Hi Stefano,
On 23/06/16 15:14, Stefano Stabellini wrote:
On Tue, 21 Jun 2016, Julien Grall wrote:
The prototype and the declaration of p2m_lookup disagree on how the
function should be used. One expect a frame number whilst the other
an address.
Thankfully, everyone is using with an address today. However, most of
the callers have to convert a guest frame to an address. Modify
the interface to take a guest physical frame in parameter and return
a machine frame.
Whilst modifying the interface, use typesafe gfn and mfn for clarity
and catching possible misusage.
Signed-off-by: Julien Grall <julien.gr...@arm.com>
---
xen/arch/arm/p2m.c | 37 ++++++++++++++++++++-----------------
xen/arch/arm/traps.c | 21 +++++++++++----------
xen/include/asm-arm/p2m.h | 7 +++----
3 files changed, 34 insertions(+), 31 deletions(-)
diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 47cb383..f3330dd 100644
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -140,14 +140,15 @@ void flush_tlb_domain(struct domain *d)
}
/*
- * Lookup the MFN corresponding to a domain's PFN.
+ * 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.
*/
-static paddr_t __p2m_lookup(struct domain *d, paddr_t paddr, p2m_type_t *t)
+static mfn_t __p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
{
struct p2m_domain *p2m = &d->arch.p2m;
+ const paddr_t paddr = pfn_to_paddr(gfn_x(gfn));
const unsigned int offsets[4] = {
zeroeth_table_offset(paddr),
first_table_offset(paddr),
@@ -158,7 +159,7 @@ static paddr_t __p2m_lookup(struct domain *d, paddr_t
paddr, p2m_type_t *t)
ZEROETH_MASK, FIRST_MASK, SECOND_MASK, THIRD_MASK
};
lpae_t pte, *map;
- paddr_t maddr = INVALID_PADDR;
+ mfn_t mfn = _mfn(INVALID_MFN);
It might be worth defining INVALID_MFN_T and just assign that to mfn.
Good idea. It will be useful in other places too.
paddr_t mask = 0;
p2m_type_t _t;
unsigned int level, root_table;
[...]
@@ -1561,11 +1565,10 @@ 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.
*/
- maddr = __p2m_lookup(current->domain, ipa, &t);
- if ( maddr == INVALID_PADDR )
+ mfn = mfn_x(__p2m_lookup(current->domain, gfn, &t));
+ if ( mfn == INVALID_MFN )
The conversion would go away if we had an INVALID_MFN which is mfn_t
Will do.
Regards,
--
Julien Grall
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