xen/531d8e34-x86-HVM-consolidate-passthrough-handling-in-epte_get_entry_emt.patch

# Commit 3089a6d82bdf3112ccb1dd074ce34a8cbdc4ccd8
# Date 2014-03-10 11:04:36 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
x86/HVM: consolidate passthrough handling in epte_get_entry_emt()

It is inconsistent to depend on iommu_enabled alone: For a guest
without devices passed through to it, it is of no concern whether the
IOMMU is enabled.

There's one rather special case to take care of: VMX code marks the
LAPIC access page as MMIO. The added assertion needs to take this into
consideration, and the subsequent handling of the direct MMIO case was
inconsistent too: That page would have been WB in the absence of an
IOMMU, but UC in the presence of it, while in fact the cachabilty of
this page is entirely unrelated to an IOMMU being in use.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: "Xu, Dongxiao" <dongxiao.xu@intel.com>
Acked-by: Keir Fraser <keir@xen.org>

# Commit 1f8b57779785bf9f55c16312bb1ec679929c314b
# Date 2014-03-28 13:43:25 +0100
# Author Jan Beulich <jbeulich@suse.com>
# Committer Jan Beulich <jbeulich@suse.com>
x86/EPT: relax treatment of APIC MFN

There's no point in this being mapped UC by the guest due to using a
respective PAT index - set the ignore-PAT flag to true.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>

--- a/xen/arch/x86/hvm/mtrr.c
+++ b/xen/arch/x86/hvm/mtrr.c
@@ -698,14 +698,24 @@ uint8_t epte_get_entry_emt(struct domain
     if ( hvm_get_mem_pinned_cacheattr(d, gfn, &type) )
         return type;
 
-    if ( !iommu_enabled )
+    if ( !iommu_enabled ||
+         (rangeset_is_empty(d->iomem_caps) &&
+          rangeset_is_empty(d->arch.ioport_caps) &&
+          !has_arch_pdevs(d)) )
     {
+        ASSERT(!direct_mmio ||
+               mfn_x(mfn) == d->arch.hvm_domain.vmx.apic_access_mfn);
         *ipat = 1;
         return MTRR_TYPE_WRBACK;
     }
 
     if ( direct_mmio )
-        return MTRR_TYPE_UNCACHABLE;
+    {
+        if ( mfn_x(mfn) != d->arch.hvm_domain.vmx.apic_access_mfn )
+            return MTRR_TYPE_UNCACHABLE;
+        *ipat = 1;
+        return MTRR_TYPE_WRBACK;
+    }
 
     if ( iommu_snoop )
     {
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2038,9 +2038,9 @@ static int vmx_alloc_vlapic_mapping(stru
     if ( apic_va == NULL )
         return -ENOMEM;
     share_xen_page_with_guest(virt_to_page(apic_va), d, XENSHARE_writable);
+    d->arch.hvm_domain.vmx.apic_access_mfn = virt_to_mfn(apic_va);
     set_mmio_p2m_entry(d, paddr_to_pfn(APIC_DEFAULT_PHYS_BASE),
         _mfn(virt_to_mfn(apic_va)));
-    d->arch.hvm_domain.vmx.apic_access_mfn = virt_to_mfn(apic_va);
 
     return 0;
 }