[Xen-changelog] [xen master] x86/domctl: rework XEN_DOMCTL_{set, get}_address_size

[p***@xen.org]

commit f969bc9fc966d3f00d756922f35c2b6ebf533967
Author: Wei Liu <***@citrix.com>
AuthorDate: Fri Nov 2 15:55:40 2018 +0000
Commit: Wei Liu <***@citrix.com>
CommitDate: Mon Nov 5 16:09:50 2018 +0000

x86/domctl: rework XEN_DOMCTL_{set,get}_address_size

Going through toolstack code, they are used for PV guests only.

Tighten their access to PV only. Return -EOPNOTSUPP if they are called
on HVM guests. Rewrite the code in a pattern that makes DCE work.

Signed-off-by: Wei Liu <***@citrix.com>
Reviewed-by: Andrew Cooper <***@citrix.com>
---
xen/arch/x86/domctl.c | 32 +++++++++++++++++++++++---------
1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index f79827e6e4..33f9a869c0 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -609,19 +609,33 @@ long arch_do_domctl(
break;

case XEN_DOMCTL_set_address_size:
- if ( ((domctl->u.address_size.size == 64) && !d->arch.is_32bit_pv) ||
- ((domctl->u.address_size.size == 32) && d->arch.is_32bit_pv) )
- ret = 0;
- else if ( domctl->u.address_size.size == 32 )
- ret = switch_compat(d);
+ if ( is_hvm_domain(d) )
+ ret = -EOPNOTSUPP;
+ else if ( is_pv_domain(d) )
+ {
+ if ( ((domctl->u.address_size.size == 64) && !d->arch.is_32bit_pv) ||
+ ((domctl->u.address_size.size == 32) && d->arch.is_32bit_pv) )
+ ret = 0;
+ else if ( domctl->u.address_size.size == 32 )
+ ret = switch_compat(d);
+ else
+ ret = -EINVAL;
+ }
else
- ret = -EINVAL;
+ ASSERT_UNREACHABLE();
break;

case XEN_DOMCTL_get_address_size:
- domctl->u.address_size.size = is_pv_32bit_domain(d) ? 32 :
- BITS_PER_LONG;
- copyback = true;
+ if ( is_hvm_domain(d) )
+ ret = -EOPNOTSUPP;
+ else if ( is_pv_domain(d) )
+ {
+ domctl->u.address_size.size =
+ is_pv_32bit_domain(d) ? 32 : BITS_PER_LONG;
+ copyback = true;
+ }
+ else
+ ASSERT_UNREACHABLE();
break;

case XEN_DOMCTL_set_machine_address_size:
--
generated by git-patchbot for /home/xen/git/xen.git#master