KVM: x86: MOV to CR3 can set bit 63

Although Intel SDM mentions bit 63 is reserved, MOV to CR3 can have bit 63 set.
As Intel SDM states in section 4.10.4 "Invalidation of TLBs and
Paging-Structure Caches": " MOV to CR3. ... If CR4.PCIDE = 1 and bit 63 of the
instruction’s source operand is 0 ..."

In other words, bit 63 is not reserved. KVM emulator currently consider bit 63
as reserved. Fix it.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -51,6 +51,7 @@
 			  | X86_CR0_NW | X86_CR0_CD | X86_CR0_PG))
 
 #define CR3_L_MODE_RESERVED_BITS 0xFFFFFF0000000000ULL
+#define CR3_PCID_INVD		 (1UL << 63)
 #define CR4_RESERVED_BITS                                               \
 	(~(unsigned long)(X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE\
 			  | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE     \

arch/x86/kvm/emulate.c

@@ -3564,7 +3564,7 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
 
 		ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
 		if (efer & EFER_LMA)
-			rsvd = CR3_L_MODE_RESERVED_BITS;
+			rsvd = CR3_L_MODE_RESERVED_BITS & ~CR3_PCID_INVD;
 
 		if (new_val & rsvd)
 			return emulate_gp(ctxt, 0);

arch/x86/kvm/x86.c

@@ -750,6 +750,8 @@ EXPORT_SYMBOL_GPL(kvm_set_cr4);
 
 int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 {
+	cr3 &= ~CR3_PCID_INVD;
+
 	if (cr3 == kvm_read_cr3(vcpu) && !pdptrs_changed(vcpu)) {
 		kvm_mmu_sync_roots(vcpu);
 		kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);