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>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 904535fe825e7ba649e579ba7d2e00481c35bc7d..dc932d388c43ac8d8d5519183e2c549f99315e8f 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/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     \

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index a2a9c18b42e40bd05b28ebaf6b024974a40dc9a8..9f960b428bb254cd351e110e194eaa5e15c05010 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/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);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 773c17ec42ddb5d08133895f2231b0d5d8ee56d5..641358865a0c98068c6c2a6f446e02fdcafd444d 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/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);