRCH;
@@ -1519,7 +1538,7 @@ mfn_t gfn_to_mfn(struct domain *d, gfn_t gfn)
* we indeed found a conflicting mem_access setting.
*/
static struct page_info*
-p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned long flag)
+p2m_mem_access_check_and_get_page(struct p2m_domain *p2m, vaddr_t gva,
unsigned long flag)
{
long rc;
paddr_t ipa;
@@ -1539,7 +1558,7 @@ p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned
long flag)
* We do this first as this is faster in the default case when no
* permission is set on the page.
*/
- rc = __p2m_get_mem_access(current->domain, gfn, &xma);
+ rc = __p2m_get_mem_access(p2m, gfn, &xma);
if ( rc < 0 )
goto err;
@@ -1588,7 +1607,7 @@ p2m_mem_access_check_and_get_page(vaddr_t gva, unsigned
long flag)
* We had a mem_access permission limiting the access, but the page type
* could also be limiting, so we need to check that as well.
*/
- mfn = __p2m_lookup(current->domain, gfn, &t);
+ mfn = __p2m_lookup(p2m, gfn, &t, NULL, NULL, NULL);
if ( mfn_eq(mfn, INVALID_MFN) )
goto err;
@@ -1671,7 +1690,7 @@ struct page_info *get_page_from_gva(struct vcpu *v,
vaddr_t va,
err:
if ( !page && p2m->mem_access_enabled )
- page = p2m_mem_access_check_and_get_page(va, flags);
+ page = p2m_mem_access_check_and_get_page(p2m, va, flags);
p2m_mem_access_check_and_get_page should take a vCPU in parameter and
not a p2m.
I know the function is already buggy because it assumes that the vCPU ==
current. But let's not broken more this function.
p2m_read_unlock(p2m);
@@ -1948,7 +1967,7 @@ int p2m_get_mem_access(struct domain *d, gfn_t gfn,
struct p2m_domain *p2m = p2m_get_hostp2m(d);
p2m_read_lock(p2m);
- ret = __p2m_get_mem_access(d, gfn, access);
+ ret = __p2m_get_mem_access(p2m, gfn, access);
p2m_read_unlock(p2m);
return ret;
Regards,
[1]
https://lists.xenproject.org/archives/html/xen-devel/2016-07/msg02952.html
--
Julien Grall
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