[PATCH 1/1] KVM: MMU: Map device MMIO as UC in EPT

[Sheng Yang <sheng@linux.intel.com>]

Software are not allow to access device MMIO using cacheable memory type, the
patch limit MMIO region with UC and WC(guest can select WC using PAT and
PCD/PWT).

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 arch/x86/kvm/mmu.c |    9 +++++++--
 arch/x86/kvm/vmx.c |    3 +--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 0798610..ef060ec 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1712,8 +1712,13 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
 	if (largepage)
 		spte |= PT_PAGE_SIZE_MASK;
 	if (mt_mask) {
-		mt_mask = get_memory_type(vcpu, gfn) <<
-			  kvm_x86_ops->get_mt_mask_shift();
+		if (!kvm_is_mmio_pfn(pfn)) {
+			mt_mask = get_memory_type(vcpu, gfn) <<
+				kvm_x86_ops->get_mt_mask_shift();
+			mt_mask |= VMX_EPT_IGMT_BIT;
+		} else
+			mt_mask = MTRR_TYPE_UNCACHABLE <<
+				kvm_x86_ops->get_mt_mask_shift();
 		spte |= mt_mask;
 	}
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9b56d21..73e8fd9 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3782,8 +3782,7 @@ static int __init vmx_init(void)
 	if (vm_need_ept()) {
 		bypass_guest_pf = 0;
 		kvm_mmu_set_base_ptes(VMX_EPT_READABLE_MASK |
-			VMX_EPT_WRITABLE_MASK |
-			VMX_EPT_IGMT_BIT);
+			VMX_EPT_WRITABLE_MASK);
 		kvm_mmu_set_mask_ptes(0ull, 0ull, 0ull, 0ull,
 				VMX_EPT_EXECUTABLE_MASK,
 				VMX_EPT_DEFAULT_MT << VMX_EPT_MT_EPTE_SHIFT);
-- 
1.5.4.5