On 07/07/2015 12:15 PM, Jan Beulich wrote:
On 07.07.15 at 17:46, <boris.ostrov...@oracle.com> wrote:
On 07/07/2015 05:11 AM, Jan Beulich wrote:
On 29.06.15 at 22:21, <boris.ostrov...@oracle.com> wrote:
@@ -737,7 +737,7 @@ int arch_set_info_guest(
/* The context is a compat-mode one if the target domain is compat-mode;
* we expect the tools to DTRT even in compat-mode callers. */
- compat = is_pv_32on64_domain(d);
+ compat = has_32bit_shinfo(d);
Furthermore, looking at uses like this, tying such decisions to the
shared info layout looks kind of odd. I think for documentation
purposes we may need a differently named alias.
Yes, it does look odd, which is why I was asking in another thread about
having another field in domain structure (well, I was asking about
replacing has_32bit_shinfo but I think I can see now that wouldn't be
right).
Are you suggesting a new macro, e.g.
#define is_32b_mode(d) ((d)->arch.has_32bit_shinfo)
or would it better to add new field? Or get_mode() hvm op, similar to
set_mode(), which can look, say, at EFER?
If looking at EFER (plus perhaps CS) is right in all the cases you
care about, then yes. And remember we already have
hvm_guest_x86_mode().
Can't use hvm_guest_x86_mode(), it asserts on 'v != current'. But adding
new op just because of that seems to be an overkill since it would
essentially do what .guest_x86_mode() does. How about
hvm_guest_x86_mode_unsafe() (with a better name) and wrap
hvm_guest_x86_mode() with the ASSERT around it?
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -496,7 +496,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t)
u_domctl)
break;
#ifdef CONFIG_COMPAT
- if ( !is_pv_32on64_domain(d) )
+ if ( !has_32bit_shinfo(d) )
ret = copy_from_guest(c.nat, op->u.vcpucontext.ctxt, 1);
else
ret = copy_from_guest(c.cmp,
@@ -902,7 +902,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t)
u_domctl)
vcpu_unpause(v);
#ifdef CONFIG_COMPAT
- if ( !is_pv_32on64_domain(d) )
+ if ( !has_32bit_shinfo(d) )
ret = copy_to_guest(op->u.vcpucontext.ctxt, c.nat, 1);
else
ret = copy_to_guest(guest_handle_cast(op->u.vcpucontext.ctxt,
Where is it written down what format 32-bit PVH guests' vCPU
contexts get passed in? It would seem to me that it would be
rather more natural for them to use the 64-bit layout. Or else
how do you intend to suppress them being able to enter 64-bit
mode?
So why do we use the 'else' clause for 32b PV guests when they also use
the same vcpu_guest_context_x86_32_t in libxc/xc_dom_x86.c:vcpu_x86_32()?
32bit PV guests use the if() branch afaict (as they use the 32-bit
shared info layout).
No, they use the 'else' part, I just confirmed it. 'd' in
is_pv_32on64_domain() is domain for which domctl is being called, not
domain that is making the call (which is what I suspect the original
intent was).
-boris
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