KVM: VMX: Implement PCID/INVPCID for guests with EPT
This patch handles PCID/INVPCID for guests.
Process-context identifiers (PCIDs) are a facility by which a logical processor
may cache information for multiple linear-address spaces so that the processor
may retain cached information when software switches to a different linear
address space. Refer to section 4.10.1 in IA32 Intel Software Developer's Manual
Volume 3A for details.
For guests with EPT, the PCID feature is enabled and INVPCID behaves as running
natively.
For guests without EPT, the PCID feature is disabled and INVPCID triggers #UD.
Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ff0b487..59b5950 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -528,6 +528,9 @@
return 1;
}
+ if (!(cr0 & X86_CR0_PG) && kvm_read_cr4_bits(vcpu, X86_CR4_PCIDE))
+ return 1;
+
kvm_x86_ops->set_cr0(vcpu, cr0);
if ((cr0 ^ old_cr0) & X86_CR0_PG) {
@@ -604,10 +607,20 @@
kvm_read_cr3(vcpu)))
return 1;
+ if ((cr4 & X86_CR4_PCIDE) && !(old_cr4 & X86_CR4_PCIDE)) {
+ if (!guest_cpuid_has_pcid(vcpu))
+ return 1;
+
+ /* PCID can not be enabled when cr3[11:0]!=000H or EFER.LMA=0 */
+ if ((kvm_read_cr3(vcpu) & X86_CR3_PCID_MASK) || !is_long_mode(vcpu))
+ return 1;
+ }
+
if (kvm_x86_ops->set_cr4(vcpu, cr4))
return 1;
- if ((cr4 ^ old_cr4) & pdptr_bits)
+ if (((cr4 ^ old_cr4) & pdptr_bits) ||
+ (!(cr4 & X86_CR4_PCIDE) && (old_cr4 & X86_CR4_PCIDE)))
kvm_mmu_reset_context(vcpu);
if ((cr4 ^ old_cr4) & X86_CR4_OSXSAVE)
@@ -626,8 +639,12 @@
}
if (is_long_mode(vcpu)) {
- if (cr3 & CR3_L_MODE_RESERVED_BITS)
- return 1;
+ if (kvm_read_cr4(vcpu) & X86_CR4_PCIDE) {
+ if (cr3 & CR3_PCID_ENABLED_RESERVED_BITS)
+ return 1;
+ } else
+ if (cr3 & CR3_L_MODE_RESERVED_BITS)
+ return 1;
} else {
if (is_pae(vcpu)) {
if (cr3 & CR3_PAE_RESERVED_BITS)