Hi Jan,
On 13/03/2015 09:23, Jan Beulich wrote:
On 12.03.15 at 21:42, <dgde...@tycho.nsa.gov> wrote:
@@ -1999,11 +2055,23 @@ int policydb_read(struct policydb *p, void *fp)
"Old xen policy does not support iomemcon");
goto bad;
}
- rc = next_entry(buf, fp, sizeof(u32) *2);
- if ( rc < 0 )
- goto bad;
- c->u.iomem.low_iomem = le32_to_cpu(buf[0]);
- c->u.iomem.high_iomem = le32_to_cpu(buf[1]);
+ if ( p->policyvers >= POLICYDB_VERSION_XEN_DEVICETREE )
+ {
+ u64 b64[2];
+ rc = next_entry(b64, fp, sizeof(u64) *2);
+ if ( rc < 0 )
+ goto bad;
+ c->u.iomem.low_iomem = le64_to_cpu(b64[0]);
+ c->u.iomem.high_iomem = le64_to_cpu(b64[1]);
+ }
+ else
+ {
+ rc = next_entry(buf, fp, sizeof(u32) *2);
+ if ( rc < 0 )
+ goto bad;
+ c->u.iomem.low_iomem = le32_to_cpu(buf[0]);
+ c->u.iomem.high_iomem = le32_to_cpu(buf[1]);
+ }
I might be completely wrong (knowing next to nothing about XSM),
but how is the permissible I/O mem range tied to DT (as expressed
by POLICYDB_VERSION_XEN_DEVICETREE)? All systems with
valid page frame number possibly being wider than 32 bits would
need this extension, i.e. namely also x86.
I guess the name POLICYDB_VERSION_XEN_DEVICETREE was arbitrarily chose.
The policy version 30 adds support for both device tree and 64 bits iomem.
Although, I'm wondering if we should deny policy < 30 on newer Xen
because a truncation on the MMIO pfns may occurs and give access to the
wrong pfn.
Regards,
--
Julien Grall
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