KVM: vmx: fix ept reserved bits for 1-GByte page

EPT misconfig handler in kvm will check which reason lead to EPT
misconfiguration after vmexit. One of the reasons is that an EPT
paging-structure entry is configured with settings reserved for
future functionality. However, the handler can't identify if
paging-structure entry of reserved bits for 1-GByte page are
configured, since PDPTE which point to 1-GByte page will reserve
bits 29:12 instead of bits 7:3 which are reserved for PDPTE that
references an EPT Page Directory. This patch fix it by reserve
bits 29:12 for 1-GByte page.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index cad37d57cc47d395887848157c214fe9c55afbde..286c2835e25c4fd4ba098b8175cc64c1d163f813 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5521,17 +5521,18 @@ static u64 ept_rsvd_mask(u64 spte, int level)
        for (i = 51; i > boot_cpu_data.x86_phys_bits; i--)
                mask |= (1ULL << i);
 
-       if (level > 2)
+       if (level == 4)
                /* bits 7:3 reserved */
                mask |= 0xf8;
-       else if (level == 2) {
-               if (spte & (1ULL << 7))
-                       /* 2MB ref, bits 20:12 reserved */
-                       mask |= 0x1ff000;
-               else
-                       /* bits 6:3 reserved */
-                       mask |= 0x78;
-       }
+       else if (spte & (1ULL << 7))
+               /*
+                * 1GB/2MB page, bits 29:12 or 20:12 reserved respectively,
+                * level == 1 if the hypervisor is using the ignored bit 7.
+                */
+               mask |= (PAGE_SIZE << ((level - 1) * 9)) - PAGE_SIZE;
+       else if (level > 1)
+               /* bits 6:3 reserved */
+               mask |= 0x78;
 
        return mask;
 }
@@ -5561,7 +5562,8 @@ static void ept_misconfig_inspect_spte(struct kvm_vcpu *vcpu, u64 spte,
                        WARN_ON(1);
                }
 
-               if (level == 1 || (level == 2 && (spte & (1ULL << 7)))) {
+               /* bits 5:3 are _not_ reserved for large page or leaf page */
+               if ((rsvd_bits & 0x38) == 0) {
                        u64 ept_mem_type = (spte & 0x38) >> 3;
 
                        if (ept_mem_type == 2 || ept_mem_type == 3 ||