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 <na...@cs.technion.ac.il>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/emulate.c | 2 +-
arch/x86/kvm/x86.c | 2 ++
3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 904535f..dc932d3 100644
--- 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 d45a57b..259c04b 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3544,7 +3544,7 @@ 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 9b90ea7..204e5b4 100644
--- 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);
--
1.9.1
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