[PATCH V1] pvh: change epte_get_entry_emt() for pvh mem types

[PATCH V1] pvh: change epte_get_entry_emt() for pvh mem types

[Mukesh Rathor]

For pvh guests, epte_get_entry_emt() is incorrectly returning WB for
all mem types because of the following check:
    if ( !v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT] )
Skip the check for pvh guests.

Also note, MTRR ranges are not maintained for pvh, and a solution is
being contrived using PAT.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/hvm/mtrr.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c
index 4ff1e55..9937f5a 100644
--- a/xen/arch/x86/hvm/mtrr.c
+++ b/xen/arch/x86/hvm/mtrr.c
@@ -693,7 +693,8 @@ uint8_t epte_get_entry_emt(struct domain *d, unsigned long gfn, mfn_t mfn,
          ((d->vcpu == NULL) || ((v = d->vcpu[0]) == NULL)) )
         return MTRR_TYPE_WRBACK;
 
-    if ( !v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT] )
+    if ( !is_pvh_vcpu(v) &&
+         !v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT] )
         return MTRR_TYPE_WRBACK;
 
     if ( !mfn_valid(mfn_x(mfn)) )
@@ -717,7 +718,10 @@ uint8_t epte_get_entry_emt(struct domain *d, unsigned long gfn, mfn_t mfn,
         return MTRR_TYPE_WRBACK;
     }
 
-    gmtrr_mtype = get_mtrr_type(&v->arch.hvm_vcpu.mtrr, (gfn << PAGE_SHIFT));
+    gmtrr_mtype = is_hvm_vcpu(v) ?
+                  get_mtrr_type(&v->arch.hvm_vcpu.mtrr, (gfn << PAGE_SHIFT)) :
+                  MTRR_TYPE_WRBACK;
+
     hmtrr_mtype = get_mtrr_type(&mtrr_state, (mfn_x(mfn) << PAGE_SHIFT));
     return ((gmtrr_mtype <= hmtrr_mtype) ? gmtrr_mtype : hmtrr_mtype);
 }
-- 
1.7.2.3

Re: [PATCH V1] pvh: change epte_get_entry_emt() for pvh mem types

[George Dunlap]

On 11/22/2013 10:29 PM, Mukesh Rathor wrote:
> For pvh guests, epte_get_entry_emt() is incorrectly returning WB for
> all mem types because of the following check:
>      if ( !v->domain->arch.hvm_domain.params[HVM_PARAM_IDENT_PT] )
> Skip the check for pvh guests.
>
> Also note, MTRR ranges are not maintained for pvh, and a solution is
> being contrived using PAT.
>
> Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>

Reviewed-by: George Dunlap <george.dunlap@eu.citrix.com>

Also, from a release perspective, this should only affect an as-yet 
unsupported feature.